Biomedical subjects

P Huie

Publications and source records attributed to P Huie.

At least 19 recordsLinked to original sources

PubMed2001

Predominance of NK1.1+TCR alpha beta+ or DX5+TCR alpha beta+ T cells in mice conditioned with fractionated lymphoid irradiation protects against graft-versus-host disease: "natural suppressor" cells.

We developed a nonmyeloablative host conditioning regimen in a mouse model of MHC-mismatched bone marrow transplantation that not only reduces radiation toxicity, but also protects against graft-vs-host disease. The regimen of fractionated irradiation directed to the lymphoid tissues and depletive anti-T cell Abs results in a marked change in the residual host T cells, such that NK1.1+ or DX5+asialo-GM1+ T cells become the predominant T cell subset in the lymphoid tissues of C57BL/6 and BALB/c mice, respectively. The latter "natural suppressor" T cells protect hosts from graft-vs-host disease after the infusion of allogeneic bone marrow and peripheral blood cells that ordinarily kill hosts conditioned with sublethal or lethal total body irradiation. Protected hosts become stable mixed chimeras, but fail to show the early expansion and infiltration of donor T cells in the gut, liver, and blood associated with host tissue injury. Cytokine secretion and adoptive transfer studies using wild-type and IL-4(-/-) mice showed that protection afforded by NK1.1+ and DX5+asialo-GM1+ T cells derived from either donors or hosts conditioned with lymphoid irradiation is dependent on their secretion of high levels of IL-4.

Animals↗

PubMed2001

Chronic antigen-specific immune-system activation may potentially be involved in the loosening of cemented acetabular components.

Previous studies have attempted to determine whether aseptic loosening and osteolysis are caused by a T cell-mediated type IV hypersensitivity reaction or a nonspecific foreign body reaction involving phagocytic macrophages. The purpose of this study was to examine the role of the B7-CD28 costimulatory pathway (which is indicative of an activated immune response) in loosening and osteolysis of total joint replacements (TJRs). We harvested periprosthetic tissues from 24 loose, cemented, all polyethylene, acetabular components in patients undergoing revision total hip replacement surgery for aseptic loosening. Prostheses were classified radiographically as to whether ballooning, scalloping osteolysis was present or not. Monoclonal antibodies were used to identify macrophages, antigen presenting cells (APCs) expressing B7-1 or B7-2, total T lymphocytes, and T cells expressing CD28 or CTLA-4. The large numbers of positive cells, including macrophages, T cells, and APCs in both groups are substantially higher than previously reported. Macrophages constituted the predominant cell type, the majority of which were APCs. B7-1 was expressed by 18.3% of all cells, and B7-2 was expressed by 61.0% of cells. Despite the fact that there were no statistically significant differences in expression of proteins in the B7-CD28 pathway between the osteolytic and nonosteolytic groups, the magnitude of positive staining suggests that the process of aseptic loosening (not osteolysis) may involve proteins of the B7-CD28 pathway, particularly B7-2. One possible antigenic stimulus is protein-coated particulate wear debris from prosthetic materials.

Adult↗

PubMed2001

Allogeneic bone marrow cells that facilitate complete chimerism and eliminate tumor cells express both CD8 and T-cell antigen receptor-alphabeta.

Nonmyeloablative host conditioning regimens have been used in clinical allogeneic bone marrow and hematopoietic progenitor transplantation to effectively treat lymphohematopoietic tumors and reduce early toxicity. However, severe graft-versus-host disease (GVHD) remains a major problem. The goal of the current study was to determine whether specific subsets of cells in allogeneic bone marrow transplants can effectively treat the BCL(1) B-cell lymphoma in nonmyeloablated BALB/c mouse hosts given a single dose of sublethal (450 cGy) total body irradiation, without inducing severe GVHD. The experimental results show that high doses of whole bone marrow cells from major histocompatiblity complex (MHC)-mismatched donors eliminate both normal and malignant host-type lymphohematopoietic cells without causing injury to nonlymphohematopoietic host tissues. The CD8(+)T-cell antigen receptor-alphabeta+ (TCRalphabeta+) T cells within the marrow transplants mediated the killing of the tumor cells via both perforin- and FasL-dependent pathways. Cells present in marrow transplants from either CD8-/- or TCRalpha-/- donors failed to eliminate malignant and normal host lymphohematopoietic cells. Addition of small numbers of blood mononuclear cells to the marrow inoculum caused lethal GVHD. Thus, the resident allogeneic bone marrow CD8(+) TCRalphabeta+ T cells had the unique capacity to eliminate the host lymphohematopoietic cells without nonlymphohematopoietic tissue injury. (Blood. 2001;97:3458-3465)

