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Biomedical subjects

H Wolf

Publications and source records attributed to H Wolf.

At least 505 records · Page 28Linked to original sources
PubMed1986

Low molecular weight heparin plus dihydroergotamine for prophylaxis of postoperative deep vein thrombosis.

In a prospective, double-blind investigation of the prophylaxis of deep vein thrombosis (DVT) in patients undergoing elective major abdominal surgery, 269 patients were randomized into two groups. One hundred and thirty-two patients received a fixed combination of heparin sodium 5000 units plus dihydroergotamine mesylate 0.5 mg (H/DHE) twice a day and 137 patients received a fixed combination of low molecular weight heparin 1500 units plus dihydroergotamine mesylate 0.5 mg (LMWH/DHE) once a day as well as one injection of placebo per day. Treatment was initiated 2 h pre-operatively in both groups and continued for 7-10 days. The frequency of DVT determined by the 125I-labelled fibrinogen uptake test and phlebography was 10.3 per cent in patients receiving H/DHE and 10.4 per cent in those receiving LMWH/DHE. DVT of the femoral vein was detected in four patients of the H/DHE group and in none of the LMWH/DHE group. Intra- and postoperative blood loss did not differ significantly between both groups. Also no difference in the development of wound haematoma and injection site haematoma was found. While intra-operative volume substitution was comparable in both groups, significantly more patients under H/DHE prophylaxis received volume substitution during the postoperative phase. These results show that once-daily prophylaxis with the combination of low molecular weight heparin and dihydroergotamine is equally as effective and as safe as the twice-daily regimen using a combination of unfractionated heparin and dihydroergotamine in patients undergoing elective, major abdominal surgery. The advantages of the once-daily regimen of LMWH/DHE include greater patient acceptance, less nursing time and greater cost effectiveness, provided the new combination can be sold at a cost which maintains this advantage.

Abdomen↗
PubMed1986

A monoclonal antibody reacting with a membrane determinant expressed on activated chicken T lymphocytes.

A monoclonal antibody (INN-CH-16) was prepared which reacts with a cell surface antigen termed chicken activated T lymphocyte antigen. This antigen is expressed on antigen- or mitogen-activated T lymphocytes and is not present on nonstimulated lymphocytes. It has an apparent molecular mass of 48-50 kDa under reducing conditions. The value of this antibody for the immunohistochemical characterization of infiltrating cells in the thyroid glands from Obese strain chickens with spontaneous thyroiditis is demonstrated.

Animals↗
PubMed1986

Dominance of the short-latency component in perturbation induced electromyographic responses of long-trained monkeys.

The effects of prolonged training of adult monkeys subjected to random, brief perturbations of alternating elbow flexions and extensions were studied over a period of four years. The training was intensive at first, for about one year, and then irregular, with long pauses, during the following three years. As a consequence of the prolonged training with the brief perturbations, the M2 component of the electromyographic (EMG) response of the biceps and triceps muscles became gradually smaller, and finally disappeared. The M1 component, on the other hand, progressively increased in amplitude and continued to do so after the loss of the M2, until it finally dominated the EMG response. The training had similar effects on the response of the biceps muscle to longer perturbations, but, only under certain conditions, did it affect the triceps muscle response. All changes occurred at earlier stages of the training in the flexor than in the extensor muscle. These observations demonstrate a long-term functional plasticity of the sensorimotor system of adult animals and suggest a growing role for fast segmental mechanisms in the reaction to external disturbances as motor learning progresses. Changes at various levels of the stretch reflex system could underlie the enlargement of the M1 component, while the lack of the M2 component should, at least partially, reflect a reduced cortical effect on alpha-motoneurones and/or changes in spinal systems processing afferent information.

Animals↗
PubMed1986

'Switching-off' of an auditory interneuron during stridulation in the acridid grasshopper Chorthippus biguttulus L.

