PubMed Health⌕ Search

Biomedical subjects

I Wolf

Publications and source records attributed to I Wolf.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Lipid, apoprotein and fibrinogen levels in the blood of male patients following myocardial infarct and the effect of diet on these parameters in ischemic heart disease].

The authors have found significantly higher the levels of two not routinely examined risk factors, fibrinogen and lipoprotein (a) in 28 male patients after myocardial infarction than the corresponding data of the PROCAM-study and in the case of fibrinogen than in 23 healthy blood donors. A positive correlation was observed between the LDL-cholesterol and total cholesterol, the LDL-cholesterol and the main apoprotein of LDL, the Apo B level, and between the HDL-cholesterol and the main apoprotein of HDL, the Apo AI. During a 3 week long treatment in the Cardiac Rehabilitation Department the effect of low cholesterol, high unsaturated fatty acid content diet on the lipid, apolipoprotein and fibrinogen levels of male patients suffering from coronary heart disease with cholesterol level higher than 5.2 mmol/l was studied. Significantly decreased the total cholesterol (from 6.21 +/- 0.96 mmol/l to 5.87 +/- 0.98 mmol/l, -5.5%), the LDL-cholesterol (from 3.87 +/- 1.02 mmol/l to 3.61 +/- 0.96 mmol/l, -6.7%), the HDL-cholesterol (from 1.16 +/- 0.39 mmol/l to 1.04 +/- 0.28 mmol/l, -10.3%), the main apoprotein of HDL, the Apo AI (from 1.47 +/- 0.23 g/l to 1.33 +/- 0.29 g/l, -9.5%) and the main apoprotein of LDL, the Apo B level (from 1.59 +/- 0.43 g/l to 1.46 +/- 0.50 g/l, -8.1%). The change of fibrinogen lipoprotein (a) level was not significant. According to the earlier observation of the authors and the data of the literature, the effect of low cholesterol diet on the change of HDL cholesterol was not favourable. The investigation of apolipoprotein levels failed to get closer to the understanding of its mechanism.

Apolipoproteins↗
PubMed1996

Identification of CYP4A11 as the major lauric acid omega-hydroxylase in human liver microsomes.

Human liver microsomes are capable of oxidizing lauric acid (laurate), a model medium-chain fatty acid, at both the omega- and omega-1 positions to form 12- and 11-hydroxylaurate, respectively. These laurate hydroxylation reactions are apparently catalyzed by distinct P450 enzymes. While the P450 responsible for microsomal laurate omega-1 hydroxylation in human liver has been identified as CYP2E1, the enzyme catalyzing omega-hydroxylation remains poorly defined. To that end, we employed conventional purification and immunochemical techniques to characterize the major hepatic laurate omega-hydroxylase in humans. Western blotting with rat CYP4A1 antibodies was used to monitor a cross-reactive P450 protein (M(r) = 52 kDa) during its isolation from human liver microsomes. The purified enzyme (7.4 nmol P450/mg protein) had an NH2-terminal amino acid sequence identical to that predicted from the human CYP4A11 cDNA over the first 20 residues found. Upon reconstitution with P450 reductase and cytochrome b5, CYP4A11 proved to be a potent laurate omega-hydroxylase, exhibiting a turnover rate of 45.7 nmol 12-hydroxylaurate formed/min/nmol P450 (12-fold greater than intact microsomes), while catalyzing the omega-1 hydroxylation reaction at much lower rates (5.4 nmol 11-hydroxylaurate formed/min/nmol P450). Analysis of the laurate omega-hydroxylation reaction in human liver microsomes revealed kinetic parameters (a lone Km of 48.9 microM with a VMAX of 3.72 nmol 12-hydroxylaurate formed/min/nmol P450) consistent with catalysis by CYP4A11. In fact, incubation of human liver microsomes with antibodies raised to CYP4A11 resulted in nearly 85% inhibition of laurate omega-hydroxylase activity while omega-1 hydroxylase activity remained unaffected. Furthermore, a strong correlation (r = 0.89; P < 0.001) was found between immunochemically determined CYP4A11 content and laurate omega-hydroxylase activity in liver samples from 11 different subjects. From the foregoing, it appears that CYP4A11 is the principle laurate omega-hydroxylating enzyme expressed in human liver.

Animals↗
PubMed1996

Correlation between the concentration of serum anti-topoisomerase I autoantibodies and histological and biochemical alterations in the skin of tight skin mice.

