Passage-dependent relationship between mesenchymal stem cell mobilization and chondrogenic potential.

OBJECTIVE: Galvanotaxis, the migratory response of cells in response to electrical stimulation, has been implicated in development and wound healing. The use of mesenchymal stem cells (MSCs) from the synovium (synovium-derived stem cells, SDSCs) has been investigated for repair strategies. Expansion of SDSCs is necessary to achieve clinically relevant cell numbers; however, the effects of culture passage on their subsequent cartilaginous extracellular matrix production are not well understood. METHODS: Over four passages of SDSCs, we measured the expression of cell surface markers (CD31, CD34, CD49c, CD73) and assessed their migratory potential in response to applied direct current (DC) electric field. Cells from each passage were also used to form micropellets to assess the degree of cartilage-like tissue formation. RESULTS: Expression of CD31, CD34, and CD49c remained constant throughout cell expansion; CD73 showed a transient increase through the first two passages. Correspondingly, we observed that early passage SDSCs exhibit anodal migration when subjected to applied DC electric field strength of 6 V/cm. By passage 3, CD73 expression significantly decreased; these cells exhibited cell migration toward the cathode, as previously observed for terminally differentiated chondrocytes. Only late passage cells (P4) were capable of developing cartilage-like tissue in micropellet culture. CONCLUSIONS: Our results show cell priming protocols carried out for four passages selectively differentiate stem cells to behave like chondrocytes, both in their motility response to applied electric field and their production of cartilaginous tissue.

Time and dose-dependent effects of chondroitinase ABC on growth of engineered cartilage.

Tissue engineering techniques have been effective in developing cartilage-like tissues in vitro. However, many scaffold-based approaches to cultivating engineered cartilage have been limited by low collagen production, an impediment for attaining native functional load-bearing tensile mechanical properties. Enzymatic digestion of glycosaminoglycans (GAG) with chondroitinase ABC (chABC) temporarily suppresses the construct's GAG content and compressive modulus and increases collagen content. Based on the promising results of these early studies, the aim of this study was to further promote collagen deposition through more frequent chABC treatments. Weekly dosing of chABC at a concentration of 0.15 U/mL resulted in a significant cell death, which impacted the ability of the engineered cartilage to fully recover GAG and compressive mechanical properties. In light of these findings, the influence of lower chABC dosage on engineered tissue (0.004 and 0.015 U/mL) over a longer duration (one week) was investigated. Treatment with 0.004 U/mL reduced cell death, decreased the recovery time needed to achieve native compressive mechanical properties and GAG content, and resulted in a collagen content that was 65 % greater than the control. In conclusion, the results of this study demonstrate that longer chABC treatment (one week) at low concentrations can be used to improve collagen content in developing engineered cartilage more expediently than standard chABC treatments of higher chABC doses administered over brief durations.

Comparison of nanosecond and femtosecond pulsed laser deposition of silver nanoparticle films.

Nanoparticle (NP) films of silver were prepared using nanosecond (ns) and femtosecond (fs) pulsed laser deposition (PLD) in vacuum. The flux and energy distribution of the ions in the plasma part of the ablation plume were measured using a Langmuir ion probe. The deposition energy efficiencies of ns and fs silver PLD were also compared. For equivalent thickness up to ∼3 nm the NPs made by ns-PLD are well separated and roughly circular, but for higher thicknesses the NPs begin to coalesce. For equivalent thickness up to 7 nm the fs films are comprised of well separated NPs, though the mean NP size and the surface coverage increase with equivalent thickness. The mean Feret diameter for both ns- and fs-PLD films increases with increasing equivalent solid-density thickness. The surface plasmon resonance peak was observed to red shift for both ns- and fs-PLD films as the equivalent solid-density thickness was increased from 1 nm to 7 nm.

A comparative in vitro toxicity assessment of electronic vaping product e-liquids and aerosols with tobacco cigarette smoke.

The use of electronic vaping products (EVPs) continues to increase worldwide among adult smokers in parallel with accumulating information on their potential toxicity and relative safety compared to tobacco smoke. At this time, in vitro assessments of many widely available EVPs are limited. In this study, an in vitro battery of established assays was used to examine the cytotoxic (Neutral red uptake), genotoxic (In vitro micronucleus) and mutagenic (Bacterial reverse mutation) responses of two commercial EVPs (blu GO™ disposable and blu PLUS+™ rechargeable) when compared to smoke from a reference cigarette (3R4F). In total, 12 commercial products were tested as e-liquids and as aerosols. In addition, two experimental base liquids containing 1.2% and 2.4% nicotine were also assessed to determine the effect of flavour and nicotine on all three assays. In the bacterial reverse mutation (Ames) and in vitro micronucleus (IVM) assays, exposures to e-liquids and EVP aerosols, with and without nicotine and in a range of flavourings, showed no mutagenic or genotoxic effects compared to tobacco smoke. The neutral red uptake (NRU) assay showed significantly reduced cytotoxicity (P < .05) for whole undiluted EVP aerosols compared to tobacco smoke, which by contrast was markedly cytotoxic even when diluted. The reduced in vitro toxicological responses of the EVPs add to the increasing body of scientific weight-of-evidence supporting the role of high-quality EVPs as a harm reduction tool for adult smokers.

