Search PubMed⌕ Search

Biomedical subjects

H Schweizer

Publications and source records attributed to H Schweizer.

At least 55 records · Page 3Linked to original sources
PubMed1983

Cloning of the ugp region containing the structural genes for the pho regulon-dependent sn-glycerol-3-phosphate transport system of Escherichia coli.

Using a novel positive selection method for G3P transport activity, lambda phages that carry either all or part of ugp, the genes of the pho regulon-dependent G3P transport system of Escherichia coli were isolated from a library of EcoRI fragments of Escherichia coli established in lambda gt7. By subcloning EcoRI fragments carried by the different phages into the multicopy plasmids pACYC184 and pUR222, it was shown that two chromosomal fragments of 6.0 and 6.6 kb are required for the expression of ugp, whereas all the structural information is located on the 6.6 kb EcoRI fragment. A restriction map of the cloned DNA was established and the extent of ugp genes determined by Tn5 insertions. Using ugp-lacZ fusions, it could be shown that the ugp region consists of at least two different operons that are transcribed in the same direction (counterclockwise) on the E. coli chromosome.

Bacteriophage lambda↗
PubMed1983

[Antibody formation against specific Epstein-Barr virus antigens in infectious mononucleosis with tonsillectomy in the acute phase of the disease].

In the present study, the clinical course and the specific humoral immunological response to Epstein-Barr virus antigens have been investigated in patients affected with infectious mononucleosis after tonsillectomy in the acute phase of the disease, compared against conservatively treated patients. Clinical results confirm that tonsillectomy in the acute phase of infectious mononucleosis has a favourable effect on the course of the disease, and reduces the duration of the disease by about half of the usual time. Statistically significant differences - indicating a confined, delayed humoral immunological response or unresponsiveness to some extent - regarding the examined antigens after tonsillectomy in the acute phase of infectious mononucleosis, could be observed between the two groups of patients in respect of the production of antibodies against viral capsid and nuclear antigens of the Epstein-Barr virus and heterophilic antibodies. For this reason, tonsillectomy should be suggested only as therapy of infectious mononucleosis in anginous courses of the disease which appear life-threatening.

Acute Disease↗
PubMed1983

[Release of chromium 51 by coxsackievirus-infected FL cells].

The time course of chromium-51 (51Cr) release was investigated on FL monolayer cells infected with different serotypes of coxsackievirus. 51Cr release was determined by means of the increase in 51Cr radioactivity in supernatants of cells saturated with 51Cr. Ten hours p.i. the 51Cr release of virus-infected cells was largely increased compared with the control cells. The greatest differences in 51Cr release between normal and virus-infected cells were observed from 10 to 30 hours p.i. The quantitative correlation between virus concentration and 51Cr release as well as the type-specific inhibition of virus-accelerated 51Cr release by virus-neutralizing antisera demonstrate the relationship between 51Cr release and coxsackievirus infection of FL cells. By the use of 51Cr labeled FL cells as an indicator system, the 51Cr release proved to be well suited for objective and quantitative evaluation of coxsackievirus-cell-interactions connected with the cytopathogenic effect (CPE).

Animals↗
PubMed1982

Characteristics of a binding protein-dependent transport system for sn-glycerol-3-phosphate in Escherichia coli that is part of the pho regulon.

The ugp-dependent transport system for sn-glycerol-3-phosphate has been characterized. The system is induced under conditions of phosphate starvation and in mutants that are constitutive for the pho regulon. The system does not operate in membrane vesicles and is highly sensitive toward osmotic shock. The participation of a periplasmic binding protein in the transport process can be deduced from the isolation of transport mutants that lack the binding protein. As with other binding protein-dependent transport systems, this protein appears to be necessary but not sufficient for transport activity. The isolation of mutants has become possible by selection for resistance against the toxic analog 3,4-dihydroxybutyl-1-phosphonate that is transported by the system. sn-Glycerol-3-phosphate transported via ugp cannot be used as the sole carbon source. Strains have been constructed that lack alkaline phosphatase and glycerol kinase. In addition, they are constitutive for the glp regulon and contain high levels of glycerol-3-phosphate dehydrogenase. Despite the fact that these strains exhibit high ugp-dependent transport activity for sn-glycerol-3-phosphate they are unable to grow on it as a sole source of carbon. However, when cells are grown on an alternate carbon source, (14)C label from [(14)C]sn-glycerol-3-phosphate appears in phospholipids as well as in trichloroacetic acid-precipitable material. The incorporation of (14)C label is strongly reduced when sn-glycerol-3-phosphate is the only carbon source. In the presence of an alternate carbon source, this inhibition is relieved, and sn-glycerol-3-phosphate transported by ugp can be used as the sole source of phosphate.

