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D C Fischer

Publications and source records attributed to D C Fischer.

At least 19 recordsLinked to original sources

Tissue concentrations of endothelial cell adhesion molecules in the lower uterine segment during term parturition.

OBJECTIVE: To determine the concentration of endothelial cell adhesion molecules in the lower uterine segment during parturition at term. METHODS: We analyzed protein extracts from the lower uterine segments of 38 women who had nonelective cesareans at term. We measured concentrations of intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and platelet endothelial cell adhesion molecule-1 by enzyme-linked immunosorbent assay. Subjects were grouped according to cervical dilatation (less than 2 cm, n = 10; 2 to less than 4 cm, n = 9; 4-6 cm, n = 9; more than 6 cm, n = 10) and duration of labor (up to 6 hours, n = 14; 6-12 hours, n = 10; 12-24 hours, n = 9; longer than 24 hours, n = 5) at the time of cesarean. RESULTS: The median concentration of intercellular adhesion molecule-1 increased significantly with increasing dilatation (from 2.24 ng/mg total protein at less than 2 cm to 6.73 ng/mg at 4-6 cm) and increasing duration of labor (from 2.53 ng/mg up to 6 hours to 5.90 ng/mg at 12-24 hours). However, this study did not have adequate statistical power to identify differences in concentrations of the other endothelial adhesion molecules. CONCLUSION: The results indicate that parturition at term is associated with expression of intercellular adhesion molecule-1.

Adult↗

Regulation of interleukin-8 synthesis in human lower uterine segment fibroblasts by cytokines and growth factors.

OBJECTIVE: To investigate the influence of lipopolysaccharide, cytokines, growth factors, and progesterone on the synthesis of interleukin-8 by human lower uterine segment fibroblasts. METHODS: Fibroblasts derived from a lower uterine segment biopsy specimen obtained from a woman undergoing elective cesarean delivery at term were exposed to lipopolysaccharide, interleukin-1beta, transforming growth factor-beta(1), platelet-derived growth factor-AB, and combinations of these substances. All experiments were performed in the absence and presence of progesterone. The concentration of interleukin-8 in the culture medium was determined by enzyme immunoassay after 24 hours. RESULTS: Compared with controls (0.71 +/- 0.04 ng interleukin-8/10(6) cells), fibroblasts exposed to lipopolysaccharide, transforming growth factor-beta(1), or platelet-derived growth factor-AB exhibited no increase, or at most, only a minor but significant increase, in interleukin-8 secretion. Incubation with interleukin-1beta led to a moderate increase, whereas the combinations interleukin-1beta/transforming growth factor-beta(1) (105.0 +/- 7.5 ng interleukin-8/10(6) cells) and interleukin-1beta/platelet-derived growth factor-AB (387.3 +/- 25.6 ng interleukin-8/10(6) cells) increased interleukin-8 secretion dramatically. No further increase was observed with the combination interleukin-1beta/platelet-derived growth factor-AB/transforming growth factor-beta(1). When progesterone was added, interleukin-8 secretion decreased significantly by 16-34%, depending on the stimulator, or did not change. CONCLUSION: The findings indicate that interleukin-8 secretion by human lower uterine segment fibroblasts in vitro is upregulated by interleukin-1beta, transforming growth factor-beta(1), and platelet-derived growth factor-AB in a synergistic fashion. Because interleukin-8 mediates the invasion of neutrophils into the cervical stroma, this may be an important mechanism controlling cervical dilatation during parturition.

Adult↗

[Immunophenotype classification of macular corneal dystrophy: first case report of immunophenotype I A outside of Saudi Arabia. A clinical histopathological correlation with immunohistochemistry and electron microscopy].

