Suramin inhibits growth of human osteosarcoma xenografts in nude mice.

The effect of suramin on tumor growth and morphology in two different human osteosarcoma xenografts (L-I OSM and L-II OSM) grown in BALB/cA-nu/nu mice was studied. Suramin (total dose, 720 mg/kg) given by i.p. injection (60 mg/kg/dose) for up to 9 weeks significantly inhibited osteosarcoma cell growth in both tumors, suramin-treated tumors showing only one-third or less of the volume of nontreated controls. Cell cycle distribution of tumor cells measured by DNA flow cytometry demonstrated that suramin treated caused accumulation of cells in the S and G2 phases of the cell cycle, in both L-I OSM and L-II OSM. In the aneuploid L-II OSM tumor suramin preferentially inhibited the growth of aneuploid cells, leading to a decrease in the ratio of aneuploid to diploid cells. Both osteosarcomas retained their histological appearance and the liver, spleen, heart, and kidneys of the treated animals were unaffected by suramin. These results are compatible with the view that suramin inhibits the growth of human osteosarcomas by cytostatic effects.

Thioredoxin blood level increases after severe burn injury.

We have investigated the thioredoxin (TRX) levels in severely burned patients and the possible origin of TRX, based on the recent understanding that TRX is a potent antioxidant with cytoprotective functions. Serum and plasma samples from burns patients and healthy blood donors were collected during the first 10 post-burn days and analyzed in a sandwich TRX enzyme-linked immunosorbent assay (ELISA). The TRX levels found were correlated to a panel of blood tests. The presence of TRX in platelets was investigated by immunoelectron microscopy and Western blotting. TRX serum levels of the severely burned patients showed a significant increase, with a mean serum TRX concentration on the day of injury of 76.5 +/- 19.5 ng/ml (mean +/- SD) and on post-burn day one 122.6 +/- 66.9 ng/ml, compared to control blood donor levels of 22.7 +/- 12.2 ng/ml (p = 0.0041 and 0.0117, respectively). A second peak of increase was found on post-burn days 7 to 9 with a four- to five-fold rise in concentration compared to controls. TRX elevation correlated well with increased platelet (p = 0.007) and leukocyte counts (p = 0.002). We also demonstrated by immunoelectron microscopy and Western blotting the presence of TRX in platelets. In conclusion, our demonstration of TRX release in burn injuries indicates that the TRX system is involved in a rapid antioxidant defense, coagulation processes, cell growth, and control of the extracellular peroxide tone intimately linked to cytoprotection and wound healing in burns. One of the cell types that delivers TRX promptly and efficiently into the blood may be the platelet.

Human malignant fibrous histiocytomas in vitro: growth characteristics and their association with expression of mRNA for platelet-derived growth factor, transforming growth factor-alpha and their receptors.

Eight human malignant fibrous histiocytomas were examined in vitro, in order to relate their growth properties to mRNA expression for platelet-derived growth factor (PDGF), PDGF receptor (PDGF-R), transforming growth factor-alpha (TGF-alpha) and the epidermal growth factor receptor (EGF-R). Reverse transcriptase-polymerase chain reaction (RT-PCR) showed that all cell lines expressed mRNA for PDGF-R alpha and/or PDGF-R beta; six cell lines expressed mRNA for the PDGF-A chain, with one cell line coexpressing PDGF-B chain mRNA; seven cell lines expressed mRNA for TGF-alpha whereas six cell lines expressed EGF-R mRNA. Conditioned medium from three cell lines contained PDGF; none of the cell lines released TGF-alpha. Two cell lines grew without serum requirements; whereas both expressed mRNA for PDGF, PDGF-R, TGF-alpha and EGF-R, other cell lines, unable to grow without serum, showed the same combination of growth factor/growth factor receptor expression. The two cell lines able to grow without serum were also shown to be stimulated by the addition of PDGF-BB. These findings show that simultaneous expression of mRNA for a growth factor and its receptor does not necessarily imply an autocrine or paracrine loop. However, two of our cell lines fulfil the requirements of possible PDGF-related autocrine and paracrine regulation.

Suramin blocks growth-stimulatory effects of platelet-derived growth factor on malignant fibrous histiocytomas in vitro.

The pattern of susceptibility of malignant cells to the cytostatic drug suramin is not fully clarified. Therefore, in the present paper we have assessed the effects of suramin on the growth of eight cell lines derived from human malignant fibrous histiocytomas, by measuring DNA synthesis. The effect of suramin (10-200 microg/ml) on cells either unstimulated, or stimulated with platelet-derived growth factor (PDGF)-AA (10 ng/ml), PDGF-BB (10 ng/ml) or 10% fetal calf serum was studied. Four out of five cell lines unable to thrive without external growth factors showed growth inhibition by suramin. The two cell lines able to grow under serum-free conditions were unaffected by high-dose suramin. The exposure to suramin, at 200 microg/ml, abolished the growth stimulation caused by PDGF-AA and -BB. In contrast, a low dose of suramin (50 microg/ml), with or without PDGF, caused growth-stimulating effects in some cell lines. Our results indicate that high doses of suramin inhibit growth of malignant fibrous histiocytomas in vitro and that suramin exerts its growth-inhibitory effects on cells dependent on external growth factors. Low-dose treatment with suramin, however, may instead promote growth in both serum-dependent and -independent tumor cell lines.

