HIV and IgA nephropathy.
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Glomerulonephritis, IGA↗
Biomedical subjects
Z Nagy
Publications and source records attributed to Z Nagy.
Relevance of ICAM-1 to alcoholic liver cirrhosis.
An elevated serum concentration of soluble intercellular adhesion molecule-1 (sICAM-1) was observed in patients with alcoholic liver cirrhosis in strong correlation with the current activity of the liver disease and the history of alcohol consumption. Circulating ICAM-1 levels were significantly elevated in the sera of all of 25 patients (1,400 +/- 850 ng/ml) compared with normal healthy subjects. The highest levels of sICAM-1 (2,650 +/- 560 ng/ml) were measured in those patients who suffered from superimposed acute alcoholic hepatitis (SAH). Regularly drinking cirrhotic patients without SAH also exhibited significantly higher results than those who had stopped drinking. The serum ICAM-1 concentration showed a negative correlation with the duration of abstinence. No elevated sICAM-1 was found in ascitic fluid of cirrhotic patients, which tends to discount a significant intraperitoneal production of this molecule. flow cytometric analysis revealed an increased expression of ICAM-1 molecules on peripheral blood monocytes of cirrhotic patients. Proliferating bile ducts and parenchymal cells of cirrhotic livers displayed a positive ICAM-1 immunohistochemical reaction in 3 autopsy cases. It is concluded that the elevated levels of sICAM-1 in the serum of patients with alcoholic liver diseases may provide useful diagnostic or prognostic information. However, determination of the exact source of circulating ICAM-1 in patients with alcoholic cirrhosis still demands further investigations.
Adult↗
Human brain microvessel endothelial cell culture as a model system to study vascular factors of ischemic brain.
Cerebral ischemia is caused by reduced blood supply at the microcirculatory level. In the microvessels, the main elements of the reperfusion injury following brain ischemia are the transformation of endothelial cell-surface from anticoagulant to procoagulant property, leukocyte adhesion, sludge or clot formation. There is a paucity of information on how hemostatic factors, cytokines, lipoprotein(a) (Lp(a)) and endothelin-1 (ET-1), being responsible for ischemic/reperfusion injury, interact with human brain microvessel endothelium (HBEC). There are no data furthermore about the expression of complement proteins of HBEC influenced by cytokines or fibrinolytic factors. Previously we established optimal conditions for culturing HBEC. Cell contraction induced by thrombin, plasmin, miniplasmin was recorded. The reassembly of F-actin was observed after thrombin treatment. ICAM-1 upregulation was measured following TNF-alpha, IL-1-alpha and thrombin incubation. Plasmin and miniplasmin downregulated the ICAM-1 in our cell culture system. Lp(a) modulated the thromboresistant cell-surface by reduction of t-PA and u-PA, but PAI-1 remained unchanged. Lp(a) modulated the ET-1 production by early increasing and late decreasing, in a bimodal manner. The increased secretion of ET-1 by cytokines (TNF-alpha, IL-1-alpha) was reduced in the presence of Lp(a). Gradual increase of complement proteins (factor H, factor B, C4) was induced by cytokines. Plasmin and miniplasmin augmented a rapid increase of C4. Some factors of complex relationship between regulators and modulators of endothelial adhesion molecules have been demonstrated in a human cell culture system prepared from brain microvessel endothelium. A unified concept of sequential events of ischemia/reperfusion in the brain has not yet developed.
Biological Factors↗
Results of microsurgical epididymal sperm aspiration (MESA) ans testicular sperm extraction (TESE) in azoospermic men using intracytoplasmic sperm injection (ICSI).
The rationale and results of using epididymal and testicular spermatozoa with intracytoplasmic sperm injection (ICSI) for zoospermic patients are reviewed. A total of 128 consecutive ICSI/MESA cycles and a total of 120 consecutive ICSI/TESE cycles were performed up to December 1994. The two-pronuclei fertilization rate per intact oocyte (observed after the injection) was 58% and 60%, respectively, when epididymal and testicular spermatozoa were used. The embryo transfer rate was similar for the two procedures (91% after ICSI/MESA and 90% after ICSI/TESE). Fifty women became pregnant (positive HCG) when epididymal spermatozoa were used (39% per cycle and 40% per embryo transfer). These results are comparable to those obtained when ejaculated spermatozoa are used.
