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H Mohr

Publications and source records attributed to H Mohr.

At least 19 recordsLinked to original sources
PubMed1996

[Duplex sonographic studies on the pathogenesis of splenic hemodynamics in liver cirrhosis].

AIM OF STUDY: The haemodynamic role of the spleen in portal hypertension remains unclear. Duplex sonography was undertaken prospectively to discover the relationship of splenomegaly and splenic vein flow to type and severity of liver cirrhosis and portal vein flow, as well as to the degree of oesophageal varices. PATIENTS AND METHODS: 89 patients (54 men, 35 women; mean age 52 [26-81] years), diagnosed in the second half of 1993 as having liver cirrhosis were consecutively included in the study. In 40 patients the cirrhosis was in stage A (according to Child-Pugh classification), in 31 in stage B and in 18 in stage C. RESULTS: Portal vein flow fell significantly with increasing degree of cirrhosis (stage A: 8.29 cm/s; stage B 7.03 cm/s; stage C 5.26 cm/s; P < 0.05). Splenic vein flow differed significantly only between stages B and C (stage A: 9.22 cm/s; stage B: 9.46 cm/s; stage C: 7.87 cm/s; B vs C, P < 0.05). There was no correlation between portal vein flow, splenic vein flow, degree of splenomegaly and extent of oesophageal varices. CONCLUSION: The results may be explained by the presence of collateral circulations and by the differing pathophysiological part played by the spleen in liver cirrhosis of different aetiologies.

Adult↗
PubMed1995

Differences between natural and recombinant interleukin-2 revealed by gel electrophoresis and capillary electrophoresis.

High-performance capillary electrophoresis (HPCE) is shown to be useful for analysis of interleukin-2 (IL-2) in its native state under non-reducing conditions. The results obtained were compared with those from analysis of IL-2 by protein blotting after sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) under denaturing and reducing conditions. In addition, resolution of the different glycosylated and non-glycosylated natural IL-2 species was achieved by HPCE. The HPCE electropherogram of native IL-2 could easily generate quantitative amounts of the different naturally occurring IL-2 species. For HPCE of IL-2 run times of less than 10 min are sufficient, and only extremely small amounts of IL-2 are needed. In this report, human IL-2 expressed in bacteria has been analysed by HPCE and the existence of two recombinant IL-2 forms was demonstrated.

Electrophoresis, Capillary↗
PubMed1995

Inactivation of viruses by chemically and photochemically generated singlet molecular oxygen.

Inactivation of viruses in blood plasma can be achieved by photodynamic procedures using methylene blue (MB) or other photoactive dyes. Singlet molecular oxygen (1O2) probably contributes to the virucidal effects of photosensitization. We report the inactivation of herpes simplex virus type 1 (HSV-1) and suid herpes virus type 1 (SHV-1) by chemically generated singlet oxygen, produced by thermal decomposition of the endoperoxide of 3,3'-(1,4-naphthylidene)dipropionate (NDPO2). We demonstrate that viruses can be inactivated by 1O2 generated by chemiexcitation in a reaction in the dark, even in the presence of human plasma. Virus inactivation in phosphate-buffered saline (PBS) was enhanced when water was replaced by deuterium oxide (D2O) and diminished when human plasma or quenchers (imidazole or histidine) were added. The singlet oxygen quenching activities of plasma, imidazole and histidine correlated with their inhibitory effects on virus inactivation. The production of 1O2 was assessed by an indicator reaction: the bleaching of p-nitrosodimethylaniline (RNO) with imidazole as 1O2 acceptor. Virus inactivation and singlet oxygen generation of NDPO2 were compared with those of MB/light-mediated photosensitization. Based on similar amounts of 1O2 generated by either procedure, virus inactivation by MB/light was more effective. Virus inactivation by MB/light was not affected by type I quenchers (e.g. mannitol), but was inhibited by human plasma or singlet oxygen quenchers. Furthermore, in D2O-based PBS, virus inactivation was more effective than that in H2O. These observations confirm that singlet oxygen is involved in virus inactivation by MB/light. Taken together, the results demonstrate that singlet oxygen produced by either procedure is virucidal. The enhanced effect of the photochemical procedure suggests that, in addition to type II, type I reactions and/or the binding affinity of the dye for the virus contribute to virus killing by MB/light.