Two phase I studies of carboplatin dose escalation in chemotherapy-naive ovarian cancer patients supported with granulocyte-macrophage colony-stimulating factor.

Recombinant human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF) may reduce myelosuppression and, thus, allow dose escalation of certain chemotherapeutic agents. We conducted two sequential phase I trials of escalating doses of carboplatin and a fixed dose and schedule of rHuGM-CSF in ovarian cancer patients who had not previously had chemotherapy, i.e., chemotherapy-naive patients. In the first trial, patients were assigned to regimens of increasing dose levels of carboplatin (starting at 400 mg/m2) and fixed doses and schedules of cyclophosphamide (600 mg/m2) and rHuGM-CSF (10 micrograms/kg given subcutaneously once daily on days 2-11). Chemotherapy was given every 3 weeks (regimen A). In the subsequent trial, the design was the same except that cyclophosphamide was omitted (regimen B). Fifteen patients received regimen A, and seven patients received regimen B. In regimen A, all three patients treated at the first dose level tolerated five cycles at full doses. Hematologic toxicity was dose limiting at the 600-mg/m2 dose level. When 500 mg/m2 carboplatin was given, six of eight patients tolerated three or four cycles at full doses before requiring dose reductions or treatment delays. In regimen B, doses could not be escalated above the first dose level (600 mg/m2) because of severe hematological toxicity. Nonhematological toxicity was tolerable and managed with acetaminophen, antihistamines, and/or nonsteroidal, anti-inflammatory medication. Compliance was excellent. We conclude that (a) rHuGM-CSF can be given safely and reliably to chemotherapy-naive ovarian cancer patients receiving these treatment regimens, (b) early and severe thrombocytopenia was a major problem with or without cyclophosphamide with doses of carboplatin at or above 600 mg/m2, and (c) 500 mg/m2 carboplatin administered every 3 weeks is the highest dose in regimen A that can be given safely in the outpatient setting.

Ovarian toxicity of cyclophosphamide alone and in combination with ovarian irradiation in the rat.

The effects of radiation and chemotherapy on gonadal function are relevant to the morbidity induced by such treatments. Cyclophosphamide given i.p. to rats on Day 30 of age delayed vaginal opening, prevented vaginal cyclicity, and caused a reduction in serum estradiol and progesterone. Antral follicular atresia increased in a dose-dependent fashion in response to cyclophosphamide (0 mg/kg, 53.5%; 1 mg/kg, 67.3%; 50 mg/kg, 65.7%; 100 mg/kg, 73.9%; 150 mg/kg, 92.2%). Despite such alterations in ovarian function, serum gonadotrophins did not rise. The concurrent administration of 0, 20, 30, 40, 50, and 60 Gy of radiation to the exteriorized ovaries in rats receiving 50 mg/kg cyclophosphamide induced widespread loss of primordial, preantral, and healthy antral follicles associated with reduction in serum progesterone and estradiol. Such irradiation induced dose-related increases in serum follicle-stimulating hormone and luteinizing hormone. Parenteral cyclophosphamide and local irradiation appear to induce ovarian toxicity by different mechanisms.

Effects of ionizing radiation and pretreatment with [D-Leu6,des-Gly10] luteinizing hormone-releasing hormone ethylamide on developing rat ovarian follicles.

To assess the effects of a gonadotropin-releasing hormone agonist, [D-Leu6,des-Gly10] luteinizing hormone-releasing hormone ethylamide, in ameliorating the damage caused by ionizing radiation, gonadotropin-releasing hormone agonist was administered to rats from day 22 to 37 of age in doses of 0.1, 0.4, and 1.0 microgram/day or vehicle and the rats were sacrificed on day 44 of age. There were no effects on estradiol, progesterone, luteinizing, or follicle-stimulating hormone, nor an effect on ovarian follicle numbers or development. In separate experiments, rats treated with gonadotropin-releasing hormone agonist in doses of 0.04, 0.1, 0.4, or 1.0 microgram/day were either irradiated or sham irradiated on day 30 and all groups sacrificed on day 44 of age. Irradiation produced a reduction in ovarian weight and an increase in ovarian follicular atresia. Pretreatment with the agonist prevented the reduction in ovarian weight and numbers of primordial and preantral follicles but not healthy or atretic antral follicles. Such putative radioprotection should be tested on actual reproductive performance.

