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Biomedical subjects

A Puckett

Publications and source records attributed to A Puckett.

At least 19 recordsLinked to original sources
PubMed2003

Evaluation of novel biodegradable cyclic carbonate polyester copolymers for cytocompatibility using MRC-5 cells.

The objective of this work was to synthesize and characterize a novel series of biodegradable cyclic carbonate polyester copolymers based on lactide and 5-methyl-5-benzyloxy-carbonyl-1,3-dioxan-2-one (MBC). Two compositions were selected for characterization. One copolymer was based on a racemic mixture of 1-lactide with 15.4 mole % MBC and the other was based on 1-lactide with 8.2 mole % MBC. These polymers contain carboxylic acid moieties along the backbone that may be used for tethering bioactive agents, forming ionic crosslinks or be reacted with vinyl containing monomers to allow free radical crosslinking. The initial materials evaluated have the carboxylic acid functionalities blocked with benzene. These polymers and the de-blocked versions may have potential applications for hard and soft tissue scaffolds, control drug delivery matrixes or a variety of other applications in medicine. The copolymer samples were pressed into 7.0-mm diameter disk using a KBr press. The disks were then sterilized using U.V radiation under a laminar flow hood. After sterilization, the copolymer disks were submerged in 2 ml of media and placed in a CO2 regulated incubator at 37 degrees C. A total of six groups per phase (n = 7 test tubes per group) were used in this study. Test tubes in groups I and III were plated with MRC-5 and subsequently treated with media alone (controls). Test tubes in groups II and IV were plated with MRC-5 and subsequently treated with media before being introduced to copolymer samples. Cell number, as well as, biochemical markers such as protein and malondialdehyde (MDA) were determined at the end of the 24, 48 and 72-hour time periods. Representative test tubes were subjected to an H&E staining procedure for microscopic morphological evaluation. The results of this evaluation suggest that the exposure of both copolymers produced a non-cytotoxic environment with the MRC-5 cell line. Although both copolymers are non-cytotoxic, the sample having the higher MBC content is the preferred composition based upon MDA levels and morphological evaluations.

Absorbable Implants↗
PubMed2001

Cytological evaluation of the tissue-implant reaction associated with S/C and I/P implantation of ALCAP and HA bioceramics in vivo.

It is well documented that several ceramic materials are highly compatible and non-immunogenic with host tissues. Recent studies have demonstrated the need for further investigation of these devices in vivo to further elucidate the possible mechanisms involved in biocompatibility. The purpose of this investigation was to study the morphological characteristics of the fibrous tissue capsule resulting from the implantation of aluminum calcium phosphate (ALCAP) and hydroxyapetite (HA) bioceramics. Implants of ALCAP and HA were implanted into 10 adult male rats subcutaneously (S/C) and intraperitoneally (I/P). At 90 days post-implantation, the animals were euthanized, and the ceramic devices, the fibrous tissue, and vital organs were harvested. Evaluation of routine stained sections (5 microm, hematoxylin & eosin) of the fibrous tissue capsule surrounding the HA and ALCAP ceramics revealed the following: 1) all the ceramic devices had fibrous connective tissue capsules of slightly varying degrees of thickness at the time of sacrifice, depending on the site of implantation and type of material, and 2) there were statistically significant differences (p < 0.05) in the numbers and types of cellular components with respect to implantation site. The number of macrophages, neutrophils, fibroblasts, degree of vascularity, and thickness of the fibrous tissue matrix was found to be statistically different between the S/C implanted ceramic groups. The number of macrophages, neutrophils, fibroblasts, and collagen content comparing the fibrous tissue surrounding the ALCAP and HA ceramics (I/P), was found to be statisically different.

Aluminum Compounds↗
PubMed2001

The prevention of osteoporotic progression by means of steroid loaded TCPL drug delivery systems.

