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H Wolf

Publications and source records attributed to H Wolf.

At least 361 records · Page 20Linked to original sources
PubMed1992

Development of a new dynamic method for quantitative evaluation of in vitro hemocompatibility of biomedical materials.

In this study a new dynamic method is introduced allowing the estimation of blood cell adhesion on flat test surfaces by measuring the cell loss in the bulk phase of surface contacting test blood under defined rheological conditions. This was achieved by constructing a novel test chamber permitting the contact of small amounts of blood with a large geometrical test surface. The construction consists of a spiral-shaped flow channel of 0.3 cm width, 0.02 cm height and 78 cm length covered with the biomaterials to be tested from both sides. Laminarity of blood flow in the conduit was confirmed theoretically by the calculation of an equivalent to the Reynolds number for curved systems the so-called Dean number. Furthermore, flow laminarity was proved experimentally finding that the flow rate of blood with different hematocrit values was proportional to the hydrostatic pressure applied. The applicability of the novel 'spiral method' for the estimation of hemocompatibility was demonstrated by evaluation of platelet adhesion onto different polymers in comparison to siliconized and fibrinogen coated glass as reference surfaces. Additionally, it was possible under distinct conditions to determine the adhesion of leucocytes and the detachment of platelet aggregates. Therefore, it was concluded that the spiral method can be used for the assessment of the hemocompatibility of flat biomedical polymers. As main advantages of the new method can be considered the high time efficiency and accuracy without labelling or optical detection of adherent cells.

Acrylic Resins↗
PubMed1992

Fetal and neonatal cerebral circulation: a pulsed Doppler study.

We studied the relation between the fetal cerebral circulation and changes in the cerebral circulation directly after birth. With a combined real time ultrasound/pulsed Doppler technique flow velocity waveforms from the fetal umbilical- and carotid-circulation were monitored. Pulsatility Index (PI) was computed and the ratio between Umbilical PI and Carotid PI was calculated. Flow velocity waveforms of the cerebral circulation before birth were related to anterior cerebral artery flow velocity waveforms recorded immediately after birth. The study shows that changes in flow velocity waveforms associated with the intra uterine brain-sparing effect are related to poor obstetrical outcome. Furthermore is shown that the brain-sparing effect in the fetal period is associated with higher PI values in the cerebrovascular circulation in the neonatal period. It is suggested that changes in these PI values, representing changes in cerebrovascular resistance, might be indicative of cerebral ischemia in the neonate.

Carotid Arteries↗
PubMed1992

Recombinant antigens in viral diagnosis.

DNA fragments coding for a variety of different viral antigens have been cloned and expressed in Escherichia coli. Selected purified recombinant antigens were used for detection of specific antibodies by means of the ELISA technique. This approach has been used for the development of four different ELISAs for the detection of HIV- and EBV-specific antibodies.

Antibodies, Viral↗
PubMed1991

Expression of proteins encoded by Epstein-Barr virus trans-activator genes depends on the differentiation of epithelial cells in oral hairy leukoplakia.

The Epstein-Barr virus (EBV) immediate early gene product BZLF1 was localized by indirect immunofluorescence to the cytoplasm of the basal epithelial layer at the lateral border and dorsum of tongue in human immunodeficiency virus-infected and -seronegative patients. Two biopsies of oral hairy leukoplakia revealed a sporadic cytoplasmic staining of the BHRF1 and BRLF1 gene products in the basal epithelial layer. The widespread presence of BZLF1 in the basal epithelial layer indicated that this cell layer contained EBV DNA and was probably directly infected by EBV. Nuclear localization of the immediate early and early gene products BZLF1, BHRF1, BRLF1, and BMLF1 was limited to oral hairy leukoplakia in human immunodeficiency virus-seropositive patients and revealed a codistribution with the virus capsid antigen. Our results indicate that the epithelium of the tongue is a potential reservoir for EBV and that in heavily immunocompromised patients EBV may move from the cytoplasm to the nucleus with increasing differentiation and be coactivated there during the terminal differentiation of epithelial cells at the lateral border and dorsum of tongue.

