[The change in hyaluronic acid (HA) in auto-and allo-skin intermingled grafting in extensive full thickness burn in rat model]

OBJECTIVE

To elucidate the changes in hyaluronic acid (HA) contents in auto-and alloskin intermingled grafting.

METHODS

HA was determined by radio-immunoassay in auto-and alloskin intermingled grafting (a large sheet of allograft inlaid with small stamps of autoskin) in experimental extensive full-thickness burn rats on 3rd, 5th, 7th, 14th, 21st, 28th postoperation days.

RESULTS

In both areas of intermingled skin grafting, the contents of HA was reduced first and increased significantly thereafter, but the contents in auto-skin areas rose earlier and higher than those in allo-ones.

CONCLUSION

The results suggest that adequate application of HA may be beneficial to the healing and remodelling of grafted area.

[Inhibition of hematopoiesis by sera from patients with myelodysplastic syndromes]

OBJECTIVE

To explore the inhibitory effect of sera from patients with myelodysplastic syndromes (MDS) on the growth of normal hematopoietic progenitor cells.

METHODS

The inhibitory activity to the growth of BFU-E and CFU-GM was analysed by in vitro methylcellulose culture. Hematopoietic cell apoptosis was assayed with a programmed cell death assay kit and flow cytometry.

RESULTS

In the 23 MDS patients studied, a potent inhibitory activity to CFU-GM and BFU-E was demonstrated in 3 and 4 patients, respectively. The inhibitory activity to BFU-E of sera from 3 patients was almost entirely neutralized by anti-TNF alpha McAb. Sera from two MDS patients induced apoptosis of normal hematopoietic progenitor cells.

CONCLUSION

Inhibitors of hematopoietic progenitor cells are present in sera from some MDS patients. One of the inhibitors might be TNF alpha, which can induce apoptosis, resulting in ineffective hematopoiesis in MDS.

An Approach to Chemorheology of a Filled SBR Compound

Three steps in complex chemorheological studies are necessary for complete rheological characterization of filled rubbers during cross-linking reaction. They include: (i) kinetic studies of cross-linking reaction, (ii) rheological studies of green rubber compounds, and (iii) correlation between the rheological parameters and the degree of cure. Basic experiments in the steps (i)–(iii) and their modeling are presented in this paper on the example of a filled SBR compound with sulfur accelerated vulcanization. The approach provides a unique possibility to trace therheological properties of rubber compounds from the green to completely cured states.

[Study on the pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura]

OBJECTIVE

To investigate the possible pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura(APATP).

METHODS

Twenty eight patients with APATP were studied. Bone marrow mononuclear cells(MNCs) from these patients were plated into methyl cellulose cultures for CFU-GM, CFU-E and CFU-MK assay. The influence of depleting T cells or adherent cells from patients' marrow cells on CFU-MK growth was observed. The humoral inhibitory effect on CFU-MK was determined by co-incubation of patients' sera or IgG with normal or autologous MNCs prior to cultures. The serum MK-CSA was also assessed.

RESULTS

Fifteen cases (53.6%) of APATP was resulted from intrinsic defect of CFU-MK. The megakaryocyte colony formation was augmented significantly in 3 T lymphocytes-depleted and 2 mono-macrophages depleted patients. Sera from 6 patients(21.4%) were inhibitor to CFU-MK. The inhibitor originated from IgG and selectively directed against the megakaryocyte. In the remaining 2 cases, the pathogenesis was not ascertained.

CONCLUSION

The intrinsic defect of megakaryocyte progenitor cell is considered to be a primary pathogenesis of APATP. In some patients the disease can result from abnormal immune mechanisms. The decompensation of MK-CSA production could also be an important cause for APATP.

