Biomedical subjects

S MacNeil

Publications and source records attributed to S MacNeil.

At least 37 records · Page 2Linked to original sources

PubMed1998

Modulation of ICAM-1 expression by alpha-MSH in human melanoma cells and melanocytes.

Alpha-MSH, a proopiomelanocortin (POMC)-derived peptide, is known to be produced in the pituitary, the skin, and melanoma tumors and to possess many biological effects, mainly on melanocyte pigmentation and growth. Moreover, the melanocyte expresses adhesion molecules, including ICAM-1. The latter has been reported to play a role in melanoma spread and associated metastatic process. We conducted a study in order to evaluate the possible effect of MSH on ICAM-1 expression in human cultured malignant and normal melanocytes. Our data show that alpha-MSH inhibits ICAM-1 expression stimulated by TNF in a concentration-dependent manner, both at the protein and gene expression level. Ninety percent inhibition was obtained with 10 nM MSH, while 50% inhibition was achieved with 1 nM. Endogenous cAMP elevation with forskolin as well as an exogenous cAMP stable analogue (Sp-cAMPS) produced the same inhibitory effect. A screening of malignant melanocytes showed that inhibition of ICAM-1 expression could be achieved only in those cells expressing detectable MSH receptors and seemed to correlate with the number of binding sites. In conclusion, our data strongly suggest alpha-MSH as a potent inhibitor of ICAM-1 expression in malignant melanocytes acting through MSH receptor stimulation and subsequent cAMP increase.

Adult↗

PubMed1998

Plasma copolymer surfaces of acrylic acid/1,7 octadiene: surface characterisation and the attachment of ROS 17/2.8 osteoblast-like cells.

The purpose of this study was: (a) to examine the effect of plasma-gas composition on plasma polymer oxygen/carbon (O/C) ratio, functional group composition and stability in water, and then (b) to examine cell attachment to surfaces containing different concentrations of O/C and functional groups. Oxygen-functionalised surfaces were deposited by means of the plasma copolymerisation of acrylic acid/1,7-octadiene. The use of a diluent hydrocarbon allowed the deposition of surfaces with a range of O/C concentrations. Plasma copolymer surfaces were characterised by X-ray photoelectron spectroscopy (XPS). Changes in functional group composition with % acrylic acid monomer and the non-dispersive and dispersive parts of the surface energy of these plasma copolymers were measured. The solubility of the plasma copolymers was assessed by means of XPS. The degree of attachment of ROS 17/2.8 osteoblast-like cells to plasma copolymer surfaces deemed to be 'stable' in aqueous medium was measured. Tissue culture polystyrene (TCPS) was included as a control. Attachment was found to be greatest to the plasma copolymer surface with an O/C of 0.11. This surface had a carboxylic acid concentration of ca. 3%. Attachment did not correlate with increased surface wettability (i.e. the non-dispersive component of the surface energy).

Acrylates↗

PubMed1998

Skin banking in the UK: the need for proper organization.

Skin banking was set up in Sheffield in 1991 to provide a readily available source of allograft material to be used both for research purposes and also as a means of providing immediate wound cover for major burns patients. Once skin was available, however, clinical demand for it both within and outside Sheffield, outstripped the resources to run the bank. Logistical difficulties were encountered in the day to day running of the bank. These revolved around shortage of staff available for harvesting, the relative lack of public awareness of skin donation, shortage of banked skin as the bank became more widely known and lack of space and finance to expand. The decision was made to transfer the now established skin bank to the National Blood Service where it now operates with staff and resources dedicated specifically to this purpose. Experience leads to the suggestion that there is a clinical need for allograft skin in the UK which is not being met at the present time. There is a need for dedicated properly resourced skin banks and for the Department of Health to introduce regulation, monitoring and inspection of skin bank facilities in order to safeguard standards.

Blood Banks↗

PubMed1998

Positive association between cytoskeletal changes, melanoma cell attachment and invasion in vitro.

