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Biomedical subjects

H Wagner

Publications and source records attributed to H Wagner.

At least 415 records · Page 23Linked to original sources
PubMed1989

Role of commissural projections in the representation of bilateral auditory space in the barn owl's inferior colliculus.

The central nucleus of the barn owl's inferior colliculus (ICc) contains a representation of both the ipsilateral and contralateral auditory hemifields. The representation of ipsilateral space is found in the "core" of the ICc, a subdivision defined by the terminal field of nucleus laminaris, the avian analogue of the medial superior olivary nucleus. The representation of contralateral space is found in the lateral portion of the "shell" of the ICc. The shell surrounds the core and is defined by the terminal field of the nucleus angularis, one of the cochlear nuclei. The representation of ipsilateral space in the core of the ICc may be accounted for by the crossed projection from the nucleus laminaris because most of the nucleus laminaris is devoted to a representation of contralateral space. We present evidence to suggest that the representation of contralateral space is due to a commissural projection from the core of one side to the lateral shell of the opposite side. Injection of horseradish peroxidase (HRP) into the lateral portion of the ICc shell produced retrogradely labeled somata in the core of the opposite side. Injection of tritiated proline into the core produced anterograde label confined to the lateral shell, thus confirming the observations made with HRP. Thus, for example, the left ICc core, which contains predominantly a representation of the left hemifield, innervates the right lateral shell, endowing it with a representation of the left, or contralateral hemifield. The representation of contralateral space in the lateral shell is ultimately conveyed to the external nucleus of the inferior colliculus where it contributes the horizontal axis to a two-dimensional map of space.

Acoustic Stimulation↗
PubMed1989

[Description and assessment of a rapid new method for measuring erythrocyte sedimentation rate].

A new method for the rapid photometric determination of the erythrocyte sedimentation rate (ESR) is described and compared with the Westergren technique. The basis of this method is the development of a new physical equation valid for transport processes, in which sedimentation processes can be described by means of a linear regression analysis. After the mathematical transformation, the measured ESR data follow a linear function. The apparatus evaluated measures within a few minutes the velocity profile of the ESR over a distance of about 2 X 10(-4) meter by kinetic determination of the optical density of a short blood column filled in a small cuvette. A microprocessor calculates the linear regression and derives the one and two hour values by extrapolation. The correlation of this method with the standard Westergren technique, determined over 20 days is acceptable (R = 0.95; n = 368). The reproducibility of the same sample (n = 20) is better than that of the conventional procedure. The reproducibility determined with different instruments (n = 20) is comparable to the precision of the Westergren method. The practical value of this new time- and blood-saving, well standardized method for an efficient patient-care is discussed.

Blood Sedimentation↗
PubMed1989

Synergy between interleukin 4 and interleukin 2 conveys resistance to cyclosporin A during primary in vitro activation of murine CD8 cytotoxic T cell precursors.

Even though cyclosporin A (CsA) suppresses in vitro production of lymphokines such as interleukin 2 (IL 2) and responsiveness of cytotoxic T cell (CTL) precursors to IL 2, thereby inhibiting the in vitro generation of CTL, in vivo CsA does not affect the induction of alloreactive CTL. This paradox suggests that CsA-resistant signals are operating in vivo. Using an in vitro model system in which the requirement for antigen-presenting cells during primary activation of resting murine CD8 T cells is bypassed by immobilized anti-CD3 monoclonal antibodies, we here describe conditions in which IL 4 conveys CsA resistance to murine CD8 T cells triggered by immobilized anti-CD3 monoclonal antibodies to respond to IL 2. CsA resistance of IL 4 and IL 2-responsive CD8 T cell parallels conditions in which signals provided by IL 4 and IL 2 synergize with each other. CsA dissociates in vitro proliferative and differentiative events by suppressing the former while enhancing the latter. In addition to the known pleiotropic effects of IL 4, our results define an IL 4-dependent, CsA-resistant signal pathway which allows CTL differentiation in the absence of significant cell proliferation.

Animals↗
PubMed1989

Free flow electrophoresis as a method for the purification of enzymes from E. coli cell extract.