Cisplatin-cyclophosphamide versus carboplatin-cyclophosphamide in advanced ovarian cancer: a randomized phase III study of the National Cancer Institute of Canada Clinical Trials Group.

PURPOSE: Given the potential for improved tolerance, a trial was initiated to compare the toxicity and efficacy of a standard regimen of cisplatin-cyclophosphamide (75 mg/m2 and 600 mg/m2, respectively) with an experimental regimen of carboplatin-cyclophosphamide (300 mg/m2 and 600 mg/m2, respectively) in women with postoperative macroscopic residual ovarian cancer. PATIENTS AND METHODS: Between 1985 and 1989, 447 (417 eligible) patients were randomized. Treatment arms were well balanced; most patients had stage III (82%), grade 3 (54%) tumors with bulky residual (greater than 2 cm in 59%), and good performance status (Eastern Cooperative Oncology Group [ECOG] 0 or 1, 77%). Response was assessed after six 4-week cycles. RESULTS: The treatments were equally deliverable, with 76% of patients completing their allocated regimen. The reported reasons for failure to complete treatment differed; toxicity/refusal predominated on the cisplatin arm, and progressive disease predominated on the carboplatin arm (P = .0092). Cisplatin-treated patients were more likely to develop neuropathy and nephropathy, and carboplatin patients experienced myelosuppression, particularly thrombocytopenia. Efficacy was similar, with no significant differences for the cisplatin and carboplatin arms in clinical response rate (57% v 59% in those with measurable disease), pathologic response rate (52% v 54% in those suitable for relaparotomy), time to progression (median, 56 v 58 weeks), or overall survival (median, 100 weeks v 110 weeks). Time to progression and survival were predicted by residual disease size, performance status, and treatment center (with those treated at centers that accrued more patients doing better). CONCLUSION: Neither regimen is optimal in that relapse remains the norm. It may be inappropriate to expect that any single regimen can be an effective therapy for all patients with advanced ovarian cancer. Both cisplatin and carboplatin are likely to have a role in future treatment strategies.

A randomised, double-blind comparison of granisetron with high-dose metoclopramide, dexamethasone and diphenhydramine for cisplatin-induced emesis. An NCI Canada Clinical Trials Group Phase III Trial.

151 patients (149 evaluable) receiving their first course of chemotherapy containing cisplatin in a dose of at least 50 mg/m2 were randomised to receive either a single dose of intravenous granisetron 80 micrograms/kg or intravenous metoclopramide 2 mg/kg every 2 h for five doses plus a single dose of dexamethasone 10 mg and diphenhydramine. After 24 h, there was no significant difference between groups with respect to nausea or vomiting: in the granisetron group 46% of patients had no emesis, versus 44% of the standard group. Granisetron is an antiemetic agent with efficacy similar to that of high-dose metoclopramide plus dexamethasone.

Quinidine-digoxin interaction: time course and pharmacokinetics.

The time course of the rise in serum digoxin concentration was followed in 18 patients treated with digoxin as quinidine treatment was started with a loading dose. The mean serum digoxin levels rose significantly during the first 24 hours after administration of quinidine was begun, and reached a new steady state concentration after about 48 hours. Digoxin kinetics were studied in two groups of normal volunteers: Group 1 (n = 7) received a small dose of quinidine, 800 mg/day, and group II (n = 8) received 1,600 mg/day. There was no significant mean change in the apparent volume of distribution of digoxin in either group. In group I (small dose), quinidine reduced the digoxin clearance values: total clearance by 30 percent, renal clearance by 32 percent and nonrenal clearance by 29 percent. In group II (large dose), quinidine reduced digoxin total clearance by 36 percent, renal clearance by 54 percent and nonrenal clearance by 22 percent. The reduction in digoxin volume of distribution and renal clearance during quinidine treatment were a function of the serum quinidine concentration. The change in nonrenal clearance of digoxin was independent of serum quinidine concentration.

Predictive value of CA 125 for ovarian carcinoma in patients presenting with pelvic masses.