The literature concerning cytoskeletal changes and metastatic progression is unresolved, some studies suggesting a positive association between the ability of cells to organize their cytoskeleton and others suggesting an inverse correlation. In an attempt to learn more about cytoskeletal changes and the ability of melanoma cells to interact with extracellular matrix proteins we examined the effects of pharmacological manipulation of cell attachment and cell invasion through fibronectin on levels of F-actin and vimentin in a highly metastatic cutaneous melanoma cell line (A375-SM cells). Additionally, we examined whether any correlation existed between the levels of the cytoskeletal proteins and subpopulations of the cell line of varying invasive ability. We report that agents which reduced cell attachment to plastic and invasion through fibronectin in vitro (tamoxifen, N-desmethyltamoxifen and 17beta-oestradiol) caused increases in levels of F-actin and vimentin, whereas agents which did not affect attachment or invasion (4-hydroxytamoxifen and dihydrotestosterone) had little or no effect on the cytoskeletal proteins. In contrast, however, those cells which were most effective at invading through fibronectin were significantly better at acutely increasing their levels of F-actin and vimentin than less invasive cells. We speculate that the ability to rapidly and possibly reversibly alter the cytoskeleton might be associated with metastatically successful cells in vivo.

Actins↗

PubMed1998

An in vitro study of the use of chelating agents in cleaning nickel-contaminated human skin: an alternative approach to preventing nickel allergic contact dermatitis.

The purpose of this study was to investigate the efficacy of organic ligands in cleaning human skin contaminated with nickel. 4 ligands were investigated, 5-chloro-7-iodoquinolin-8-ol (either as HL(1) or NaL(1)), ethylenediaminetetraacetic acid (either as H4L(2) or Na2H2L(2)), sodium diethyldithiocarbamate (NaL(3)) and L-histidine (HL(4)). The cytotoxicity of these ligands was assessed using HaCaT cells (a transformed human keratinocyte cell line). The cytotoxicity order of the ligands was NaL(1) >Na2H2L(2)>NaL(3)>HL(4). An in vitro methodology for examining nickel removal from viable human skin was developed. This methodology was then used to compare the efficiency of the ligands in removing nickel from skin, both alone and in combination with soap solutions. HL(1) and NaL(3) were no more effective than control solutions in removing nickel over the pH range 2-11. In contrast, both H4L(2) and HL(4) removed between 74 and 87% (mean=82+/-3%) of nickel from human skin over the same pH range. Nickel removal from skin by sodium lauryl ethoxy sulfate (SLES, the active ingredient in most liquid skin cleansers) was independent of concentration and no more effective than phosphate-buffered saline (PBS). The amount of nickel removed by PBS solutions of Na2H2L(2) and HL(4) was significantly greater than the amount removed by SLES and was concentration dependent. An evaluation of nickel removal from skin by commercial solid soap, liquid soap and PBS, both alone and with added Na2H2L(2) or HL(4), was conducted. Commercial liquid soap with added HL(4) was more effective than the untreated soap. PBS with either added Na2H2L(2) or HL(4) was more effective than PBS alone.

Buffers↗

PubMed1998

Human melanoma cell lines show little relationship between expression of pigmentation genes and pigmentary behaviour in vitro.