BACKGROUND: Macular corneal dystrophy can be classified into three different immunophenotypes according to presence and distribution of sulfated keratan sulfate (SKS) in the cornea and serum levels of SKS. Immunophenotype I A has yet only been reported in patients with macular corneal dystrophy from Saudi Arabia. MATERIAL AND METHODS: Case report of a patient with macular corneal dystrophy type I A from Germany. Indirect immunohistochemistry for sulfated keratan sulfate was performed on the corneal buttons obtained after perforating keratoplasty (monoclonal antibodies 3D12/H7 and 5-D-4). The serum concentration of SKS was determined using the monoclonal antibody 5-D-4 in a serum antigen-inhibition assay. Immunogold labeling with the 5-D-4 antibody was performed to allow ultrastructural localization of SKS in the cornea. RESULTS: The patient demonstrated the typical clinical picture of macular corneal dystrophy. Serum levels of SKS were not detectable. Positive immunohistochemistry for SKS was found only within single keratocytes of both corneae without staining of the stroma (3D12/H7 and 5-D-4). Immunogold labeling localized SKS within stromal keratocytes and proved this patient to suffer from macular corneal dystrophy immunophenotype I A. CONCLUSION: Macular corneal dystrophy immunophenotype I A can be found outside Saudi Arabia in a German patient. All three immunophenotypes of macular corneal dystrophy are present in corneal buttons from German patients.

Adult↗

Recurrent macular corneal dystrophy type II 49 years after penetrating keratoplasty.

Recurrence of macular corneal dystrophy after keratoplasty is rare. We report light microscopic, immunohistochemical, electron microscopic, and serologic findings in a 78-year-old woman who underwent regrafting 49 years following the first penetrating keratoplasty. Examination of the corneal button revealed deposits of glycosaminoglycans in the graft beneath the Bowman layer, throughout the stroma, and in the endothelium with positive staining for antigenic keratan sulfate. By transmission electron microscopy, intracellular and extracellular deposits of a fibrillogranular material were detected in the stroma, Descemet membrane, and endothelium. The serum level of antigenic keratan sulfate was normal. Our findings indicate that macular corneal dystrophy type II may show late recurrence after penetrating keratoplasty with intense deposition of antigenic keratan sulfate in all corneal layers.

Aged↗

Induction of alpha1-antitrypsin synthesis in human articular chondrocytes by interleukin-6-type cytokines: evidence for a local acute-phase response in the joint.

OBJECTIVE: We have previously shown that human articular chondrocytes synthesize large amounts of interleukin-6 (IL-6) upon stimulation with proinflammatory cytokines and that they express the IL-6 receptor. The present study was undertaken to analyze whether different IL-6-type cytokines can induce synthesis of the acute-phase protein alpha1-antitrypsin in human articular chondrocytes. METHODS: Chondrocytes from human articular cartilage, cultured in agarose, were stimulated with IL-6-type cytokines. Total RNA was isolated and analyzed by Northern blotting. Levels of alpha1-antitrypsin protein were determined by enzyme immunoassay. RESULTS: Stimulation of chondrocytes with oncostatin M (OSM) and IL-6 led to a 5-10-fold increase in alpha1-antitrypsin synthesis. This increase was dose and time dependent. Furthermore, OSM and IL-6 induced IL-6 synthesis in chondrocytes, resulting in an autocrine amplification loop. CONCLUSION: Our data strongly suggest the existence of a local acute-phase response in the joint. Synthesis of the acute-phase protein alpha1-antitrypsin, a major inhibitor of serine proteinases, may be an important protective mechanism of articular chondrocytes to prevent cartilage damage in inflammatory joint diseases.

Acute-Phase Proteins↗

Collagenolysis in the lower uterine segment during parturition at term: correlations with stage of cervical dilatation and duration of labor.

OBJECTIVE: The objective of this study was to quantify the extent of neutrophil infiltration and the concentrations of enzymes involved in collagenolysis in the lower uterine segment in relation to the degree of cervical dilatation and the duration of labor. STUDY DESIGN: Biopsy specimens of the lower uterine segment were obtained from 62 women undergoing cesarean section at term. The number of extravascular neutrophils was assessed with enzyme histochemical evaluation, and the concentrations of matrix metalloproteinase-8, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinases-1 by were assessed by enzyme-linked immunosorbent assay. RESULTS: The neutrophil count and the concentrations of matrix metalloproteinase-8, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinases-1 increased with increasing cervical dilatation. At >6 cm the neutrophil count and the concentrations of matrix metalloproteinase-8, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinases-1 were significantly higher than at <2 cm. An association with the duration of labor was found for the neutrophil count and the concentrations of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1. Multiple linear regression analysis showed that the degree of cervical dilatation is more closely related to the 4 laboratory parameters investigated than to the duration of labor. CONCLUSION: The findings support the hypothesis that local changes (ie, collagenolysis) in the lower uterine segment unrelated to uterine activity play a crucial role in cervical dilatation at term.