The application of the four techniques of free flow electrophoresis (zone electrophoresis, isotachophoresis, isoelectric focusing and field step electrophoresis) for the purification of proteins from a complex protein mixture was investigated. For this purpose alpha-amylase (EC 3.2.1.1) from Aspergillus oryzae was added and reisolated from E. coli cell extract. The chosen enzyme and the biological extract are models for many industrial separation problems. In optimized experiments purity, purification factor, yield, throughput and efficiency were calculated. The best results were obtained with field step electrophoresis in combination with zone electrophoresis. High purity (0.82 mg enzyme/mg total protein) and high throughput (111 mL sample/h) were achieved using this technique. Field step electrophoresis gave the best throughput (330 mL sample/h), but low purity (0.63 mg enzyme/mg total protein). This technique can also be used for a simple concentration of the sample. With zone electrophoresis a purity of more than 0.95 mg enzyme/mg total protein was obtained, which was the best of all techniques. However, the enzyme concentration was decreased due to dilution with buffer solution after the separation. Isotachophoresis was the most difficult technique, combined with a relatively low recovery of 31% of the enzyme activity. In a purification scheme, free flow electrophoresis is able to substitute one or even several chromatography steps with a negligible loss of biological activity.

Aspergillus oryzae↗
PubMed1989

Adoptive transfer of human peripheral blood lymphocytes (PBL) in scid mice.

Two protocols were examined for the ability to transfer a human T cell system into SCID mice. Upon intraperitoneal injection (i.p.) of human peripheral blood lymphocytes (PBL) into SCID mice the injected cells could be recovered over weeks from the peritoneal cavity, yet human T cells did not seed into secondary lymphoid organs such as the spleen, lymph nodes or bone marrow. In contrast, SCID mice grafted with human embryonal thymus tissue contained high numbers of CD4+CD8- and CD8+CD4- human T cells in their lymph nodes and spleen when they had been injected i.p. with human PBL.

Animals↗
PubMed1989

A previously unrecognized large fraction of cytotoxic lymphocyte precursors is present in CD4+ human peripheral blood T cells.

We describe a limiting dilution (LD) culture system in which cell sorter-purified CD4+ (and CD8+) peripheral blood T cells are cocultured with irradiated, anti-CD3 mab-producing OKT3 hybridoma cells. Under these conditions, one out of 2-3 CD4+ (and CD8+) T cells is induced to clonal proliferation. In striking contrast to previously described LD culture systems, every growing CD4+ cell clone displayed cytotoxic activity when tested in a lectin-facilitated 51Cr release assay against P815 target cells. This contrasts with the development of cytotoxic CD4+ T cells in alloantigen-stimulated LD cultures, where only one out of 15-20 proliferating CD4+ cells killed P815 in the presence of PHA, and one out of 300-500 proliferating CD4+ cells displayed alloantigen-specific cytotoxic activity. Furthermore, we have established antigen-specific proliferating CD4+ T cell clones which do not exert antigen-specific cytotoxicity but can be cytotoxic when crosslinked to target cells via lectin or monoclonal antibody (anti-CD3, anti-TCR). Our results show that a previously unrecognized large fraction (at least 30-50%) of all peripheral blood CD4+ T cells can give rise to cytotoxic effector cells. The mode of CD4+ T cell activation (OKT3 hybridoma versus alloantigen) thus determines whether the intrinsic cytotoxic capacity of CD4+ T cells is functionally activated or not.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Interleukin 2 production by alloantigen-stimulated CD4+ and CD8+ human T cell subsets: frequency of HLA class I or class II-reactive precursor cells and clonal specificity of activated T cells.

A recently developed limiting dilution (LD) method was used to analyze the frequency and specificity of IL2-producing cells within alloantigen-stimulated human CD4+ and CD8+ T cell subsets. Cell sorter-separated CD4+ and CD8+ responder cells were cocultured under LD conditions with HLA class I and/or class II different Epstein Barr virus (EBV)-transformed lymphoblastoid cells line (LCL) stimulator cells in the absence of additional factors. After 3 days, IL2 in cell-free culture supernatants was measured by a colorimetric assay on IL2-dependent murine CTLL cells. Under these conditions, one out of 200-500 CD4+ and one out of 300 to 1000 C8+ T cells produced IL2 when stimulated by HLA class I and class II disparate LCL. By using selected responder and stimulator cells differing only in HLA class I (A, B, C) or class II (DR) antigens, it was found that CD4+ T cells produced IL2 in response to HLA class II antigens, while CD8+ T cells produced IL2 in response to HLA class I antigens. Surprisingly, high frequencies of IL2-secreting CD4+ T cells were noted in certain HLA-DR-identical responder-stimulator combinations. To investigate whether HLA class II antigens other than DR (i.e., DQ or DP) activate CD4+ cells to IL2 secretion, we analyzed a set of HLA-A,B,C and -DR,DQ-identical responder-stimulator cells which differed only in DP antigens. In several of these instances, we measured high frequencies (f = 1/1000 to 1/2000) of HLA-DP-reactive CD4+ IL2 producers, while the frequencies in LD cultures stimulated with autologous LCL were low (f = 1/10,000 to 1/30,000). The specificity of alloantigen-activated IL2-secreting T cells was assayed by restimulation with the original or HLA-mismatched third-party LCLs. CD4+ responder cells could be efficiently and specifically restimulated to IL2 production after a resting period of 3 to 4 days, while CD8+ cells were refractory to restimulation under these conditions. Together these data demonstrate that: 1) CD4+ and CD8+ cells are stimulated to IL2 production by HLA class II and class I antigens, respectively; 2) alloantigen-activated CD4+ IL2 producers are highly specific for stimulating HLA antigens as shown by a split culture and restimulation approach; and 3) significant numbers of CD4+ IL2-producing T cells can be activated by selected HLA-DR-identical, DP-different stimulator cells.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Search for new plant constituents with potential antiphlogistic and antiallergic activity.