Numerous studies have suggested that there is a link between the age-related decreases in Estradiol and adrenal androgens, and the subsequent development of senile osteoporosis. The specific objectives of this investigation were: 1) to deliver Dehydroepiandrosterone (DHEA), Diosgenin (DG), and Estradiol (E) at sustained levels by Tri-Calcium Phosphate Lysine drug delivery systems (TCPL), and 2) to study the effects of the sustained delivery of DHEA, DG, and E on the bone turnover of adult female rats following withdrawal of the endogenous hormonal milieu by means of ovariectomization (OVX). In this study, 20 female Sprague-Dawley rats were randomly divided into five groups containing four rats per group. The rats in Group 1 served as intact controls. Animals in groups 2-5 were ovariectomized, and groups 3-5 were implanted immediately with TCPL drug delivery capsules containing DHEA, DG, and E, respectively. Group 2 served as the SHAM (OVX only) group. At the end of 33 days post implantation, the vital organs, reproductive organs, and femurs were collected and evaluated. Bone histomorphometric analyses as well as mechanical strength testing was performed. Data obtained from this study demonstrated that body weights were increased in all OVX animals, and that E replacement resulted in body weights that were not significantly different from intact controls. No differences were seen in the wet weights of any vital organs. However, a decrease in the weights of the cervix and oviducts were evident in all ovariectomized groups, with the exception of the E group. Thirty-three days following OVX, the OVX-only group exhibited an increased inner medullary area, decreased thickness of the cortical layer of bone, and decreased mechanical strength. The group treated with DHEA and the group treated with E were shown to maintain both the medullary area and the cortical thickness (as compared to the intact control group). The three point bending test of the femora showed that OVX-only induced a slight decline in mechanical strength, and that DHEA and DG, but not E, showed increases in mechanical strength. Results of this experiment suggest that DHEA and E may reduce bone remodeling as evidenced by the reduction in the medullary area, and that DHEA may possibly be used in postmenopausal patients to reduce osteoporotic progression.

Animals↗
PubMed2001

The use of estrogen, DHEA, and diosgenin in a sustained delivery setting as a novel treatment approach for osteoporosis in the ovariectomized adult rat model.

It is well established that the pattern of bone loss from the cortex in osteoporotic bone begins from the endosteal surface of the cortex, where there is enlargement of the medullary canal at the expense of the inner cortex. Bone loss does not occur at the periosteal surface. The objective of the following study was to induce osteoporosis in female rats by ovariectomy, followed by treatment with sustained delivery of Diosgenin (DG), dehydroepiandrosterone (DHEA), or estrogen (E) after clinical signs of osteoporosis. Female Sprague Dawley rats were divided randomly into five groups containing four rats/group. Rats comprising group 1 were left intact and served as a control group. Animals in groups 2-5 were ovariectomized (OVX) and, after a 14 day delay to allow for induction of osteoporosis, were implanted with TCPL capsules containing DG, DHEA, and E, respectively. The experiment was ceased after 33 days of treatment, at which time the vital and reproductive organs for each group were collected, weighed, and analyzed histomorphometrically for differences. Further analysis of the progression of osteoporosis in the experimental animals was obtained by performing x-ray analysis of each group on a semi-weekly basis. By collecting and analyzing the femurs from each animal, we were also able to obtain important information about the histologic changes associated with osteoporosis (left femur), as well as data regarding the effects of osteoporosis on the mechanical strength of bone via three point bending analysis (right femur). The data generated by this study revealed important information as to the efficacy and safety of the alternative treatments DHEA, E, and DG for osteoporosis. First, histomorphometric analysis revealed that treatment with DHEA, E, and DG reduced the endosteal perimeter and cortical area to values very similar to controls (intact). Second, results of the bending stress and modulus in OVX and treated animals were not statistically different from the intact control animals, which suggests that the material properties of the bone were unaltered. Third, there is an increase in total body weight associated with OVX that is reduced to control levels after replacement therapy. Finally, OVX also resulted in reproductive tissue atrophy, which was reversed by all three of the treatment regimens in this study. These data suggest that bone loss after OVX can be significantly reduced by supplementation with sustained levels of DHEA, E, and DG without jeopardizing other body organs.