Adoptive Transfer↗

PubMed2001

Granulysin expression is a marker for acute rejection and steroid resistance in human renal transplantation.

Differentiating etiologies of transplant dysfunction without biopsy and optimizing therapy for acute rejection by predicting steroid resistance will reduce patient morbidity. Granulysin is a cytolytic molecule released by CTL and NK cells and coexpressed with effectors of acute allograft rejection, like perforin and granzymes. Granulysin mRNA and protein expression were studied in peripheral blood lymphocytes (PBL; n = 61 total, n = 10 with intercurrent infections) and biopsy tissue from adult and children renal transplant recipients (n = 97) by competitive quantitative-reverse transcriptase-PCR (QC-RT-PCR) and immunohistochemistry. Differences in cell phenotypes were studied in steroid sensitive and resistant acute rejection biopsies. Granulysin was studied in phytohemagglutinin (PHA) stimulated cell lines (donor PBL and CD45RO(+) T cells) by FACS, Western blotting, and RT-PCR after pretreating with cyclosporine A (CSA), azathioprine, mycophenolic acid, and steroids. Granulysin mRNA was significantly increased in patient PBL and transplant biopsies during acute rejection (p < 0.0001) and infection (p < 0.001). Rejecting biopsies alone (n = 53) had mononuclear cell granulysin staining. Steroid resistant biopsies (n = 25) had denser granulysin staining (>2 cells/high power field) and CD45RO(+) lymphocytes, when compared with steroid sensitive (n = 28) rejecting tissue. Granulysin levels were unchanged after azathioprine and mycophenolic acid treatment, decreased after treating activated PBL with steroids and cyclosporine A (CSA), and paradoxically, increased (p < 0.05) after treating CD45RO(+) CTL with CSA. Elevated PBL granulysin is a peripheral marker for acute rejection and infection and dense granulysin staining a tissue marker for steroid resistance. Memory CTL abound in steroid resistant grafts and may have a markedly different response to CSA immunotherapy, suggesting a possible mechanism for steroid resistance.

Acute Disease↗

PubMed2001

Expression of insulin-like growth factor-I and transforming growth factor-beta in hypokalemic nephropathy in the rat.

BACKGROUND: Potassium deficiency (KD) in the rat retards body growth but stimulates renal enlargement caused by cellular hypertrophy and hyperplasia, which is most marked in the outer medulla. If hypokalemia persists, interstitial infiltrates appear and eventually fibrosis. Since early in KD insulin-like growth factor-I (IGF-I) levels in the kidney are elevated, suggesting that it may be an early mediator of the exaggerated renal growth, and as transforming growth factor-beta (TGF-beta) promotes cellular hypertrophy and fibrosis, we examined the renal expression of these growth factors in prolonged KD. METHODS: Rats were given a K-deficient diet or were pair fed or ad libitum fed a K-replete diet for 21 days. Growth factor mRNA levels were measured in whole kidney and protein expression localized by immunohistochemistry. RESULTS: KD rats weighed less than pair-fed controls, while the kidneys were 49% larger. Their serum IGF-I and kidney IGF-I protein levels were depressed, as were their IGF-I mRNA levels in liver, kidney, and muscle. These changes can largely be attributed to decreased food intake. In contrast, kidney IGF binding protein-1 (IGFBP-1) mRNA and TGF-beta mRNA levels were increased significantly. Histology of outer medulla revealed marked hypertrophy and adenomatous hyperplasia of the collecting ducts and hypertrophy of the thick ascending limbs of Henle with cellular infiltrates in the interstitium. Both nephron segments immunostained strongly for IGF-I and IGFBP-1, but only the nonhyperplastic enlarged thick ascending Henle limb cells immunostained for TGF-beta, which was strongly positive. Prominent interstitial infiltrates with ED1 immunostained monocytes/macrophages were present. CONCLUSIONS: These findings are consistent with a sustained role for IGF-I in promoting the exaggerated renal growth of KD and appear to be mediated through local trapping of IGF-I by the overexpressed IGFBP-1, which together with IGF-I can promote renal growth. The selective localization of TGF-beta to hypertrophied nonhyperplastic nephron segments containing IGF-I raises the possibility that TGF-beta may be serving to convert the mitogenic action of IGF-I into a hypertrophic response in these segments. It is also conceivable that TGF-beta may be a cause of the tubulointerstitial infiltrate. Finally, the low circulating IGF-I levels likely contribute to the impaired body growth.

