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Biomedical subjects

G Hahn

Publications and source records attributed to G Hahn.

At least 91 records · Page 5Linked to original sources
PubMed1985

Arthrogryposis. Pediatric review and habilitative aspects.

A precise diagnosis among the types of arthrogryposis must be made. For amyoplasia, the recurrence risk is nonexistent, the natural history favorable. During the first weeks, frequent stretching supported by maintenance casting and splinting of severe or generalized contractures is indicated in a residential multidisciplinary center. The key to deformity is the rigidity of the periarticular structures. With limb growth, contractures progress or recur. The growth years must therefore be dominated by physical management, which consists of stretching, casting, and bracing interspersed by staged soft-tissue procedures. At completion of limb growth, final corrections should be attained by osteotomies. Adolescence should be a time to follow social and prevocational pursuits in preparation for a place in society.

Adolescent↗
PubMed1984

Prostaglandin synthesis by cells comprising the calf pulmonary artery.

Prostaglandin (PG) production was evaluated in the three cell types (endothelial, smooth muscle, and fibroblast) comprising the bovine pulmonary artery. Prostacyclin (PGI2) was the predominant prostaglandin (PG) produced by endothelial, smooth muscle, and fibroblast cells as they exist in culture or in freshly excised tissue fragments. In addition to PGI2, measurable amounts of PGE2, PGF2a, and thromboxane A2 (TXA2) were also produced by these cells. Endothelial cells were the most active producers of PGs. However, the type of PG produced was characteristic of the particular cell type, while the level of production was dependent on external factors. Prostaglandin production by cultured cells, both under basal conditions and in response to stimulatory agents, was quite similar to that of the respective freshly excised tissue fragments containing a given cell type. These cells in culture could be stimulated to produce PGI2 by both angiotensin and bradykinin at very low (physiological) concentrations, a further indication of the retention of the physiological responsiveness of these cells in culture. Endothelial cells and fibroblasts were activated by bradykinin at concentrations as low as 10(-12) M but did not respond to angiotensin. Smooth muscle cells in primary and first passage cultures were activated by both bradykinin and angiotensin at 10(-12) M concentrations. Serial subcultivations of smooth muscle cells resulted in a progressive loss in their responsiveness to bradykinin stimulation. The state of cell growth proved to be an important determinant of PG production. Actively growing cells in culture synthesized less PG when compared to cells which had entered into a "quiescent" nongrowth state.

Angiotensins↗
PubMed1984

Influence of dietary casein or soy protein on serum lipids and lipoproteins of monkeys (Macaca fascicularis).

In order to learn whether a complete exchange of dietary soy protein for casein causes a change of serum lipid levels in primates, 8 Macaca fascicularis monkeys were fed a semi-purified ration; its basic composition was similar to diets consumed in Western Europe. In a crossover experiment, casein was exchanged for a soy protein isolate and vice versa. Plasma and lipoprotein cholesterol and triglyceride levels were determined following a 3-week dietary regimen. There was no significant difference of total serum cholesterol levels between the soy protein and casein periods (4.6 vs. 4.7 mmol/l). However, high-density lipoprotein (HDL) cholesterol levels were significantly higher (1.6 vs. 1.2 mmol/l, p less than 0.01) and very-low-density lipoprotein (VLDL) cholesterol levels were significantly lower (0.39 vs. 0.55 mmol/l, p less than 0.01) following the soy protein diet. There was no distinct change in total or lipoprotein triglyceride levels following exchange of the dietary protein. It is concluded that in nonhuman primates a complete exchange of soy protein for casein produces changes of HDL, but not of total or low-density lipoprotein (LDL) cholesterol.

Animals↗
PubMed1984

[Occurrence and identification of enterotoxin-producing E. coli strains in milk and dairy products].

Enteric diseases caused by enterotoxigenic E. coli strains (ETEC) become more and more important all over the world. Frequently food is implicated as a vector. --From this the necessity arises to identify ETEC strains and/or their heatlabile (LT) and heat-stable enterotoxins (ST). The examinations carried out for the presented paper showed the following results: Detection of LT by coagglutination is a simple and rapid test and may be helpful for screening. Most suitable, however, is the application of ELISA which enables the detection of 1 ng/ml LT with a good reproducibility. For identification of ST the suckling mouse assay (SMA) yields reliable results. ELISA and SMA have proved to be useful in practice for examination of food samples. By means of these methods 157 E. coli strains predominantly isolated from milk and milk products were examined. Hereby, five ETEC strains could be identified (3.2%). For the purpose of food examination a procedure was developed which ensures a reliable and efficient identification of E. coli enterotoxin. The essential steps are enrichment in E.E.-broth, subcultivation in CAYE-2-broth, identification of LT by ELISA resp. coagglutination and the detection of ST with aid of the SMA. So, isolation of single colonies can be omitted, which is an essential advantage.