Animals↗
PubMed1995

The role of autoimmunity in hepatitis C infection.

Viral infections are considered a possible trigger of autoimmune diseases. In autoimmune liver diseases the hepatotropic viruses, especially hepatitis C virus (HCV), have received particular attention as possible etiological agents. The present study was undertaken to investigate the relation between hepatitis virus infections and autoimmune liver diseases. We found a very low incidence of HCV infection in patients with autoimmune liver diseases. Only 5% (n = 7) of patients with AIH types I and III had antibodies against HCV antigens, but only two of these seven were HCV-RNA positive. Similar results were obtained in patients with PBC and PSC. Furthermore, the coexistence of LKM autoantibodies with chronic HC is a rare event and less common than low-titer ANA and SMA in viral liver diseases. In conclusion, a link between hepatitis viruses B or C and AI-liver diseases is very unlikely. Autoantibodies in viral liver diseases appear to be an expression of a generalized immune activation by cytokines, as observed during interferon treatment in viral liver diseases.

Autoantibodies↗
PubMed1995

Relation between autoimmune liver diseases and viral hepatitis: clinical and serological characteristics in 859 patients.

An etiopathological link between hepatitis virus infection and autoimmune liver disease, in particular autoimmune hepatitis has been suggested. In some patients features of both viral and autoimmune disease are present. We have studied 352 patients with autoimmune liver disease and 507 patients with viral hepatitis for diagnostic characteristics as well as for evidence of an etiological connection. 38 of the 201 patients with hepatitis C (19%) and 42 of the 306 patients with hepatitis B (14%) had significant titres of autoantibodies (ANA, SMA or LKM). SLA autoantibodies were found exclusively in patients with autoimmune liver disease. LKM auto-antibody was found in only one of the 201 HCV patients. Evidence of past or present hepatitis B virus and past hepatitis A virus infection was most common in the hepatitis C virus patients and least common in autoimmune hepatitis. 28 of the 352 patients with autoimmune liver diseases tested positive in the second generation anti-HCV ELISA, but only five patients (two with autoimmune hepatitis, one with primary sclerosing cholangitis and two with primary biliary cirrhosis) were positive in confirmatory anti-HCV assays, and only in these could HCV-RNA be isolated. Autoimmune hepatitis patients had significantly higher transaminase, GLDH and IgG levels. HLA-B8, HLA-DR3 and HLA-DR4 were significantly more common in autoimmune hepatitis. Distinction between autoimmune liver disease and viral hepatitis C could be made reliably on clinical and laboratory grounds. Our data show that a link between hepatitis A, B, or C virus infection and autoimmune liver diseases is highly unlikely.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Rapid inactivation of HIV-1 in single donor preparations of human fresh frozen plasma by methylene blue/light treatment.

Human fresh frozen plasma (FFP) was spiked with highly titered HIV-1 and illuminated with visible light in the presence of 1 microM of the photoactive dye methylene blue (MB). As shown by titration on MT-4 cells, the infectivity of the virus containing plasma was rapidly lost during illumination: after 5 min the infective titer was reduced by 4.3 and after 10 min by at least 6.32 log10, i.e. it was below the detection limit of the assay applied. Methylene blue without illumination and illumination alone had only a marginal effect on HIV-1 infectivity. Thus our data indicate that the MB/light treatment of FFP is an effective method to eliminate the risk of HIV-1 infection through use of the product. This is especially important for those cases in which the plasma is collected during the 'window period' between infection of the donor and the subsequent seroconversion.

Blood↗
PubMed1994

Gene expression of nitrite reductase in Scots pine (Pinus sylvestris L.) as affected by light and nitrate.

A partial cDNA clone (PSnir) encoding the C-terminal region of nitrite reductase was isolated from a lambda gt11 library of the gymnosperm Pimus sylvestris (L.). Nucleotide sequence analysis showed that PSnir contains a reading frame encoding 105 amino acid residues. The amino acid sequence revealed a homology to NiR of 63-68% to dicotyledoneous and of 57-59% to monocotyledoneous species. The protein region implicated to be involved in binding of the prosthetic group is highly conserved between the NiR of the gymnosperm and of angiosperms. In all organs (cotyledonary whorls, hypocotyls, roots) the pattern of NiR gene expression in response to nitrate and light is the same at the level of transcript accumulation and at the enzyme level. This suggests that regulation of NiR gene expression in the Scots pine seedling is predominantly at the level of transcript accumulation. The highest NiR appearance was observed in roots and hypocotyls. In the cotyledonary whorls only small amounts of NiR were found. In roots and hypocotyls the accumulation of NiR mRNA and the appearance of NiR protein is mainly controlled by nitrate, whereas the regulation of NiR gene expression in the whorls is strongly affected by light and the inducive effect of nitrate is only weak.