Cell Differentiation↗
PubMed1991

Expression of class I major histocompatibility complex antigens in Epstein-Barr virus-carrying lymphoblastoid cell lines and Burkitt lymphoma cells.

Epstein-Barr virus (EBV) carrying lymphoblastoid cell lines (LCLs) and EBV-positive Burkitt lymphoma (BL) cells were compared for their expression of class I antigens of the major histocompatibility complex. Five common BL lines, LCLs, pokeweed mitogen-stimulated blasts and resting B-cells from healthy donors, and eight pairs of BL cells and LCLs, each pair originating from one patient, were tested. Quantitative analysis was performed using a radioimmunoassay; qualitative aspects were studied by one- and two-dimensional gel electrophoresis. In general, LCLs expressed significantly higher amounts of class I antigens than BL cells, the latter showing class I densities similar to or lower than peripheral resting B-cells. From analysis of the expression of class I-specific RNA, there is some evidence that class I antigen expression is regulated on the transcriptional level. In two BL cells studied, class I expression could be enhanced by gamma-interferon, whereas the corresponding LCLs seemed to be refractory to this treatment. One- and two-dimensional gel electrophoresis showed that in some BL lines, in addition to the generally lower class I expression, distinct class I specificities were down-regulated. None of these alterations in class I expression was EBV specific; however, they may well play a role in the recognition of BL cells and LCLs by cellular immune mechanisms. Thus, down-regulation of class I antigens may contribute to the resistance of BL cells to cytotoxic T-lymphocytes, whereas their enhanced expression may improve the recognition of EBV-infected LCLs.

Blotting, Northern↗
PubMed1991

Prenatal diagnostic procedure for leukocyte adhesion deficiency.

Leukocyte adhesion deficiency (LAD) is a rare autosomal recessive disorder which leads to recurrent severe infections due to impaired leukocyte functions. The disorder is caused by an absence or deficiency of leukocyte cell adhesion molecules (LeuCAMs) on the leukocyte membranes. The diagnosis is established with monoclonal antibodies against the LeuCAMs. We have carried out a prenatal diagnostic procedure by means of cordocentesis in a mother who was 20 weeks pregnant and had previously given birth to a child with LAD. This previous child had the severe form of LAD with undetectable mRNA for the beta chain, the common subunit of the LeuCAMs. We found that the fetal granulocytes expressed the LeuCAMs normally. At birth, the baby was physically normal and showed no signs of impaired leukocyte functions.

Antibodies, Monoclonal↗
PubMed1991

Is placental mosaicism associated with poor perinatal outcome?

In 37 pregnancies with placental mosaicism detected at first-trimester chorionic villus sampling in 2000 pregnancies, two pregnancies (5.4 per cent) ended in a spontaneous abortion at 15 weeks (46,XX 47,XX, + 16) and in a perinatal loss in a term pregnancy (46,XY/47,XY, + 10), respectively. The outcome of the other 35 pregnancies was normal. The total pregnancy loss rate before 28 weeks in the first 1000 pregnancies was previously reported to be 3.6 per cent.

Abortion, Spontaneous↗
PubMed1991

Patterns of antibody reactivity to selected human immunodeficiency virus type 1 (HIV-1) gp160 epitopes infected individuals grouped according to CD4+ cell levels.

We examined sera from 160 HIV-infected individuals for antibodies reactive to HIV-1 gp160 epitopes defined by seven synthetic peptides. Seropositive individuals were placed into three groups based upon levels of circulating CD4+ cells. These groups consisted of individuals with (1) more than 400 CD4+ cells, (2) 200-400 CD4+ cells, and (3) fewer than 200 CD4+ cells/mm3. The percentage of sera containing antibodies reactive with two immunodominant gp160 epitopes (a.a. 304-321 and 600-611) was unchanged between groups, regardless of CD4 cell numbers. The percentage of sera containing antibodies reactive with weakly immunogenic gp160 epitopes, such as those defined by peptides 425-448 and 846-860, declined in the groups as CD4 values decreased. Our results suggest that the patterns of antibody reactivity to gp160 epitopes change as CD4 levels decline. A narrowing of the humoral immune response to epitopes on the envelope of HIV-1 appears to occur with disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Cellular immunodeficiency in protein-losing enteropathy. Predominant reduction of CD3+ and CD4+ lymphocytes.

