PubMed Health⌕ Search

Biomedical subjects

H Müller

Publications and source records attributed to H Müller.

At least 685 records · Page 38Linked to original sources
PubMed1983

Kinetic studies on the membrane-bound and the purified coupling factor-ATPase from Rhodopseudomonas sphaeroides.

The activity of membrane-bound and purified ATPase (EC 3.6.1.3) was potentiated by several divalent cations. Highest rates of ATP hydrolysis were obtained when the activity was measured with the (cation-ATP)2- complex. Free ATP and free divalent cations in excess were found to be competitive inhibitors to the complex. The apparent Km (complex) values were lower than the Ki values for free ATP indicating that the (cation-ATP)2- complex is bound more tightly to the enzyme than the free ATP. Based on these results, a binding of the complex to the active site at two points is suggested, namely through the ATP and through the cation. Removal of the coupling factor from the membrane apparently caused conformational changes which resulted in a pronounced alteration of the kinetic parameters of ATPase activity. Whereas highest values in chromatophore-bound ATPase activity were observed in the presence of Mg2+, the purified enzyme became even more active in the presence of Ca2+. The Ki values for free ATP decreased upon solubilization of the enzyme. Free Mg2+ in excess was more inhibitory on the purified ATPase than Ca2+, while free Ca2+ in excess was more inhibitory on the membrane-bound enzyme if compared to Mg2+. Ki values for product inhibition by ADP and Pi were determined. Kinetic analyses of photophosphorylation activity revealed that the (cation-ADP)- complex is the functional substrate. The apparent Km values for the complex and for Pi were estimated. Excess of free cations and ADP inhibited competitively the phosphorylation. Ki(ADP), Ki(Ca2+), and Ki(Mg2+) were calculated by Dixon analyses.

Adenosine Diphosphate↗
PubMed1983

Binding of autologous IgG to human red blood cells before and after ATP-depletion. Selective exposure of binding sites (autoantigens) on spectrin-free vesicles.

Binding of autologous IgG to fresh, ATP-depleted red blood cells as well as to spectrin-free vesicles was studied by a non-equilibrium binding assay using 125I-iodinated protein A from Staphylococcus aureus. IgG binding was 14-times higher to spectrin-free vesicles than to ATP-maintaining red blood cells and 4-times higher than to ATP-depleted erythrocytes from which these vesicles were released. Protein A binding to vesicles that were released from washed and nutrient-deprived erythrocytes, was dependent on added autologous IgG. However, spectrin-free vesicles that were spontaneously released from erythrocytes conserved in whole blood, bound similar amounts of protein A with or without added autologous IgG (0.45-0.55 ng/micrograms band 3 protein). These findings demonstrate that opsonization of spectrin-free vesicles by autologous IgG occurs not only in the test tube, but also under blood blank conditions. The binding characteristics of IgG to spectrin-free vesicles are indicative of a natural autoantibody rather than an unspecific binding of autologous IgG. The preferential binding of IgG to spectrin-free vesicles implies a selective exposure of corresponding autoantigens in membrane regions that have lost cytoskeletal anchorage and bud off.

Adenosine Triphosphate↗
PubMed1983

Scintigraphic documentation of lymph drainage of cutaneous tumours.

A method of lymphoscintigraphy is described which provides additional diagnostic information, of particular value prior to surgery for the removal of cutaneous tumours. The technique demonstrates the individual physiology of the lymphatic drainage system from a particular region of the skin. However, it is not the aim of the method to diagnose possible lymph node metastases.

Adult↗
PubMed1983

Silver staining of nucleolus organizer regions during human spermatogenesis.

The sizes and staining intensities of the nucleolus organizer regions (NORs) in human spermatogenesis were studied qualitatively and quantitatively with the silver (Ag)-staining technique. The Ag-stainability of the NORs is a measure of the transcriptional activity of the ribosomal RNA genes. Ag-stained NORs are present during the whole period of meiotic prophase up to pachytene and totally absent in the two meiotic metaphases. In the early spermatids the Ag-stainability of the NORs reappears and persists up to the beginning of the elongation phase of the nuclei. This pattern of NOR-activity during spermatogenesis is common for all vertebrates. However, in human spermatogenesis the absolute sizes of the NORs in the pre- and postmeiotic stages as well as the interphase arrangement of the postmeiotically reactivated NORs show characteristic properties not found in any other species. The cytochemistry of the argentophilic material, the significance of the synthesis of ribosomal RNA in spermatogenesis, and the characteristic arrangement of the Ag-stained NORs in the spermatids are discussed.