Agglutination Tests↗
PubMed1984

Serum cortisol concentrations in gilts and sows housed in tether stalls, gestation stalls and individual pens.

Three experiments were conducted to determine whether housing in tether stalls, gestation stalls or individual pens imposes a stress upon gilts and sows. Changes in serum cortisol concentrations were used as the indicator for stress. In the first experiment, gilts were placed in tether stalls and individual pens to determine cortisol concentrations after tethering and to see if this response was different from gilts that were previously tethered for two weeks. In the second experiment, gilts were tethered in order to determine if penning in tether stalls altered the circadian rhythm of cortisol. In the third experiment, breeding sows were placed in tether stalls, gestation stalls or individual pens to determine if a ten-hour profile of cortisol concentrations were altered and if such housing affected a sow's response to transfer to farrowing crates. The results indicate that the initial response to tethering varied among gilts and sows and this variation appeared to be due to previous penning and human handling experiences. When tethering was stressful, acclimation required up to four days. However, once acclimated, tethering resulted in higher morning concentrations which may be associated with the greater activity that occurs at this time. Housing in tether stalls, gestation stalls or individual pens was not a stress for breeding sows and did not alter sows' responses to transfer into the farrowing crate.

Animals↗
PubMed1983

Polyclonal activation of immunoglobulin secretion without prior DNA synthesis in human B lymphocytes induced by Klebsiella pneumoniae.

The capacity of various cell preparations of Klebsiella pneumoniae K43 (Klebs) to induce [3H]thymidine uptake and immunoglobulin (Ig) secretion by human mononuclear blood cells (MNC) and their lymphocyte subpopulations was investigated. All Klebs preparations were virtually devoid of mitogenic properties, in contrast to control preparations of pokeweed mitogen (PWM) and group A streptococcal cell membranes (A-ScM). Klebs induced differentiation of B cells into Ig-secreting cells. B-cell populations that were sufficiently depleted of T cells to be unresponsive to A-ScM ("highly purified B cells") showed a marked response to Klebs. Similarly, the number of plaque-forming cells (PFC) in Klebs-driven cultures did not change after restitution of T cells, whereas the presence of restituted T cells augmented the B-cell response to PWM and A-ScM. Radical removal of adherent MNC ("monocytes"), however, completely abrogated the PFC response and [3H]thymidine uptake of both MNC activated by Klebs and MNC activated by PWM or A-ScM.

Adult↗
PubMed1983

HLA-related lymphocyte responsiveness in psoriasis.

In order to find associations among the genetic, immunological and environmental factors that might be important in the pathogenesis of psoriasis, the relationship between streptococcal antigen- or mitogen-induced lymphocyte responses in vitro and HLA phenotypes was studied in 23 patients with psoriasis. Patients showed an elevated lymphocyte response to somatic A-streptococcal antigens when compared with healthy controls. In contrast, the response to mitogens (PHA, Con A, PWM) was impaired in patients with psoriasis. The impaired mitogen-induced lymphocyte transformation was found mostly in psoriatics with HLA-B13/B17. The elevated cellular immune response to somatic A-streptococcal antigens, on the other hand, was observed mainly in psoriatics without HLA-B13/B17. The results indicate that gene products of the HLA region known to be associated with psoriasis are involved in the cellular immune response, as expected from clinical trials. These findings also provide further evidence of at least two different subtypes of psoriasis, characterized by genetically and immunologically defined markers.

Antibodies, Bacterial↗
PubMed1983

[Stimulation of human and bovine lymphocytes by various Streptococcus species].

Concerning the question of species specifity of lymphokines in the presented examination the effect of the leukocyte migration inhibition factor (LIF) secreted by human and bovine lymphocytes was tested using PMN leukocytes of man and different animal species as indicator cells. The method was the so called indirect leukocyte migration inhibition test according to Clausen. As antigens for stimulating the lymphocytes cell wall preparations of group A- and B-Streptococci and as a mitogen Concanavalin A was used. From the results the following facts can be stated: --Human LIF has no inhibiting effect on the migration of leukocytes from cattle, sheep and pigs--independent of the way of stimulation by specific antigens or by the mitogen. --A corresponding factor to human LIF can be demonstrated from bovine lymphocytes which, however, inhibits only the migration of bovine indicator cells. This phenomenon is also independent of the kind of stimulation. --Migration inhibiting substances from bovine lymphocytes are only produced after stimulation with group A- and B-streptococci cell walls if the donor animals have been sensitized with these antigens. --The interaction between LIF and indicator leukocytes obviously is dependent on host specifity and not on a peculiar relation of macro- and microorganisms.