Cellular immunological abnormalities were studied in a patient with protein-losing enteropathy associated with constrictive pericarditis. Analysis of lymphocyte subpopulations in peripheral blood showed lymphopenia with a decrease of CD3+ and CD4+ T cells, whereas CD8+ lymphocytes, B cells and NK cells were within the normal range. Fecal loss of lymphocytes as a cause of lymphopenia was evidenced by a marked excretion of 111-indium-labeled peripheral blood mononuclear cells via stool. Proliferative responses against several mitogens were severely reduced as was in vitro IgG production. Delayed-type hypersensitivity reaction against a variety of antigens was absent. Vaccination with tick-borne encephalitis virus, used for primary immunization, and with the recall antigen tetanus toxoid resulted in a blunted antibody response. After pericardectomy, the severity of enteric protein loss declined, serum immunoglobulin levels returned to the normal range, and total lymphocytes and CD3+ and CD4+ counts increased but remained low even 12 months after surgery. Fecal loss of lymphocytes was found to be reduced after pericardectomy, but was higher than that seen in a disease control patient with active inflammatory bowel disease. In vitro immunoglobulin production returned to normal, DTH could be demonstrated against purified protein derivative and proteus antigen, but mitogen-driven blastogenic response of lymphocytes remained low. Revaccination with tick-borne encephalitis and tetanus toxoid antigens seven months after surgery resulted in a dramatic increase of serum levels of antibodies against both antigens, comparable to that seen in healthy control individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The BI'LF4 trans-activator of Epstein-Barr virus is modulated by type and differentiation of the host cell.

We have analyzed the activity and regulated expression of a new Epstein-Barr virus (EBV) trans-activator (I'ta) encoded by left reading frame 4 (BI'LF4) of the BamHI I'fragment. The gene was detected in all genomes of established EBV strains and individual isolates, with the exception of B95-8, where the type-specific deletion of this open reading frame is tolerated in vitro. Specific trans-activation of two EBV promoters (early MS and I'ta promoter) could be shown in cotransfection assays. The I'ta product affected autoactivation but had no influence on heterologous target promoters. The I'ta promoter segment was shown to be costimulated in the process of host cell differentiation in the absence of other EBV gene products. Expression of the reading frame in bacteria identified a 48-kDa protein as a stable gene product. I'ta-specific antibodies were detected in sera from EBV-positive persons (nasopharyngeal carcinoma). When expressed with suitable eucaryotic vectors, a nuclear protein could be immunostained in transfected cells. Our experiments suggest a cell type-specific requirement for I'ta in the lytic cycle of EBV at a determined differentiation stage of the host cell.

Animals↗
PubMed1991

Frequency and mechanism of Lewis antigen expression in human urinary bladder and colon carcinoma patients.

Changes in the expression of Lewis antigens have been associated with cancer diseases, and recent results have pointed at a possible increased risk of cancer development among Lewis negative patients. The frequency of the erythrocyte Lewis phenotypes Le(a- b+), Le(a+ b-) and Le(a- b-) was analysed in patients suffering from urinary bladder cancer (82), colon cancer (21), and benign urological diseases (45). An increased frequency of Lewis negative individuals was found among colon cancer patients (P less than 0.004) and bladder cancer patients (P = 0.05). The Lewis negative phenotype was shown to be associated with unfavourable disease parameters: invasion (P less than 0.02) and high grade of atypia (P less than 0.01) in bladder cancer patients, and high Dukes stage (P less than 0.05) in colon cancer patients. alpha 1-4fucosyltransferase activity (Lewis transferase) was shown to be present in saliva from four out of eight erythrocyte Lewis negative cancer patients, indicating that some patients with advanced cancer disease may have converted from a Lewis positive to a Lewis negative phenotype.