Animals↗

PubMed2000

Proliferating cell nuclear antigen as the cell cycle sensor for an HLA-derived peptide blocking T cell proliferation.

Synthetic peptides corresponding to structural regions of HLA molecules are novel immunosuppressive agents. A peptide corresponding to residues 65-79 of the alpha-chain of HLA-DQA03011 (DQ65-79) blocks cell cycle progression from early G1 to the G1 restriction point, which inhibits cyclin-dependent kinase-2 activity and phosphorylation of the retinoblastoma protein. A yeast two-hybrid screen identified proliferating cell nuclear Ag (PCNA) as a cellular ligand for this peptide, whose interaction with PCNA was further confirmed by in vitro biochemistry. Electron microscopy demonstrates that the DQ65-79 peptide enters the cell and colocalizes with PCNA in the T cell nucleus in vivo. Binding of the DQ65-79 peptide to PCNA did not block polymerase delta (pol delta)-dependent DNA replication in vitro. These findings support a key role for PCNA as a sensor of cell cycle progression and reveal an unanticipated function for conserved regions of HLA molecules.

Cell Cycle↗

PubMed2000

Set domain-dependent regulation of transcriptional silencing and growth control by SUV39H1, a mammalian ortholog of Drosophila Su(var)3-9.

Mammalian SET domain-containing proteins define a distinctive class of chromatin-associated factors that are targets for growth control signals and oncogenic activation. SUV39H1, a mammalian ortholog of Drosophila Su(var)3-9, contains both SET and chromo domains, signature motifs for proteins that contribute to epigenetic control of gene expression through effects on the regional organization of chromatin structure. In this report we demonstrate that SUV39H1 represses transcription in a transient transcriptional assay when tethered to DNA through the GAL4 DNA binding domain. Under these conditions, SUV39H1 displays features of a long-range repressor capable of acting over several kilobases to silence basal promoters. A possible role in chromatin-mediated gene silencing is supported by the localization of exogenously expressed SUV39H1 to nuclear bodies with morphologic features suggestive of heterochromatin in interphase cells. In addition, we show that SUV39H1 is phosphorylated specifically at the G(1)/S cell cycle transition and when forcibly expressed suppresses cell growth. Growth suppression as well as the ability of SUV39H1 to form nuclear bodies and silence transcription are antagonized by the oncogenic antiphosphatase Sbf1 that when hyperexpressed interacts with the SET domain and stabilizes the phosphorylated form of SUV39H1. These studies suggest a phosphorylation-dependent mechanism for regulating the chromatin organizing activity of a mammalian su(var) protein and implicate the SET domain as a gatekeeper motif that integrates upstream signaling pathways to epigenetic regulation and growth control.

3T3 Cells↗

PubMed2000

Reduction of aortic wall motion inhibits hypertension-mediated experimental atherosclerosis.

