Reversed-flow affinity elution applied to the purification of carboxypeptidase Y

BACKGROUND: Despite curative resection for colorectal cancer, many patients develop recurrence at the primary site or distant organs. These patients are candidates for (neo)-adjuvant chemotherapy. Very little is known about the effect of preoperative 5-fluorouracil (FU) on the healing of colonic anastomoses. The aim of this study was to assess this in a rat model. METHODS: Eighty male Wistar rats, weighing 160-215 g, were divided into three groups; (1) a control group underwent left colon resection and primary anastomosis (n = 20); (2) a sham group received 1 ml saline intraperitoneally (n = 30); (3) a study group received 5-FU intraperitoneally (20 mg kg-1). Both saline and 5-FU injections were given intraperitoneally for 5 days before operation. RESULTS: There was no difference in the rate of wound complications, intraperitoneal adhesions and anastomotic complications among the groups. Three and seven days after operation, mean bursting pressure of the anastomosis was 36.5 and 198 mmHg in group 1, 34 and 200 mmHg in group 2, and 39 and 190 mmHg in group 3 respectively (P not significant). Although the myeloperoxidase and hydroxyproline content were significantly lower after 5-FU therapy (P < 0.01, compared with others), the clinical outcome was similar. CONCLUSION: Preoperative 5-FU consecutive days before operation had no effect on the healing of colonic anastomoses.     

Bacteria inhibit biosynthesis of bone matrix proteins in human osteoblasts

The effect of extracts from Staphylococcus aureus and Staphylococcus epidermidis on bone matrix production were assessed by analyzing the biosynthesis of osteocalcin and Type I collagen in a human osteoblastic osteosarcoma cell line (MG-63). In MG-63 cells, extracts from Staphylococcus aureus and Staphylococcus epidermidis decreased 1,25(OH)2-vitamin D3 stimulated osteocalcin biosynthesis, and insulin-like growth factor I induced production of Type I collagen in a concentration dependent manner. The basal rate of osteocalcin and Type I collagen formation was unaffected by the bacterial extracts. The inhibitory effect of the bacteria on osteocalcin biosynthesis was seen after 24 hours of treatment and was maintained for at least 96 hours. The extracts of Staphylococcus aureus and Staphylococcus epidermidis enhanced prostaglandin E2 formation in the MG-63 cells. Abolition of the prostaglandin E2 response by treatment with indomethacin and flurbiprofen did not affect bacteria induced inhibition of osteocalcin production. Stimulation of osteocalcin biosynthesis by 1,25(OH)2-vitamin D3 was associated with a decreased rate of cell proliferation. The inhibitory action of the bacterial extracts was not linked to any inhibition of [3H]-thymidine incorporation into deoxyribonucleic acid. These data show that extracts of Staphylococcus aureus and Staphylococcus epidermidis have the ability to inhibit the biosynthesis of bone matrix proteins by a nonprostaglandin and noncytotoxic dependent mechanism and suggest that bone loss in inflammatory processes containing Staphylococcus aureus or Staphylococcus epidermidis may not be caused only by enhanced bone resorption but also by decreased bone formation.     

Liquid chromatography of aromatic amines with photochemical derivatization and tris(bipyridine)ruthenium(III) chemiluminescence detection

We have shown by flow injection that tris(bipyridyl)ruthenium(III) [Ru(bpy)3(3+)] chemiluminescence (CL) detection of some aromatic amines can be enhanced by on-line photochemical derivatization. Two of the aromatic amino acids, tryptophan, and tyrosine as well as the peptide phenylalanine-alanine and other primary aromatic amines such as L-dopa, phentermine, and tryptamine upon irradiation with UV light are found to give an increased CL signal on the order of 4-9 times that for nonirradiated compounds. For benzylamine, phenethylamine, and phenylalanine, the improved CL detectability upon photolysis is about 15-16 times better. Chemiluminescence detection limits of the photolyzed compounds are generally 2-20 pmol, significantly better than those by UV-Vis detection at 254 nm. GC-MS work has been done to identify the products of some of the photolysis reactions and explain the enhanced CL detectability. The fact that other aromatic amines without a one or two carbon spacer from the aromatic ring to the amine group such as aniline, m- and p-phenylenediamine, and N,N'-dimethylaniline did not show any CL signal improvement upon irradiation with UV light suggests that there is some selectivity in the reaction. CL detection of aromatic amino acids after on-line photochemical derivatization and HPLC has been shown.     