Amino Acid Sequence↗
PubMed1994

Coaction of blue light and light absorbed by phytochrome in control of glutamine synthetase gene expression in Scots pine (Pinus sylvestris L.) seedlings.

The level of plastidic glutamine synthetase (GS; EC 6.3.1.2) in the cotyledonary whorl of the Scots pine (Pinus sylvestris L.) seedling was previously reported to be regulated by light. In the present paper we report on the control by light of the GS transcript level. A full-length GS cDNA clone of Scots pine was isolated (pGS1), sequenced and employed to measure GS transcript levels. Using dichromatic light treatments it was found that the transcript level is regulated by phytochrome. The strong specific effect of blue light is to be attributed to an increase of the responsiveness to phytochrome. Since no direct correlation between the transcript level and the rate of GS protein synthesis was observed, it was concluded that GS gene expression is only coarsely regulated at the level of transcript accumulation. Synthesis of GS protein is by itself light-dependent (light-mediated fine tuning of gene expression). This control at the translational level is also exerted via phytochrome with blue light determining the responsiveness of the process toward phytochrome. If the level of the far-red absorbing form of phytochrome (Pfr) is kept very low, blue light is not capable of bringing about synthesis of GS protein.

Amino Acid Sequence↗
PubMed1993

Blood donations indeterminate in HIV-1 western blot analysed by IgM immunoblot and polymerase chain reaction.

The presence of IgM antibodies to human immunodeficiency virus 1 (HIV-1) was investigated in blood donor sera which were indeterminate in anti-HIV-1 IgG Western blot testing. In 7 of 173 instances out of approximately 1,000,000 blood donation sera with an isolated anti-p24 IgG produced an anti-gp41-45 IgM immunoblot reaction. Applying polymerase chain reaction (PCR) to 29 indeterminate samples out of approximately 125,000 blood donations it was found that 2 of them were IgM-positive and also contained HIV-1-specific DNA sequences. Eleven months later 1 of these 2 donors was retested and found IgM and PCR negative.

Blood Donors↗
PubMed1993

[Optimizing parameters in photodynamic virus inactivation of fresh frozen plasma].

Fresh plasma from single-blood donations is virus-inactivated by illuminating the plasma units in their respective plastic bags with visible light for 1 h in the presence of 1 microM of the photoactive dye methylene blue. For "soft" viruses, e.g. the togavirus Semliki Forest, 0.3 microM are sufficient to achieve complete inactivation within 5-10 min. The infectious titer is reduced by 5-6 log 10 steps. To achieve the same degree of reduction in infectivity for more resistant viruses, e.g. vesicular stomatitis virus or SV 40, the virus-containing plasma at a dye concentration of 1 microM has to be light-treated for 30-45 min. More time is required at lower dye concentrations. These findings determined the conditions chosen for photodynamic virus inactivation of fresh plasma from single-blood donations.

Blood Banks↗
PubMed1993

Photo-inactivation of viruses in therapeutical plasma.

Photodynamic virus inactivation of human fresh plasma is achieved by illuminating single units of plasma in their plastic containers with light from fluorescent tubes in the presence of the phenothiazine dye methylene blue. The effective dye concentration is 1 microM, i.e. approx. 300 micrograms per litre of plasma. Under the conditions used, all enveloped viruses tested so far have been sensitive to photodynamic treatment, although some had to be illuminated for a longer time than others. For example, under production conditions the infectivity of SFV-containing plasma was reduced by more than 7 log10 within five minutes, whereas 30 minutes were required to reduce the infectivity of plasma containing VSV by c. 5 log10. Among the non-enveloped viruses tested some were sensitive to photodynamic treatment (e.g. SV40 and calicivirus) and some were not (e.g. encephalomyocarditis and polioviruses). Using the optimized procedure, plasma proteins remain largely unaffected. Photodynamically treated fresh frozen plasma (FFP) has been routinely produced and distributed since February 1992. Requested reporting of adverse drug reactions indicates that the virus inactivated product is a well tolerated as conventional FFP.