Cell Separation↗
Mapping the intersubunit region of influenza virus hemagglutinin: comparative CD and FTIR spectroscopic studies on multiple antigenic peptides.
An A/PR/8/34 (IHN1) influenza virus hemagglutinin (HA)-specific monoclonal antibody (Z38) was found to react with the solid phase adsorbed influenza virus expressing uncleaved (HA0) molecules but not to bind to virus particles bearing enzymatically cleaved hemagglutinin. Synthetic peptides corresponding to the uncleaved HA0 317-341 intersubunit region of subtypes H1-H3 (IP1-IP3) or comprising either the C-terminal 317-329 amino acids of HA1 (CP1) or the N-terminal 330-341 of HA2 (fusion peptide, FP) subunits of cleaved HA were used to characterize the fine specificity of Z38 mAb. Circular dichroism and Fourier-transform infrared spectroscopy showed that, compared to IP2 and IP3 comprising the H2 and H3 subtype fragments of the intact intersubunit region, IP1 has relatively low helicity but a tendency to adopt beta-turns in trifluoroethanol. The immunological and conformational properties of multiple antigenic peptides (MAPs) containing four copies of CP1 were also studied. Based on the appearance of an infrared component band at 1637 cm-1 (beta-turn band), the CP1 arms of MAPs also contain repeats of beta-turns. However, it is only the MAP1-FP construct comprising also the fusion peptide, which binds Z38 mAb as strongly as IP1 does. This puts emphasis on the role of the fusion region in modifying conformation and consequently the ability of peptides to elicit an antibody response. The results obtained for peptide conformation also suggests a beta-turn(s)/beta-sheet/beta-turn/beta-sheet conformational motif in the recognition by the hemagglutinin subtype-specific Z38 monoclonal antibody or by peptide-induced polyclonal antibodies.
Amino Acid Sequence↗
The site and stage of anti-DNA B-cell deletion.
Antibodies to DNA and nucleoproteins are found in sera of individuals with systemic autoimmune disease. In the population (and in the autoimmune mouse strain MRL/lpr) there is a great variety of such antinuclear antibodies, but individuals with systemic lupus erythematosus or single MRL mice express a subset only of the antinuclear specificities found in the population. These observations have been interpreted to mean that these antibodies arise by immunization. The oligoclonal nature of the autoantibody response and the evidence of selection acting on somatically mutated autoantibodies favour this interpretation. Specific activation of autoantibodies in disease implies either that autoantibodies are regulated in non-diseased individuals or that autoantigen availability is variable. The former has been demonstrated in anti-DNA transgenic mice. In normal mice, transgene-encoded antibodies against double-stranded (ds) DNA are not expressed in serum or on B cells. Here we describe modified anti-dsDNA transgenic mice which allow us to study the site and developmental stage at which such B-cell regulation occurs. This model shows that in normal mice B cells expressing anti-DNA specificity are deleted in the bone marrow at a pre-B to immature B transitional stage.
Animals↗
Inhibition of tumor necrosis factor production and ICAM-1 expression by pentoxifylline: beneficial effects in sepsis syndrome.
Tumor necrosis factor (TNF) has a pivotal role in the pathogenesis of sepsis and septic shock. Suppression of its biosynthesis might therefore be one of the strategies in the treatment of sepsis. When peripheral white blood cells were stimulated with either E. coli lipopolysaccharide (LPS) or Staphylococcus aureus, pentoxifiline (PTX) inhibited TNF production. In contrast, only a moderate inhibitory effect was observed on the induction of interleukin 6 (IL-6). PTX inhibited not only the TNF production of monocytes, but also the TNF secretion of both granulocytes and unseparated whole blood. The in vitro TNF and IL-6 producing capacities were higher in septic patients (n = 31) than in healthy blood donors (n = 15). Administration of PTX (400 mg/day) to 20 of the septic patients resulted in TNF production similar to that found in healthy controls. It also subsequently led to an improvement of the clinical status classified by the APACHE II score. The soluble intercellular adhesion molecule-1 (sICAM-1) level was significantly higher in the sera of septic patients before PTX treatment (800-1200 ng/ml) than in normal individuals (50-150 ng/ml), but it decreased following PTX therapy. Cytofluorometric analysis revealed that the expression of ICAM-1 on stimulated mononuclear cells was inhibited by PTX. It is presumed that the suppressive effect of pentoxifylline on TNF production may be of clinical importance, improving the therapeutic strategies in septic syndrome.