Animals↗
PubMed1983

[Animal experimental studies of passive oral immunization against staphylococcal enterotoxin B (SEB)].

Intoxications by S. aureus enterotoxins are predominant in our country, together with enteric infections by Salmonella spp. For lack of a specific therapy the possibility was examined to neutralize orally provided toxin in vivo. For this purpose before and after the intoxication, respectively, antitoxin and normal rabbit serum as a control were also applied per os. In extensive trials SPF-mice were used as a model in spite of their insensitivity to staphylococcal toxins even with 10000 times the emetic dose for monkeys. By serological means, the rate of free toxin in stomach, intestinal contents and fecal matter after and before application of antiserum was identified as an indicator for the neutralization of the toxin in vivo. As toxin, S. aureus enterotoxin B (SEB) was used which could be identified in the samples up to three hours after oral feeding. Antiserum was obtained by immunization of rabbits with toxoid. The application of antiserum one hour after intoxication resulted in an average reduction of free toxin in the intestine of 87,5 and 86,5%, (10 independent trials) one and two hours, respectively after serum administration. In contrast, administration of antiserum one hour before experimental intoxication did not produce statistically confirmed differences between the experimental and the control animals.

Administration, Oral↗
PubMed1982

Continuous-flow NMR culture system for mammalian cells.

A continuous-flow NMR culture system for mammalian cells has been developed on which 31P-NMR experiments under complete and strictly physiologic conditions have been performed. Observations on the response of the cellular metabolism to stresses such as starvation, low temperature and changes in environmental pH monitored by 31P-NMR are reported. The response of the intracellular pH relative to the external pH of the growth medium is studied. We find that under the experimental conditions used there exists a delta pH varying between less than 0.2 and more than 0.6 pH units. These results are compatible with those obtained using other techniques.

Animals↗
PubMed1981

[Results from the Central Laboratory for Streptococci Research in Kiel from 1965 to 1980 - group D-streptococci (enterococci) (author's transl)].

In accordance with previous papers published within a series of publications which describe the results obtained from the Central Laboratory for Streptococcal Research in Kiel (1. Survey, 2. Mastitis-Streptococci) the group of Enterococci is discussed herewith. On the basis of more than 6000 strains which are stored in our databank including all biological characteristics, the distribution of the cultural, biochemical and serological parameters is listed in percentages, and the usefulness and reliability for the identification of the enterococcal group and also the differentiation of particular species is discussed. The results are tabulated for every single species and additionally, for serologic-positive and negative strains. For example, it can be shown that a third of all Str. faecium strains are motile, that lack of growth at 45 degrees C varies between 1.1% and 31.3% and that lack of serological reaction with group D-serum between 0.9% and 70%. In a comprehensive table and flow diagram these figures result in a proposal for a simple but sufficient identification procedure on different stages (enterococci, faecalis- or faecium-group, single species) depending on the individual requirements. With regard to the incidence of enterococci in man and animals, which was presented in the first paper, the organ sources of the different species are compared now. Apart from some interesting findings it can be stated that a typical predominance of the faecalis and faecium-group resp. in man or animals cannot be confirmed. But there seems to be a relation between the species and the organ source. For example, in humans the faecium-group predominates in the respiratory tract, but in the urogenital tract the presence of Str. faecalis is seven times higher than the faecium-group. The above results may also be of interest for ecological reasons and may be important for the pathogenesis and epidemiology of this streptococcal group.

Animals↗
PubMed1979

Erythromelalgia.

Erythromelalgia is an extraordinary disorder of unknown etiology and pathophysiology that resembles the post-traumatic reflex dystrophy syndromes but has not been described previously in the orthopedic literature. Its distinctive triad of intense burning extremity pain associated with erythema and increased skin temperature are diagnostic. Primary or idiopathic and a secondary or associated form have been identified. The latter occurs in association with an underlying disease process, especially myeloproliferative disorders. Treatment with pharmacologic agents and surgery are ineffective except in the secondary group where treatment of the associated disorder generally results in a remission. Symptoms in the primary group can be minimized by appropriate environmental control with cooling and avoiding heat-producing situations that would raise skin temperature above a critical thermal threshold.

Adolescent↗