Structure-activity relationships obtained from in vitro screening results obviously indicate that the highest inhibition effects on cyclooxygenase and 5-lipoxygenase are found amongst the class of phenolic compounds (flavonoids, polyphenols, coumestans, phenol carboxylic acids) and arachidonic acid analogous (alkylamides, retinoids, arylheptanoids, thiosulfinates, sulfinyl disulfides). The antiinflammatory activities of some triterpenenic acids, sesquiterpene lactones, and polysaccharides may be due to their immunomodulating activities on the complement and/or T-lymphocyte populations, respectively. In the search for potential antiallergic and antiasthmatic compounds, the thiosulfinates of onion were found to be active principles of the drug. The mechanism of action of some other antiallergic plant drugs (i.e. Tylophora asthmatica, Adhatoda vasica, etc.) has not yet been clarified.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

New antihepatotoxic naphtho-pyrone glycosides from the seeds of Cassia tora.

Two new naphtho-pyrone glycosides, 9-[(beta-D-glucopyranosyl-(1----6)-O-beta-D-glucopyranosyl)oxy]-10- hydroxy-7-methoxy-3-methyl-1H-naphtho[2,3-c]pyran-1 -one (5) and 6-[(alpha-apiofuranosyl-(1----6)-O-beta-D-glucopyranosyl)oxy]- rubrofusarin (6), together with cassiaside (3) and rubrofusarin-6-beta-gentiobioside (4) were isolated from the seeds of Cassia tora L. Their structures were elucidated on the basis of chemical and spectral data. The naphtho-gamma-pyrone glycosides (3, 4, and 6) were found to have significant hepato-protective effects against galactosamine damage, which were higher than that of silybin from Silybum marianum.

Cassia↗
PubMed1989

[Biologically active compounds from the aqueous extract of Urtica dioica].

From the water extract of the roots of Urtica dioica (stinging nettle) a polysaccharide fraction was isolated which revealed activity in the carrageenan rat paw edema model and lymphocyte transformation test. Ion exchange chromatography and gel filtration of this fraction afforded 4 different polysaccharides, one of which reduced dose dependent hemolysis in the classical pathway of the complement test. The Urtica dioica lectin (UDA) was reisolated and found to stimulate the proliferation of human lymphocytes.

Animals↗
PubMed1989

New cucurbitacin glycosides from Picrorhiza kurrooa.

From the roots of Picrorhiza kurrooa Royle and Benth., seven cucurbitacin glycosides have been isolated and structurally elucidated mainly by NMR and mass spectroscopy. Four of them (4, 5, 6, 7) are new and two, the 2-O-glycoside of cucurbitacin B (25-acetoxy-2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norl anosta-5, 23-diene-3,11,22-trione) and the 2-O-glucoside of 23,24 didydrocucurbitacin B (25-acetoxy-2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norl anost-5-ene-3, 11-22-trione) were so far not reported as constituents of this plant. The four new cucurbitacins could be identified as 2-beta-glucosyloxy-3,16,20,25-tetrahydroxy-9-methyl-19-norlanos ta-5, 23-diene-22-one, 2-beta-glucosyloxy-3,16,20,25-tetrahydroxy-9-methyl-19-norlanos t-5-ene-22-one, the 2-O-glucoside of cucurbitacin Q (25-acetoxy-2-beta-glucosyloxy-3,16,20-trihydroxy-9-methyl-19-n orlanosta-5, 23-diene-11,22-dione), and the 2-O-glucoside of deacetoxycucurbitacin B (2-beta-glucosyloxy-16,20-dihydroxy-9-methyl-19-norlanosta-5 , 24-diene-3,11,22-trione).

Animals↗
PubMed1989

Studies of the mechanism of tolerance induced by short-term immunosuppression with cyclosporine in high-risk corneal allograft recipients. I. Analysis of CTL precursor frequencies.