Cervix Uteri↗

Parturition at term: parallel increases in interleukin-8 and proteinase concentrations and neutrophil count in the lower uterine segment.

A relationship was sought between the tissue concentrations of interleukin (IL)-8, matrix metalloproteinase (MMP)-8 and MMP-9, and the numbers of the various leukocytes infiltrating the lower uterine segment stroma during parturition. Biopsy specimens of the lower uterine segment were obtained from 63 women undergoing Caesarean section at various stages of cervical dilatation at term. The concentrations of IL-8, MMP-8 and MMP-9 were determined with enzyme-linked immunosorbent assays, and the leukocytes were quantified immunohistochemically. The median IL-8 concentration (pg/mg total protein) rose significantly from 17.2 at < 2 cm dilatation, to 26.5 at 2 to < 4 cm dilatation, and 1954.0 at 4-6 cm dilatation, and remained at approximately this concentration at > 6 cm dilatation. The median MMP-8 concentration (ng/mg total protein) increased significantly from 32.2 at < 2 cm dilatation to 114.2 at > 6 cm dilatation. The median MMP-9 concentration (ng/mg total protein) rose significantly from 15.4 at < 2 cm dilatation to 102.1 at > 6 cm dilatation. The number of neutrophils was significantly higher at 4-6 cm and > 6 cm dilatation than at > 2 cm, reaching maximum values at > 6 cm dilatation. The findings in this study support the hypothesis that IL-8-induced infiltration of the cervical stroma by neutrophils and subsequent release of proteinases may play a key role in parturition.

Adult↗

Lidocaine pharmacokinetics during hyperbaric hyperoxia in humans.

METHODS: The disposition of drugs may be influenced by hyperbaric conditions, in particular by changes of liver perfusion. The effect of hyperbaric hyperoxia on the pharmacokinetics of lidocaine, a drug eliminated in the liver with a perfusion-limited clearance, was investigated in human volunteers in a crossover trial. METHODS: A single dose lidocaine i.v. bolus (0.69 or 0.75 mg x kg(-1)) was administered to two volunteers under normobaric conditions (NB: 1 bar or 0.1 MPa, air) and under hyperbaric/hyperoxic conditions (HBO: 2.5 bar or 0.25 MPa, alternating 100% O2-breathing for 20 min and air breathing for 5 min). Blood samples were serially collected for 5 h (NB) or 75 min (HBO), and lidocaine concentration in serum was measured by immunoassay. Data were analyzed assuming linear kinetics and an open two-compartment model. RESULTS: At 1 bar or 0.1 MPa, lidocaine injection caused only slight dizziness and buzzing in the ear. Heart rate and blood pressure were not influenced. Under HBO, lidocaine injection caused marked dizziness and buzzing in the ears, sweating, tremor and coordination-disturbances, even though maximal lidocaine concentrations (0.63 mg x L(-1) and 0.70 mg x L(-1)) were far below therapeutic serum concentrations (1.5-5.0 mg x L(-1)). Pharmacokinetic parameters of lidocaine were similar to those published earlier (T1/2beta: 110+/-16 min; CI: 12.6+/-2.9 ml x min(-1) x kg(-1); Vss: 1.73+/-0.18 L x kg(-1)). There was no indication for effects of HBO on the disposition of lidocaine (p > 0.05). CONCLUSION: The pharmacokinetics of lidocaine do not seem to be influenced in a clinically relevant way in humans by a single HBO-exposure under usual therapeutic conditions. Side effects of lidocaine at 2.5 bar or 0.25 MPa may be caused by pharmacodynamic interactions between lidocaine and hyperbaric/hyperoxic conditions.

Adult↗

Reference hematologic and plasma chemistry values of brown tree snakes (Boiga irregularis).