Several laboratories are pursuing the question of whether the expression of pigment genes can be used as a useful marker for tumour progression. However, many melanoma tumours are amelanotic in vivo. The purpose of this study was to examine the relationship between the expression of tyrosinase-related genes [tyrosinase, tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2)] and pigmentation of melanoma cells. Fourteen cutaneous melanoma cell lines were examined for visible pigment, melanin content, and dopa oxidase activity and findings were related to the previously determined expression of the three tyrosinase-related genes in these cells in culture. Four of the cell lines were also stimulated with alpha-MSH, isobutylmethylxanthine, and forskolin to examine the relationship between induced pigmentation and upregulation of pigmentation genes. There was no simple correlation between pigmentation gene expression and dopa oxidase activity or total melanin content of the 14 melanoma cell lines in culture. In the majority of cells, there was no appreciable pigment, whereas, in contrast, half of the cells showed significant dopa oxidase activity. Upregulation of dopa oxidase activity was achieved by alpha-MSH in two out of four cell lines examined in detail and with IBMX in three out of four of these cell lines. IBMX increased tyrosinase gene expression in all four cell lines; alpha-MSH was without effect; and TRP-1 and TRP-2 expression were largely unaffected by IBMX or alpha-MSH. Modest changes in morphology were noted in response to IBMX. Overall, however, human melanoma cell lines were, with two exceptions, amelanotic in culture despite the fact that 10 out of the 14 lines expressed tyrosinase-related genes. We conclude that measurable pigmentation is not a necessary consequence of the expression of pigmentation genes. An implication of this work is that amelanotic tumours in vivo may nevertheless be positive for tyrosinase-related genes.

Biomarkers, Tumor↗

PubMed1997

Keratinocytes contract human dermal extracellular matrix and reduce soluble fibronectin production by fibroblasts in a skin composite model.

Composites of human de-epidermised acellular dermis and normal adult human keratinocytes and fibroblasts were examined for the ability of cells to contract these composites. Image analysis of the outline of the composites showed that, in this model, keratinocytes alone or in the presence of fibroblasts caused highly significant contraction (of the order of 25% by day 12). There was no significant contraction of the dermis with fibroblasts alone or in the absence of cells. The presence or absence of basement membrane antigens did not influence the effect of keratinocytes on dermal contraction. Analysis of the conditioned media from these composites showed that the greatest fibronectin production was seen with fibroblasts alone in the presence of basement membrane. Keratinocytes alone produced little fibronectin irrespective of the presence of the basement membrane. If keratinocytes were present with fibroblasts, however, then fibronectin production was significantly reduced both in the presence and absence of the basement membrane, indicating that keratinocytes modify dermal fibroblast extracellular matrix production. This study shows that while keratinocytes and fibroblasts are clearly influencing each other's activity in this human skin composite model, under the circumstances we describe it is the keratinocyte and not the fibroblast which causes contraction of the human de-epidermised acellular dermis.

Adult↗

PubMed1997

Extracellular matrix proteins induce changes in intracellular calcium and cyclic AMP signalling systems in cultured human keratinocytes.

The purpose of this study was to investigate whether extracellular matrix proteins which influence human keratinocyte behaviour are capable of altering intracellular signalling systems in these cells. The effects of extracellular matrix proteins on two major signal transduction pathways, intracellular calcium and cyclic adenosine monophosphate (cyclic AMP), were investigated. The extracellular matrix proteins examined were the basement membrane preparation matrigel, collagens type I and IV, vitronectin and its active tripeptide component Arg-Gly-Asp (RGD). Acute additions of matrigel, vitronectin and RGD caused rapid transient increases in intracellular calcium and, together with collagen type I, also caused sustained elevations in basal calcium when cells were grown on these substrates. Cyclic AMP production was unaffected by acute exposure to these extracellular matrix proteins. Culture of cells on matrigel, collagen type I or IV, however, significantly reduced basal cyclic AMP accumulation and increased the response of the cells to the receptor-independent agonist forskolin. It is concluded that in vitro some extracellular matrix proteins can initiate both acute and sustained changes in intracellular signalling in human keratinocytes.

Calcium↗

PubMed1997

Tamoxifen, 17beta-oestradiol and the calmodulin antagonist J8 inhibit human melanoma cell invasion through fibronectin.