Hypertension is a well-known risk factor for coronary artery disease and carotid and lower extremity occlusive disease. Surgically induced hypertension in hypercholesterolemic animals results in increased aortic wall motion and increased plaque formation. We tested the hypothesis that reduction in aortic wall motion, despite continued hypertension, could reduce plaque formation. New Zealand White rabbits (n=26) underwent thoracic aortic banding to induce hypertension and were fed an atherogenic diet for 3 weeks. In 13 rabbits, a segment of aorta proximal to an aortic band was externally wrapped to reduce wall motion. All animals were fed an atherogenic diet for 3 weeks. Four groups were studied: 1, coarctation control (no wrap, n=7); 2, coarctation with loose wrap (n=6); 3, coarctation with firm wrap (n=7); and 4, control (noncoarcted, n=6). Wall motion, blood pressure, and pulse pressure were measured at standard reference sites proximal and distal to the coarctation by use of intravascular ultrasound. Quantitative morphometry was used to measure intimal plaque. Mean arterial pressure and cyclic aortic wall motion were equally increased proximal to the aortic coarctation in all 3 coarcted rabbit groups compared with the control group (P:<0.001). Wall motion in the segment of aorta under the loose and firm wraps was no different from the control value. The external wrap significantly reduced intimal thickening in the 4 groups by the following amounts: group 1, 0.30+/-0.03 mm(2); group 2, 0.06+/-0.02 mm(2); group 3, 0. 04+/-0.02 mm(2); and group 4, 0.01+/-0.01 mm(2) (P:<0.001). Localized inhibition of aortic wall motion in the lesion-prone hypertensive aorta resulted in significant reduction in intimal plaque formation. These data suggest that arterial wall cyclic motion may stimulate cellular proliferation and lipid uptake in experimental atherosclerosis.

Animals↗

PubMed1999

Comparison of chimeric acid and non-chimeric tolerance using posttransplant total lymphoid irradiation: cytokine expression and chronic rejection.

BACKGROUND: Previous studies showed that an intravenous infusion of donor blood cells facilitates tolerance to ACI heart allografts in Lewis rat hosts given posttransplant total lymphoid irradiation (TLI) and anti-thymocyte globulin (ATG). The object of the current study was to compare tolerance induction using donor cells that do or do not induce chimerism. METHODS: Normal peripheral blood mononuclear cells (PBMC), granulocyte colony-stimulating factor (G-CSF)-mobilized PBMC, and bone marrow (BM) cells from ACI donors were tested for their capacity to prolong ACI heart allograft survival in Lewis hosts. Chimerism, anti-donor cell reactivity, and cytokine gene expression in grafts were determined. RESULTS: Intravenous injections of equal numbers of all three donor cells markedly prolonged graft survival (median: >164 to >175 days) as compared to uninjected controls (median: 53 days). Chimerism among T and B cells in the blood was determined by immunofluorescent staining in hosts bearing long-term (> 150 days) grafts. Although no chimerism was detected in hosts given normal or G-CSF-mobilized PBMC, chimerism was detected at variable levels in all hosts given BM cells. Vigorous anti-donor reactivity in the mixed leukocyte reaction was present only in non-chimeric hosts. Long-term grafts from hosts given normal ACI PBMC developed chronic rejection, but those from hosts given ACI BM cells did not. The latter hosts showed the lowest levels of intragraft cytokine mRNA. CONCLUSIONS: Chimeric tolerance is more robust than non-chimeric tolerance in the model of posttransplant TLI, ATG, and donor cell infusion, and is associated with less chronic rejection.

Animals↗

PubMed1999

Components of an SCF ubiquitin ligase localize to the centrosome and regulate the centrosome duplication cycle.