Adult↗
The effect of WSEWS pentapeptide and WSEWS-specific monoclonal antibodies on constitutive and IL-6 induced acute-phase protein production by a human hepatoma cell line, HEPG-2.
Interleukin-6 receptor (IL-6R) is a member of the cytokine receptor superfamily characterised by the obligatory presence of WSXWS (Trp-Ser-X-Trp-Ser) sequence motif near the transmembrane domain. To more clearly understand the role of this motif, we treated the HepG2 hepatoma cell line with synthetic WSEWS peptide (E is glutamic acid) and checked the spontaneous and IL-6-induced production of acute-phase protein fibrinogen and C1-inhibitor (C1-INH). The peptide revealed a definitely stimulatory effect both on the constitutive synthesis of C1-INH and on the IL-6-induced fibrinogen synthesis of HepG2 cells. Monoclonal antibody specific for WSEWS pentapeptide was stimulatory for the spontaneous secretion of both fibrinogen and C1-INH. However, the IL-6-induced elevations of these acute-phase proteins were oppositely regulated, since the anti-WSEWS monoclonal antibody was inhibitory on the production of fibrinogen induced by IL-6 but strongly augmented the IL-6 induced production of C1-INH. Our study indicates that the WSEWS motif is critical in the effect of IL-6 on the acute-phase protein production influencing either the ligand binding by the WSEWS-containing receptor molecule or the signal transduction.
Acute-Phase Proteins↗
Influence of the apolipoprotein E genotype on amyloid deposition and neurofibrillary tangle formation in Alzheimer's disease.
The effect of the apolipoprotein E genotype on the development of late onset Alzheimer's disease is still debated. Neuropathological studies of Alzheimer's disease have found a great extent of amyloid deposition in cortex and blood vessel walls in association with the apolipoprotein E epsilon 4 genotype [Rebeck G. W. et al. (1993) Neuron 11, 575-580; Schmechel et al. (1993) Proc. natn. Acad. Sci. U.S.A. 90, 9649-9653]. In contrast, the relationship of apolipoprotein E genotype to neurofibrillary pathology in Alzheimer's disease has been less clear. In this study we present evidence on the influence of the apolipoprotein E genotype on Alzheimer's disease related pathology in a series of 76 autopsy cases that had pathology that fulfilled the CERAD criteria for Alzheimer's disease. We found that the presence of the apolipoprotein E epsilon 4 allele is correlated with increased amounts of both amyloid and neuritic pathology in the neocortex as determined using an image analysis system. Comparison of plaque and tangle densities with the allele doses of epsilon 2 and epsilon 4 revealed a striking parallelism, suggesting that the alleles exert their effects very early in the pathological process before deposition of plaques and tangles. Although the apolipoprotein E epsilon 2 allele had a protective effect against both amyloid deposition and neurofibrillary tangle formation, in the presence of the epsilon 4 allele this protective effect against neuritic pathology was less marked than against amyloid deposition. This differential effect on amyloid deposition and the accumulation of neuritic pathology suggests that different molecular mechanisms are involved in the effect of apolipoprotein E on amyloid deposition and on tau phosphorylation.
Aged↗
Immunoglobulin heavy chain gene replacement: a mechanism of receptor editing.