Prolongation of the p53 response to DNA strand breaks in cells depleted of PARP by antisense RNA expression

The observation that 3-aminobenzamide, which inhibits a variety of ADP-ribose transferases, prolongs the gamma-irradiation-induced increase in intracellular p53 concentration suggested that one or more of such enzymes may determine the duration of the p53 response during G1 arrest. The role of poly(ADP-ribose) polymerase (PARP), an abundant nuclear enzyme activated by DNA strand breaks, in the p53 response to y-irradiation was investigated in Burkitt's lymphoma AG876 cells stably transfected with an inducible PARP antisense construct. Immunoblot analysis revealed that the cellular content of PARP was reduced to virtually undetectable levels after incubation of transfected cells for 72 h with the inducer dexamethasone. In noninduced antisense cells, the p53 concentration reached a maximum 2 h after exposure to 6.3 Gy of gamma-radiation and returned to control values by 4 h. In contrast, the p53 response in PARP-depleted antisense cells peaked at 4 h, with the levels of p53 remaining elevated for up to 12 h after y-irradiation. The maximal increase in p53 concentration was similar in both induced and noninduced cells. These results thus indicate that PARP activity, in part, determines the duration, but not the magnitude, of the p53 response to DNA damage.

cut11(+): A gene required for cell cycle-dependent spindle pole body anchoring in the nuclear envelope and bipolar spindle formation in Schizosaccharomyces pombe

The "cut" mutants of Schizosaccharomyces pombe are defective in spindle formation and/or chromosome segregation, but they proceed through the cell cycle, resulting in lethality. Analysis of temperature-sensitive alleles of cut11(+) suggests that this gene is required for the formation of a functional bipolar spindle. Defective spindle structure was revealed with fluorescent probes for tubulin and DNA. Three-dimensional reconstruction of mutant spindles by serial sectioning and electron microscopy showed that the spindle pole bodies (SPBs) either failed to complete normal duplication or were free floating in the nucleoplasm. Localization of Cut11p tagged with the green fluorescent protein showed punctate nuclear envelope staining throughout the cell cycle and SPBs staining from early prophase to mid anaphase. This SPB localization correlates with the time in the cell cycle when SPBs are inserted into the nuclear envelope. Immunoelectron microscopy confirmed the localization of Cut11p to mitotic SPBs and nuclear pore complexes. Cloning and sequencing showed that cut11(+) encodes a novel protein with seven putative membrane-spanning domains and homology to the Saccharomyces cerevisiae gene NDC1. These data suggest that Cut11p associates with nuclear pore complexes and mitotic SPBs as an anchor in the nuclear envelope; this role is essential for mitosis.

Changes in extracellular glutamate and GABA levels in the hippocampal CA3 and CA1 areas and the induction of glutamic acid decarboxylase-67 in dentate granule cells of rats treated with kainic acid

For the evaluation of glutamatergic and GABAergic transmission during seizures, rat hippocampal CA1 and CA3 areas were separately assessed by brain microdialysis, and extracelluar glutamate and GABA were measured through the course of the seizures after a systemic administration of kainic acid (KA). The generalized convulsion started at about 1.5 h and was suppressed by diazepam at 2 h after the KA treatment. In the CA3 area, extracellular glutamate started to increase soon after the KA injection and returned to the control level at about 1.5 h. A decrease and then slight increase of the extracellular glutamate level in CA3 followed the diazepam injection. In the CA1 area, in contrast, a long-lasting decrease of extracellular glutamate was observed. The extracellular GABA concentration in the CA3 area increased immediately after the systemic administration of KA and returned to the normal level at about 3.5 h. A second increase in the extracellular GABA in this area began at about 4.5 h after the KA treatment. In the CA1 area, an increase of extracellular GABA began at about 3.5 h after KA administration (much later than that observed in the CA3 area) and was maintained throughout the observation. In situ hybridization showed a transient expression of glutamic acid decarboxylase (GAD)-67 mRNA in the granule cell layer of the dentate gyrus at 4 and 6 h, whereas GAD65 mRNA was unaffected. GABA immunoreactivity in the same area and mossy fibers in the CA3 were increased most significantly at 8 h after administration of KA. The possible relation of GABA induction in mossy fibers with the delayed increase in extracellular GABA in CA3 was discussed.