Animals↗
PubMed2000

The effects of growth hormone and insulin-like growth factor on the proliferation rate and morphology of RAW 264.7 macrophages.

UNLABELLED: It is well documented that growth hormone (GH) functions to regulate both cell growth and cell number and is considered the master hormone because it affects almost every cell of the body. Growth hormone stimulates the liver to secrete insulin-like growth factor (IGF-1), which is also capable of binding insulin as well as insulin-like binding receptors on the cell surface. It is possible that GH cellular effects are mediated by IGF-1 rather than GH itself. In this study, RAW 264.7 cells were challenged with a high dose of GH (48 ng/microliter), a low of dose GH (4.8 ng/microliter), a high dose of IGF-1 (26 ng/microliter) or low doses of IGF-1 (6.3 ng/microliter) for 24, 48, 72, and 96 hours. Cell number, cell protein concentration, cell damage, and cellular morphology were measured at each time point and compared to untreated RAW 264.7 cells. The results show significant increases in cell number for cells treated with low doses of GH and IGF-1 at 24 hour phase. Cell proliferative effects were also observed at 48 hours in IGF-1 treated cells. Cellular damage (MDA levels) was not statistically significant for any treated group for the entire duration of the experiment. Most notable differences were observed in cellular morphology for both IGF-1 and GH treated cells. IGF-1 resulted in condensation of the nuclear material as early as 24 hours after treatment. IN CONCLUSION: (1) RAW 264.7 responded to both IGF-1 and GH equally (viability and proliferation), and (2) morphological changes were observed in all cells treated with both hormones compared to control group. This study indicates that GH hormone could induce its effect directly or indirectly through IGF-1.

Animals↗
PubMed2000

Development of sustained delivery system as a novel technique for tissue culture.

One of the greatest advances for biomedical research has been the use of tissue culture to study the effects and the mode of action of various organic compounds. However, there are myriad problems associated with the classical approach to pharmaceutical studies in tissue culture, such as contamination, the logistical problems inherent in intermittent dosing, and near-lethal drug doses required to achieve effective physiological doses. This has given impetus to a search for better means of effective delivery routes in a tissue culture setting. The specific objectives of this investigation were: (1) to develop a ceramic delivery system for the novel purpose of releasing sustained levels of the anti-cancer drug combination inositol hexaphosphate (IP6) + inositol (I) in a tissue culture setting; (2) to assess the proliferation rate and viability of HTB 122 Intraductile Breast Cancer (IBC) cells exposed to sustained levels of IP6 + I compared to conventional means of drug delivery (dissolved in media); (3) to evaluate the morphological changes associated with this treatment process. Sterile aseptic techniques were employed during the entire study (72 hours of incubation). Data obtained from this investigation suggests the following: (1) TCPL delivery system can be utilized in the tissue culture setting to deliver IP6 + I in a sustained manner for 72 hours; (2) the use of IP6 + I at the physiological dose did not induce any significant change in the biochemical marker (MDA); (3) morphological evaluation of cells treated with sustained delivery resulted in cellular atrophy, as well as fragmentation, compared to the treatment by conventional means and to the sham group (empty capsule); and (4) regardless of route of administration, treatment with IP6 + I resulted in a decrease in total protein content compared to the sham capsules and control groups. In conclusion, this approach is a novel use of ceramic delivery systems in tissue culture that gives breakthrough information for basic research on limiting and eliminating contamination and the logistical problems associated with intermittent dosing in tissue culture.

Antineoplastic Agents↗
PubMed2000

The role of the route of administration of poly-chlorinated biphenyls (PCBs) on the reproductive and vital organs of adult female rats.