Invasion through stromal extracellular matrix (ECM) is part of the complex, multistep process of tumour cell invasion and metastasis. Our group has previously demonstrated that calcium and calmodulin are important in another step in the metastatic cascade - that of attachment of cells to ECM. Interestingly, the non-steroidal anti-oestrogen tamoxifen (which also has calmodulin antagonist activity), used in the treatment of breast cancer and now in metastatic cutaneous melanoma, can inhibit the attachment of normal and neoplastic cells to ECM. In this study, we investigated whether such drugs, known to inhibit cell attachment, could also subsequently reduce their invasion through a layer of human fibronectin. We examined the ability of the specific calmodulin antagonist J8, tamoxifen and its two major metabolites, N-desmethyltamoxifen (N-des) and 4-hydroxytamoxifen (4-OH), as well as the pure anti-oestrogen ICI 182,780 and 17beta-oestradiol to inhibit invasion of the human cutaneous melanoma cell line, A375-SM, uveal melanoma cells and uveal melanocytes. A375-SM cells and uveal melanoma cells showed a high level of invasion (15.2% and 33.7% respectively) compared with melanocytes (around 5%) under the experimental conditions used. Submicromolar concentrations of N-des, tamoxifen, J8 and 17beta-oestradiol significantly reduced the invasiveness of the A375-SM cell line. The uveal melanoma cells also showed similar inhibition, although at higher concentrations of these agents. 4-OH and ICI 182, 780 had little or no effect on invasion of A375-SM cells (these were not tested on uveal melanoma cells). All cells used in this study were found to be negative for type I nuclear oestrogen receptors, reinforcing the possibility that tamoxifen and 17beta-oestradiol can act via mechanisms unrelated to binding to classical oestrogen receptors to inhibit tumour cell invasion.

Antineoplastic Agents↗

PubMed1997

Urinary and serum type III collagen: markers of renal fibrosis.

BACKGROUND: The progression of chronic renal failure is characterized by the progressive fibrosis of the kidneys. Such fibrosis reflects the increased deposition of collagens (I, III, and IV) as well as fibronectin within scarred kidneys. In this study, we determined whether changes in renal extracellular matrix (ECM) components are reflected by parallel changes in their circulating or urinary levels. PATIENTS AND METHODS: We studied 40 patients with a range of subacute and chronic nephropathies who underwent a renal biopsy. At the time of the biopsy, their serum and urinary levels of collagens III (amino terminal peptide of procollagen III; PIIINP) and IV, as well as fibronectin were measured. Clinical, biochemical and histological parameters were correlated. Multiple regression analysis was applied to determine the predictive value of circulating and urinary ECM components for the severity of renal fibrosis. RESULTS: We noted an increase in circulating and urinary levels of collagens III and IV but not fibronectin in patients with nephropathies compared to healthy volunteers. Increased immunoreactivity for these ECM components was also detected in kidney biopsies when compared to normal kidneys. A strong positive correlation was detected between circulating and urinary procollagen III (PIIINP) and the severity of renal interstitial fibrosis (serum PIIINP: r = 0.49, P < 0.01; urine PIIINP: r = 0.51, P < 0.01). CONCLUSION: We conclude that the measurements of urinary collagen III (PIIINP), and to a lesser extent serum collagen III (PIIINP), are useful indicators of the extent of renal fibrosis. This may have diagnostic implications and may prove useful for the monitoring of disease progression.

Adolescent↗

PubMed1997

Detection of tyrosinase autoantibodies in patients with vitiligo using 35S-labeled recombinant human tyrosinase in a radioimmunoassay.

Tyrosinase antibodies recently have been reported to occur frequently in patients with vitiligo. We describe the detection of tyrosinase antibodies in vitiligo patients using in vitro 35S-labeled human tyrosinase in a radioimmunoassay. Of 46 vitiligo sera examined in the assay, five (10.9%) were found to be positive for tyrosinase antibodies. In contrast, 20 control sera and sera from 10 patients with Hashimoto's thyroiditis were negative. Four of the sera positive in the radioimmunoassay were also positive in an ELISA using mushroom tyrosinase as antigen. Absorption studies indicated that pre-incubation with mushroom tyrosinase absorbed out the immunoreactivity of the positive sera in the radioimmunoassay, suggesting cross-reactivity, but this absorption was never complete, indicating that there are tyrosinase antibodies in human sera that do not react with the mushroom protein. There was no obvious association between the presence of tyrosinase antibodies and the age of the patients (range: 22-62 y), their duration of disease (range: 5-20 y), or the type of vitiligo (one segmental, one symmetrical/periorificial, three symmetrical), although the three patients with the highest antibody levels also had an associated autoimmune disorder (one with Graves' disease; two with autoimmune hypothyroidism). The results confirm that tyrosinase autoantibodies are present in the sera of vitiligo patients but at a low frequency. The technique described is sensitive and quantitative and allows the detection of conformational epitopes. It will be useful in longitudinal studies to determine the relation between the clinical features of vitiligo and tyrosinase antibody levels.

