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Biomedical subjects

H Burger

Publications and source records attributed to H Burger.

At least 199 records · Page 11Linked to original sources
PubMed1982

[Investigation about the stability of a fixateur-externe using a new screw nail (author's transl)].

Since former investigations showed that the 4.5 mm Steinmann-nails hitherto were the weakest part of fixateur-externe systems, we developed a screw nail with a shank thickness of 7 mm and a thread identical to that of the cortical screw developed by the Arbeitsgemeinschaft für Osteosynthese (Workshop Society for Osteosynthesis). By conducting experiments with a metal alloy (square tube made of aluminium) in cadaver bones, the bending stress of a frame assembly R and of a three-dimensional assembly with 2 Schanz-screws Z2S was examined with 4.5 mm Steinmann-nails as well as with screw nails. The systems mounted with the new screw nails bent considerably less than the other systems. The improvement in stability achieved by screw nails is relatively more significant for the external frame fixator and in cases of a defect at the fracture gap than for the three dimensional fixateur externe with 2 Schanz-screws and in case of a compression at the fracture gap.

Bone Screws↗
PubMed1980

[Investigations of stability with the fixateur externe during strain of bending. Vertical and eccentric strain during compression of the fracture line and while the distance of support is changed (author's transl)].

The Fixateur externe was investigated under vertical and eccentric load when the fracture line was compressed and the distance of support was changed. Three kinds of mounting were used: R (Fixateur externe as frame), Z (three dimensional Fixateur externe) and Z2S (three dimensional Fixateur externe with two screws according to Schanz). If the distance of outer support was increased, the stability became greatly reduced. A compression increased the stability around the fracture line and on the free end of the system. A compression force of 10 kp at the fracture line yielded the greatest increase in stability. If in case of the methods R and Z, the compression was increased beyond 70 kp, there resulted even an instability, which depended on the distance of support. The most stable method of mounting was the three-dimensional Fixateur externe with two screws according to Schanz. The stability was compared if there was either a defect or a compression at the line of the fracture: there resulted a strikingly increased instability, if the distance of support was increased. The compression made it possible to compensate partly for the loss of stability.

Biomechanical Phenomena↗
PubMed1979

Sexual impotence.

Explore the source record for details and available documents.

Androgens↗
PubMed1979

In vitro proliferation of haemopoietic cells in the presence of adherent cell layers. I. Culture conditions and strain dependence.

The culture system, in which a marrow-derived adherent cell population, established in vitro, exerts a long-term promoting influence on proliferation of haemopoietic cells, is reproduced. Essential parameters of the system are investigated; it is confirmed that the system is critically dependent on horse serum, and on the in vitro age of the adherent cell layer. The growth-promoting effect on haemopoietic cells seems to be independent of the number of marrow cells per culture flask initially inoculated into the cultures to establish the adherent cell layer. In vitro established marrow-derived adherent cell layers from RFM (H-2f) and BALB/c (H-2d) mice can promote the long-term proliferation of syngeneic and allogenic haemopoietic cells; haemopoietic marrow cells from C3H (H-2k) cannot be maintained on syngeneic or allogeneic (BALB/c, H-2d) adherent cell layers; adherent cell layers of C3H (H-2k) can maintain haemopoietic cells of the H-2d (BALB/c) genotype. This culture system does not reproduce the in vivo phenomenon of allogeneic resistance. The relevance of these findings to the suggestion that the growth-promoting activity of adherent marrow cells on haemopoietic stem cells in vitro duplicates aspects of the in vivo haemopoietic microenvironment is discussed.

Animals↗
PubMed1979

In vitro proliferation of haemopoietic cells in the presence of adherent cell layers. II. Differential effect of adherent cell layers derived from various organs.

Mouse bone marrow-derived adherent cell populations promoted proliferation of haemopoietic cells in vitro in a liquid culture system for at least 4 weeks. Adherent cell layers derived from other haemopoietic organs (foetal liver, adult spleen) and fibroblasts from embryonic tissues did not maintain haemopoietic cells in this system. Medium, conditioned by adherent cells derived from foetal liver, spleen and embryonic tissues displayed a considerable colony stimulating activity (CSA). Marrow-derived adherent cells produced no detectable CSA. A possible relationship between the in vitro expression of a growth-promoting activity of an adherent cell population on haemopoietic cells, and its endogenous CSA production, is discussed.

Animals↗
PubMed1977

Oestrogens and menopausal and postmenopausal women.