Centrosomes organize the mitotic spindle to ensure accurate segregation of the chromosomes in mitosis. The mechanism that ensures accurate duplication and separation of the centrosomes underlies the fidelity of chromosome segregation, but remains unknown. In Saccharomyces cerevisiae, entry into S phase and separation of spindle pole bodies each require CDC4 and CDC34, which encode components of an SCF (Skp1-cullin-F-box) ubiquitin ligase, but a direct (SCF) connection to the spindle pole body is unknown. Using immunofluorescence microscopy, we show that in mammalian cells the Skp1 protein and the cullin Cul1 are localized to interphase and mitotic centrosomes and to the cytoplasm and nucleus. Deconvolution and immunoelectron microscopy suggest that Skp1 forms an extended pericentriolar structure that may function to organize the centrosome. Purified centrosomes also contain Skp1, and Cul1 modified by the ubiquitin-like molecule NEDD8, suggesting a role for NEDD8 in targeting. Using an in vitro assay for centriole separation in Xenopus extracts, antibodies to Skp1 or Cul1 block separation. Proteasome inhibitors block both centriole separation in vitro and centrosome duplication in Xenopus embryos. We identify candidate centrosomal F-box proteins, suggesting that distinct SCF complexes may direct proteolysis of factors mediating multiple steps in the centrosome cycle.

3T3 Cells↗

PubMed1999

The characterization of macrophages and osteoclasts in tissues harvested from revised total hip prostheses.

The differentiation and maturation of macrophages and osteoclasts at the prosthetic interface in cases of implant loosening are poorly understood. Using histochemical and immunohistochemical staining methods, we compare macrophage differentiation in tissues from revised hip replacements in patients with specific clinical-radiological appearances. Periprosthetic tissues were harvested from 12 cemented acetabular and 12 cemented femoral components in 24 patients undergoing revision hip replacement. The prostheses were all radiographically and clinically loose. Six acetabular and six femoral components demonstrated radiographic ballooning osteolysis. Serial 6 microm frozen sections of the periprosthetic tissues were processed with hematoxylin and eosin for general tissue morphology, and analyzed for the presence of tartrate resistant acid phosphatase (TRAP, an osteoclast marker). Immunoperoxidase staining using monoclonal antibodies to CD68 (macrophages and osteoclasts) and CD51 (the alpha chain of the vitronectin receptor, an osteoclast marker) was also performed. Approximately 8-30% of the total cells in the tissues were positive for TRAP and the vitronectin receptor, and comprised a subset of the CD68 positive macrophages and macrophage polykaryons. However, there were no statistically significant differences between specific groups (femoral vs. acetabular, osteolysis vs. no osteolysis) for the numbers or percentages of macrophages or osteoclast-like cells. Once prosthetic loosening has occurred, few differences in the macrophage-osteoclast profile of tissues from different periprosthetic locations, with and without osteolysis, are noted. This suggests a final common biologic pathway for periprosthetic bone resorption, once implant loosening has transpired.

Acid Phosphatase↗

PubMed1998

Monocyte-derived dendritic cell precursors facilitate tolerance to heart allografts after total lymphoid irradiation.

BACKGROUND: Previous studies have shown that posttransplant total lymphoid irradiation, anti-thymocyte globulin, and an intravenous donor blood cell infusion induce tolerance to ACI heart allografts in Lewis rat hosts. METHODS: In the current study, fresh ACI monocytes and dendritic cell precursors, derived from short-term culture of the latter cells in granulocyte macrophage colony-stimulating factor, were tested for their capacity to prolong heart allograft survival in this model. RESULTS: The experimental results show that significant prolongation of graft survival was achieved after injection of the fresh donor monocytes or 2-day or 6-day cultured cells. The 2-day cultured cells were most effective, and more than 60% of hosts maintained graft survival for more than 160 days. Ten-day cultured cells and fresh splenic dendritic cells failed to prolong graft survival. Studies of cell surface markers showed that the 2-day cultured cells had up-regulated class II major histocompatibility complex and CD80, but not CD86 molecules. On the other hand, the 10-day cultured cells and splenic dendritic cells showed intense expression of all three markers. The latter cells stimulated vigorous proliferative and cell-mediated lympholysis responses in the mixed leukocyte reaction, but the fresh and 2-day cultured cells were weak stimulators. CONCLUSION: The intravenous injection of donor dendritic cell precursors derived from blood monocytes facilitates long-term acceptance of heart allografts.

Adoptive Transfer↗

PubMed1998

Donor blood monocytes but not T or B cells facilitate long-term allograft survival after total lymphoid irradiation.