In freely moving grasshoppers of the species Chorthippus biguttulus compound potentials were recorded from the neck connectives with chronically implanted hook electrodes. The spikes of one large auditory interneuron, known as the G-neuron (Kalmring 1975a, b) were clearly distinguishable in the recordings and the neuron was identified by its physiology and morphology. In quiescent grasshoppers the G-neuron responds to auditory and vibratory stimuli, but responses to both stimuli are suppressed during stridulation in males. When a male's wings were removed so that the stridulatory movements of its hindlegs produced no sound, the suppression of the G-neuron response still occurred. When proprioceptive feedback from the hindlegs was reduced, by forced autotomy of the legs, the switching-off remained incomplete (production of stridulatory patterns was inferred on the basis of electromyograms from the relevant thoracic musculature). Imposed movement of the hindlegs, on the other hand, suppressed the G-neuron response in a graded fashion, depending on the frequency of the movement. These experiments suggest that the switching-off is brought about by a combination of proprioceptive feedback and central efferences. The switching-off phenomenon could either protect the grasshopper's auditory pathway from undesired effects of overloading by its own intense song (e.g. self-induced habituation as described by Krasne and Wine 1977) and should therefore apply for most auditory neurons. Alternatively it could prevent escape reflexes from being triggered by stridulatory self-stimulation and consequently might apply only for neurons involved in such networks (as the G-neuron might be).

Animals↗
PubMed1986

Islet cell antibodies and the development of diabetes mellitus in relation to mumps infection and mumps vaccination.

Islet cell antibodies were investigated in 127 non-diabetic children after mumps infection and in four out of seven children who developed diabetes mellitus shortly after active mumps vaccination. Twenty-one of the children who had mumps and all four vaccinated children who were tested had islet cell cytoplasmic antibodies. In contrast, islet cell surface antibodies were detected in 43 out of 68 patients with mumps infection and in 32 out of 44 patients with other viral diseases. All but one mumps-infected child and all the other viral infected patients investigated did not develop diabetes mellitus. The mumps-infected ICA positive children did not show those HLA-frequencies associated with Type 1 diabetes.

Antibodies↗
PubMed1986

Effect of polymeric IgG on human accessory cell function.

Circulating immune complexes are considered to have a profound effect on host defense mechanisms against invading pathogens and to modulate cellular interactions required for an appropriate course of the immune response. In this study we have investigated the influence of polymeric IgG (used as a model system for immune complexes) on accessory functions of human monocytes. We show that a short (1 hr) incubation of human monocytes in the presence of polymeric IgG (16 hr prior to antigen pulsing) led to a significant decrease of these cells' antigen-presenting capacity while accessory functions in alloantigen- or mitogen-driven proliferation systems remained unimpaired. The polymeric IgG-induced impairment of antigen presentation, which was assessed by diminished proliferation of antigen-reactive T cells following stimulation by antigen-pulsed polymeric IgG-treated or Dulbecco's phosphate-buffered saline (PBS-D)-treated control monocytes, could not be attributed to the generation of suppressor mechanisms (no release of soluble suppressor factors, no induction of suppressive monocytes). The release of interleukin-1 by polymeric IgG-treated monocytes and PBS-D-treated monocytes was comparable and polymeric IgG did not down modulate major histocompatibility complex (MHC) class II molecules already expressed in the monocyte plasma membrane. Profound changes in the monocyte plasma membrane occurring subsequent to polymeric IgG treatment possibly accompanied by altered kinetics of MHC class II reexpression are likely to contribute to the observed decrease of antigen presentation.

Antigen-Presenting Cells↗
PubMed1986

Sandwich nucleic acid hybridization: a method with a universally usable labeled probe for various specific tests.