Rectal and intranasal immunizations with recombinant urease induce distinct local and serum immune responses in mice and protect against Helicobacter pylori infection

To determine the optimal inductive sites for immunization against Helicobacter pylori infection, the protective efficacy of recombinant urease (rUre) was assessed for mice given the vaccine by either the oral (p.o.), intranasal (i.n.), or rectal route. When mice were immunized with rUre (25 microg p.o. or rectally or 10 microg i.n.) plus heat-labile toxin from Escherichia coli as the mucosal adjuvant, all routes afforded protection against challenge with H. pylori, as indicated by a significant reduction in gastric urease activity (P < 0.0005) compared to that of sham-immunized controls. Quantitative H. pylori culture of stomach tissue demonstrated a >97% reduction in bacterial burden in mice immunized by all routes (P < 0.05). Induction of antiurease immunoglobulin A (IgA) levels in gastric luminal secretions after p.o. immunization was greater than after i.n. administration (means, 6.0 and 1.02 ng/ml, respectively) and was dependent upon challenge with H. pylori. However, immunization by the rectal route resulted in the generation of the highest levels of gastric antiurease IgA (mean, 40. 89 ng/ml), which was detectable prior to challenge with H. pylori. Immunohistochemical staining of stomach tissue for cells secreting urease-specific antibody and CD4(+) T cells showed levels of recruitment to be dependent upon challenge with H. pylori and equivalent for all routes. These results identify both the rectum and nasal passages as suitable inductive sites for urease immunization.

Global control of meiotic recombination genes by Schizosaccharomyces pombe rec16 (rep1)

The Schizosaccharomyces pombe rec16-125 mutation reduces meiotic recombination, delays premeiotic DNA synthesis, and reduces the accumulation of some but not other rec gene transcripts. To elucidate the function of the Rec16 global meiotic regulator, we cloned and sequenced rec16. The data revealed that rec16 is identical to rep1, which was previously shown to encode a protein with a zinc-finger motif required for pre-meiotic DNA synthesis. Transcripts of rec16 (rep1) were strongly induced and subsequently degraded during meiosis. In a rec16 (rep1) deletion mutant, meiotic induction of the seven rec genes tested, which appear to be directly involved in meiotic recombination, was significantly reduced or essentially abolished. Deletion of 80% of the gene essentially abolished meiotic recombination, whereas strains deleted for approximately one-quarter of the gene, from either end, retained partial activity. The rec16-125 mutation strongly reduced recombination in the intervals tested on chromosomes I and III, a phenotype characteristic of mutations in rec genes, such as rec7, whose expression requires Rec16 (Rep1). These results show that Rec16 (Rep1) does not have the regional specificity of Rec10. We infer that Rec16 (Rep1) is a transcriptional activator that is required for meiotic replication and recombination because it plays a role in the transcriptional induction of the rec and other meiosis-specific genes.

In vivo expression of transforming growth factor-beta1 in humans: stimulation by cyclosporine

BACKGROUND

Transforming growth factor-beta1 (TGF-beta1) is an immunoregulatory and fibrogenic cytokine. In an earlier in vitro study, we demonstrated that cyclosporine (CsA) increases TGF-beta1 transcription rate in human T lymphocytes. Herein, we explored whether CsA augments the in vivo expression of TGF-beta1 in humans.

METHODS

The inherent difficulty in studying the in vivo effect of CsA in humans was circumvented by investigating stable end-stage renal disease patients who were preconditioned with CsA before their living donor renal transplantation. Sera and peripheral blood mononuclear cells were obtained from CsA-preconditioned patients and quantified for TGF-beta1 expression at the mRNA (by competitive polymerase chain reaction) and protein (sandwich enzyme-linked immunosorbent assay) levels.

RESULTS

Our studies demonstrated a significant increase in TGF-beta1 expression after CsA therapy. The stimulatory effect was unique to TGF-beta1, and CsA did not increase interleukin (IL)-10, IL-6, IL-2, or tumor necrosis factor-alpha expression.

CONCLUSIONS

Our first-time demonstration of a TGF-beta1-selective in vivo stimulatory effect of CsA in humans: (1) advances a TGF-beta1-centered hypothesis for the beneficial (immunosuppression) and detrimental (fibrosis, hypertension) effects of CsA use, and (2) broadens the mechanism of immunosuppressive action of CsA to include heightened expression of an endogenous immunosuppressive cytokine.