Studies have shown that high doses of Polychlorinated biphenyls (PCBs) given by conventional methods (orally or injections) have adverse effects on the reproductive and vital organs of adult female rats. However, there has not been documentation as to the effects of PCBs on adult female rats by means of a sustained delivery system. The specific objectives of this study were: (1) to investigate the effects of sustained delivery (TCPL ceramics) of PCB versus conventional mode of administration (injection) on the reproductive and vital organs of the adult female rat, (2) to evaluate the role that PCB that might have on the estrus events of adult female rats upon the exposure by sustained delivery (TCPL ceramics) and conventional mode (injection), and (3) to histopathologically evaluate the effect that PCB might have on the ovarian and accessory organs upon the sustained delivery for 21 days. A total of 10 adult female rats (BW 270-300 gm) were randomly divided into three groups. Group 1 (n = 3) served as the control, group 2 (n = 4) was injected intramuscularly every other day with Aroclor 1254 (0.1 cc), and each rat in-group 3 (n = 3) was implanted with TCPL capsules (5 mg of 2,3,3',4,5-Pentachlorobiphenyl). Aseptic surgical techniques were performed throughout the experiment. Blood (1 cc) was collected biweekly for biochemical analysis, and body weights were recorded as well. Pap smears were taken daily at approximately the same time for 25 days, and two slides were made for each pap taken (1 pap stain, 1 Diff Quik). At the end of 21 days post-implantation, all control and experimental animals were sacrificed following standard lab procedures (overdose of Halothane). The reproductive and vital organs were collected, weighed, fixed, embedded, sectioned, and stained (H&E) for histological evaluations. Data obtained from this investigation suggest the following: (1) TCPL devices were able to deliver PCB at sustained levels for 21 days, (2) regardless of the route of PCB administration no significant change was observed in total body weight compared to the controls, (3) conventional administration of PCB resulted in a remarkable changes in the fallopian tubes compared to control and sustained delivery implanted animals, (4) there were no obvious change was observed in the phases of estrus cycles upon the exposure of PCB, and (4) histopathological evaluation of spleen, kidneys, heart, adrenals, ovaries, uterus, and cervix tissues exposed to PCB did not reveal any significant changes compared to the intact group.

Adrenal Glands↗
PubMed1999

Morphological and biochemical modifications of human macrophages treated with various biomaterials.

Although tissue culture techniques are used extensively to explore the biocompatibility of various biomaterials used in orthopaedic, dental and pharmaceutical fields, the role of these materials towards human monocytes/macrophages has not been fully elucidated. The specific objectives of this investigation were: (1) to determine the biochemical markers resulting from exposure of the human monocytes/macrophages to titanium (TI), large size polyethylene (LSP), submicron polyethylene (SPE), hydroxyapatite (HA), large particle size tricalcium phosphate (LTCP), and small particle size tricalcium phosphate (STCP), and (2) to morphologically evaluate the viability of the cells treated with the aforementioned biomaterials. Approximately 15 volunteers donated blood for each phase (24, 48, and 72 hours) of the experiment. The monocytes were isolated by following established lab procedures (Histopaque 1077 and 1119). Aseptic techniques were followed throughout each phase. Each phase contained four experimental groups (TI, LSP, SPE, HA). Each group was comprised of six wells. The total protein, catalase, LDH, MDA, and cell count were measured using established lab protocols. Data obtained suggests that: (I) regardless of the biomaterial being used all experimental groups experienced remarkable phagocytosis in the first two phases (24, 48 hours), (II) during the 24 hour phase MDA activities were increased in TI, LTCP, and STCP treated wells when compared to the control and other experimental groups, (III) in the 48 hour phase the MDA level increased in LPE and STCP treated cells, (IV) there were significant differences in LDH levels in LPE, STCP, and SPE at 24 hours compared to the control and other experimental groups, (V) LDH activities were increased in LPE, STCP, SPE, and LTCP at 48 hours, and (VI) at 72 hours there were significant increases in catalase activity in HA, TI, SPE and LPE when compared to the control group and other experimental groups. Information obtained from this study provided new ideas about the interrelationship of various biomaterials, the effect of size and cell response to the various biomaterials.