Blood↗
PubMed1993

[Methylene blue/light treatment of virus inactivated human plasma: production and clinical experience].

A photodynamic procedure to inactivate viruses in fresh plasma for therapeutical use is carried out by illuminating single units of plasma with visible light in the presence of the phenothiazine dye methylene blue. The blood bag systems of all common suppliers can be used for this purpose. Photodynamic treatment only moderately influences the activities of plasma proteins. One of the most sensitive parameters is the thrombin time which is prolonged, dependent on dye concentration and illumination time. Under the chosen conditions (1 microM methylene blue, 1 h illumination time, about 50,000 lx), the increase is approximately 25%. A drug monitoring study indicated that photodynamically treated fresh plasma is as well tolerated as conventional fresh-frozen plasma. Between February and the end of July 1992 about 31,000 units of the virus-inactivated product were distributed to clinics within Lower Saxony.

Antiviral Agents↗
PubMed1992

No evidence for neoantigens in human plasma after photochemical virus inactivation.

Photodynamic virus inactivation of human fresh plasma mediated by visible light in the presence of the phenothiazine dyes methylene blue or toluidine blue was investigated to determine whether it influences functional, structural, and immunological properties of plasma proteins. The activities of the coagulation factors I, VIII, IX, X, and XI were affected to a certain degree, while those of most other plasma proteins were not. The elution profiles obtained by ion exchange chromatography of untreated and photodynamically treated plasma were almost identical. Using a number of antisera against human plasma and single plasma proteins, different immunochemical techniques revealed identical patterns for untreated and treated plasma. Thus, there was no indication that the photodynamic virus inactivation procedure applied considerably influences the properties of plasma proteins.

Antigens↗
PubMed1992

Virus inactivated single-donor fresh plasma preparations.

Photodynamic virus inactivation of single units of human fresh plasma in their plastic containers can be achieved by illuminating the plasma with visible light in the presence of low concentrations of one of the phenothiazine dyes methylene blue or toluidine blue. This procedure abrogates the infectivity of numerous lipid-enveloped viruses including that of human immune deficiency virus-1. In contrast, the functional activities and immunological properties of plasma proteins are only moderately influenced. Animal studies and the first clinical data suggest that photodynamically virus inactivated fresh plasma is as well tolerated as conventional fresh frozen plasma.

Blood Banks↗
PubMed1991

The development of neutralizing antibodies in a patient receiving subcutaneous recombinant and natural interleukin-2.

Systemic administration of interleukin-2 (IL-2) in humans may induce antibodies specific to IL-2. The case is reported of a patient with metastatic rectal carcinoma who was treated with long-term subcutaneous IL-2 and a combination of subcutaneous IL-2 and interferon-alpha 2b (IFN-alpha 2b). This patient developed nonneutralizing and neutralizing anti-IL-2 antibodies recognizing both the recombinant and natural cytokine. Detectable serum levels of neutralizing antibodies were accompanied by the inhibition of immune responsiveness to systemic IL-2 in vivo.

Antibodies↗
PubMed1991

Modulation of natural and interleukin-2-induced tumour-cytolytic activities by the members of a protein family related to beta-thromboglobulin.

A preparation of three C-terminal fragments of the platelet protein beta-thromboglobulin was previously described to have immunomodulatory properties on phagocytic cells. One of the components is obviously identical to the recently described neutrophil-activating peptide 2 (NAP-2). In further investigations on this protein preparation (called factor C) we are able to show an additional influence on the tumour-cytolytic activities of mononuclear cells. Total neutralization of the factor C effect, by treating a factor C preparation with specific monoclonal antibody C24 prior to application in cell culture, proved that the effect is really restricted to factor C proteins. If factor C is given in combination with natural interleukin-2 (IL-2) a dose-dependent suppression of IL-2-mediated natural killer lymphokine-activated killer activity can be measured, which is first detectable 72 h after addition of factor C. Suppression does not occur if the both factors are added within a time interval of more than 12 h. Depletion of monocytes from mononuclear cells has no effect on factor-C-mediated cytotoxicity, demonstrating that factor C acts directly on lymphoid cells.

Amino Acid Sequence↗