Relationship between hepatic cytochrome P450 3A content and activity and the disposition of midazolam administered orally

It was recently shown by others that the clearance of midazolam/kg body weight after iv administration correlates with hepatic cytochrome P450 (CYP or P450) 3A content in liver transplant patients. However, after po administration midazolam undergoes significant first-pass metabolism, with significant intestinal extraction. The relationship between hepatic CYP3A and midazolam disposition after po administration had not previously been investigated. The aim of this study was to compare intraindividually hepatic CYP3A content and activity with the in vivo pharmacokinetics of midazolam (7.5 mg) administered po. For 15 patients scheduled for partial liver resection, the AUC values for the observed time period (AUC0-5hr) and to infinity (AUCinf) and the clearance were determined. In a macroscopically normal area of resected liver tissue, the microsomal CYP3A4 content (nanomoles per nanomole of total P450) was measured by immunoblot analysis and parameters (apparent Vmax, apparent KM, and intrinsic clearance) for the microsomal alpha-hydroxylation of midazolam were determined. Clearance/kg in vivo correlated with the apparent Vmax (r2 = 0.45, p < 0.01) and the CYP3A4 content (r2 = 0.29, p < 0.05). We conclude that interindividual variability in the pharmacokinetics of po administered midazolam is in part determined by interindividual variability in the hepatic microsomal Vmax for the alpha-hydroxylation of midazolam. However, the relationship between the disposition of midazolam administered po and hepatic CYP3A content is weaker than that reported after iv administration, indicating the importance of the contribution of intestinal CYP3A to the in vivo disposition of midazolam administered po.

Gastritis in urease-immunized mice after Helicobacter felis challenge may be due to residual bacteria

BACKGROUND & AIMS

Oral immunization with recombinant Helicobacter pylori urease (rUre) coadministered with a mucosal adjuvant protects mice against challenge with Helicobacter felis. In this study, the duration of protection and gastritis after challenge were characterized at sequential time intervals up to 1 year.

METHODS

Outbred Swiss-Webster mice were orally immunized with rUre plus adjuvant and examined for the presence of H. felis infection and leukocyte infiltration into the gastric mucosa.

RESULTS

When defined by gastric urease activity, 70%-95% of rUre-immunized mice were protected for between 2 and 57 weeks. Challenge with H. felis increased the inflammatory response in the gastric mucosa of rUre-immunized mice, which also had elevated CD4+ and CD8+ T cells. The CD8+ cells represented a population of gastric intraepithelial cells, which expressed the mucosal alpha E-integrin. Epithelial changes consisting of parietal cell loss and hyperplasia of the epithelium occurred in approximately 20% of the mice. Antimicrobial triple therapy significantly decreased the degree of gastritis and epithelial alteration in the stomach.

CONCLUSIONS

These results indicate that oral immunization of mice with rUre produces a long-lasting inhibition of H. felis infection but that residual bacteria may produce a persistent lymphocytic infiltration under these experimental conditions.

The spindle pole body of Schizosaccharomyces pombe enters and leaves the nuclear envelope as the cell cycle proceeds

The cycle of spindle pole body (SPB) duplication, differentiation, and segregation in Schizosaccharomyces pombe is different from that in some other yeasts. Like the centrosome of vertebrate cells, the SPB of S. pombe spends most of interphase in the cytoplasm, immediately next to the nuclear envelope. Some gamma-tubulin is localized on the SPB, suggesting that it plays a role in the organization of interphase microtubules (MTs), and serial sections demonstrate that some interphase MTs end on or very near to the SPB. gamma-Tubulin is also found on osmiophilic material that lies near the inner surface of the nuclear envelope, immediately adjacent to the SPB, even though there are no MTs in the interphase nucleus. Apparently, the MT initiation activities of gamma-tubulin in S. pombe are regulated. The SPB duplicates in the cytoplasm during late G2 phase, and the two resulting structures are connected by a darkly staining bridge until the mitotic spindle forms. As the cell enters mitosis, the nuclear envelope invaginates beside the SPB, forming a pocket of cytoplasm that accumulates dark amorphous material. The nuclear envelope then opens to form a fenestra, and the duplicated SPB settles into it. Each part of the SPB initiates intranuclear MTs, and then the two structures separate to lie in distinct fenestrae as a bipolar spindle forms. Through metaphase, the SPBs remain in their fenestrae, bound to the polar ends of spindle MTs; at about this time, a small bundle of cytoplasmic MTs forms in association with each SPB. These MTs are situated with one end near to, but not on, the SPBs, and they project into the cytoplasm at an orientation that is oblique to the simple axis. As anaphase proceeds, the nuclear fenestrae close, and the SPBs are extruded back into the cytoplasm. These observations define new fields of enquiry about the control of SPB duplication and the dynamics of the nuclear envelope.