Reference hematologic and plasma chemistry values were determined from 103 blood samples collected from 53 clinically healthy brown tree snakes (Boiga irregularis). Female snakes had significantly higher mean plasma values for total solids, total protein, calcium (Ca), phosphorus (P), uric acid, and blood monocyte percentage than did males, whereas males had significantly higher mean plasma fibrinogen values. The variances for hematocrit, monocyte percentage, azurophil percentage, plasma total solids, plasma total protein, albumin, Ca, and P also differed significantly between sexes. The higher mean values and greater variances for plasma total protein, plasma total solids, Ca, and P in the female snakes were probably associated with yolk synthesis and accumulation.

Animals↗

Interleukin-1beta and interleukin-8 concentrations in the lower uterine segment during parturition at term.

OBJECTIVE: To assess the roles of interleukin-1beta, interleukin-8, and fibroblasts in the lower uterine segment during parturition. METHODS: Lower uterine segment biopsy specimens were obtained from 36 women undergoing cesarean delivery at various stages of cervical dilation (less than 2 cm, n = 8; 2 to less than 4 cm, n = 9; 4-6 cm, n = 10; more than 6 cm, n = 9). The concentrations of interleukin-1beta and interleukin-8 in protein extracts prepared from the tissue samples were measured by enzyme immunoassays. The effect of incubation with interleukin-1beta (30 U/mL) on interleukin-8 secretion by lower uterine segment fibroblasts in vitro also was determined. RESULTS: The median interleukin-1beta concentration in the specimens increased from 1.3 pg/mg of total protein at less than 2 cm of dilation to 22.2 pg/mg of total protein at 4-6 cm of dilation (P < .05). No further increase was detectable after 6 cm of dilation. The interleukin-8 concentration increased from 17.2 pg/mg of total protein at less than 2 cm of dilation to 2080.7 pg/mg of total protein at 4-6 cm of dilation (P < .05), thus paralleling the increase in interleukin-1beta concentration. Interleukin-1beta induced a significant increase in interleukin-8 secretion by fibroblasts in vitro, from 0.8 ng/10(6) cells to 35.6 ng/10(6) cells. CONCLUSION: The increase in interleukin-8 concentration in the lower uterine segment during parturition may be induced by interleukin-1beta and fibroblasts may be one of the sources of this interleukin-8.

Adult↗

Specific properties of the extracellular chondroitin sulphate proteoglycans in the mandibular condylar growth centre in pigs.

The developing condylar cartilage of the temporomandibular joint responds to changes in load by adaptive growth. Because local regulatory events taking place during growth processes are not well understood, investigation of extracellular matrix composition could provide new information about which matrix molecules are involved in the regulation of growth processes in this avascular tissue. The large chondroitin sulphate-rich proteoglycans in the mandibular condyle were compared to the proteoglycans in the weight-bearing femoral condyle of juvenile domestic pigs with respect to their buoyant density, chemical composition and immunological identity after isolation by dissociative extraction and CsCl density-gradient centrifugation. The distribution of these proteoglycans was studied in cryosections of mandibular condyle by immunohistochemistry using polyclonal antibodies produced against pig large proteoglycans. In the mandibular condyle, predominantly in the articular zone, the relative amount of proteoglycans with a low glycosaminoglycan content was greater than in femoral cartilage. The large proteoglycan immunologically related to aggrecan gave a protein core of 450 kDa after enzymatic deglycosylation and clearly possessed less keratan sulphate than in femoral aggrecan. Furthermore, the mandibular tissue contained another large proteoglycan with a protein core of 550 kDa after enzymatic deglycosylation, which was immunologically related to the fibroblast-like versican. Immunohistochemistry showed aggrecan increasing in amount inferiorly. In contrast, "versican' was exclusively found in the fibrous and differentiation layers. Aggrecan is mainly responsible for shock absorption and versican and its homologues may be involved in the control of cell proliferation and differentiation. Thus the matrix components of the mandibular condyle seem to be adapted to its special functional needs including parallel articulation and growth.

Aggrecans↗

Development of an enzyme immunoassay specific for a core protein epitope of a novel small basement membrane associated heparan sulphate proteoglycan from human kidney.