ABO Blood-Group System↗
PubMed1991

Lewis antigen expression in benign and malignant tissues from RBC Le(a-b-) cancer patients.

Eight red blood cell (RBC) Le(a-b-) individuals were selected from a series of patients with bladder or colon cancer. Defined by the presence or absence of alpha 1-4-L-fucosyltransferase activity in saliva, four of these patients were characterized as non-genuine Lewis negative [RBC Le(a-b-) with alpha 1-4-L-fucosyltransferase activity in saliva], and four as genuine Lewis negative [RBC Le(a-b-) with no alpha 1-4-L-fucosyltransferase activity in saliva]. Stainings of paraffin embedded formalin fixed tissue sections for Lea and Leb antigens were performed by means of an indirect immunohistochemical method on all malignant and benign tissue previously removed from these eight patients. Leb antigens were always expressed independently of both the Lewis and the secretor status of the individual. Lea antigens, on the other hand, showed a different staining pattern. Although primarily expressed in non-genuine Le(a-b-) individuals, Lea antigens were expressed in genuine Le(a-b-) individuals as well--to a limited extent, but still detectable. Thus, these findings seem to show that the Lewis antigen expression is tissue dependent, and it is not possible to predict tissue Lewis antigen expression by merely examining erythrocytes or saliva.

ABO Blood-Group System↗
PubMed1991

Antisperm antibodies on epididymal spermatozoa.

Still under debate is the location in the genital tract where antisperm antibodies transuded from serum and locally produced antibodies, respectively, become attached to the surface of the spermatozoa. The mixed antiglobulin reaction (MAR) for immunoglobulin (Ig) G, IgA, and locally produced secretory IgA (sIgA) could be carried out on motile spermatozoa from epididymis from 13 of 34 men undergoing vasovasostomy. Four months and one year after the operation the MAR was repeated on a fresh semen sample from all patients. It was found that transuded as well as locally produced antisperm antibodies were bound to spermatozoa at the epididymal level of the genital tract. The follow-up results on semen were almost identical to the results obtained with epididymal spermatozoa.

Adult↗
PubMed1991

New oligopeptide immunoglobulin G test for human parvovirus B19 antibodies.

A new, highly sensitive and specific enzyme immunoassay using oligopeptides as antigen (enzyme-linked immunosorbent assay [ELISA] B19-OP) for detecting parvovirus B19-specific immunoglobulin G (IgG) was established. As antigens, B19-specific oligopeptides of 24 and 30 kDa derived from a 196-kDa fusion protein of beta-galactosidase and viral capsid protein (VPI) of B19 after CNBr cleavage and separation by high-pressure liquid chromatography were used. Of 139 serum specimens tested in parallel for anti-B19 IgG by standard ELISA using B19 particles as antigen and by ELISA B19-OP, 73 (52.5%) were positive and 63 (45.3%) were negative in both tests, and 3 (2.2%) were negative by standard ELISA but positive by ELISA B19-OP and by immunoblot. By using ELISA B19-OP, it was possible to detect anti-B19 IgG in an asymptomatic blood donor 4 weeks after acute infection, and anti-B19 IgG titers of 10(-5) could be measured in convalescent-phase sera.

Antibodies, Viral↗
PubMed1991

Immunohistochemical evidence of estrogen and progesterone receptors in the female lower urinary tract and comparison with the vagina.

Tissue biopsies from the lower urinary tract and the vagina were obtained from 51 and 45 women, respectively, during incontinence surgery or other gynecological operation procedures in order to calculate hormone receptor content. We compared the results between premenopausal, postmenopausal patients with and those without hormonal treatment. Utilizing the enzyme immunohistochemical assay we were able to demonstrate nuclear estrogen and progesterone receptors in the smooth muscle of the trigone and the posterior part of the bladder neck. But only in about 50% of the patients receptor proteins were detected in the frozen thin sections of these tissues. Biopsies from the anterior part of the bladder neck and the bladder vault were never receptor positive. In the vagina the rate of receptor-positive tissues was about 80%; in comparison, a smaller number of patients had receptor-positive cells in the bladder. From 29 patients we obtained specimens from the trigone and the vagina as well. The correlation of receptor-positive and -negative tissues of both organs was only 66%. Thus tissue biopsies obtained from the vagina only are not sufficient to discuss the probability of hormonal influence of the lower urinary tract.