[The changes of fibrinolysis in plasma and wounds in rats inflicted with deep partial thickness burns]

We observed the changes in wound histopathology and fibrinolysis of rats with deep partial thickness burns during 10 days after scalding in order to study the relations of early progressive damage of deep partial thickness burn wound and the healing of the wound to fibrinolysis. Using Masson's trichrome stain of collagen, we demonstrated that partial thickness burn wound progressively deteriorated within 72 hours postburn, and epidermal cells on wound edge proliferated, creeping between necrotic and residual collagen by 10th day postburn. The results of assays of fibrinolytic parameters in plasma and 24 hour exudate from wound showed that fibrinolysis activated at 2 hour postburn but had been suppressed by 24 hour postburn till last day (10 day postburn) of the observation. The analysis of dynamic changes and relations in fibrinolytic parameters revealed that the suppressive factors of fibrinolysis might be enhanced activities of PAI, alpha 2-antiplasmin and antithrombin II after injury. Results suggested that suppression of fibrinolysis might protect fibrin deposited in the wound from lysis and play an important role in early progressive deterioration of deep partial thickness burn and regulation of its healing.

Intact cell evidence for the early synthesis, and subsequent late apopain-mediated suppression, of poly(ADP-ribose) during apoptosis

Poly(ADP-ribose) polymerase (PARP), which is catalytically activated by DNA strand breaks, has been implicated in apoptosis, or programmed cell death. A protease (CPP32) responsible for the cleavage of PARP and necessary for apoptosis was recently purified and characterized. The coordinated sequence of events related to PARP activation and cleavage in apoptosis has now been examined in individual cells. Apoptosis was studied in a human osteosarcoma cell line that undergoes a slow (8 to 10 days), spontaneous, and reproducible death program in culture. Changes in the abundance of intact PARP, poly(ADP-ribose) (PAR), and a proteolytic cleavage product of PARP that contains the DNA-binding domain were examined during apoptosis in the context of individual, whole cells by immunofluorescence with specific antibodies. The synthesis of PAR from NAD increased early, within 2 days of cell plating for apoptosis, prior to the appearance of internucleosomal DNA cleavage and before the cells become irreversibly committed to apoptosis, since replating yields viable, nonapoptotic cells. Strong expression of full-length PARP was also detected, by immunofluorescence as well as by Western analysis, during this same time period. However, after approximately 4 days in culture, the abundance of both full-length PARP and PAR decreased markedly. After 6 days, a proteolytic cleavage product containing the DNA-binding domain of PARP was detected immunocytochemically and confirmed by Western analysis, both in the nuclei and in the cytoplasm of cells. A recombinant peptide spanning the DNA-binding domain of PARP was expressed, purified, and biotinylated, and was then used as a probe for DNA strand breaks. Fluorescence microscopy with this probe revealed extensive DNA fragmentation during the later stages of apoptosis. This is the first report, using individual, intact cells, demonstrating that poly(ADP-ribosyl)ation of nuclear proteins occurs prior to the commitment to apoptosis, that inactivation and cleavage of PARP begin shortly thereafter, and that very little PAR per se is present during the later stages of apoptosis, despite the presence of a very large number of DNA strand breaks. These results suggest a negative regulatory role for PARP during apoptosis, which in turn may reflect the requirement for adequate NAD and ATP during the later stages of programmed cell death.