Effects of human platelet-derived growth factor-AB on sarcoma growth in vitro and in vivo.

Platelet-derived growth factor (PDGF) has been proposed to play an important role in the growth of tumors. In order to study the effects of PDGF-AB on tumor growth in vivo, sarcoma-bearing mice were treated with PDGF-AB. The tumors, a malignant fibrous histiocytoma and an osteosarcoma, had functional PDGF receptors in vitro, as demonstrated by stimulation of PDGF-AB using a [3H]thymidine incorporation assay. Immunohistochemistry also revealed that both sarcoma xenografts expressed PDGF receptors. The tumor-bearing mice were given human PDGF-AB for 14 days, either continuously by an intraperitoneally placed mini-osmotic pump, or by daily injections. No effects on tumor growth in vivo were observed, as measured by tumor volume, autoradiography or cell cycle distribution. The histological appearance and ploidy of the tumors remained unaltered. The results indicate that, although the tumor cells are stimulated by PDGF-AB in vitro, the in vivo milieu or tumor growth pattern may render the tumors less susceptible to exogenously administered PDGF-AB in vivo.

Uptake of 125I-PDGF-AB to the blood after extravascular administration in mice.

The kinetics of exogenously given 125I-platelet-derived growth factor-AB (PDGF-AB) was studied in mice. 125I-PDGF-AB was injected either intraperitoneally, intramuscularly or subcutaneously and the resulting concentrations of 125I-radioactivity monitored in the blood at different times. The serum levels of 125I-radioactivity rose to a maximum 2-4 hours after injection, before decreasing. Precipitation of serum with trichloroacetic acid demonstrated that 50 per cent or more of the 125I remained in macromolecular form. Further, gel chromatography studies showed that the molecular size of the labelled material in serum, three hours after injection, was the same as that of the original 125I-PDGF-AB. In addition, a low-molecular weight fraction was observed, indicating the presence of degradation products. The largest proportion of degraded material was obtained after subcutaneous administration. The absence of partially degraded 125I-labelled fragments, e.g. 125I oligopeptides, indicates complete rather than limited degradation and suggests that the 125I-PDGF-AB had been processed by cellular uptake. It is concluded that extra-vascularly given PDGF-AB in mice is taken up into the blood in intact macromolecular form. This finding suggests that it is possible to administer PDGF extravascularly to obtain a prolonged increase in the concentration of intact PDGF in the blood.

The functional result two years after a microsurgical penile replantation. Case report.

We describe the technique of microsurgical penile replantation and a case followed up after two years. The patient was a young man with decompensated schizophrenia who emasculated himself with a kitchen knife. A particularly good functional result was achieved including restoration of sensation in the penile shaft and in the glans, and return of erectile capacity.

Responses of algesic and metabolic substances to 8 h of repetitive manual work in myalgic human trapezius muscle.

The trapezius muscle often develops pain as the result of repetitive and stressful work tasks although it is unclear to what extent this pain is due to alterations in muscle concentrations of algesic/nociceptive substances. Twenty women with chronic neck- and shoulder pain (TM) whose work required highly repetitive work tasks and 20 pain-free female colleagues (CON) were studied during and after a full 8-hour workday. We collected microdialysates from their dominant/most painful trapezius muscle; concentrations of serotonin, glutamate, lactate, pyruvate, potassium, bradykinin, and cytokines and blood flow were determined. In addition, we measured surface electromyogram, task exposure level, pain intensity, perceived mental stress, and urine-cortisol. In connection to the clinical neck and shoulder examination, we determined pressure pain thresholds (PPTs) over the trapezius and tibialis muscles. TM had higher concentrations of glutamate (71+/-42 vs. 36+/-15 micromol l(-1)) and pyruvate (187+/-89 vs. 125+/-63 micromol l(-1)) than CON. Interstitial serotonin was higher in TM (before work: 10.6+/-10.8 vs. 2.2+/-1.2 nM; after work: 9.2+/-8.3 vs. 1.5+/-2.9 nM). The trapezius blood flow during the working day was higher in TM than in CON. TM had lower PPT and higher pain intensity throughout the working day. No differences in EMG, task exposure level, mental stress, or urine-cortisol in the groups were found. These findings support the idea that peripheral nociceptive processes are activated in occupationally active subjects, who are diagnosed with trapezius myalgia. In contrast, no sign of low blood flow or increased stress or muscle activity markers were found in TM.

Hyperoxaemia does not change concentrations of serotonin and beta-thromboglobulin in blood of healthy humans.