We have generated a site-directed transgenic (sd-tg) mouse model in which the JH locus has been replaced with a rearranged VDJ coding for the heavy chain of an anti-DNA antibody. In these mice, B cells expressing the anti-dsDNA specificity are negatively regulated. We observe a novel mechanism for B cell tolerance, receptor editing at the heavy chain locus. In most sd-tg B cells, the inserted anti-DNA VH gene has been replaced by the upstream endogenous VH, or DH, or both genes through recombination with the heptamer embedded at the 3' end of most VH genes. Three types of recombination events have been identified. VH-to-VDJ, DH-to-VDJ, and VH-to-DH-VDJ. Analysis of the junctional sequences revealed features of classical V(D)J rearrangement, namely N sequence addition and nucleotide deletion. A conserved nonamer was found 12 bp upstream of the embedded heptamer. This nonamer may represent a novel recombination signal sequence used for VH editing. The sd-tg model thus provides direct evidence for secondary rearrangement at VH-D-JH. This process may play a role in tolerance by editing autoreactive receptors and may also serve to diversify the VH repertoire.
Amino Acid Sequence↗
Using ejaculated, fresh, and frozen-thawed epididymal and testicular spermatozoa gives rise to comparable results after intracytoplasmic sperm injection.
OBJECTIVE: To describe the preparation of fresh or frozen-thawed epididymal and testicular sperm for intracytoplasmic single sperm injection and to compare the fertilization, embryo quality, and pregnancy rates (PRs) obtained after using these spermatozoa to the results when freshly ejaculated sperm was used for microinjection. DESIGN: Retrospective analysis of 1,034 consecutive microinjection cycles. Ejaculated (965 cycles), fresh epididymal (43 cycles), frozen-thawed epididymal (9 cycles), and testicular sperm (17 cycles) was used for intracytoplasmic sperm injection. SETTING: Procedures were performed in a tertiary IVF center coupled with an institutional research environment. MAIN OUTCOME MEASURES: Semen density and motility were judged by the World Health Organization criteria and sperm morphology was evaluated by the Tygerberg's strict criteria. After microinjection, oocyte intactness, fertilization, embryo cleavage, transfer, and PRs were evaluated and compared. RESULTS: The median values of total sperm count, total motility and normal morphology were 17.85 x 10(6), 37%, 8% for freshly ejaculated sperm; 46.20 x 10(6), 12%, 9% for fresh epididymal sperm; 0.15 x 10(6), 0%, 0% for frozen-thawed epididymal sperm; and 0.54 x 10(6), 0% for testicular sperm (morphology was not determined). The percentage of intact oocytes after microinjection ranged from 84% to 90%. Normal fertilization rates were high when fresh or frozen-thawed epididymal and testicular spermatozoa were used for the injection (56%, 56%, 48%, respectively) but were significantly lower than for ejaculated sperm (70%). There was a higher proportion of transferable embryos obtained after ejaculated sperm injection than after testicular sperm injection. Forty percent, 58%, 33%, and 46% of cycles had positive serum hCG using ejaculated, fresh, or frozen-thawed epididymal and testicular sperm. Initial pregnancy loss occurred in 26.3% of the conception cycles. CONCLUSION: Intracytoplasmic sperm injection can provide high normal fertilization, cleavage, and PRs when fresh or frozen-thawed epididymal and testicular spermatozoa are used, but normal fertilization rates are significantly lower than after microinjection with ejaculated sperm.
Adult↗
Intracytoplasmic sperm injection (ICSI): the Brussels experience.
The present report covers the results of a 26-month period in which 1275 consecutive treatment cycles by intracytoplasmic sperm injection (ICSI) were performed in 919 couples. These couples were afflicted with male factor infertility and had had at least one previous failed conventional in vitro fertilization (IVF) treatment cycle. In other couples, the husband had semen parameters incompatible with conventional IVF or suffered from excretory azoospermia which required microsurgical epididymal sperm aspiration or testicular sperm retrieval. Overall, the 2 pronuclear (PN) fertilization rate was 47.7% per retrieved oocyte-cumulus complex and 66.4% per successfully injected metaphase II oocyte. Embryo transfer was performed in 90.8% of started cycles and 362 clinical pregnancies were recorded, giving a clinical pregnancy rate of 28.4% per started cycle or 31.3% per transfer. In addition, updated results on the outcome of pregnancies after microassisted fertilization are presented. As of 30 August 1994, 416 children have been born. Although 16 major congenital malformations have been observed (3.9%), there appears to be no reason for serious concern as regards the occurrence of major congenital anomalies after ICSI.