Nucleic acid hybridization is widely used for scientific applications but essentially restricted to specialized laboratories. The use of recombinant m 13 phages as hybridization probes (Hu and Messing (1980) Gene 17, 271; Messing (1983) Methods Enzymol. 101, 20) offers a considerable advantage over the commonly used recombinant plasmids as the preparation of the DNA probe is very simple and it can easily be labeled directly, e.g. with isotopes with long half-life like 125I (Commerford (1971) Biochemistry 10, 11 (1983); Gu et al. (1983) Cancer (China) 2, 129; Han and Harding (1983) Nucleic Acids Res. 11, 14) and used for hybridization. However, as the application of nucleic acid hybridization for diagnostic and epidemiological purposes becomes almost unavoidable, the logistic problems of keeping numerous individually labeled hybridization probes increase considerably and may reach prohibitory levels in less well-equipped laboratories. In a new sandwich technique, the first step involves hybridization with an unlabeled recombinant m 13 DNA carrying an insert of the desired specificity. In a second step a universally usable labeled probe directed against the m 13 part of the recombinant phage DNA is applied. This reduces considerably the problems of preparing and keeping multiple labeled probes in stock.

Bacteriophages↗
PubMed1986

Expression of the Epstein-Barr virus major membrane proteins in Chinese hamster ovary cells.

The gene of the major membrane antigen (gp250/350) of the Epstein-Barr virus (EBV) was isolated and inserted under the control of the SV40 early promoter into a eukaryotic expression vector, which allows selection for dhfr+ phenotype. Following transfection with this vector, Chinese hamster ovary cells express on their surfaces proteins immunologically similar to the major EBV membrane antigen. The transcript encoding gp250/350 is processed by partial splicing similarly but more efficiency than in B95-8 cells from which the DNA originates.

Animals↗
PubMed1986

Expression of the Epstein-Barr virus 138-kDa early protein in Escherichia coli for the use as antigen in diagnostic tests.

We have attempted to produce the 138-kDa early protein (ep 138) of Epstein-Barr virus (EBV) in Escherichia coli. This protein was found, by immunoprecipitation, to be a clinically relevant antigen, especially for the determination of the IgA-titer in patients with nasopharyngeal carcinoma (NPC). Since the expression of the entire ep 138 coding region was unsuccessful, we synthesized only the antigenic parts of this protein. Potential antigenic sites were predicted from the amino acid sequence by combining values for hydrophilicity with calculated estimates of the secondary structure. The two predicted fragments were found to be antigenic, but only one of them was stably expressed in E. coli as a non-fusion protein. This stable protein fragment was, in turn, able to stabilize the second antigenic fragment forming an autologous fusion protein, consisting exclusively of EBV-derived sequences. The resulting product reacts particularly well with IgA antibodies of NPC patients indicating its diagnostic value for NPC.

Antigens, Viral↗
PubMed1986

Characterization of two related Epstein-Barr virus-encoded membrane proteins that are differentially expressed in Burkitt lymphoma and in vitro-transformed cell lines.

Two related but differentially expressed potential membrane proteins of Epstein-Barr virus are encoded by the same reading frame in the EcoRI D het region of the viral genome. Potential antigenic sites in the amino acid sequence of these proteins were selected by computer-aided prediction of the secondary structure and two oligopeptides corresponding to regions located in different parts of the proteins were synthesized chemically. Rabbit antisera to these peptides were used for immunoprecipitation of the native viral proteins from Epstein-Barr virus-positive cell lines from various sources. Both predicted membrane proteins could be precipitated from cell lines that had been transformed in vitro with EBV or from cell lines derived from infectious mononucleosis patients. In cell lines established from Burkitt lymphoma, only the smaller polypeptide, which lacks 138 amino acids from the amino terminus, could be identified. Using the synthetic peptides as antigens in ELISA, we detected elevated antibody titers in sera from patients with infectious mononucleosis and nasopharyngeal carcinoma.

Amino Acid Sequence↗
PubMed1986

Demonstration of pseudorabies virus DNA in the mouse inner ear by an in situ nucleic acid hybridization technique in plastic embedded bony material.