Detection of DNA breaks in apoptotic cells utilizing the DNA binding domain of poly(ADP-ribose) polymerase with fluorescence microscopy

The DNA binding domain (DBD) of poly(ADP-ribose) polymerase (PARP) has proved to be a novel, highly sensitive probe for detecting DNA breaks in intact cells undergoing apoptosis. A recombinant peptide spanning the DNA binding domain of PARP was expressed, purified and used to detect DNA strand breaks in fixed cells. Fluorescence microscopy with this probe followed by detection with anti-PARP antisera initially revealed an increased binding following treatment of cells with DNA strand-breaking agents (such asN-methyl-N'-nitro-N-nitrosoguanidine) and, subsequently, using biotinylated PARP DBD, during the later stages of apoptosis in several cell systems, when internucleosomal strand breaks became evident. This procedure was found to be at least as sensitive and required fewer steps to detect DNA strand breaks than those utilizing Klenow incorporation of biotinylated nucleotides.

[Change in nitric oxide contents of knee joint fluid in patients with degenerative osteoarthritis]

The degenerative osteoarthritis (DOA) is a common disease of aged people. But its pathogenesis and mechanism are not very clear. We compared the Nitric Oxide content in knee fluid of DOA with the normal people as matched age. The results indicated that the Nitric oxide has a high concentration in DOA. This suggested that the Nitric Oxide may play an important role in the mechanism of this disease.

Mice lacking the 65 kDa isoform of glutamic acid decarboxylase (GAD65) maintain normal levels of GAD67 and GABA in their brains but are susceptible to seizures

The gene encoding of the 65 kDa isoform of the gamma-aminobutyric acid (GABA)-synthesizing enzyme, glutamic acid decarboxylase (GAD), GAD65, was targeted in mice by homologous recombination. Viable GAD65 -/- mice were obtained with the expected mendelian frequency and displayed no gross morphological defects. Despite the complete loss of GAD65 mRNA and protein in a homozygous mutant, there was no difference in GABA content in the brains of GAD65 +/+, +/-, and -/- mice. As for the other 67 kDa isoform (GAD67), the levels of mRNA and protein were largely unchanged by the GAD65 mutation. General behavior, including locomotor activity and performance in the Morris water maze task, appeared normal, but seizures were more easily induced by picrotoxin and pentylenetetrazol: the latencies to seizures induced by picrotoxin were shorter and the dose of pentylenetetrazol required for induction of seizures was lower.

Suppression of haematopoiesis by sera from patients with aplastic anemia

To describe the suppressive effect of sera from patients with aplastic anemia (AA) on heamatopoietic progenitor cells and explore further the features of serum inhibitor, we first examined the inhibiting activity of the serum on the colony formation of burst-forming units of erythrocyte (BFU-E) and colony-forming units of granulocyte/macrophage (CFU-GM). The potent inhibiting activity was demonstrated in six of 20 patients. Five of the six patients were severe AA (SAA). The suppressive effect did not change after elimination of monocyles and lymphocytes from target MNC. The haematopoietic inhibitory activity of sera from three of the six patients was almost totally neutralized by the MoAb against gamma-IFN. All these three patients were SAA. These data suggest that inhibitor of haematopoietic progenitor cells is present in most of SAA patients. In some patients, the inhibitor was gamma-IFN, which play an important role in the pathogenesis of SAA.

Pharmacokinetics of a new microemulsion formulation of cyclosporin A (Neoral) in young patients after renal transplantation

Pharmacokinetics of the new galenic formulation of cyclosporin A, Neoral, (Sandoz) was examined in 12 stable young patients after renal transplantation. Six of these patients were tested before and 4 weeks after switching from the standard formulation Sandimmun to Neoral. No significant changes were observed in trough levels, Lmax, Cmax, and AUC0-12 h, but the absorption rate constant (Ka) increased (P = 0.03). Glomerular filtration rate, as assessed by inulin clearance, increased by more than 10% in three patients and decreased in two, and was usually associated with a respective drop and rise in Cmax and AUC0-12 h of cyclosporin A. The large interindividual variability in the response to the conversion to the new formulation points to a need for close monitoring of cyclosporin A trough levels and renal function after switching from Sandimmun to Neoral in this age group in order to avoid nephrotoxicity.