Cutaneous hyperplasia observed in tight skin mice is due to a mutation located on chromosome 2. While homozygous mice die in utero, the heterozygotes survive. TSK syndrome is associated with the presence of autoantibodies specific for scleroderma target autoantigens. The presence of autoantibodies specific for topoisomerase I is characteristic of both human and murine disease. We have generated two distinct genotypes of mice, TSK/+ and +/+ with respect to the TSK trait by breeding TSK mice with immunodeficient mouse strains. Since the mutated gene of TSK syndrome has not yet been cloned, only histological and biochemical criteria were used for defining TSK genotype. In the F1 mice derived by mating TSK/+ mice with RAG2-/-, JH-/-, or C57BLvit/vit mice, we have found a good correlation between the amount of serum anti-topoisomerase I autoantibodies present and the histopathological and biochemical alterations that are characteristic of TSK scleroderma-like syndrome.

Animals↗
PubMed1996

Laser-supported high-temperature MAS NMR for time-resolved in situ studies of reaction steps in heterogeneous catalysis.

The temperature of zeolite samples containing various adsorbed molecules was rapidly changed (within 15 s) from room temperature to 600 K by means of a laser beam. The location of the sealed glass ampoule in a boron nitride container decreases the temperature gradient in the sample and avoids laser-induced reactions. The technique facilitates time-dependent magic-angle-spinning (MAS) NMR spectroscopy of high-temperature reactions which take place within 60 s. The H-D exchange in the hydrogen form of zeolites loaded with fully deuterated molecules, the methanol-to-gasoline conversion and the catalytic ethylbenzene disproportionation in zeolites were monitored by 13C and 1H MAS NMR by means of a "stop and go" method.

Benzene Derivatives↗
PubMed1996

Engineering of doubly antigenized immunoglobulins expressing T and B viral epitopes.

BACKGROUND: Concomitant with the advent of molecular biology techniques and the ability of immunoglobulins (Ig) to recognize proteins, carbohydrates, lipopeptides and nucleic acids, vaccinologists have taken advantage to develop a variety of prophylactic and therapeutic vaccine prototypes. Presentation of epitopes to the immune system by Ig molecules as a carrier platform offers several advantages: (i) long exposure of the antigen to antigen processing cells (APCs) by virtue of their long half life, (ii) lack of the immune response to self Ig, focusing the immune response to protective epitopes rather than irrelevant epitopes, (iii) it takes advantage of the properties of Fc fragment of various isotypes like crossing the placenta (IgG) or homing in epithelia (IgA), and (iv) targeting various antigens by virtue of their binding specificity. OBJECTIVES: This study was aimed to genetically and enzymatically engineer immunoglobulins (Igs) able to express and to deliver concomitantly immunodominant T and B viral epitopes. STUDY DESIGN: Using a genetic engineering approach we replaced the complementary determining region 3 (CDR3) and complementary determining region 2 (CDR2) of an anti-arsonate 91A3 mAb with the immunodominant HA110-120 T cell epitope and HA150-159 B cell epitope of hemagglutinin (HA) of influenza A/PR8 virus, respectively. The second doubly antigenized Ig (Ig-HA-Gal-B) was constructed on an Ig in which CDR3 was replaced with HA110-120 T cell epitope while the HA150-159 B cell epitope was enzymatically assembled through an imidic bond on the galactose (Gal) residues of the carbohydrate moiety. RESULTS AND CONCLUSIONS: Both genetically and genetically/enzymatically doubly antigenized Ig constructs (dAIg) were properly folded and they were able to activate peptide-specific T cells and to elicit anti-viral antibody response in mice. This demonstrates that the CDR loops as well as carbohydrate moieties of immunoglobulins represent permissive sites for grafting foreign epitopes without altering the structural integrity of immunoglobulins and the immunogenicity of the viral peptides.

Animals↗
PubMed1996

Immunopotency of a viral peptide assembled on the carbohydrate moieties of self immunoglobulins.