Animals↗
PubMed1983

Factors influencing peripheral nerve suture results.

Besides the surgical treatment, other factors do greatly influence the results following peripheral nerve suture. On the basis of our own findings in more than 80 patients, we analyze those factors, the exclusion of which prevents a satisfactory comparison between the different results in peripheral nerve suturing, as well as a valid discussion of their implications.

Adolescent↗
PubMed1983

Monoclonal antibodies against tetanus toxin and toxoid.

Monoclonal antibodies against tetanus toxin and its toxoid were produced by immunizing mice with toxoid or toxin. They were measured by an enzyme-linked immunosorbent assay (ELISA), by a toxin neutralization test in mice (in vivo prevention test), and by their ability to prevent binding of 125I-toxin to brain membranes or gangliosides (in vitro prevention test). Six monoclonal antibodies obtained by immunization with toxoid (anti-toxoid 1-6) were investigated in more detail. They belonged to IgG class 1. Three of them (anti-toxoid 1, 2 and 3) recognized both toxoid and toxin as well as fragment B and the light chain of toxin, but not fragment C. Two other antibodies (anti-toxoid 4 and 5) were directed against toxoid only. Neither of them prevented toxin action in vitro or in vivo. Anti-toxoid 6 recognized toxin, toxoid and fragment C, but not light chain, and prevented toxin action in vitro and in vivo. Immunization against toxin was initiated with a toxin-antitoxin complex and boosted with toxin. We studied six antibodies in more detail, all of IgG type 2. Their KD against 125I-tetanus toxin varied from 10(-9) to 10(-10) M. Anti-toxin 2 recognized toxin, toxoid, light chain and fragment B, but not fragment C. The others reacted with toxin, toxoid and fragment C, but not with light chain or fragment B. All of them prevented toxin action in vitro and in vivo. As calculated from the maximal extinction achieved in the ELISA, tetanus toxin combined with a maximum of two different antibody molecules from our set. Gel filtration data indicate that tetanus toxin reacts with monoclonal antibodies one by one. Compared with polyclonal antiserum, monoclonal antibodies yield flatter slopes in both in vitro and in vivo prevention tests. Thus, they cannot substitute for the polyclonal antibodies in clinical situations, and cannot be calibrated in international units.

Animals↗
PubMed1983

Central fibroma of the jaw, odontogenic or desmoplastic.

Discerning desmoplastic fibroma from odontogenic fibroma may present considerable diagnostic difficulty. In the present article five cases of jaw fibroma serve to emphasize the various problems. Two cases represented desmoplastic fibroma. Both were treated by curettage, which was successful in one case but failed to provide a cure in the other. Factors responsible for this differing clinical course are discussed. A third case of desmoplastic fibroma proved to have been misdiagnosed, being a low-grade fibrosarcoma that subsequently showed dedifferentiation, and two cases were diagnosed as central odontogenic fibroma. After a discussion of the various histologic aspects of the reported cases, it is concluded tha desmoplastic fibroma is a well-delineated entity. Odontogenic fibroma, on the contrary, can exhibit a varying histomorphology, perhaps because of the existence of different entities that at present are taken together. To prevent the uncertainties concerning the odontogenic fibroma from making the definition of desmoplastic fibroma also indistinct, it is proposed that a central jaw fibroma that does not show the typical morphology of a desmoplastic fibroma should be considered an odontogenic fibroma.

Adult↗
PubMed1983

Verrucous hyperplasia or verrucous carcinoma. An analysis of 27 patients.