BACKGROUND: Previous studies showed that a combination of posttransplant total lymphoid irradiation (TLI), rabbit antithymocyte globulin (ATG), and a single donor blood transfusion induced tolerance to ACI heart allografts in Lewis rats. All three modalities were required to achieve tolerance. The objective of the current study was to determine the subset(s) of cells in the donor blood that facilitated long-term allograft survival. METHODS: Lewis hosts received TLI, ATG, and donor cell infusion after heart transplantation. Graft survival, mixed leukocyte reaction (MLR), and intragraft cytokine mRNA were studied. RESULTS: The intravenous injection of 25 x 10(6) ACI peripheral blood mononuclear cells (PBMC) significantly prolonged graft survival as compared with that of Lewis hosts given TLI and ATG alone. Injection of highly enriched blood T cells or splenic B cells adjusted for the number contained in 25 x 10(6) PBMC failed to induce significant graft prolongation. Unexpectedly, depletion of monocytes (CD11b+ cells) from PBMC resulted in the loss of graft prolongation activity. Enriched populations of monocytes obtained by plastic adherence were more efficient in prolonging graft survival than PBMC on a per cell basis. Hosts with long-term grafts (>100-day survival) showed evidence of immune deviation, because the MLR to ACI stimulator cells was vigorous, but secretion of interferon-gamma in the MLR was markedly reduced. In situ hybridization studies of long-term grafts showed markedly reduced levels of interferon-gamma mRNA as compared with rejecting grafts. CONCLUSION: Infusion of donor monocytes facilitated graft prolongation via immune deviation.

Animals↗

PubMed1998

Inducible nitric oxide synthase messenger RNA levels in hip periprosthetic tissue: a preliminary study.

Nitric oxide (NO) is a ubiquitous molecule that has been associated with inflammation, arthritis, autoimmune disease, bone resorption, and other biological processes. Elucidating the role of NO at the bone-implant interface may further our understanding of the biological processes of osseointegration, loosening, and osteolysis. This study demonstrates the use of a molecular biological technique to investigate the possible role of NO in prosthetic loosening and periprosthetic bone resorption following total hip arthroplasty. Periprosthetic tissue from 12 patients undergoing revision hip arthroplasty was harvested and total ribonucleic acid (RNA) was extracted. In six of the 12 patients, multiple samples from different anatomic locations along the same interface were studied. To estimate the amount of NO present in the tissues in vivo, the level of inducible NO synthase (iNOS) messenger RNA (mRNA) was determined using a ribonuclease (RNase) protection assay. Inducible NOS mRNA was detected in every tissue sample: there was no correlation between iNOS mRNA levels and clinical loosening or osteolysis. Analysis of multiple tissue samples from the same prosthetic component revealed that the levels of iNOS mRNA vary greatly, confirming the heterogeneous nature of the interface.

Adult↗

PubMed1998

Backleak, tight junctions, and cell- cell adhesion in postischemic injury to the renal allograft.

Postischemic injury in recipients of 3-7-d-old renal allografts was classified into sustained (n = 19) or recovering (n = 20) acute renal failure (ARF) according to the prevailing inulin clearance. Recipients of optimally functioning, long-standing allografts and living donors undergoing nephrectomy served as functional (n = 14) and structural controls (n = 10), respectively. Marked elevation above control of fractional clearance of dextrans of graded size was consistent with transtubular backleak of 57% of filtrate (inulin) in sustained ARF. No backleak was detected in recovering ARF. To explore a structural basis for backleak, allograft biopsies were taken intraoperatively, 1 h after reperfusion in all recipients, and again on day 7 after transplant in a subset (n = 10). Electron microscopy revealed disruption of both apical and basolateral membranes of proximal tubule cells in both sustained and recovering ARF, but cell exfoliation and tubule basement membrane denudation were negligible. Histochemical analysis of membrane-associated adhesion complexes confirmed an abnormality of proximal but not distal tubule cells, marked in sustained ARF but not in recovering ARF. Staining for the zonula occludens complex (ZO-1) and adherens complex (alpha, beta, and gamma catenins) revealed diminished intensity and redistribution of each cytoskeletal protein from the apico-lateral membrane boundary. We conclude that impaired integrity of tight junctions and cell-cell adhesion in the proximal tubule provides a paracellular pathway through which filtrate leaks back in sustained allograft ARF.