The T-cell receptor recognizes peptides bound to the major histocompatibility complex antigens. Synthetic peptides corresponding to microbial epitopes can efficiently stimulate the in vitro proliferation of T-cell hybridoma or in vivo primed T cells. However, the in vivo immune responses elicited by synthetic peptides are weak because of their short half-life and poor immunogenicity. We previously showed that a genetically engineered immunoglobulin (Ig-HA), in which the CDR3 region of VH gene was replaced with a viral peptide recognized by CD4+ T cells, was able to deliver this epitope in the correct frame to antigen-processing cells that efficiently presented the peptide to T cells. Recently, we developed an enzymatic method to assemble viral peptides on the sugar moieties of immunoglobulins without alteration of the biological functions of either molecule. The viral peptide carried by these conjugates was twenty times more efficient in activating a T-cell hybridoma than the free peptide as calculated on a molar basis. We show that such conjugates are able to prime in vivo the precursors of peptide-specific T cells and to induce proliferation of naive lymphocytes from transgenic mice expressing a peptide-specific T-cell receptor in both CD4 and CD8 T-cell subsets. Our results suggest that peptides enzymatically linked to the carbohydrate moieties of immunoglobulins, using galactose residues as peptide acceptor, can be used as a safe and efficient delivery system of protective epitopes for the prevention of infectious diseases. The enzymatic engineering of immunoglobulins may also allow the development of immunotherapeutic agents to deliver antagonist peptides to autoreactive T cells or to direct immunomodulatory agents such as interleukins or cytolytic drugs to tumor cells.

Animals↗
PubMed1995

Enzymatically mediated, glycosidic conjugation of immunoglobulins with viral epitopes.

We developed a novel enzymatic procedure to couple a peptide to the sugar moieties of immunoglobulins (Igs). The synthesis of the conjugates consists in galactose (Gal) oxidation of desialylated Igs followed by covalent attachment of the peptides with concurrent stabilization of the Schiff bases upon mild reduction. The peptide used in this study, corresponds to the amino acid residues 110-120 of hemagglutinin (HA) of PR8 A virus and is recognized by CD4 T helper cells in association with I-Ed class II major histocompatibility complex (MHC). The degree of coupling as determined by competitive inhibition of radioimmunoassay (IRIA) using FPLC purified conjugates was estimated at 11.4 peptides per IgG molecule. Coupling of HA110-120 peptide to the sugar moiety of various mouse and human Igs was confirmed by Western blot analysis developed with anti-HA110-120 antibodies. Complete detachment of the peptide from the conjugates by N-deglycosylation with PGNase F indicated a defined specificity of coupling HA peptide to the N-linked oligosaccharides of Igs. To facilitate quick release of the peptides from the conjugates into the lysosomal compartment of the antigen processing cells (APC) we introduced at the alpha amino terminus of the peptide (HAc110-120), a cleavage site for cathepsins (AAAL). The immunoglobulin-galactose-HAc110-120 conjugates (IGP) were able to activate HA110-120 specific T hybridoma cells as efficient as influenza PR8 A virus and 40-100-fold higher than the synthetic peptide itself.

Amino Acid Sequence↗
PubMed1995

[Changes in the serum lipid levels in males with ischemic heart disease under the effect of diets with various cholesterol and fat contents].

In the treatment of hyperlipoproteinaemia the diet still has a primary importance. The authors have investigated the effect of different fat, cholesterol and unsaturated/saturated fatty acid content diets on the lipid levels of men suffering from coronary heart disease during 3 weeks long hospital treatment in the Cardiac Rehabilitation Department. On a diet containing daily 65 g fat, 230 mg cholesterol with a 1.23 unsaturated/saturated fatty acid ratio the total cholesterol level of 66 patients showed a 5.8% decrease (P < 0.05). The 1% decrease of triglyceride, the 3.9% decrease of HDL-cholesterol, the 7.3% decrease of LDL-cholesterol levels were not significant. There was a positive correlation between the cholesterol level at the beginning and the degree of its change (0.7043): the patients with 6.5 mmol/l or less cholesterol level at the entry in the study showed a 2.8% decrease in serum cholesterol level, the patients with more than 6.5 mmol/l 8.1%. On a diet containing daily 105 g fat, 420 mg cholesterol, with a 0.7 unsaturated/saturated fatty acid ratio the triglyceride level showed a 20.6%, the total cholesterol 0.5% increase, at the same hand the HDL-cholesterol 1.1%, the LDL-cholesterol 5.1% decrease (only the change of triglyceride level was significant). The results emphasise the strong relation between diet and level of serum lipids.

Adult↗
PubMed1994

Solid-state nuclear magnetic resonance studies of acid sites in zeolites.

2H Magic-angle spinning nuclear magnetic resonance (MAS NMR), echo 27Al NMR, two-dimensional (2D) echo 1H MAS NMR and 1H, 27Al and 29Si MAS NMR have been applied to study the acid sites of dehydrated zeolites. The quadrupole coupling constants CQCC determined from 2H MAS NMR spectra of Si-OH-Al sites increase with the framework aluminium content of the zeolites from 208 Hz (H-ZSM-5) to 236 kHz (H-X and H-Y) due to the decreased acid strength of the bridging OH groups. The 27Al signal of the Si-OH-Al sites, which was considered "NMR-invisible" in the past, yields CQCC = 16 MHz for zeolite H-ZSM-5. The majority of non-framework aluminium species could also be observed in dealuminated and dehydrated zeolites H-ZSM-5 giving CQCC approximately 9 mHz. 2D echo 1H MAS NMR spectra yield values of 16-40 ms for the lower limits of the lifetime of hydroxyl species at room temperature. A lifetime of more than 40 ms was obtained from echo 2H MAS NMR spectra for protonated sites giving a signal at ca. 6.5 ppm in partially dealuminated and weakly rehydrated samples.

