Biomedical subjects

H Darmani

Publications and source records attributed to H Darmani.

17 recordsLinked to original sources

PubMed2006

Effects of extracts of miswak and derum on proliferation of Balb/C 3T3 fibroblasts and viability of cariogenic bacteria.

OBJECTIVES: This study examined the effects of extracts of two chewing sticks on proliferation of fibroblasts and viability of cariogenic bacteria. METHODS: Aqueous extracts of miswak (Salvadora persica; Arak tree) and derum (Juglans regia; walnut tree) were prepared and their effects investigated on growth of Balb/C 3T3 mouse fibroblasts by measuring the mitochondrial succinic dehydrogenase activity. Furthermore, the effects on the viability of various cariogenic bacteria (Streptococcus mutans, Streptococcus salivarius, Lactobacillus casei and Actinomyces viscosus) was also determined. RESULTS: The data revealed that Balb/C 3T3 fibroblasts exposed to aqueous extracts of miswak or derum showed an increase in cell proliferation by 156% and 255%, respectively, in comparison with controls (p < 0.0001). Furthermore, extracts from both miswak and derum had adverse effects on the growth of the cariogenic microorganisms, with derum having significantly greater antimicrobial effects than miswak and at much lower concentrations against all the bacteria tested. The most sensitive organisms were A. viscosus, followed by S. mutans, S. salivarius, with L. casei being the most resistant. CONCLUSION: The results show that aqueous extracts of miswak and derum enhance the growth of fibroblasts and inhibit the growth of cariogenic bacteria, with the derum extract showing greater activity than miswak.

3T3 Cells↗

PubMed2005

An in vivo microfabricated scaffold for tendon repair.

A new type of in vivo tissue engineering system for tendon repair in situ after cut or crush of a flexor tendon is described. The system is based on the topographical reaction, alignment, migration and perhaps proliferation of tendon cells on micrometrically grooved substrates made in a biodegradable polymer. Macrophage trapping in the structure may also help to prevent inflammation. Tendon damage including crush and section injury is a fairly frequent occurrence. The conventional treatment is surgical repair, however frequently this leads, especially in hand wounds, to attachment of the tendon surface to the surrounding synovium, which is very undesirable. We present an approach based on using a biodegradable device to ensure that the healing of severed or crushed flexor tendons is aided, synovial adhesion prevented and the final result anatomically correct. The biodegradable sheath carries microgrooves fabricated into the polymer by embossing that orient and guide the cells towards each other from either side of the region of damage. After six weeks an apparently normal functional tendon is reformed.

Animals↗

PubMed2005

Cytotoxicity evaluation of dental resin composites and their flowable derivatives.

The release of components from dental composite into surrounding tissue may cause an adverse tissue reaction. Thus, this study investigated the cytotoxicity of three types of dental composites with their flowable derivatives and determined the compounds released from these materials by high-performance liquid chromatography (HPLC) analysis. Fifteen specimens from each composite (Admira, Z250, Tetric Ceram) with fifteen of their flowables (Admira Flow, Tetric Flow, Feltik Flow) were prepared in the form of discs and divided into two groups of 10 and 5 for each material. The first group (10 discs) was used to evaluate the cytotoxicity of the material on balb/c 3T3 fibroblasts by measuring cellular metabolic activity (3{4,5-dimethylthiazol-2-yl}-2,5-diphenyltetrazolium bromide [MTT] assay) relative to Teflon controls, while the second group (5 discs) was used to determine the leached components from each material into culture medium by HPLC analysis. The results revealed that Z250 and Tetric Ceram were less cytotoxic than their flowable derivatives. However, the ormocer, Admira, was significantly more cytotoxic than Admira Flow. Among the standard composites, Tetric Ceram was the least cytotoxic and Admira the most. Furthermore, Tetric flow was the most cytotoxic and Admira flow was significantly the least cytotoxic among the flowable materials tested. HPLC analysis revealed bisphenol A glycerolate dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) in the eluates of all the materials, while urethane dimethacrylate (UDMA) was present in all eluates except that of Feltik Flow. In conclusion, the flowable derivatives are more cytotoxic than the traditional composites whereas the ormocer Admira Flow is less cytotoxic than the Admira composite.