Biopsy↗
PubMed1991

Helper-inducer and suppressor-inducer lymphocyte subsets in alcoholic cirrhosis.

Peripheral blood lymphocytes from patients with alcoholic cirrhosis, alcohol-induced fatty liver, and healthy controls were analyzed for helper-inducer (CD4+CD29w+) and suppressor-inducer (CD4+CD45R+) T lymphocytes. In confirmation of earlier reports, patients with alcoholic cirrhosis were found to have a significantly reduced absolute number of peripheral lymphocytes (p = 0.03), an elevated relative percentage of CD3+ cells (median, 76% versus 68%; p = 0.0004) and CD4+ T cells (median, 56% versus 51%; p = 0.0011), and a reduced percentage of CD8+ T lymphocytes (median, 11% versus 20%; p = 0.0007) as compared with the control group. No difference in lymphocyte subsets was observed between controls and patients with alcohol-induced fatty liver. Within the CD4+ T-cell population a change in the relative proportion of two complementary lymphocyte subsets (CD4+CD29+ helper-inducer and CD4+CD45R+ suppressor-inducer T cells) was observed in patients with alcoholic cirrhosis: a higher percentage of CD4+CD29w+ helper-inducer T cells were circulating in their peripheral blood than in healthy controls (median, 33% versus 28%; p = 0.0036), whereas the CD4+CD45R+ suppressor-inducer T-cell subset did not differ (median, 21% versus 21%) between the two groups. Owing to the reduction of lymphocyte counts in cirrhotic patients the absolute number of CD4+CD29w+ cells was not different from that of control individuals; however, CD4+CD45R+ T cells in peripheral blood (p = 0.0063) were absolutely reduced. More CD4+ cells were simultaneously CD29w+ in cirrhotic patients (61%) than in controls (52%), whereas a lower percentage of CD4+ lymphocytes was also CD45R+ in these patients (33%) as compared with controls (40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Subcellular distribution and life cycle of Epstein-Barr virus in keratinocytes of oral hairy leukoplakia.

The authors investigated the life cycle of Epstein-Barr virus (EBV) in keratinocytes of oral hairy leukoplakia by combining immunohistochemistry. DNA in situ hybridization, and lectin histochemistry with electron microscopy. Diffuse-staining components of the EBV early antigen complex (EA-D), EBV 150-kd capsid antigen (VCA), EBV membrane antigen (gp350/220), and double-stranded DNA were labeled with monoclonal antibodies. An EBV-DNA probe was used to locate EBV DNA. Wheat-germ agglutinin (WGA) was employed to distinguish Golgi-associated compartments. The authors found EBV proteins and EBV DNA only in keratinocytes with apparent viral assembly. In situ hybridization showed EBV DNA in free corelike material and in electron-dense cores of mature nucleocapsids. Monoclonal antibodies to nonspecific double-stranded DNA attached to the same structures and to marginated chromatin. Components of EA-D were dispersed throughout the nuclei but accumulated near condensed chromatin and in 'punched-out' regions of the chromatin. Epstein-Barr virus 150-kd capsid antigen was found only in the nuclei, where it appeared preferentially on mature nucleocapsids. As yet unexplained arrays of intranuclear particles that remained unlabeled with all EBV-specific probes reacted intensely with an antiserum against common papillomavirus antigen. Gp350/220 was detectable in various cellular membrane compartments and was highly concentrated on EBV envelopes in peripheral Golgi-associated secretory vesicles. It was less abundant on the extracellular EBV, indicating that viral membrane antigen partly dissociates from the mature virus. Combined lectin-binding histochemistry and electron microscopy demonstrated for the first time that EBV is processed in the Golgi apparatus, which eventually releases the virus by fusion with the plasma membrane. These results provide insight into the biologic events that occur during complete EBV replication in vivo.

Adult↗