Transplantation of unmatched allogeneic corneas into highly vascularized recipient eyes under the cover of short-term immunosuppression with cyclosporine enables permanent engraftment. The aim of this study was to further elucidate the mechanism(s) underlying this tolerant state. In eight "high-risk" cornea recipients the clone sizes of donor-specific and third-party reactive cytotoxic T cell precursors were assessed by limiting dilution analyses before and at three and six months after transplantation. Acquired allograft tolerance in these patients was not accompanied by clonal reduction of donor-specific CTL-p, whereas in the case of an irreversible rejection the donor-specific CTL pool size was significantly enlarged. This donor-specific CTL-p increase could already be seen two months before clinical manifestation. These patterns differed from that of tolerant renal transplant patients, in whom marked and donor-specific reduction of CTL-p was observed. During rejection identical patterns with increasing donor-specific CTL-p frequencies were seen in both groups of patients. We conclude that induction of tolerance by short-term CsA to unmatched cornea grafts is not caused by clonal reduction of the effector precursor cell pool.

Adult↗
PubMed1989

Cyclosporine A prevents the generation of single positive (Lyt2+ L3T4-, Lyt2- L3T4+) mature T cells, but not single positive (Lyt2+ T3-) Immature thymocytes, in newborn mice.

The influence of cyclosporine A (CsA) on T-cell maturation was investigated in newborn mice. CsA treatment during the pre- and postnatal periods resulted in a hypoplasia of peripheral lymphatic organs, and absence of mature T3+ T cells in lymph nodes and spleens; no functional T-cell reactivity was observed. In thymuses of CsA-treated mice, no T3+ single positive Lyt2+ or T3+L3T4+ thymocytes could be found, but double positive (DP) cells were readily detected. A thymocyte subset with the phenotype Lyt2+L3T4-T3- was still discernible; this population was non-functional in vitro. The data show that the maturation of single positive (SP) T cells is critically influenced by CsA; under the conditions used here we found no evidence that 'leaky' autoreactive SP T cells develop in CsA-treated newborn mice.

Animals↗
PubMed1989

Design of a load cell for the Wagner distractor.

A leg length inequality can be treated by using a Wagner distractor. With this apparatus, it is possible to extend the upper or lower leg slowly. By analysing the measurements of the axial force acting on the femur or tibia the treatment can be optimized and soft tissue damage prevented. To measure the axial force, a load cell has been designed and constructed. This load cell is built into a Wagner distractor and connected with a specially designed measuring amplifier. The load cell and amplifier do not interfere with the lengthening procedure. They are safe for the patient and have an acceptable error of 7 per cent. So far, some test measurements were performed on two patients in the Rummelsberg Hospital in West Germany. The load cell proved to function in a clinical situation.

Adolescent↗
PubMed1989

Cyclosporine A prevents the generation of single positive mature T cells in newborn mice.

The effect of Cyclosporin A (CsA) during T cell development was investigated in newborn mice. CsA treatment completely blocked the generation of peripheral single positive (SP) mature T cells: the lymphatic tissues were hypoplastic. However, double negative (DN) T3 expressing lymphocytes were still detectable. Thymuses from CsA-treated mice lacked the SP L3T4(CD4)+ subset, DN and double positive (DP) thymocytes were still present. We further defined a SP Lyt2(CD8)+ thymic subpopulation which lacked CD3 expression and displayed no functional activity in vitro. Thus, CsA critically interferes with the maturation of SP T lymphocytes; we found no evidence for 'leaky' autoreactive peripheral SP T cells in CsA-treated newborn mice.

Animals↗
PubMed1989

Antiasthmatic effects of onions. Prevention of platelet-activating factor induced bronchial hyperreactivity to histamine in guinea pigs by diphenylthiosulfinate.

Thiosulfinates are responsible for antiasthmatic and anti-inflammatory properties of onions. We tested the effect of diphenylthiosulfinate on platelet-activating factor (PAF)-induced bronchial hyperreactivity to histamine: According to a randomized crossover protocol, groups of 14 guinea pigs inhaled histamine, were then treated orally with either vehicle or with 10-100 mg/kg diphenylthiosulfinate, inhaled 1 microgram PAF, and thereafter the same histamine dose given prior to PAF. In the control group the histamine response increased threefold; in the treated group the histamine response decreased. The effect of 100 mg diphenylthiosulfinate lasted 12 h. Antihistamine effects were not demonstrable in this test system. We conclude that thiosulfinates inhibit PAF-induced hyperreactivity.

Allium↗