Acrylic Resins↗

PubMed2003

The effect of an extract of Salvadora persica (Meswak, chewing stick) on fertility of male and female mice.

This study investigated the toxic effects of an extract of Meswak from Salvadora persica for 30 days on the reproductive system of the mouse. The results showed that exposure to Meswak extract did not have much effect on female mouse fertility, although it caused a significant decrease in the relative weights of the ovary and an increase in uterine weights. Exposure of male mice to Meswak extract resulted in a 72% reduction in pregnancies in untreated females impregnated by test males. The relative weights of the testes and preputial glands were significantly increased and that of the seminal vesicles was significantly decreased in test males. The results indicate that Meswak has adverse effects on male and female reproductive system and fertility.

Animals↗

PubMed2001

Effects of long-term exposure to manganese chloride on fertility of male and female mice.

The effect of long-term ingestion of manganese (II) chloride tetrahydrate was investigated on fertility of male and female Swiss mice. Adult male or female mice ingested a solution of manganese chloride along with drinking water at concentrations of 1000, 2000, 4000 and 8000 mg/l for 12 weeks. Fertility was significantly reduced in male mice exposed to manganese chloride solution at a concentration of 8000 mg/l, but not at the other concentrations. There were no treatment-related effects on the number of implantation sites, viable fetuses or the number of resorptions in female rats impregnated by males who had ingested manganese chloride. Fertility was not significantly reduced in female mice exposed to manganese chloride solution at all concentrations used in this study. However, the numbers of implantations and viable fetuses were significantly reduced in females exposed to manganese chloride solution at a concentration of 8000 mg/l. There was no significant effect on the number of resorbed fetuses in females exposed to manganese chloride solution compared to their control counterparts. Absolute body weight was not significantly affected in females exposed to manganese chloride solutions. However, ovarian weight was significantly increased in females exposed to manganese chloride solution at concentrations of 4000 and 8000 mg/l. A significant increase in the uterine weight was also observed at all concentrations used in the study. These results indicate that ingestion of manganese chloride by adult male and female mice causes some adverse effects on fertility and reproduction.

Administration, Oral↗

PubMed2001

Effects of extremely low frequency magnetic field on fertility of adult male and female rats.

To investigate the effects of an extremely low-frequency (ELF) magnetic field on their fertility, adult male and female Sprague-Dawley rats were exposed to a 50 Hz sinusoidal magnetic field of approximately 25 microT (rms) for 90 days before they were mated with unexposed counterparts. Exposure to a 50 Hz field reduced male rat fertility. The number of pregnant females was reduced when mated with exposed males, and the number of resorptions increased. The effects of magnetic field on male fertility were shown to be partly reversible, when the same exposed group of males were remated 45 and 90 days after being removed from the fields. Exposure of adult female rats to 50 Hz magnetic fields for 90 days before mating significantly reduced their fertility. The mean numbers of implantations and living fetuses per litter were statistically significantly decreased in the 50 Hz group. These results suggest that low frequency magnetic fields have some adverse effects on fertility of male and female rats.

Animals↗

PubMed2001

Effects of sodium nitrite on natural killer cells isolated from human peripheral blood.

The effect of different concentrations (0, 0.1, 0.2, 0.4, and 0.8 mg/ml) of sodium nitrite on the anti-tumor activity of natural killer (NK) cells isolated from human peripheral blood was examined. Sodium nitrite induced significant inhibition (25.3-66.6%) of NK cell activity against WEHI-164 cells. This reduction in NK cell cytotoxicity was found to be partially due to inhibition of NK cell production of interferon-gamma (25.7-92.8%) and tumor necrosis factor-alpha (26.6 76.6%). In addition, exposure to sodium nitrite resulted in a significant decrease (17.5-81.1%) in proliferation of control and interleukin-2-stimulated NK cells. Furthermore, the release of granzyme A and N-acetyl-beta-D-glucosaminidase by NK cells was also decreased by 21.7-72.2% and 33.5-81.2%, respectively. Therefore, sodium nitrite is of environmental concern in view of its inhibitory effects on NK cell activity that might contribute to tumor promotion in vivo.

Acetylglucosaminidase↗

PubMed2001

Evaluation of the toxic potentials of cypermethrin pesticide on some reproductive and fertility parameters in the male rats.