Biocompatible Materials↗
PubMed1999

Biochemical markers evaluation of RAW transformed cells during treatment with various biomaterials.

Upon introduction into the human body, biomaterials initially trigger a foreign-body inflammatory response. Furthermore, the wear debris associated with such materials as those used for orthopedic implants, artificial heart valves, and dental implants can cause the body to mount an inflammatory response. This involves the production of phagocytic macrophages that ingest the foreign material while simultaneously producing cytokines that serve as chemotactic agents for an amplified immune response. Currently titanium (Ti), polyethylene (PE), tricalcium phosphate (TCP) and hydroxyapatite (HA) are widely used as biomaterials in medical implants, and particle size is an important factor in the development of orthopedic, dental, and medical implants. The objective of this study was to investigate the effect of various biomaterials (Ti, mixed particle size polyethylene (MPE), ultra high molecular weight polyethylene (UHMWPE), mixed particle size TCP (MTCP), < 0.38 micron TCP (S-TCP), and hydroxyapatite (HA)) on the inflammatory reactions expressed by transformed RAW macrophages. RAW transformed monocytes were obtained from the American Cell Culture Line, (Rockville, MD). The cells were allowed to incubate in contact with the materials for intervals of 24, 48, and 72 hours. Biochemical tests and morphological evaluations were performed after each time point, including screening for cell number, cell protein levels, supernatant protein levels, lactate dehydrogenase (LDH), Maliondialdehyde (MDA), catalase by following standard lab protocols.

Biocompatible Materials↗
PubMed1999

The effect of polymer coating biomaterials individually and incombination on the behavior of transformed RAW macrophage cells.

The use of homopolymers as coatings for biomaterials has received much attention in the last decade. However, the modifications and alterations induced by using such materials towards inflammatory cells have not been fully investigated. The specific objectives of this study were to investigate the role of hetero and homopolymers of amino acids on cell proliferation, and to determine the biochemical behavior associated with the incubation of RAW cells with various polymers. The RAW macrophage cell line was obtained from the American Type Culture Collection (Rockville, MD) and maintained in sterile media (RPMI) supplemented with 10% fetal bovine serum and 1% antibiotics and antimycotics. The cells were plated at a density of 1 x 10(6) cells/ml onto 24 well plates. The plates were divided into four groups of six wells per group per phase (24, 48, and 72 hours). Cells in the first group were treated with RGD, cells in group II were treated with poly-L-lysine, group III cells were treated with RGD + poly-L-lysine, and cells in group IV were treated with media alone, and served as controls. Cell number, as well as, protein, MDA, lactate dehydrogenase (LDH), and cytochrome C (cyto C) were determined at the end of 24, 48 and 72 hours. Data obtained from this investigation revealed that: (I) there were no significant difference in total cell counts between all experimental groups and control at the end of the 48 hour phase. However, at 24 hours there were fewer cells in the poly-L-lysine treated wells in comparison to control group (p < 0.05), (II) RGD and poly-L-lysine treatments did not cause changes in MDA or protein concentrations for the entire duration of the experiment, and (III) RGD treatment for 48 and 72 hours did not cause a reduction in the LDH activity compared to control and poly-L-lysine treated groups. Data obtained from this investigation could provide more insight regarding the design and development for safe and biocompatible orthopedic, dental and drug delivery devices.

Biocompatible Materials↗
PubMed1999

Quantitative analysis of the cellular components of the fibrous tissue matrix surrounding ALCAP, HA, and TCP bioceramics using adult male rats as a model.