Amino Acids↗
PubMed1982

Mapping of two ugp genes coding for the pho regulon-dependent sn-glycerol-3-phosphate transport system of Escherichia coli.

Two genes, ugpA and ugpB, coding for a binding protein-dependent sn-glycerol-3-phosphate transport system, were mapped at 75.3 min on the Escherichia coli chromosome. A Tn10 insertion in ugpA resulted in loss of transport activity but still allowed the synthesis of the sn-glycerol-3-phosphate-binding protein. This Tn10 insertion was found to be linked by P1 transduction to pit, aroB, malA, asd, and livH with 2.5, 2.8, 25, 63.5, and 83% cotransduction frequency. An insertion of Mud (Ampr lac) in ugpB resulted in the loss of the binding protein. ugpB is closely linked to ugpA. It is either the structural gene for the binding protein or located proximal to it. The analysis of the crosses allowed the ordering of the markers in the clockwise direction as follows: aroB, malA, asd, ugpA, ugpB, livH, pit.

ATP-Binding Cassette Transporters↗
PubMed1981

Localization of brain stem motoneurons innervating the laryngeal muscles in the rufous horseshoe bat, Rhinolophus rouxi.

The motoneurons innervating the laryngeal muscles were localized in the rufous horseshoe bat, Rhinolophus rouxi, using the HRP method. HRP was applied to the cricothyroid muscle and to the cut end of the recurrent laryngeal nerve. Labeled motoneurons were found in two completely separated regions of the nucleus ambiguus. The motoneurons innervating the cricothyroid muscle via the superior laryngeal nerve (SLN) are located within the ventrolateral portion of the nucleus reaching the caudal pole of the motor nucleus of the facial nerve. The motoneurons innervating the other intrinsic laryngeal muscles via the recurrent laryngeal nerve (RLN) are situated in the caudal half of the nucleus ambiguus. The innervation is strictly homolateral.

Animals↗
PubMed1981

The connections of the inferior colliculus and the organization of the brainstem auditory system in the greater horseshoe bat (Rhinolophus ferrumequinum).

The connections of the inferior colliculus, the mammalian mid-brain auditory center, were determined in the greater horseshoe bat (Rhinolophus ferrumequinum), using the horseradish peroxidase method. In order to localize the auditory centers of this bat, brains were investigated with the aid of cell and fiber-stained material. The results show that most auditory centers are highly developed in this echolocating bat. However, the organization of the central auditory system does not generally differ from the mammalian scheme. This holds also for the organization of the superior olivary complex where a well-developed medial superior olivary nucleus was found. In addition to the ventral and dorsal nuclei of the lateral lemniscus a third well-developed nucleus has been defined which projects ipsilaterally to the inferior colliculus and which was called the intermediate nucleus of the lateral leminiscus. All nuclei of the central auditory pathway project ipsi-, contra-, or bilaterally to the central nucleus of the inferior colliculus with the exception of the medial nucleus of the trapezoid body and the medial geniculate body. The tonotopic organization of these projections and their possible functions are discussed in context with neurophysiological investigations.

Animals↗
PubMed1981

[Comparison of the in vitro activities of ammonium humate and of enzymically oxidized chlorogenic and caffeic acids against type 1 and type 2 human herpes virus (author's transl)].

Ammonium humate (prepared from marsh water humic acids) as well as enzymically oxidized diphenolic compounds such as the oxidation products of chlorogenic and caffeic acids have strong antiviral activities in vitro. The effective concentrations lie considerably outside the cytotoxic range of the compounds mentioned.

Adsorption↗
PubMed1980

Diagnosis of Herpesvirus hominis infections with the use of Ehrlich mouse ascites tumour cells.