Adult↗

PubMed1996

Oxidative damage to muscle protein in Duchenne muscular dystrophy.

The hypothesis that reactive free radical species (ROS) may contribute to the pathogenesis of Duchenne muscular dystrophy (DMD) has been suggested previously, but experimental data obtained in support of the above have to date proved inconclusive. The recent discovery that nitric oxide synthase (required for muscle relaxation) is associated with the sarcolemmal protein dystrophin normally and that both proteins are absent in DMD has heightened interest in the potential role of ROS in this disorder. We therefore investigated oxidative damage to proteins in the quadriceps femoris muscle by quantifying protein carbonyl levels in six patients with DMD and six normal controls. In DMD, the mean protein carbonyl level in the quadriceps femoris muscle was increased by 211% (p < 0.005) compared with the normal control subjects. The data thus support the hypothesis for the role of ROS induced protein oxidation of muscle cell damage in DMD.

Adolescent↗

PubMed1996

Influence of extracellular matrix proteins on human keratinocyte attachment, proliferation and transfer to a dermal wound model.

The aim of this study was to investigate whether prior culture of cells on ECM proteins might positively influence the performance of keratinocytes when cells are transferred to a dermal in vitro wound bed model. Keratinocytes were cultured using a method for producing cultured epithelial autografts for severely burned patients (essentially using Green's medium, a mitogen-rich medium containing fetal calf serum, cholera toxin, EGF, insulin, transferrin and triiodothyronine). Cells were cultured either on irradiated 3T3 fibroblasts (as in the standard Rheinwald and Green technique) or, alternatively, on collagen I, collagen IV, matrigel, RGD, vitronectin or fibronectin. Under these conditions matrigel, collagen I and IV enhanced initial attachment, RGD, vitronectin, fibronectin and irradiated 3T3 fibroblasts did not. Proliferation of cells was positively influenced by matrigel, collagen I and IV and irradiated 3T3 fibroblasts; of these, however, only matrigel and 3T3 fibroblasts had sustained significant effects on keratinocyte proliferation over 4 days. Cells on fibronectin showed significantly reduced proliferation. An acellular non-viable dermis was then used to mimic the homograft allodermis onto which cultured epithelial autograft sheets are grafted clinically and cells cultured on the various ECM proteins for 96 h were transferred to this in vitro wound model. None of the substrates enhanced keratinocyte performance on this model. It was concluded that under these conditions some ECM proteins can significantly affect keratinocyte attachment and, to a lesser extent, proliferation but that the culture of keratinocytes on these ECM proteins does not appear to confer any lasting benefit to the attachment of these keratinocytes to an in vitro wound-bed model.

Cell Division↗

PubMed1996

Investigation of the influence of extracellular matrix proteins on normal human melanocyte morphology and melanogenic activity.