This investigation was specifically an attempt to correlate the thickness of this fibrous capsule and the various histological components that are seen in the fibrous capsule surrounding ALCAP, HA, and TCP ceramics at the S/C and I/P implantation sites in order to further elucidate the mechanisms of tissue-implant interaction. Eighteen male albino rats were randomly divided into three experimental groups (n = 5/group) and one control (n = 3). Animals in Groups I, II, and III were implanted with the ALCAP, HA, and TCP ceramics, respectively. Animals in Group IV were not implanted and acted as the control group. At 90 days post-implantation, the animals in all groups were euthanized and the fibrous tissue surrounding the ceramic devices and internal organs were harvested. After routine histological processing, sections of tissue was stained with hematoxylin and eosin and evaluated using light microscopy. Analysis of the data revealed the following: 1) The presence of macrophages, neutrophils, fibroblasts, vascularity, and thickness of the fibrous tissue matrix was found to be statistically different among the subcutaneously implanted ceramic groups (ANOVA, p < 0.01). 2) The presence of collagen (S/C) is not statistically different among the three ceramic groups (ANOVA, p = 0.76). 3) The presence of macrophages, neutrophils, fibroblasts, and collagen comprising the fibrous tissue surrounding the ALCAP, HA, and TCP ceramics (I/P), was found to be statistically different (ANOVA, p < 0.01). 4) Vascularity and thickness of the fibrous tissue surrounding the three I/P ceramics were not found to be statistically different among the three ceramic groups (ANOVA, p > 0.05).

Aluminum Compounds↗
PubMed1999

Bioceramics surface modification by means of osteoclasts in culture.

The specific objectives of this study was: (I) to investigate the effect of various biomedical ceramics such as tricalcium phosphate (TCP), hydroxyapatite (HA), and aluminum-calcium-phosphorous oxide (ALCAP) on the adherence and viability of mice osteoclasts (OT) in vitro, and (II) to evaluate the role of OT that might have on the surfaces of such bioceramics. The OT cells were isolated from adult male mice and seeded at a density of 5 x 10(5) cells/well according to standard laboratory procedures. Cells were plated in each micrometer-well pretreated with ceramic capsules (HA, TCP and ALCAP) and buffered control. At the end of 1, 2, 3 and 5 days, the viability and cell number of OT were determined using an established assay. Cell number was determined in control wells with known number of cells, and a standard curve was generated by plotting absorbency units versus cell number. Biochemical analysis was performed on the aliquots obtained from the experimental and control wells at the end of each phase of the investigation. The data from this experiment suggest that: (I) OT are capable of adhering to the surface of HA, TCP and ALCAP in an in vitro environment for over a 5-day period. (II) Long-term incubation of ceramic capsules with OT revealed that the cells experienced gradual disassociation phenomenon with a greater numbers of cell detachments seen in the ALCAP contained wells. (III) SEM analysis of representative capsules demonstrated that there was an increase in the number of micro/macropores on the surface of the materials after contacting a cellular environment. This observation suggest that the material surface has been modified (TCP > HA = ALCAP). Information obtained from this study provided new insights on the interrelationship between bioceramics and the possible OT response during chronic inflammation at the site of implantation.

Aluminum Compounds↗
PubMed1999

The effect on bioadhesive polymers either freely in solution or covalently attached to a support on human macrophages.