Acute Kidney Injury↗

PubMed1998

Subsets of transgenic T cells that recognize CD1 induce or prevent murine lupus: role of cytokines.

T cells with T cell receptor (TCR) transgenes that recognized CD1 on syngeneic B cells stimulated B cells to secrete immunoglobulins in vitro. The CD4+, CD8+, or CD4-CD8- T cells from the spleen of the TCR transgenic BALB/c donors induced lupus with anti-double stranded DNA antibodies, proteinuria, and immune complex glomerulonephritis in irradiated BALB/c nude mice reconstituted with nude bone marrow. Injection of purified CD4-CD8- T cells from the marrow of transgenic donors prevented the induction of lupus by the transgenic T cells. Transgenic T cells that induced lupus secreted large amounts of interferon (IFN)-gamma and little interleukin (IL)-4, and those that prevented lupus secreted large amounts of IL-4 and little IFN-gamma or IL-10.

Animals↗

PubMed1998

Nature of glomerular dysfunction in pre-eclampsia.

BACKGROUND: Pre-eclampsia is characterized by hypertension, proteinuria and edema. Simultaneous studies of kidney function and structure have not been reported. We wished to explore the degree and nature of glomerular dysfunction in pre-eclampsia. METHODS: Physiologic techniques were used to estimate glomerular filtration rate (GFR), renal plasma flow and afferent oncotic pressure immediately after delivery in consecutive patients with pre-eclampsia (PET; N = 13). Healthy mothers completing an uncomplicated pregnancy served as functional controls (N = 12). A morphometric analysis of glomeruli obtained by biopsy and mathematical modeling were used to estimate the glomerular ultrafiltration coefficient (Kf). Glomeruli from healthy female kidney transplant donors served as structural controls (N = 8). RESULTS: The GFR in PET was depressed below the control level, 91 +/- 23 versus 149 +/- 34 ml/min/1.73 m2, respectively (P < 0.0001). In contrast, renal plasma flow and oncotic pressure were similar in the two groups (P = NS). A reduction in the density and size of endothelial fenestrae and subendothelial accumulation of fibrinoid deposits lowered glomerular hydraulic permeability in PET compared to controls, 1.81 versus 2.58 x 10(-9) m/sec/PA. Mesangial cell interposition also curtailed effective filtration surface area. Together, these changes lowered the computed single nephron Kf in PET below control, 4.26 versus 6.78 nl/min x mm Hg, respectively. CONCLUSION: The proportionate (approximately 40%) depression of Kf for single nephrons and GFR suggests that hypofiltration in PET does not have a hemodynamic basis, but is a consequence of structural changes that lead to impairment of intrinsic glomerular ultrafiltration capacity.

Adult↗

PubMed1998

Cellular profile and cytokine production at prosthetic interfaces. Study of tissues retrieved from revised hip and knee replacements.

The tissues surrounding 65 cemented and 36 cementless total joint replacements undergoing revision were characterised for cell types by immunohistochemistry and for cytokine expression by in situ hybridisation. We identified three distinct groups of revised implants: loose implants with ballooning radiological osteolysis, loose implants without osteolysis, and well-fixed implants. In the cemented series, osteolysis was associated with increased numbers of macrophages (p = 0.0006), T-lymphocyte subgroups (p = 0.03) and IL-1 (p = 0.02) and IL-6 (p = 0.0001) expression, and in the cementless series with increased numbers of T-lymphocyte subgroups (p = 0.005) and increased TNF alpha expression (p = 0.04). For cemented implants, the histological, histochemical and cytokine profiles of the interface correlated with the clinical and radiological grade of loosening and osteolysis. Our findings suggest that there are different biological mechanisms of loosening and osteolysis for cemented and cementless implants. T-lymphocyte modulation of macrophage function may be an important interaction at prosthetic interfaces.

Aged↗