The majority of women experience a variety of symptoms at the time of the menopause, but these are frequently regarded as being unworthy of management by their doctors. Recent reports of a possible association between exogenous oestrogens and endometrial carcinoma have increased professional reluctance to prescribe oestrogens for menopausal symptoms. This report describes the initial 50 patients who have attended a special clinic established to manage symptomatic menopausal women; common complaints included hot flushes, lack of energy, altered temperament, dyspareunia and headache. Oestrogen therapy was effective in the alleviation of symptoms and the practical aspects of oestrogen use are discussed. It is recommended that with due recognition of its potential complications, oestrogen therapy should be made available to symptomatic menopausal women, and that it requires further study in regard to its place in the long-term prophylaxis of osteoporosis.

Climacteric↗
PubMed1976

Intracellular forms of adenovirus DNA: integrated form of adenovirus DNA appears early in productive infection.

In KB cells productively infected with adenovirus type 2, alkali-stable greater than 100S and 40-100S viral DNAs are synthesized starting 2-4 hr postinfection, i.e., before unit length (34 S) viral DNA is made. The amount of greater than 100S and 40-100S viral DNA increases when 34S viral DNA synthesis begins, and at 16-18 hr postinfection, the 40-100S viral DNA represents 5-20% of the total intracellular viral DNA. The 40-100S viral DNA is synthesized throughout infection. Part of the 40-100S DNA synthesized 5-8 hr postinfection has a density in alkaline CsCl gradients intermediate between those of viral and cellular DNAs. This finding indicates that newly synthesized viral DNA is covalently linked to cellular DNA. Viral sequences can be excised from the cellular DNA of infected cells with the EcoRI restriction endonuclease. Fragments of viral DNA are detected in polyacrylamide-agarose gels by DNA-DNA hybridization, and these fragments correspond in size to most of the known EcoRI fragments of adenovirus 2 DNA. Viral DNA sequences in size-classes between the EcoRI-A and -C fragments are also found and probably represent viral DNA linked to cellular sequences.

Adenoviridae↗
PubMed1975

Solar abundance of platinum.

Three lines of neutral platinum, located at lambda 2997.98 A, lambda 3064.71 A, and lambda 3301.86 A have been used to determine the solar platinum abundance by the method of spectral synthesis. On the scale, log A(H) = 12.00, the thus-derived solar platinum abundance is 1.75 +/- 0.10, in fair accord with Cameron's value of log A(Pt) = 1.69 derived by Mason from carbonaceous chondrites and calculated on the assumption that log A(Si) = 7.55 in the sun.

Journal Article↗
PubMed1975

Variations of neurohypophysial function in normally cycling women.

Using a neurophysin radioimmunoassay, we have studied basal neurohypophysial function in seven normal women. An increase in neurophysin blood levels has been demonstrated during the ovulatory and/or luteal phase as compared to the follicular phase; these variations are related to the changes in the circulating levels of 17beta-estradiol. The data provide additional evidence for a relationship between estrogens and neurohyprophysial function, as previously shown following exogenous administration of estriol and ethinyl estradiol in man.

Adult↗
PubMed1974

Intracellular forms of adenovirus DNA. 3. Integration of the DNA of adenovirus type 2 into host DNA in productively infected cells.

KB cells productively infected with human adenovirus type 2 contain an alkalistable class of viral DNA sedimenting in a broad zone between 50 and 90S as compared to 34S for virion DNA. This type of DNA is characterized as viral by DNA-DNA hybridization. It is extremely sensitive to shear fragmentation. Extensive control experiments demonstrate that the fast-sedimenting viral DNA is not due to artifactual drag of viral DNA mechanically trapped in cellular DNA or to association of viral DNA with protein or RNA. Furthermore, the fast-sedimenting DNA is found after infection with multiplicities between 1 and 1,000 PFU/cell and from 6 to 8 h postinfection until very late in infection (24 h). Analysis in dye-buoyant density gradients eliminates the possibility that the fast-sedimenting viral DNA represents supercoiled circular molecules. Upon equilibrium centrifugation in alkaline CsCl density gradients, the fast-sedimenting viral DNA bands in a density stratum intermediate between that of cellular and viral DNA. In contrast, the 34S virion DNA isolated and treated in the same manner as the fast-sedimenting DNA cobands with viral marker DNA. After ultrasonic treatment of the fast-sedimenting viral DNA, it shifts to the density positions of viral DNA and to a lesser extent to that of cellular DNA. The evidence presented here demonstrates that the 50 to 90S viral DNA represents adenovirus DNA covalently integrated into cell DNA.

Adenoviridae↗