Adult male Sprague-Dawley rats were exposed to tap water containing 0, 8,571, 17,143, or 34,286 ppm cypermethrin for 12 weeks. Based on water consumption per animal per day the rats received 13.15, 18.93, and 39.66 mg cypermethrin, respectively. Fertility was significantly reduced in male rats ingesting cypermethrin at a concentration of 13.15 and 18.93 mg in that the number of females impregnated by them was significantly reduced. The number of implantation sites was significantly reduced in females mated with males that had ingested cypermethrin at a concentration of 39.66 mg. A significant reduction in the number of viable fetuses was observed in females impregnated by the exposed males at all three doses of cypermethrin. The body weight gain was significantly lower in the treated males. Ingestion of cypermethrin at a concentration of 18.93 or 39.66 mg per day resulted in a significant increase in the weights of testes and seminal vesicles. Preputial gland weights were increased at all three concentrations of cypermethrin. Epididymal and testicular sperm counts as well as daily sperm production were significantly decreased in exposed males. The serum levels of testosterone, follicle-stimulating hormone and luteinizing hormone were significantly reduced in males exposed to 39.66 mg per day. Ingestion of cypermethrin at 18.93 and 39.66 mg/animal/day also resulted in a significant decrease in the perimeter and number of cell layers of the seminiferous tubules. The testes of treated animals were infiltrated with congested blood vessels with marked hemorrhage and a significant accumulation of connective tissue surrounding the seminiferous tubules, which contained a large number of immature spermatids. These results clearly demonstrate the adverse effects of cypermethrin pesticide on fertility and reproduction in male rats.

Animals↗

PubMed2000

Fetotoxic potentials of Globularia arabica and Globularia alypum (Globulariaceae) in rats.

Adult female Sprague-Dawley rats received by intragastric application, ethanolic extracts of Globularia arabica and Globularia alypum dried leaves. The effect of the extracts was monitored on fertility. The ingestion by female rats of 800 mg/kg of ethanolic extracts of G. arabica and G. alypum, from day 1 to day 6 of pregnancy, did not cause pregnancy failure. However, the ingestion of ethanolic extracts of G. alypum significantly reduced the number of viable fetuses. The number of resorptions was significantly increased in pregnant females administered ethanolic extracts of both G. arabica and G. alypum. The ingestion of 800 mg/kg of ethnologic extracts of G. arabica and G. alypum for 30 consecutive days by adult female rats had no significant effect on the occurrence of pregnancy. However, the ingestion of extracts of both species increased the number of resorptions and only G. alypum extract caused a significant reduction in the number of viable fetuses. These results indicate that ingestion of G. arabica and G. alypum could have some reproductive toxicity in female rats.

Abortifacient Agents↗

PubMed1995

Differential effects of interferon-gamma and -beta on fatty acid turnover, lipid bilayer fluidity and TNF-alpha release in murine macrophage J774.2 cells.

The effects of interferon (IFN)-gamma and IFN-beta on the incorporation of 14C-linoleic acid into J774.2 cell membrane phospholipids were examined. Interferon-gamma induced a statistically significant increase in incorporation of 14C-linoleic acid into all the major phospholipid classes. In contrast, IFN-beta induced a slightly reduced incorporation of this fatty acid into the phospholipids. Neither IFN-gamma nor IFN-beta had any effect on the incorporation of the saturated fatty acid 14C-stearic acid into the cellular phospholipids. Interferon-gamma had no effect on the metabolism of 14C-linoleic acid in the fibroblast cell line L929. Macrophage membrane fluidity was assessed by spin-label ESR spectroscopy after incubation with either IFN-gamma or IFN-beta. Interferon-gamma significantly increased membrane fluidity whereas IFN-beta significantly decreased the fluidity. The findings of this study reveal that IFN-gamma might act on the enzymes controlling the labelling of the sn2 position of phospholipids (linoleic acid) but not the sn1 position (stearic acid), and this increases the polyunsaturated fatty acid content of macrophage membranes. This increase in polyunsaturation is reflected in the increased membrane fluidity. We also conclude that IFN-beta and IFN-gamma have different mechanisms of action on macrophage membrane lipid metabolism.