Belgium↗
High fertilization and pregnancy rate after intracytoplasmic sperm injection with spermatozoa obtained from testicle biopsy.
In cases requiring microsurgical epididymal sperm aspiration (MESA) for congenital absence of the vas deferens (CAVD) or irreparable obstructive azoospermia, often no spermatozoa can be retrieved from the epididymis, or there may even be no epididymis present. We wished to see whether testicular biopsy with testicular sperm extraction (TESE) in such cases could yield spermatozoa that would result in successful fertilization and pregnancy (despite the absence of epididymal spermatozoa) using intracytoplasmic sperm injection (ICSI). In the same setting during the same 2-week period, 28 patients with CAVD or irreparable obstruction were treated; 16 consecutive fresh MESA-ICSI cycles and 12 cycles which required testicular biopsy with testicular sperm extraction (TESE-ICSI) were performed. Normal two-pronuclear fertilization rates were similar in both groups: 45% for epididymal spermatozoa and 46% for testicular biopsy-extracted spermatozoa. Cleavage rates were also similar (68% for epididymal and 65% for testicular spermatozoa). The ongoing pregnancy rates in this series were 50 and 43% respectively. We conclude that epididymal spermatozoa and testicular spermatozoa yield similar fertilization, cleavage and ongoing pregnancy rates using ICSI. When epididymal spermatozoa cannot be retrieved, a testicular biopsy can be performed and the few barely motile spermatozoa thus obtained can be used for ICSI. It appears that all cases of obstructive azoospermia can now be successfully treated.
Biopsy↗
Pregnancies after testicular sperm extraction and intracytoplasmic sperm injection in non-obstructive azoospermia.
In this study (May 1 until August 31, 1994) a total of 15 azoospermic patients suffering from testicular failure were treated with a combination of testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI). Spermatozoa were available for ICSI in 13 of the patients. Out of 182 metaphase II injected oocytes, two-pronuclear fertilization was observed in 87 (47.80%); 57 embryos (65.51%) were obtained for either transfer or cryopreservation. Three ongoing pregnancies out of 12 replacements (25%) were established, including one singleton, one twin and one triplet gestation. The ongoing implantation rate was 18% (six fetal hearts out of 32 embryos replaced).
Adult↗
Intracytoplasmic sperm injection in the mouse.
Intracytoplasmic sperm injection (ICSI) into mouse oocytes involves a very low survival rate. This study was designed to determine why ICSI frequently fails in mice. Metaphase II oocytes were obtained from superovulated 4-6 week old F1 hybrid mice. Spermatozoa were retrieved from the epididymis of 12-14 week old F1 hybrid mice. The spiked microinjection pipette used to inject a spermatozoon into the ooplasm had outer and inner diameters of 10 and 8 microns respectively. The oocytes used in the first part of the study were not activated (group 1). Some oocytes were incubated with calcium ionophore for 5 min (group 2). The injected oocytes were evaluated 6, 20, 48 and 72 h after injection. A total of 143 eggs in each group underwent ICSI. In group 1, sperm heads escaped into the perivitelline space. In all, 63 (47%) of the remaining oocytes were damaged during the injection or had degenerated by the first evaluation. The survival rate was 53%, but fertilization did not occur. In group 2, 31 oocytes (22%) were damaged during microinjection or soon degenerated. Two oocytes underwent accidental subzonal insemination. Six oocytes were fertilized (4.2%) among the 78% of survivors. After injection, the sperm tail was found in the cytoplasm (27 and 31% in groups 1 and 2 respectively), the perivitelline space (45% in both groups) or protruding through the zona pellucida (28 and 23% respectively). More oocytes degenerated when the tail remained in the cytoplasm, i.e. 78% in group 1 and 36% in group 2.
Animals↗
Successful fertilization and establishment of pregnancies after intracytoplasmic sperm injection in patients with globozoospermia.