This investigation is concerned with the possibility of identifying viral DNA using the in situ DNA hybridization method in methylmethacrylate-embedded material. As an experimental model we chose viral labyrinthitis produced by intranasal infection of the mouse with pseudorabies virus. Fixation and embedding methods specially adapted to this procedure and bony histology preparation technique (specimens by grinding or micromilling) made it possible to identify viral DNA directly morphologically and virologically in the inner ear. Quantitative microphotometric analyses of trans-sagittal sections of the entire skull after in situ DNA hybridization are presented and discussed here as an explicit method of investigating the path of distribution of viral DNA in the brain and the inner ear.

Animals↗
PubMed1986

The role of genetically-determined primary alterations of the target organ in the development of spontaneous autoimmune thyroiditis in obese strain (OS) chickens.

Immunologists working in the field of autoimmunity tend to concentrate all their efforts on the elucidation of possible malfunctions of the immune system, particularly pathologic changes of immune regulation. Also in the OS model various groups of investigators emphasized this approach, although it was already clear early in the history of this model that SAT has a multigenic background. The fact that this disease cannot be transferred into normal, histocompatible animals without an appropriate non-MHC linked genetic background was a strong indication that detailed studies of thyroid-associated factors may be warranted for the elucidation of the pathogenesis of this disease and perhaps also its human counterpart, Hashimoto thyroiditis. Since several reviews on the immunologic aspects in the OS model have been published in recent years we have in this communication attempted to discuss the - mostly still rudimentary - findings concerning the target organ itself, including morphological changes before the beginning of infiltration, the analysis of Tg, the altered thyroid function before onset of SAT, the results of cross-breeding studies of OS and inbred normal chickens in respect to the susceptibility of the offspring for the transfer of SAT, the possible role of a virus infection and the aberrant expression of MHC class II antigens on TEC. Cross-breeding studies revealed that most probably a single gene is responsible for the primary altered thyroid function and at least 3 genes code for the susceptibility of the OS thyroid gland to the autoimmune attack. It is not yet clear for which of the above-mentioned observations each of these genes is responsible and what is/are the initial triggering mechanism(s). Ongoing studies in our laboratory concentrate on this question, specifically the potential role of endogenous viruses in this process.

Animals↗
PubMed1986

Unique antibiotic sensitivity of archaebacterial polypeptide elongation factors.

The antibiotic sensitivity of the archaebacterial factors catalyzing the binding of aminoacyl-tRNA to ribosomes (elongation factor Tu [EF-Tu] for eubacteria and elongation factor 1 [EF1] for eucaryotes) and the translocation of peptidyl-tRNA (elongation factor G [EF-G] for eubacteria and elongation factor 2 [EF2] for eucaryotes) was investigated by using two EF-Tu and EF1 [EF-Tu(EF1)]-targeted drugs, kirromycin and pulvomycin, and the EF-G and EF2 [EF-G(EF2)]-targeted drug fusidic acid. The interaction of the inhibitors with the target factors was monitored by using polyphenylalanine-synthesizing cell-free systems. A survey of methanogenic, halophilic, and sulfur-dependent archaebacteria showed that elongation factors of organisms belonging to the methanogenic-halophilic and sulfur-dependent branches of the "third kingdom" exhibit different antibiotic sensitivity spectra. Namely, the methanobacterial-halobacterial EF-Tu(EF1)-equivalent protein was found to be sensitive to pulvomycin but insensitive to kirromycin, whereas the methanobacterial-halobacterial EF-G(EF2)-equivalent protein was found to be sensitive to fusidic acid. By contrast, sulfur-dependent thermophiles were unaffected by all three antibiotics, with two exceptions; Thermococcus celer, whose EF-Tu(EF1)-equivalent factor was blocked by pulvomycin, and Thermoproteus tenax, whose EF-G(EF2)-equivalent factor was sensitive to fusidic acid. On the whole, the results revealed a remarkable intralineage heterogeneity of elongation factors not encountered within each of the two reference (eubacterial and eucaryotic) kingdoms.