Animals↗

PubMed1994

Interferon-gamma and polyunsaturated fatty acids increase the binding of lipopolysaccharide to macrophages.

We have previously shown that interferon-gamma (IFN-gamma) increases the polyunsaturated fatty acid content of membrane phospholipids in cells that were sensitive to endotoxin. In this study, IFN-gamma was found to stimulate the binding of endotoxin to the murine macrophage cell line J774.2 and the human monocyte cell line U937. Interferon-gamma-activated J774.2 cells showed a 66% increase in fluoresceine isothiocyanate (FITC) labelled LPS binding (P < 0.0005 vs control cells) and a 49% increase in tritium labelled LPS binding (P < 0.0001 vs control cells). Interferon-gamma also induced a 35% increase in binding of FITC-LPS in U937 cells (P < 0.0001 vs control cells). In contrast, pretreatment of J774.2 cells with interferon-beta (IFN-beta) had no effect on binding of FITC-LPS. Preincubation with exogenously supplied polyunsaturated fatty acids, linoleic and arachidonic acids, resulted in increases of 74% and 69% in FITC-LPS binding, respectively (both P < 0.0005 vs control cells). On the other hand, pretreatment with the saturated fatty acid, palmitic acid, had no effect on FITC-LPS binding. We propose that IFN-gamma-induced changes in the membrane phospholipid fatty acid composition of macrophage-like cells influence the binding of endotoxin.

Animals↗

PubMed1993

Interferon-gamma-stimulated uptake and turnover of linoleate and arachidonate in macrophages: a possible pathway for hypersensitivity to endotoxin.

When P388D macrophage cells were exposed to [14C]linoleic acid, phosphatidylcholine (PC) phosphatidylethanolamine (PE), phosphatidylinositol (PI), and triacylglycerol (TAG) were major labelled lipid classes. PC was the major labelled phospholipid class at shorter incubation times with PE and PI becoming proportionally better labelled with time. Interferon-gamma (IFN-gamma) stimulated the labelling of all phospholipid classes at the expense of triacylglycerol (TAG) labelling whether it was added coincidently to the [14C]linoleic acid or after a prelabelling period. A similar pattern of labelling of all major phospholipid classes by interferon-gamma in J774.2 macrophage cells was also observed. Interferon-gamma also exerted a stimulatory effect on incorporation of [14C]arachidonic acid into the phosphatidylinositol fraction of the membrane phospholipids. However, uptake of [14C]stearic acid was not different in control compared with IFN-gamma-activated cells. Uptake of linoleic acid into the plasmalogen fraction of PE was also considerably enhanced in IFN-gamma-treated cells. The results suggest that IFN-gamma has a direct effect on the activity of enzymes controlling fatty acid turnover in phospholipids. This altered uptake and turnover of unsaturated fatty acids may have important consequences for the subsequent activation of macrophages by endotoxin.

Animals↗

PubMed1993

Effect of interferon-gamma on membrane conformation in the macrophage-like cell line P388D.

Interferon-gamma (IFN-gamma) specifically induced the uptake of the unsaturated fatty acid [14C]linoleic acid into membrane phospholipids of the murine macrophage-like P388D cell lineage, but did not alter the incorporation of the saturated fatty acid [14C]stearic acid. Spin label ESR spectroscopy was used to examine any effects of these IFN-gamma-induced changes on membrane fluidity and the results revealed significant increases in plasma membrane fluidity. This alteration in membrane fluidity may have important consequences in the dynamic properties of cellular physiochemical interactions and some of the stimulatory effects of IFN-gamma on macrophages might be attributed to its effects on the plasma membrane composition.

Animals↗

PubMed1992

Interferon-gamma increases macrophage phospholipid polyunsaturation: a possible mechanism of endotoxin sensitivity.

Incubation of murine macrophages or the macrophage-like cell line P388D with interferon-gamma in vitro induced a significant increase in the polyunsaturated fatty acid content of phosphatidylethanolamine. These increases were time and dose-dependent, being maximal at 12 hours and with 5000 U/ml interferon and were inhibited in the presence of anti-interferon-gamma monoclonal antibody. Interferon-gamma induced a significant increase in linoleate in peritoneal macrophages while in the cell line arachidonate was significantly increased. These results are of interest because such increases in the polyunsaturated fatty acid content of phosphatidylethanolamine were previously shown by us to be associated with increased sensitivity to endotoxin in mice in vivo. The implications for interferon-gamma sensitizing to endotoxin are discussed.