Between November 1984 and May 1986, 56 patients presenting with a pelvic mass to the Gynecologic Oncology Service of McMaster University and the Hamilton Regional Oncology Center underwent laparotomy for possible ovarian cancer. All patients had blood drawn for CA 125 three days before operation. Levels above 35 U/mL were considered positive; CA 125 had a positive predictive value of 60%. False positives occurred in patients with nongynecologic malignancies and with benign gynecologic conditions. On the other hand, CA 125 had a negative predictive value of 100%, suggesting that this test may be useful in identifying those patients with pelvic masses at higher risk for malignancy, who may require transfer for surgery at a tertiary care center.

Toxicity of abdominopelvic radiation in advanced ovarian carcinoma patients after cisplatin/cyclophosphamide therapy and second-look laparotomy.

Twenty-seven advanced ovarian carcinoma patients who had received six courses of cyclophosphamide/cisplatin and had either microscopic disease (15 patients) or no pathologically detectable disease (12 patients) after second-look laparotomy were treated with abdominopelvic radiation (2250 cGy to the abdomen and pelvis and a 2250-cGy pelvic boost). Acute myelosuppression or gastrointestinal toxicity prevented completion of treatment in only three patients. However, bowel obstruction occurred in 13 (48%), ten of whom required surgery. Five of these ten had recurrent tumor, but the other five did not. Subsequently two of the latter five did develop a recurrence, one in the lung and one in the liver. A third patient died as an indirect result of radiation damage to the bowel. Median follow-up duration is 17 months from completion of radiation. So far, 13 (48%) have developed progressive disease: four (33%) of the 12 who had a negative second-look laparotomy and nine (60%) of the 15 who had microscopic disease before radiation. While acute toxicity is tolerable, the incidence of serious chronic bowel toxicity is high. Efforts should be made to alter this therapy in order to decrease the frequency of long-term morbidity.

How do individuals expect to be viewed by members of lower status groups? Content and implications of meta-stereotypes.

Three studies demonstrated that meta-stereotypes held by members of dominant groups about how their group is viewed by a lower status group have important implications for intergroup relations. Study 1 confirmed that White Canadians hold a shared negative meta-stereotype about how they are viewed by Aboriginal Canadians; Studies 2 and 3 extended these results to people's beliefs about an individual out-group member's impressions of them. Feeling stereotyped was associated with negative emotions about intergroup interaction as well as decreases in current self-esteem and self-concept clarity. The perceptions of low- and high-prejudiced persons (LPs and HPs) diverged in a manner consistent with their distinct personal values and group identifications. LPs held a more negative meta-stereotype than did HPs. However, in a one-on-one interaction, HPs sensed that they were stereotyped, whereas LPs felt that they conveyed a counterstereotypical impression.

The short-term reproductive toxicity of cyclophosphamide in the female rat.

Cyclophosphamide (CTX) is a potent ovarian toxicant. Previous studies of the acute effects of CTX in the rat have demonstrated widespread ovarian follicle atresia, reduced serum estradiol, and progesterone with normal serum LH and FSH. The present investigations demonstrate that a single injection of CTX induces ovarian toxicity that reflects the loss of growing ovarian follicles. CTX induces a sensitization of serum FSH in response to GnRH within 24 h; this sensitization is lost by 7 days, and after 14 days the animals are capable of normal mating behavior. The observed protection of primordial follicles from the acute administration of CTX under these experimental circumstances may be related to the stage of the granulosa cell cycle of these follicles.

Potentiometric flow-injection determination of iodide and iodine.

A potentiometric flow-injection system is described, in which iodide in the concentration range 10(-6)-10(-1)M may be determined at rates of up to 360 samples/hr at a flow-rate of 17.8 ml/min. Iodine, after on-line reduction to iodide with 0.1M sodium metabisulphite, can also be determined, with a throughput of 60 samples/hr for 10(-5)-10(-3)M iodine. Analyses of two pharmaceutical preparations for iodide and iodine are reported, and the results are in reasonable agreement with titrimetric values.

Flow-injection determination of phosphate with a cadmium ion-selective electrode.

A flow-injection method is described, in which phosphate standards are introduced into a reagent stream containing Cd(2+) ,resulting in the formation of Cd(3)(PO(4))(2). The associated reduction in free metal concentration is sensed by a cadmium-selective electrode. With the exception of major interference from iodide and moderate interference from bromide and thiocyanate, the system exhibits excellent response to phosphate and selectivity over several common anions in solutions buffered at pH 8.4. A maximum sampling rate of 160/hr is possible for phosphate standards in the concentration range 10(-1)-10(-1)M with a 10(-4)M Cd(2+) reagent stream at a total flow-rate (carrier and reagent stream combined) of 8.4 ml/min.