BACKGROUND: The mechanisms of oxygen-induced effects on blood vessels (vasoconstriction in hyperoxaemia and vasodilatation during hypoxaemia) are uncertain. Many investigators have suggested that the vasoconstriction seen during hyperoxia/hyperoxaemia is mediated through the endothelium as a result of either increased release or activity of vasoconstrictors (oxygen radicals, endothelin, norepinephrine, angiotensin II, or serotonin (5-HT)), or reduced activity of vasodilators (prostaglandin E2 and nitric oxide). Serotonin has been assumed to have a central role. METHODS: Eight healthy volunteers were exposed to FiO2 of 1.0 for 20 min and serum concentrations of serotonin and activated platelets were measured (indicated by concentrations of beta-thromboglobulin (beta-TG)). RESULTS: During hyperoxaemia in humans, serum concentrations of scrotonin and beta-TG remained unchanged. CONCLUSION: If serotonin is involved in oxygen-induced vasoconstriction, the mechanism is more likely to be either a potentiating effect of serotonin on other vasoconstrictors or increased activity of serotonin on its receptor.

The effect of low dose diclofenac sodium administered locally on heterotopic bone formation in rats.

The effect of a low dose of diclofenac sodium, administered locally, on heterotopic bone formation in rats was investigated. Heterotopic bone was induced by implantation of demineralised bone matrix into the gluteal muscles. Diclofenac was released continuously for 2 weeks from micro-osmotic pumps for each demineralised bone implant in the rats. Each had a control implant in the opposite gluteal muscle to which saline was released in the same way. The yield of new woven bone was determined after 4 weeks by measuring the ash-weights of the implants. Those of the diclofenac samples were significantly decreased compared to the controls. These results suggest that a low dose of diclofenac given locally decreases heterotopic bone formation in rats.

Effect of platelet derived growth factor on heterotopic bone formation in rats.

Platelet derived growth factor (PDGF) and induction of newly woven bone growth were studied in rats. PDGF (20 ng/mL) was administered continuously for 2 weeks via micro-osmotic pumps to 6-mm-long pieces of demineralized rat femur inserted into muscle pouches. Each rat had a control piece of demineralized bone inserted into the contralateral gluteal muscle. The samples were collected after 4 weeks, and wet and ash weight were recorded. Fourteen rats were evaluated. There were no differences as regards wet weights. PDGF increased the ash weights.

Alpha-smooth muscle actin is expressed in a subpopulation of cultured and cloned fibroblasts and is modulated by gamma-interferon.

Clinical and experimental investigations have shown that, during wound healing and fibrocontractive diseases, fibroblasts acquire, more or less permanently according to the situation, morphological and biochemical features of smooth muscle (SM) cells including the expression of alpha-SM actin. Primary and passaged cultures of rat and human fibroblasts contain a subpopulation of cells expressing alpha-SM actin. These cells could derive from SM cells and/or pericytes present in the tissue from which cultures have been produced or represent bona fide fibroblasts. We have investigated the presence of alpha-SM actin in fibroblast cultures, clones, and subclones. In all cases the fibroblastic populations studied showed a proportion of alpha-SM actin expressing cells. Even after cloning, we never obtained populations negative for alpha-SM actin. We conclude that alpha-SM actin expression in fibroblastic cultures is not due to contaminant cells but is a feature of fibroblasts themselves. Our results support the view that fibroblastic cells are a heterogeneous population. It has been previously shown that gamma-interferon (gamma-IFN) decreases alpha-SM actin expression in SM cells. In rat and human fibroblasts, gamma-IFN decreases alpha-SM actin protein and mRNA expression as well as proliferation. The properties of this cytokine make it a good candidate for exerting an anti-fibrotic activity in vivo.

Dissociated secretion of islet amyloid polypeptide and insulin in serum-free culture media conditioned by human pancreatic adenocarcinoma cell lines.

CONCLUSION: The cosecretion of insulin and islet amyloid polypeptide (IAPP) is altered when isolated rat pancreatic islets are incubated in culture media conditioned by human pancreatic cancer cells. BACKGROUND: Pancreatic cancer is usually associated with impaired glucose tolerance. This study investigates the tumor-derived influence on beta-cell secretion of pancreatic islets. METHODS: Four conditioned media were prepared from two human pancreatic cancer cell lines (Panc-1 and HPAF), a hamster pancreatic cancer cell line (PC-1), and a fibroblast cell line (Ag1523). Isolated rat pancreatic islets were incubated first in the conditioned media or nonconditioned control medium for 24 h, then in the same kind of media containing 100 microM carbamylcholine for 90 min. Insulin and IAPP secretion were measured by radioimmunoassay. RESULTS: Islets in media conditioned by Panc-1 and HPAF cells demonstrated dissociation of insulin and IAPP secretion. During 24-h incubation, the dissociation was expressed as selectively decreased insulin secretion. With addition of 100 microM carbamylcholine, the dissociation was expressed as normal secretion of insulin and hypersecretion of IAPP. As a result, the IAPP/insulin molar ratios were increased in both groups during both time periods. The islets in PC-1 and Ag1523 media did not show any significant changes in insulin and IAPP secretion.