27 patients with verrucous lesions of the oral mucosa were studied with reference to the validity of a separation of the entity verrucous hyperplasia from verrucous carcinoma, based on an exophytic or an endophytic growth pattern of the hyperplastic epithelium. The occurrence of other mucosal lesions in these patients was also recorded. It is concluded that verrucous hyperplasia probably represents a morphological variant of verrucous carcinoma. In 37% of the patients, squamous cell carcinoma was found as a coexisting or separately occurring disease and in 26% epithelial dysplasia was also present. It is postulated that the existence of a verrucous carcinoma must be considered to be an expression of an ubiquitous premalignant change in the whole oral mucous membrane. Finally, some notes are made on the entities florid oral papillomatosis and chronic hyperplastic candidosis in relation to oral verrucous carcinoma.

Adult↗
PubMed1983

[Value of hilus tomography in tuberculin positive, non BCG vaccinated children].

X-ray films of the thorax in two levels were prepared of 15 children of 3-14 years of age who had not been BCG-inoculated, after the tuberculin test had shown a positive reaction. Besides bacteriology and bronchoscopy, tomography of the hilus and of the anterior mediastinum was performed to exclude hilar lymph node enlargements. In this manner, it became possible to disclose an enlargement of lymphatic nodes in four children in whom plain radiography of the thorax had not yielded any abnormal findings.

Adolescent↗
PubMed1983

[Clinical experiences with betahistine].

50 patients with disorders of the cochleo-vestibular system due a wide variety of causes were treated with Betahistine (Betaserc). The reaction of Betaserc was different in vertigo, tinnitus and hearing loss. As expected, the result of the treatment depends on kind and duration of the disease. Best results were found for M. Ménière. Summarizing Betaserc can be said to be most effective in treating vertigo, less effective in treating tinnitus, but inappropriate in treating hearing loss.

Adult↗
PubMed1983

[Continuous peridural opiate administration with an implanted pump. Implantation technic and 1st results].

Epidurally administered opiates provide pain relief and may also be used for treatment of chronic pain of malignant origin. Compared to single-shot injection via externalized catheter continuous epidural morphine infusion via implantable pump and epidural catheter offers some advantages. The authors have used this method since October 1982. Functional characteristics of a low-flow continuous system, technique of implantation and preliminary results of this method are presented as a case report.

Aged↗
PubMed1983

[Therapeutic problems with indomethacin in preterm infants with persistent ductus arteriosus].

Inhibition of PGE production in eight preterm infants with persistent ductus arteriosus and respiratory distress syndrome was associated with marked improvement in the respiratory and circulatory function in all of them. However, in six of them this effect was only transient. In the posttreatment period of five and a half days reopening of the ductus arteriosus was frequently associated with increased PGE production and a drop of indomethacin serum levels. Three of these six infants were transferred for surgical ligation and the other three infants were successfully treated with a second course of indomethacin. The margin between closure of the ductus arteriosus and the deterioration of kidney function in preterm infants treated with a presently recommended indomethacin dosage is too narrow. Before an improved therapeutic procedure has been developed indomethacin treatment for the closure of persistent ductus arteriosus should not generally be recommended in preterm infants.

Ductus Arteriosus, Patent↗
PubMed1983

[Evaluation of a new apparatus for determining sodium and potassium via ion-selective electrodes].

Evaluation of an apparatus for the direct measurement of sodium and potassium by means of ion-selective electrodes yielded very good results. This apparatus is notable for excellent linearity. It possesses a low detection threshold, the lowest identification limit being 4.43 mmol./l. for sodium and 0.21 mmol./l. for potassium. The sensitivity is high, since it is approximately 1.5 mmol./l. for sodium in whole blood and approximately 0.15 mmol./l. for potassium. On checking the accuracy of the instrument, a mean recovery of 100% was seen for both electrolytes. An examination of the precision of the instrument yielded, in serial determinations of sodium, variation coefficients between 0.2 and 0.4%, and in case of potassium, variation coefficients around 1%; even in respect of day-to-day precision, all variation coefficients were definitely below 5%. Hence, the overall precision of the apparatus can be rated as good. However, when using whole blood samples anticoagulated with sodium heparinate solution, it is necessary to take the dilution effect into account when arriving at the potassium value.

Blood Chemical Analysis↗