Globozoospermia or round-headed spermatozoa is a rare type of teratozoospermia where the acrosome is absent resulting in male infertility with no known therapy. A few studies have shown that round-headed spermatozoa cannot bind to or penetrate the zona pellucida, and no normal fertilization has been observed in in-vitro fertilization (IVF) after insemination of human oocytes with round-headed spermatozoa. In this study, the fertilization capacity of round-headed spermatozoa after intracytoplasmic sperm injection (ICSI) into human oocytes has been examined. In pre-clinical experiments, 45 oocytes were injected; 41 oocytes were intact after injection, 15 oocytes were fertilized normally, and 13 of these 15 oocytes developed further in vitro. ICSI was carried out in 11 treatment cycles of seven infertile couples with globozoospermia. Normal fertilization and embryo transfer occurred in four cycles (three patients). Positive serum human chorionic gonadotrophin was observed in three cycles (two patients); one patient had a pre-clinical abortion and the other patient became pregnant twice; the first pregnancy was ectopic and the second pregnancy is a twin pregnancy which is currently at 16 weeks of gestation.
Acrosome↗
Ongoing pregnancies and birth after intracytoplasmic sperm injection with frozen-thawed epididymal spermatozoa.
In seven patients who did not become pregnant following microsurgical epididymal sperm aspiration (MESA) and intracytoplasmic sperm injection (ICSI), a subsequent ICSI was performed using previously cryopreserved super-numerary epididymal spermatozoa without re-operating on the husband. During the original MESA procedure a mean sperm concentration of 12.3 x 10(6)/ml was achieved. The supernumerary spermatozoa were cryopreserved for later use. After thawing frozen epididymal spermatozoa a mean concentration of 1.9 x 10(6) spermatozoa/ml was obtained in straws containing a total volume of sperm suspension of 250 microliters. From 68 intact oocytes injected with frozen-thawed epididymal spermatozoa, a two pronuclear fertilization rate of 45% and a cleavage rate of 82% were obtained. A total of 17 embryos were replaced in the seven patients, resulting in two ongoing singleton pregnancies and one twin delivery. Six embryos were cryopreserved. In conclusion, it would appear mandatory to cryopreserve supernumerary spermatozoa during a MESA in order to avoid subsequent further scrotal surgery.
Adult↗
The use of epididymal and testicular spermatozoa for intracytoplasmic sperm injection: the genetic implications for male infertility.
The results and rationale of using testicular and epididymal spermatozoa with intracytoplasmic sperm injection (ICSI) for severe cases of male infertility are reviewed. A total of 72 consecutive microsurgical epididymal sperm aspiration (MESA) cases were performed for congenital absence of the vas (CAV) and for irreparable obstructive azoospermia. ICSI was used to obtain normal embryos for transfer and fertilization in 90% of the cases. The overall fertilization rate was 46% with a normal cleavage rate of 68%. The pregnancy and delivery rates per transfer were 58 and 37% respectively. The delivery rate per cycle was 33%. In many cases, no epididymal spermatozoa were available and so testicular sperm extraction (TESE) was used for sperm retrieval. The transfer rate was lower with TESE (84 versus 96%) and the spermatozoa could not be frozen and saved for use in future cycles. However, there was little difference in pregnancy rates using epidiymal or testicular spermatozoa. The results were not affected by whether the obstruction was caused by CAV or failed vasoepididymostomy. Both fresh and frozen spermatozoa gave similar results; the only significant factor appeared to be the age of the female. Because of the consistently good results obtained using epididymal sperm with ICSI when compared with conventional IVF, and the similarly good results with testicular tissue spermatozoa, ICSI is mandatory for all future MESA patients. All CAV patients and their partners should be offered genetic screening for cystic fibrosis; hence pre-implantation embryo diagnosis should be available in any full service MESA programme. It is now clear that even with non-obstructive azoospermia, e.g. Sertoli-cell only, or maturation arrest, there are usually some small foci of spermatogenesis which allow TESE with ICSI to be carried out. This means that even in men with azoospermia due to absence of spermatogenesis or to a block in meiosis, there are usually a few spermatozoa available in the testes that are adequate for successful ICSI. Finally, it is likely that some forms of severe male factor infertility are genetically transmitted and although ICSI offspring have been shown to be completely normal, it is possible that the sons of these infertile couples will also require ICSI when they grow up and wish to have a family.
Adult↗