Heparan sulphate proteoglycans are major components of the glomerular basement membrane and play a key role in their molecular organization and function. Moreover, their presence is essential for the maintenance of the selective permeability of the glomerular basement membrane. Recently, we have isolated and characterized a novel, small basement membrane associated heparan sulphate proteoglycan from human aorta and kidney. Using specific monoclonal antibodies we have shown that the novel heparan sulphate proteoglycan is predominantly located in the glomerular basement membrane, to a lesser extent in the basement membrane of tubuli, and also in the mesangium. Turnover or, in the course of kidney diseases, degradation of heparan sulphate proteoglycan from glomerular basement membranes may lead to urinary excretion of heparan sulphate proteoglycan. Therefore, changes in the structure and function of glomerular basement membranes may be directly detected by measuring the excretion of a component of this basement menbrane, e. g. heparan sulphate proteoglycan into urine. Here we describe the establishment of an enzyme immunoassay for the sensitive detection of the novel, small heparan sulphate proteoglycan in urine. In this assay the specific monoclonal antibody 1F10/B8, which recognizes a core protein epitope, was used to detect the polyanionic heparan sulphate proteoglycan bound to the surface of a cationic charge modified microtitre plate. This assay allows the sensitive and specific detection of the small heparan sulphate proteoglycan, which is released from the glomerular basement membrane into urine during normal turnover and also in the course of kidney diseases.

Animals↗

Evidence for the presence of a large keratan sulphate proteoglycan in the human uterine cervix.

Profound changes occur in the uterine cervix during pregnancy. In particular, the extracellular matrix of the connective tissue is remodelled extensively. To elucidate the mechanisms involved in this process, we have analysed the proteoglycan pattern in the human cervix from pregnant and non-pregnant women. Proteoglycans of the cervix tissue specimen were extracted with 4 M guanidine hydrochloride and precipitated with 80% ethanol. Purification of proteoglycans was performed by several chromatographic steps. Characterization of proteoglycans was done by SDS/PAGE before and after digestion with glycosaminoglycan-specific enzymes. Proteoglycans were detected by combined Alcian Blue/silver staining or, after blotting of biotin-labelled proteoglycans on to poly(vinylidene difluoride) membrane, with peroxidase-conjugated avidin or by the use of keratan sulphate- or decorin-specific monoclonal antibodies. In contrast with previous reports, where only chondroitin/dermatan sulphate proteoglycans have been found in the uterine cervix, we have shown in the present study the existence of a large keratan sulphate proteoglycan with an M(r) > 220,000 in cervix samples from non-pregnant and pregnant women. This proteoglycan showed a strong reaction with the keratan sulphate-specific monoclonal antibody 5D4 and could be degraded by keratanases. The size of the core protein of this keratan sulphate proteoglycan was estimated to be about M(r) 220,000.

Cervix Uteri↗

A novel keratan sulphate domain preferentially expressed on the large aggregating proteoglycan from human articular cartilage is recognized by the monoclonal antibody 3D12/H7.

Monoclonal antibodies (mAbs) were prepared against aggrecan which has been isolated from human articular cartilage and purified by several chromatographic steps. One of these mAbs, the aggrecan-specific mAb 3D12/H7, was selected for further characterization. The data presented indicate that this mAb recognizes a novel domain of keratan sulphate chains from aggrecan: (1) immunochemical staining of aggrecan is abolished by treatment with keratanase/keratanase II, but not with keratanase or chondroitin sulphate lyase AC/ABC; (2) after chemical deglycosylation of aggrecan no staining of the core-protein was observed; (3) different immunochemical reactivity was observed against keratan sulphates from articular cartilage, intervertebral disc and cornea for the mAbs 3D12/H7 and 5D4. For further characterization of the epitope, reduced and 3H-labelled keratan sulphate chains were prepared. In an IEF-gel-shift assay it was shown that the 3H-labelled oligosaccharides obtained after keratanase digestion of reduced and 3H-labelled keratan sulphate chains were recognized by the mAb 3D12/H7. Thus it can be concluded that the mAb 3D12/H7 recognizes an epitope in the linkage region present in, at least some, keratan sulphate chains of the large aggregating proteoglycan from human articular cartilage. Moreover, this domain seems to be expressed preferentially on those keratan sulphate chains which occur in the chondroitin sulphate-rich region of aggrecan, since the antibody does not recognize the keratan sulphate-rich region obtained after combined chondroitinase AC/ABC and trypsin digestion of aggrecan.