Cell surface adhesion receptors interact with a family of adhesion molecules known as integrins. It is assumed that the cells recognize and bind a specific amino acid sequence. It is likely that the host inflammatory response may be mediated via the recognition of the inflammatory cells with the specific integrin molecules. The mechanism of such behavior has not been fully elucidated. This investigation was designed to provide more insight regarding the cellular response associated with incubation of macrophages with polymers either freely in solution or adhered to surfaces. Peripheral macrophages were seeded at a density of 4 x 10(6) cells on supports coated with either amino-acid heteropolymers of RGE, RGD, or amino-acid homopolymer Poly-L-lysine. Cells were also seeded at the same density in 24 well plates and the wells were treated with RGD, RGE or Poly-L-lysine. The cells were examined morphologically and biochemically at 24, 48, and 72 hours. The results showed cells growing on supports coated with RGD had significantly (p < 0.05) higher numbers of cells adhering and remaining viable, in comparison to cells growing on Poly-L-lysine or RGE supports. Cells growing on supports coated with RGE appeared irregularly (elongated and spindle) shaped and unevenly spaced. The cells growing on Poly-L-Lysine coated supports showed cellular disruption and lysis, whereas cells growing on the RGD appeared intact, regularly spaced and began fusing into giant cells. Lactate dehydrogenase activity was used as a measure of membrane integrity, and cells grown on coated supports with Poly-L lysine showed a two-fold increase in activity over control and peptide treated groups. On the other hand, cells growing in media containing the free RGE, RGD and Poly-L-lysine showed no statistical differences in cell number, and did not show increased activity of LDH for the entire duration of the experiment. The data suggests that the RGD, RGE and Poly-L-lysine dissolved in solution are highly biocompatible to the macrophages. However, when they are attached to a support they can affect cellular adherence as well as cellular activation.

Amino Acid Sequence↗
PubMed1999

Exposure of transformed and non-transformed phagocytic cells to novel glass ionomers in culture.

The use of glass ionomers as a novel bone cement is currently being investigated. Although acceptable for use as a dental restorative material, there is little information regarding how ionomers interact with inflammatory macrophage cell types. The specific objective of this experiment was to investigate the possible interrelationship between RAW and human monocyte/macrophage cells at the biochemical and morphological level after being in contact with three different dental cement ionomers (Fuji Duet, Fuji IX, and GC-Fuji-Ortho, GC America Inc., Chicago IL) for 72 hours. Transformed RAW macrophages were obtained from the American Type Culture collection (ATCC), and the non-transformed human macrophages were obtained from the peripheral blood of 25 male and female volunteers. The cells were plated at a density of 4 x 10(6) cells/ml in twenty-four well plates. Each plate was divided into four groups of six cells/group. Twenty-four hours after plating, the cells in groups I-III were incubated with Fuji Duet, Fuji IX, GC Fuji Ortho, respectively, and cells in Group IV were incubated with media alone to serve as controls. Immediately after addition of the ionomers, the cellular morphology was monitored for both transformed and non-transformed cells. Cell number data revealed that normal non-transformed cells were similar in number to control cells in media alone. This result suggests that the polymer treatment did significantly alter cellular viability. On the other hand, RAW cell number was markedly reduced in cells treated with ionomers in comparison to cell growing in media alone. The data suggests that the prescence of the ionomer may reduce the proliferation rate of RAW cells. Biochemical analysis of cellular supernatants to determine cellular alterations at 72 hours revealed increased levels of lactate dehydrogenase activity and levels of malionaldehyde bis diethyl acetal in all ionomer-treated groups of RAW cells compared with media alone. Non-transformed macrophages treated with the same ionomers did not differ significantly from the control cells in media alone. However, when comparing the levels of lactate dehydrogenase activity between the transformed and non-transformed cells it was apparent that the normal cells exhibited statistically higher activity than the RAW transformed cells. The results of this study suggest that although the three ionomers tested were found to be highly biocompatible with fully differentiated non-transformed macrophages, the behavior of transformed and non-transformed phagocytic cells towards these ionomers may not be similar under similar conditions.

Biocompatible Materials↗
PubMed1997

The synergistic effect of sustained delivery of DHT, DHEA, and E on the ventral prostate of adult male rodents.