Animals↗

PubMed1991

Contact patterns in concanavalin A agglutinated erythrocytes.

Agglutination of human erythrocytes by the lectin concanavalin A is enhanced when the erythrocytes are pretreated with neuraminidase, which removes sialic acids, or with pronase, which degrades both the glycophorins and band 3 protein. In the present work transmission electron microscopy of the enzymatically pretreated erythrocytes shows a regular pattern of interruption of contact between interacting plasma membranes. The lengths characteristic of the pattern were 0.66 and 0.50 microns for pronase- and neuraminidase-pretreated cells, respectively. Agglutination of normal erythrocytes and of neuraminidase-pretreated erythrocytes can be fully reversed by exposure to the competitive inhibitor methyl alpha-D-mannopyranoside. Complete reversal of contact does not occur with pronase-pretreated cells. The comparatively greater tenacity of contact between cells that were treated with pronase before exposure to lectin argues for an involvement of nonspecific interactions in the agglutination process. The results are compared with previously published studies of spatially periodic contact patterns induced by a range of other polymers.

Binding, Competitive↗

PubMed1990

Membrane-membrane interactions: parallel membranes or patterned discrete contacts.

Theoretical and experimental studies of thin liquid films show that, under certain conditions, the film thickness can undergo a sudden transition which gives a stable narrower film or ends in film rupture at spatially periodic points. Theoretical analysis have also indicated that similar transitions might arise in the thin aqueous layer separating interacting membranes. Experiments described here show spatially periodic intermembrane contact points and suggest that spontaneous rapid growth of fluctuations can occur on an intermembrane water layer. Normal and pronase pretreated erythrocytes were exposed to 2% Dextran (450,000 Mr) and the resultant aggregates were examined by light and transmission electron microscopy. Cell electrophoresis measurements were used as an index of pronase modification of the glycocalyx. Erythrocytes exposed to dextran revealed a uniform intercellular separation of parallel membranes. This equilibrium between attractive and repulsive intermembrane forces is consistent with the established Derjaguin, Landau, Verwey, Overbeek (DLVO) model for colloidal particle interaction. In contrast to the above uniform separation a spatial pattern of discrete contact regions was observed in cells coming together in dextran following pronase pretreatment. The lateral contact separation distance was 3.0 microns for mild pronase pretreatment and decreased to 0.85 micron for more extensive pronase pretreatments. The system examined here is seen as a useful experimental model in which to study the principles involved in producing either uniform separation or point contacts between interacting membranes.

Cell Adhesion↗

PubMed1990

Spreading of wheat germ agglutinin-induced erythrocyte contact by formation of spatially discrete contacts.

The time dependence of agglutination and cell-cell contact spreading in human erythrocytes exposed to wheat germ agglutinin (WGA) was characterized by light and electron microscopy. Cells (3 x 10(7)/mL) had a threshold lectin concentration in the range of 0.6-2.0 micrograms/mL for initial cell contact. Spreading was essentially completed within 60 and 2 min in undisturbed and gently agitated suspensions, respectively. The cells in large WGA agglutinates retained features of their initial disk form in contrast to the convex outlines of polycation or polyethylene glycol-induced agglutinates. Spreading of contact area was accompanied by development of a pattern of discrete contact regions separated by a distance of the order of 1 micron. Freeze fracture electron microscopy and studies with ferritin-labeled WGA showed no significant aggregation of intramembrane particles or specific lectin receptors under conditions when contact spreading occurred. It is argued that flow stress effects on cells in suspended agglutinates give rise to a situation where opposite membranes, at the leading edge of cell contact, are separated by a thin aqueous layer. When this intercellular water layer exceeds a critical length, it becomes unstable. The layer breaks up by surface wave development to form an array of intracellular water spaces. Formation of the aqueous spaces causes opposite membrane regions to move synchronously toward each other. Lectin molecules crosslink the wave crests to give spatially periodic contact points.

Cell Communication↗