Several studies have indicated that extracellular matrix (ECM) proteins can influence melanocyte behaviour in vitro. However, the choice of medium is known to have a profound effect on melanocyte behaviour and it is currently difficult to ascribe which reported effects are due to ECM proteins and those which are attributable to the medium used in these different studies. The purpose of this study was to learn more about the influence of ECM proteins on melanocyte function by examining a range of cell-derived and individual ECM proteins for their impact on melanocyte tyrosinase activity in cells cultured under conditions of varying mitogenic drive. We found that ECM derived from human dermal fibroblasts, bovine endothelial cells and a human endothelial cell line as well as collagen I, collagen IV, fibronectin, and to a lesser extent laminin, were all capable of increasing tyrosinase activity in cultures of normal melanocytes. Effects of these ECM were seen most consistently in media with relatively few mitogens, for example ECM proteins influenced melanocyte morphology and this was seen most readily in cells cultured in medium without any mitogens (which ordinarily fails to support melanocyte survival). This study illustrates that ECM proteins can influence melanocyte morphology, proliferation, and tyrosinase activity in vitro and supports a possible role of ECM proteins in the regulation of melanocyte function in vivo.

Cell Count↗

PubMed1996

Human ocular melanocytes and retinal pigment epithelial cells differ in their melanogenic properties in vivo and in vitro.

PURPOSE: The vertebrate eye contains both melanocytes and retinal pigment epithelial (RPE) cells. Little is known of the pigmentary behaviour of these embryologically dissimilar cells. The aim of this study was to examine aspects of the pigmentary properties of both cell types in vitro and ex vivo to learn more of the function of these cells. METHODS: Sections of normal adult human eye were stained for tyrosinase related protein 1(TRP1), and cultures of RPE cells and choroidal melanocytes were examined immunocytochemically for TRP1 and 2 and enzymatically for tyrosinase activity (by assaying dopa oxidase activity). RESULTS: Over half of the choroidal melanocytes expressed TRP1 ex vivo; in contrast, a very small percentage of RPE cells were TRP1 positive. In vitro, passage 1 to 3 ocular melanocytes expressed TRP1 and TRP2 and had tyrosinase activity, which was influenced by the choice of substrate on which the cells were grown. Tyrosinase activity was highest when cells were grown on fibronectin and plastic, intermediate on laminin and lowest on vitreous extracellular matrix (ECM) containing pigment to which they attached and spread out poorly. In contrast, passage 3 RPE cells (which were unpigmented) showed little evidence of tyrosinase activity in short-term culture, irrespective of the substrate on which they were grown, and failed to express TRP1 and TRP2. When cells were grown on plastic for greater than 3 weeks in culture, a very low percentage of cells (< 0.1%) became TRP1 positive and this percentage was increased threefold if cells were cultured on laminin in the presence of bFGF. A few cells were also seen to contain pigment but cultures failed to show any tyrosinase activity. In contrast, RPE cells (but not melanocytes) showed a marked ability to take up pigment granules in vitro. CONCLUSIONS: The data suggest that normal human ocular melanocytes retain the capacity to produce pigment throughout adult life, and this can be demonstrated both ex vivo and in vitro. In contrast, we were unable to confirm that the majority of RPE cells play any significant role in active pigment production in the adult.

Adult↗

PubMed1996

Additive effects of extra cellular matrix proteins and platelet derived mitogens on human retinal pigment epithelial cell proliferation and contraction.

PURPOSE: In proliferative vitreoretinopathy (PVR) retinal pigment epithelial cells (RPE) cells are thought to synthesize and interact with extracellular matrix (ECM) proteins to form fibrocellular membranes attached to the retina, which the cells then progressively contract detaching the retina. Haemorrhage into the eye is an exacerbating factor in the pathology. To investigate some of the possible interactions between ECM proteins, platelet mitogens and RPE cells in this study, we examined the combined effect of platelet derived mitogens and ECM proteins on RPE cell proliferation and contraction. METHODS: Cells were cultured on a range of individual ECM proteins as well as on the ECM deposited by normal vitreous fluid and exposed to platelet mitogens. Effects on cell proliferation and cell detachment from these substrates and tissue culture plastic were examined. RESULTS: We report additive/synergistic effects of platelet mitogens (PDGF and TGFb1) as well as bFGF, with ECM proteins (laminin, fibronectin, collagen 1 and vitreous-deposited ECM) on RPE proliferation. Further we report stimulation of RPE cell contraction on vitreous proteins when exposed to serum prepared from platelet-rich plasma. In this context it was noticeable that it was cells grown on vitreous matrix plus pigment rather than cells grown on clear vitreous that exhibited this behaviour. CONCLUSIONS: This study supports a combined action of platelet mitogens and matrix proteins in inducing RPE cell proliferation and contractility and provides a simple in vitro model of some of the late stages of PVR.