Previously, our laboratory has reported that tricalcium phosphate lysine drug delivery system (TCPL) can be used successfully to deliver dihydrotestosterone (DHT) and testosterone (T) at a sustained manner for long duration. The objective of this study was to evaluate the effects of estrogen (E), DHT and dehydroepiandrosterone (DHEA), delivered in a sustained manner, individually or in combination, by means of TCPL delivery system on the morphological changes of ventral prostatic tissue. Adult male rats (BW 300-350 gm) were randomly divided into four equal groups. Animals in Group I served as our intact unimplanted controls. Capsules implanted in Group II rats were loaded with TCPL containing 100 mg of DHEA. Rats in Group III were implanted with TCPL loaded with 100 mg of DHEA and 500 mg of DHT, while rats in Group IV were implanted with TCPL loaded with 100 mg of DHEA, 500 mg of DHT and 200 mg of E. Surgical aseptic techniques were performed according to standard laboratory procedures. The animals were maintained at the University of Mississippi Medical Center Animal Facilities following the rules and regulations established by NIH on the Care and Use of Laboratory Animals. At the end of 8 weeks post implantation, all animals were sacrificed and the prostatic tissues were collected, weighed and embedded for histopathological evaluations. Statistical analysis was conducted by using standard computer programs (STATEVIEW, JANDEL, ANOVA at 95% CI). The data obtained in this investigation demonstrated that exogenous intake of E + DHEA + DHT delivered in a sustained manner for eight weeks induced several pathophysiological conditions in ventral prostatic tissue in comparison to prostatic tissue collected from control animals. Cytopathological evaluations of tissue collected from Group II animals demonstrated the following: (i) atrophic pattern of the epithelium, (ii) small, round glands with low cuboidal epithelium, (iii) hypertrophy alone or in conjunction with occasional hyperplasia of the epithelial cells, and (iv) an increased presence of connective tissue stroma. In contrast, ventral prostate collected from animals in Group IV showed an increase in weights of the net prostatic tissues in comparison to the control group. Histopathological observations such as pleomorphism, low cuboidal to pseudostratified glands, prostatic hyperplasia of the epithelial cells, occasional mitotic activity, and occasional presence of connective tissue stroma were detected. In conclusion, the results of this study suggest that the use of TCPL capsules loaded with steroid hormones, individually or in combination can be used to regulate the growth and functional behavior of prostatic tissue in male rodents.

Animals↗
PubMed1997

Interaction of cells with UHMWPE impregnated with the bioactive peptides RGD, RGE or Poly-L-lysine.

Several reports have suggested that encapsulation of orthopaedic and dental implants with fibrous tissue can lead to implant failure. The binding of cells to the surface of the implants is specific to amino-acid sequences, typically RGD. The specific objective of this study was to investigate the interaction of cultured human peripheral macrophages with specific amino-acid sequences to determine if adherence is due to the specificity of such sequence. Macrophages were seeded at a density of 1 x 10(5) cells on ultra high molecular weight polyethylene (UHMWPE) coated with either amino-acid heteropolymers of RGE, RGD, or amino-acid homopolymer Poly-L-Lysine. Cells were observed daily and morphology was recorded. The results showed that cells growing in the presence of RGD had significantly (p < 0.05) higher numbers of cells adhering and remaining viable, in comparison to cells growing on Poly-L-lysine or RGE. Cells growing on UHMWPE coated with RGE appeared irregularly (elongated and spindle) shaped and unevenly spaced. The cells growing in the presence of Poly-L-Lysine showed cellular disruption and lysis, whereas cells growing on the RGD appeared intact, regularly spaced and began fusing into giant cells. Lactate dehydrogenase activity was used as a measure of membrane integrity, and cells grown on UHMWPE coated with Poly-L-lysine showed a two-fold increase in activity over control and peptide treated groups. Immunochemical analysis for cytokine (IL-1) release as a measure of cellular reactivity revealed an increase level in the experimental groups after 24 hours and remained measurable over the duration of the experiment. Cells incubated on uncoated polyethylene showed no evidence of increased cytokine response. Overall, the results show macrophages can interact with specific coating on the material surface, and these surfaces can affect the adhesion process adherence. Use of RGE, which inhibits binding of the cells, may be a factor that can be used to coat implants to increase their longevity.

Amino Acid Sequence↗