A new technique for the detection of Herpesvirus hominis (HVH) in materials from patients, based on mixed haemadsorption with Ehrlich mouse ascites tumour cells, was proposed. Investigations on 100 pustule punctates and smears from 75 patients with typical clinical signs of various primary and recurrent infections yielded positive results in 80% of cases. This was in good accordance with HVH isolations in various cell cultures. The new technique can, therefore, be recommended for routine diagnosis. Its main advantage is the rapid virus diagnosis.

Animals↗
PubMed1979

Human cytomegalovirus induced changes in rabbit cells. Brief report.

After infection with human cytomegalovirus, rabbit lung fibroblasts showed, during the four week period of the experiment, cytopathic changes and virus-specific antigens demonstrable by fluorescent antibody. Infectious virus could be recovered from the infected cells by co-cultivation with human lung fibroblasts.

Animals↗
PubMed1979

Determination of antibodies against cytomegalovirus-induced early antigens by using rabbit lung fibroblasts. Brief report.

The determination of antibodies against cytomegalovirus-induced antigens in 30 patients with acute cytomegalovirus infection and in 100 healthy control persons, using early antigen preparations of human lung fibroblasts and of rabbit lung fibroblasts, yielded results showing a high degree of agreement. For such investigations, however, the use of rabbit cells proved to be of advantage because the preparation of the early antigens can be carried out without inhibition of the DNA synthesis of the host cells.

Adult↗
PubMed1977

[Virus-induced autoimmunity phenomena in experimental animals (author's transl)].

QUESTION: It may happen that the virus infection causes changes of the immunogenicity of the host cells that may theoretically result in disturbances of the "self-recognition" of the organism. In this paper we report on the immunization of rabbits by autologous testes cells infected with herpes-virus hominis (HVH) types 1 and 2. MATERIAL AND METHODS: In 20 rabbits the excision of one testis was carried out. The testes cells were cultivated in L 15-medium (Leibowitz) and lactalbumine hydrolysate supplemented with 12% autologous serum. The virus strains herpesvirus hominis type 1 (Kupka) and type 2 (US) were passaged three times on autologous testes cells, in order to remove host-foreign proteins out of the envelope. Thereafter, the monolayer cultures grown in Demeter flasks were infected with 15 ml virus suspension containing 10(4) to 10(5) TCID50. For the immunization three antigen preparations were applied: a) Supernatant of virus-infected cell cultures, b) Pellets of the virus-infected cell cultures, c) Pellets of the non-infected cell cultures. Two times at an interval of 3 weeks the animals were immunized by intramuscular and intraperitoneal injections with prepared antigens. Altogether, 20 animals were immunized: 15 rabbits with virus antigen, 5 control animals with non-infected autologous cells. After 28 days, 13 rabbits were bled, the second testis, liver, spleen, and kidneys were taken out. From 7 rabbits, only the second testis was taken out. These animals got a further injection on the 40th day post infectionem, and on the 50th day, they were bled. From the tissue samples, frozen sections were cut, fixed with acetone, and treated with fluorescein isothiocyanate-labelled antirabbit globulin, in order to elicite the tissue-bound antibodies. For histological studies, paraffin sections were stained with hematoxylin and eosin, and with azan, besides the PAS reaction was carried out. The determination of humoral antibodies was done by means of indirect-immunofluorescence antibody technique (IFAT). As antigen, autologous cells grown on slides were used; a part of them was infected with HVH types 1 or 2, while another part was not infected. RESULTS: After immunization with autologous testes cells which were infected with HVH types 1 or 2, histologically homogeneous eosinophilic PAS-positive substances were detected in 14 out of 15 rabbits, mainly in the interstitium of the testes (fig. 2). These substances corresponded to globulin deposits that could be demonstrated by the reaction of labelled antirabbit globulin (fig. 1). The testes sections of thoses 5 rabbits that were injected with noninfected autologous cells, did not react. On the 28th day post infectionem, the antibody levels against virus antigen were found at the degree of 1:32 to 1:1024. Only after the removal of the second testis, there occurred antibodies against autologous testes cells. The immunization conditions exclude the formation of isoantibodies...

Animals↗