Aluminum↗
PubMed1994

Poly(ADP-ribose) polymerase activity in intact or permeabilized leukocytes from mammalian species of different longevity.

Poly(ADP-ribosyl)ation is a eukaryotic posttranslational protein modification catalyzed by poly(ADP-ribose) polymerase (PARP), a highly conserved nuclear enzyme which uses NAD as substrate. We have previously tested PARP activity in permeabilized mononuclear blood cells (MNC) from 13 mammalian species as a function of the species-specific life span. A direct and maximal stimulus of PARP activation was provided by including saturating amounts of a double-stranded oligonucleotide in the PARP-reaction buffer. The data yielded a strong positive correlation between PARP activities and the species' maximal life spans (r = 0.84; p << 0.001). Here, we investigated the formation of poly(ADP-ribose) in living MNC from two mammalian species with widely differing longevity (rat and man) by immunofluorescence detection of poly(ADP-ribose). The fraction of positive cells was recorded, following gamma-irradiation of intact MNC, as a semiquantitative estimation of poly(ADP-ribose) formation. Human samples displayed a significantly higher percentage of positivity than did those from rats, consistent with our previous results on permeabilized cells. While rat MNC had a higher NAD content than human MNC, the number of radiation-induced DNA strand breaks was not significantly different in the two species. Since poly(ADP-ribosyl)ation is apparently involved in DNA repair and the cellular recovery from DNA damage, we speculate that the higher poly(ADP-ribosyl)ation capacity of long-lived species might more efficiently help to slow down the accumulation of unrepaired DNA damage and of genetic alterations, as compared with short-lived species.

Animals↗
PubMed1994

Selective expression of the murine homologue of the G-protein-coupled receptor BLR1 in B cell differentiation, B cell neoplasia and defined areas of the cerebellum.

The Burkitt's lymphoma receptor 1 (BLR1) identified initially in Burkitt lymphoma cells has been the first member of the superfamily of G-protein-coupled receptors with a lymphocyte specific expression pattern. BLR1 shows significant relationship to receptors for chemokines (IL-8, MIP-1 beta) and neuropeptides. The gene encoding the murine homologue of the human BLR1 receptor was isolated and used to study its tissue-specific expression. Blr-1 consists of two exons encoding a protein of 374 amino acid residues which shows 83% identity with the human homologue. Screening of normal tissues of adult BALB/c mice revealed that blr-1-specific RNA is detected consistently at low levels in secondary lymphatic organs. The blr-1 gene is expressed regularly and strongly in lymphomas of mature B cells but not in plasmacytomas. SCID mice deficient in the development of mature B cells have strongly reduced levels of blr-1-specific RNA in the spleen. Cytokine mediated induction (IL4, IL6) of terminal differentiation of resting B cells towards Ig-secreting plasma cells completely downregulates expression of blr-1. RNA in situ hybridization using brain sections demonstrates blr 1 transcription in the granule and Purkinje cell layer of the cerebellum. The precise delineation of the restricted expression pattern of the blr-1 gene will support the identification of its ligand and may provide a clue to understand how BLR1 exerts its biological function within the immune and nervous system.

Amino Acid Sequence↗
PubMed1993

The G protein-coupled receptor BLR1 is involved in murine B cell differentiation and is also expressed in neuronal tissues.

The BLR1 gene, isolated initially from Burkitt's lymphoma cells (Eur. J. Immunol. 1992. 22: 2795), encodes a G protein-coupled receptor with significant relationship to receptors for chemokines (IL-8, MIP-1 alpha) and neuropeptides. The murine homologue of human BLR1 was cloned and used to investigate its expression in vivo. blr1-specific transcripts are observed in secondary lymphatic organs and to a lesser extent in brain of adult mice but not in other tissues. RNA in situ hybridization localizes blr1 transcription to primary follicles and to the mantle zone of secondary follicles. SCID mice in which mature B cell development is severely impaired exhibit a strongly reduced level of blr1-specific RNA in the spleen. The analysis of murine lymphoid tumor cell lines representing distinct stages of the B cell lineage reveals elevated expression of blr1 in B cell lymphomas but not in pre-B lymphomas or plasmacytomas. Induction of differentiation of resting B cells by cytokines or mitogens down-regulates expression of blr1. RNA in situ hybridization using brain sections of adult mice detects blr1 transcription in the granule and Purkinje cell layer of the cerebellum. Interestingly, the blr1 gene is also expressed during late embryogenesis in fetal liver and brain. In view of the remarkable expression pattern in the B cell lineage we suggest that murine BLR1 may represent a cytokine/neuropeptide receptor exerting regulatory functions on recirculating mature B lymphocytes.