Aminoglycosides↗
PubMed1986

Detection of pseudorabies virus DNA in the inner ear of intranasally infected BALB/c mice with nucleic acid hybridization in situ.

Evidence for the pathogenicity of pseudorabies virus for the auditory and vestibular organs of experimentally infected mice is presented. We demonstrate viral genomes in cells of the peripheral sensory organs, the nerve structures, and the affected areas of the brain in single sections from an entire cranium of an adult mouse. The data were obtained by an in situ hybridization technique adapted for use with fixed, plastic-embedded materials. In contrast to conventional methods which use frozen sections, we were able to analyze cartilaginous and bony materials with high resolution.

Animals↗
PubMed1986

Strain-specific transcription and translation of the BamHI Z area of Epstein-Barr Virus.

The expression of the 1,800-base-pair BamHI Z region of Epstein-Barr virus DNA was analyzed by hybrid-selected translation with several DNA subclones and RNA from different cell lines. Furthermore, large segments of the three reading frames extending in this area were expressed as fusion proteins into Escherichia coli. The fusion proteins were partially purified and used to immunize rabbits. These sera were used to confirm our mapping assignments and to identify the respective posttranslationally modified proteins in in vivo labeling experiments. The reading frame BRLF1 (the first reading frame starting in the BamHI R fragment in leftward orientation) encoded a 93- to 96-kilodalton (kDa) protein depending on the cell line. The molecular weight of in vivo-labeled proteins was increased relative to that of in vitro-translated proteins, indicating that a posttranslational modification had occurred. The BZLF1 reading frame encoded a 35-kDa protein. It was posttranslationally cleaved from a 38-kDa precursor in induced B95-8 and induced Raji cells and from a 40-kDa precursor in induced P3HR1 cells. In Raji cells superinfected with virus derived from P3HR1 cells, the protein seemed to be expressed both from endogenous Raji genomes and from infecting genomes. The transcripts for the 93- to 96-kDa and the 35-kDa protein overlapped partially. The serum against the expressed third reading frame BZLF2 specifically precipitated a 140-kDa protein. This reading frame contains only 650 nucleotides, and therefore further coding sequences were presumably spliced to BZLF2. The latter is deleted in the Raji cell line; therefore, the observed 140kDa protein in superinfected Raji cells was expressed from infecting P3HR1 genomes.

Chromosome Mapping↗
PubMed1986

Identification of binding site for heparin and other polysulfated glycosaminoglycans on human thrombocytes.

Heparin and other polysulfated glycosaminoglycans (GAGPS) can evoke an immune response when complexed to the surface of platelets in vivo. We have previously reported on the detection and characteristics of such antibodies leading to thrombocytopenia. Here we report data concerning the biochemical characterization of the heparin-/GAGPS-binding site on human thrombocytes. By means of heparin affinity chromatography, GAGPS chromatography and subsequent 'Western blotting' of specifically eluted proteins we were able to detect two proteins of apparent molecular mass of 207 and 170 kilodaltons, which could be reduced to 57 and 142 kilodaltons, respectively. The 170-kilodalton glycoprotein was stained by the carbohydrate specific PAS-reagent and by surface labeling with 3H. The second molecule binding to heparin (GAGPS)-Sepharose was detected by platelet surface labeling with 125I, protein-specific staining Coomassie brilliant blue and PAS staining. Binding studies using enzyme-labeling techniques with five monoclonal antibodies (MCA) against platelet surface proteins GPI, GPIIb/IIIa complex, GPIIIa and CRI (C3b receptor) revealed specific interaction of the 170-kilodalton heparin-binding glycoprotein with an MCA to GPI, suggesting identity or immunological cross-reactivity of these two moieties. No specific reactions were observed between the 207-kilodalton glycoprotein and any of the MCA tested. For further evaluation of the antigenicity of separated platelet proteins, an ELISA in microtiter plates was developed, and a cellular sandwich ELISA for serological detection of antibodies against whole native thrombocytes or GAGPS-derivatized proteins was set up.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