Blood Platelets↗

PubMed1996

Chromium- and nickel-induced cytotoxicity in normal and transformed human keratinocytes: an investigation of pharmacological approaches to the prevention of Cr(VI)-induced cytotoxicity.

Chromium and nickel compounds cause irritancy but can also induce allergic contact dermatitis. The aims of this study were to characterize the direct cytotoxic effects of Cr(VI), Cr(III) and Ni(II) salts on keratinocytes, and to investigate pharmacological strategies to protect cells against Cr(VI)-induced cytotoxicity. Normal human keratinocytes and the HaCaT keratinocyte cell line were used. Cell viability was assessed by neutral red dye uptake, the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) eluted stain assay and measurement of lactate dehydrogenase (LDH) activity in the medium. The assays varied slightly in their sensitivities (neutral red > MTT > LDH) although all three gave similar results. In both cell types, the relative order of cytotoxicity of the salts was Cr(VI) >> Ni(II) > Cr(III). There were no major differences between chromium salts of a common valency. Normal human keratinocytes showed a much greater variability in their response to Cr(VI) and Ni(II) salts than HaCaT cells and were generally more resistant to Cr(VI)- and Ni(II)-induced cytotoxicity. Several drugs were screened for their potential to protect both cell types against the cytotoxic effects of Cr(VI), specifically the reducing agents ascorbic acid, cysteine and glutathione, and the Cr(VI) cellular uptake inhibitors 4,4'-diisothiocyanato-2,2'-stilbenedisulphonic acid (DIDS) and 4-acetamido-4'-isothiocyanato-2,2'-stilbenedisulphonic acid (SITS). All five drugs provided concentration-dependent protection against Cr(VI)-induced cytotoxicity but only ascorbic acid offered complete protection. Several of these pharmacological approaches to the prevention of Cr(VI) cytotoxicity confirm previous clinical studies on the inactivation of Cr(VI), while the clinical potential of others has yet to be investigated.

Ascorbic Acid↗

PubMed1995

Effect of glycerol on intracellular virus survival: implications for the clinical use of glycerol-preserved cadaver skin.

Glycerol has long been used for the preservation of skin allografts. The antimicrobial activity of glycerol has not been fully documented. This paper reports the results of an investigation of a model studying the effect of glycerol on the inactivation of intracellular viruses. Two viruses--herpes simplex type I (HSV-1) and poliovirus--were cultured within human dermal fibroblasts. These intracellular viruses were incubated with 50 per cent, 85 per cent and 98 per cent glycerol at 4 degrees C and 20 degrees C for 4 weeks. Each week, the cultures in glycerol and controls in fibroblast maintenance medium were assayed for virus infectivity by examining the ability of harvested viruses to infect further fibroblasts. At 4 degrees C, 85 per cent glycerol could not fully inactivate intracellular HSV-I or poliovirus even after 4 weeks; 98 per cent glycerol inactivated intracellular HSV-I (after 3 weeks) but could not fully inactivate intracellular poliovirus after 4 weeks. At 20 degrees C, 85 per cent glycerol inactivated intracellular HSV-I (within 1 week) but could not fully inactivate intracellular poliovirus after 4 weeks; 98 per cent glycerol inactivated intracellular HSV-I (within 1 week) and inactivated intracellular poliovirus (after 2 weeks). It is suggested that, on the basis of this study, glycerol can reduce intracellular virus infectivity but that its effects are very dependent on concentration, time and temperature such that we would recommend that allograft skin be exposed to 98 per cent glycerol for a minimum of at least 4 weeks at a minimum temperature of 20 degrees C before clinical use.

Cadaver↗