Amino Acid Sequence↗
PubMed1992

Differentiation-specific expression of a novel G protein-coupled receptor from Burkitt's lymphoma.

Deregulation of the proto-oncogene MYC by specific chromosomal translocations has been shown to be essential but not sufficient for the development of Burkitt's lymphoma (BL). To identify other genes which either mark important steps in tumorigenesis or which reflect the cellular differentiation state of BL cells we have compared tumor cells to immortalized lymphoblastoid B cells by subtractive hybridization. We have identified a complementary DNA clone which encodes a novel member of the superfamily of GTP-binding (G) protein-coupled receptors, designated BLR1. The corresponding mRNA is expressed in BL and lymphatic tissues but not in other cell lines either of the B cell lineage or of other hematopoietic or non-hematopoietic origin. This exclusive expression of BLR1 and the oncogenic potential of this receptor class supports the hypothesis that BLR1 exerts a regulatory function in BL lymphomagenesis and/or B cell differentiation. Moreover, the protein sequence is highly related to that of receptors for the cytokine interleukin (IL)-8 and other neutrophil chemoattractants. We conclude that BLR1 may represent a potential candidate involved in the process of physiologic trafficking, cell-cell interactions, and activation of mature B lymphocytes in lymphatic tissues.

Amino Acid Sequence↗
PubMed1991

A novel divergently transcribed human histone H2A/H2B gene pair.

A genomic clone containing a novel closely linked human histone H2A/H2B gene pair has been isolated and sequenced along with extensive 5' and 3' flanking regions. Both genes are devoid of introns and code for core histone proteins. The nucleotide sequences are 84% and 87% homologous to the coding regions of a human genomic H2A and H2B gene, respectively. A comparison of the nucleotide-derived amino acid sequences shows that the histone H2A protein corresponds to the human H2A.1 subtype, whereas the H2B histone gene predicts an H2B protein sequence which is almost identical to the histone H2B.2 variant from human and bovine obtained by direct protein sequencing. The 3' flanking regions contain previously identified conserved sequence elements thought to be involved in transcription termination and processing of replication-dependent histone gene poly(A)- mRNAs. Primer extension analyses of the histone mRNAs encoded within this clone demonstrate that both genes are divergently transcribed from a 313 bp intergene promoter region. The spatial arrangement and orientation of two TATA-boxes, four CAAT-boxes, and one H2B-box within this region suggests that the linked genes share common promoter elements for transcriptional regulation.

Amino Acid Sequence↗
PubMed1991

[Quantitative determination of crystallin insulin in insulin-zinc suspensions as an in-process control].

A method is described for the quantitative determination of amorphous and crystalline insulin contents in insulin zinc suspensions. The different resolving rates of the modifications in acid dilutions are utilized for the test. Measurements are made by UV spectroscopy. Information is given on the application of this method for the analysis of the course of insulin crystallization and it is compared with the USP XXI method.

Crystallization↗
PubMed1991

[The crystallization behavior of chromatographically pure swine insulin].

Crystallization tests are performed with porcine insulin previously purified by single chromatography to produce Lente insulins. The following parameters are changed under the test: crystallization temperature, stirring rate, pH of crystallization, and the period from the beginning of insulin precipitation until the isoelectric point is reached. The effects of these parameters on crystallization kinetics, crystal size and crystal size distribution are being studied.

Animals↗
PubMed1990

[Production and characterization of a high affinity monoclonal antibody with digoxin and digitoxin specificity].

A monoclonal antibody with a high affinity for digoxin (KA = 5.5 x 10(10) M-1) and digitoxin KA = 5.0 x 10(10) M-1) was produced by somatic cell fusion. This antibody, designated 2A3, displayed little cross reactivity with other glucosides and no cross reactivity with endogenous steroids. It was shown that 2A3 is a suitable tool in an enzyme immunoassay for digoxin and digitoxin.

Antibodies, Monoclonal↗