Aggrecans↗

Limited heterogeneity of rearranged T cell receptor V alpha and V beta transcripts in synovial fluid T cells in early stages of rheumatoid arthritis.

OBJECTIVE: The identification of activated T cells in synovial fluid and synovium, and the association of rheumatoid arthritis (RA) with specific HLA-DR restriction elements, strongly suggest that these T cells play a critical role in the etiology and pathogenesis of RA. Analysis of the T cell receptor (TCR) repertoire in the early stages of RA might be an approach to identify those T cells involved in the initiation and/or perpetuation of the disease. METHODS: TCR V alpha and V beta transcripts of synovial T cells, sampled at the early stages of RA, were amplified by reverse transcriptase-polymerase chain reaction. HLA-DR subtyping was determined by serologic analysis and dot-blot hybridization of polymerase chain reaction amplification products using digoxigenin-labeled, sequence-specific oligonucleotide probes. RESULTS: Our findings showed a limited heterogeneity of V alpha and V beta TCRs in synovial fluid T cells, and a preferential usage of TCR V alpha 17 in early RA. In contrast, in the later stages of RA, a more polyclonal TCR V alpha and V beta gene usage was observed. CONCLUSION: Our results support the view that induction of RA is driven by an oligoclonal immune response to an unknown antigen. These findings also suggest a pathogenetic role for V alpha 17 T cells in the early stages of RA.

Adult↗

The soft tissue cover of the mandibular condyle: age-related changes in high buoyant density proteoglycans, free tissue water and remodelling activity.

Age-related changes in the relative proportion of high buoyant density proteoglycans of the soft tissue cover of the mandibular condyle of domestic pigs and the chemical composition of these proteoglycans were investigated by biochemical methods. The relative proportion of high buoyant density proteoglycans has been shown to decrease with age, with their chemical composition varying as follows: With age, the relative proportions of protein increased, galactosamine decreased, glucosamine was similar in newborns and juveniles, but clearly increased in adults, galactosamine plus glucosamine decreased. As measured by 1H-NMR-relaxation spectroscopic methods, the concentration of free tissue water of the soft tissue cover of the mandibular condyle decreased with age. Its mobility, however, was greater in newborns than in juveniles, but similar in juveniles and adults. The concentration of free tissue water, but not its mobility, correlated weakly with relative proportions of polyanionic side chains (e.g. chondroitin sulphate plus keratan sulphate chains) of the high buoyant density proteoglycans. By affecting the concentration of free tissue water and in turn of matrix solutes and cellular environments, the high buoyant density proteoglycans of the soft tissue cover of the mandibular condyle seem to be involved in regulation of age-related changes in the adaptive remodelling activity of the mandibular condyle.

Aging↗

Transforming growth factor beta 1, a major stimulator of hyaluronan synthesis in human synovial lining cells.

OBJECTIVE: To investigate the role of cytokines and growth factors in the regulation of hyaluronan synthesis in human synovial lining cells. METHODS: Synovial lining cells were obtained from human knee joints, isolated by the explant method, and characterized by immunocytochemistry using monoclonal antibodies against monocyte/macrophage markers as well as antibodies against hyaluronan synthase. After stimulation by cytokines and growth factors, hyaluronan was measured by radiometric assay. The molecular weight distribution of the hyaluronan synthesized was determined by high-performance gel-permeation liquid chromatography. To test the effect of oxygen-derived free radicals, the concentration and molecular weight distribution of hyaluronan were determined in the presence and absence of catalase and superoxide dismutase. RESULTS: Hyaluronan synthesis was stimulated in synovial lining cells by transforming growth factor beta 1 (TGF beta 1), interleukin-1 beta (IL-1 beta), and to a lesser extent by tumor necrosis factor alpha (TNF alpha). Analysis of the molecular weight distribution of hyaluronan after stimulation of synovial lining cells with TGF beta 1, IL-1 beta, and TNF alpha indicated that hyaluronan is synthesized in a high molecular weight form and might be degraded in the course of inflammatory processes by oxygen-derived free radicals. CONCLUSION: Our findings suggest that TGF beta 1 is a major stimulator of hyaluronan synthesis in human synovial lining cells and might be involved in the pathogenic mechanisms of joint swelling in inflammatory and degenerative joint diseases.

Adult↗