Histamine and interleukin-2 in acute myelogenous leukemia

Interleukin-2 (IL-2) activates natural killer (NK)-cells to destroy leukemic blasts from patients with acute myelogenous leukemia (AML), but even aggressive regimens of IL-2 fail to prevent relapse or prolong remission time in AML. Results obtained in studies of NK-cell-mediated killing of AML blasts show that monocytes inhibit IL-2-induced lysis of AML blasts in vitro. Histamine, a biogenic amine, prevents the monocyte-derived, inhibitory signal; thereby, histamine and IL-2 synergize to induce killing of AML blasts. Here we present updated results of a post-consolidation trial in which histamine (0.5-0.7 mg s.c. bid) has been administered together with IL-2 (1 micro/kg s.c. bid) to 22 AML patients (aged 29-79, mean 59) in repeated courses of three weeks, continued until relapse or until a disease-free remission of 24 months. Low-dose therapy with cytarabine and thioguanine was given between the initial courses of histamine/IL-2. In 13 patients, treatment according to this protocol was started in first complete remission (CR1). The mean remission time in CR1 patients is 19 (median 14) months, and 9/13 remain in CR. Nine patients have entered the protocol in CR2 (n=6), CR3 (n=2), or CR4 (n=1). The mean remission time in CR2-4 is 19 (median 21) months, and 6/9 patients remain in CR. Seven out of seven evaluable patients have achieved a duration of CR which exceeds that of the foregoing remission. Histamine has been well tolerated, and 21/22 CR patients have treated themselves at home throughout the trial. We conclude that the putative benefit of histamine treatment in AML should be the focus of a randomized trial.     

Immunoprocedures for detecting human chorionic gonadotropin: clinical aspects and doping control

The pregnancy hormone human chorionic gonadotropin (hCG) is also present at low concentrations in plasma and urine of men and nonpregnant women. hCG immunoreactivity occurs in various molecular forms: Besides the intact hCG heterodimer, considerable amounts of proteolytically cleaved forms, free subunits, and fragments are found in plasma and urine. Especially in urine, proteolytic fragments constitute a major part of the hCG immunoreactivity. The different forms of hCG cross-react to various degrees in immunoassays and constitute a problem for standardization of specific hCG determinations. After injection of hCG (10,000 IU of Pregnyl; Organon), above-normal concentrations of hCG can be detected in serum and urine for 7-11 days. Most immunoassays for hCG also measure hCG beta. Quantitative hCG determinations are mainly performed on serum samples, and very few commercial hCG determinations have been validated for determination of urine samples. Considerable care must therefore be exercised when utilizing such assays to analyze urines for doping control.     

Expression of beta 2-integrins and L-selectin on polymorphonuclear leukocytes in septic patients

Adhesion molecules on polymorphonuclear leukocytes (PMNL) play an important role in nonspecific defense mechanisms directed at invading microorganisms. When local infection, however, cannot be controlled, a systemic inflammatory response syndrome (SIRS) ensues which may progress to septic shock and multiple organ failure, these being major determinants of the patient's outcome. In the present study, the expression of beta 2-integrins and L-selectin on blood PMNL was measured on subsequent days in patients with sepsis (n = 17) and in healthy volunteers (n = 15). beta 2-Integrins and L-selectin molecules were detected by flow cytometry, using the monoclonal antibodies IB4 (anti-CD18) and Dreg200 (anti-CD62L), respectively. Adhesion molecules were determined at baseline immediately after blood collection and also 45 min after incubation of cells in vitro at body temperature to allow for spontaneous regulation. In addition, PMNL were activated by receptor-dependent and receptor-independent stimuli to characterize stimulus-specific adhesion molecule expression. In parallel with the measurement of adhesion molecules, severity of sepsis was assessed by the Elebute score. The results demonstrate significant differences in the basal, spontaneous and stimulus-induced expression of adhesion molecules between healthy volunteers, survivors (n = 11) and nonsurvivors (n = 6). Moreover, when survivors and nonsurvivors with severe sepsis (Elebute score > 12) were compared, basal expressions of both beta 2-integrins and L-selectin were significantly lower in patients who did not survive. Thus, measurement of adhesion molecules on circulating PMNL may be useful to identify septic patients at high risk for lethal outcome.     

Role of Mg in the stress corrosion cracking of an Al-Mg alloy

The corrosion and stress corrosion cracking (SCC) susceptibility of an Al-Mg alloy, AA5083, has been shown to depend on the precipitation of the Mg-rich β phase, (Al₃Mg₂), but not the enrichment of elemental Mg at grain boundaries to an enrichment ratio of 1.4. These results were determined by measuring the progress of Mg enrichment at grain boundaries, for increasing thermal-treatment times, using auger electron spectroscopy (AES) of grain boundaries exposed by fracture within the spectrometer and by analytical electron microscopy (AEM) of thin foils. The progress of the β phase precipitation was followed by AEM and scanning electron microscopy (SEM), for the same thermal-treatment times. The lack of a Mg-segregation effect on SCC was demonstrated by results obtained with X-ray photoelectron spectroscopy (XPS) analysis of Mg-implanted Al following in-situ electrochemical tests and SCC tests, while the dominance of β phase precipitation was demonstrated by electrochemical analysis and SCC testing. Crack-growth tests of alloy AA5083 demonstrated faster cracking at potentials anodic to the open circuit potential (OCP) with no increase at potentials cathodic to the OCP.     

Endothelial selectins and vascular cell adhesion molecule-1 promote hematopoietic progenitor homing to bone marrow

The adhesive mechanisms allowing hematopoietic progenitor cells (HPC) homing to the bone marrow (BM) after BM transplantation are poorly understood. We investigated the role of endothelial selectins and vascular cell adhesion molecule-1 (VCAM-1) in this process. Lethally irradiated recipient mice deficient in both P-and E-selectins (P/E-/-), reconstituted with minimal numbers (相似文献