Biomedical subjects

Michelle Tucci

Publications and source records attributed to Michelle Tucci.

66 records · Page 4Linked to original sources

PubMed2003

Histomorphometric evaluation of renal glomeruli exposed to sustained delivery of estrogen using adult ovariectomized rats.

Hormonal replacement therapy (HRT) has shown to be efficacious in treatment and preventing of heart disease, osteoporosis and reducing mortality in postmenopausal and ovariectomized females. Several attempts to utilize the native estrogen and its analogs such as Depo-Provera, conjugated estrogen and estrogen benzoate have shown different physiological responses. In addition, the route of administration and its mode of action is lacking in the literature. The specific objective of this study was to investigate the role of sustained delivery of estrogen on the functional and structural capacity of the kidney using adult female rats as a model. A total of 24 adult female rats were subdivided into four equal groups. Groups I and II were ovariectomized (OVX) by following standard laboratory surgical procedures. Each rat in groups II and III (intact) were implanted with tricalcium phosphate lysine (TCPL) drug delivery system loaded with 40 mg of estrogen. Rats in group IV were unimplanted and untreated to be served as a control group. At the end of 45 days post treatment the animals were sacrificed by using overdose of Halothane and assured by cervical dislocation. Vital and reproductive organs were retrieved, weighed and subjected to H&E staining procedure. The results of this investigation suggest: (i) TCPL delivery system released estrogen at a sustained level for 45 days without any untoward response, (ii) the wet weights of kidneys (normalized to body weight) were increased (p < 0.05) in intact rats treated with estrogen compared to control, (iii) sustained delivery of estrogen resulted in a maintenance of kidney weights compared to the control level, however, the lack of estrogen treatment resulted in a remarkable regression in the kidney weights of OVX rats, (iv) the ratio of renal arteries-diameter (normalized to arterial wall thickness) was significantly increased in intact rats treated with estrogen compared to the control and other experimental groups, (v) histopathological evolutions of renal tubules revealed tubular epithelial damage in intact rats received estrogen treatment compared to the control and other groups. In conclusion, this study suggests that exogenous estrogen therapy could lead profound tubular damage and consequently major renal insufficiency. HRT also could lead to hypertensive renal damage.

Animals↗

PubMed2003

Down regulation of CD14 expression through pretreatment with glucocorticoids.

Glucocorticoids such as cortisol are potent immunosuppressive agents that act on many cells of the body, including macrophages. Macrophages express CD14 in response to lipopolysaccharides (LPS) extracted from bacterial coats. The objectives of this study were: (1) to determine if pretreatment of macrophages with cortisol for 30 minutes prior to challenging the cells with endotoxin results in increased cell loss, cell damage (MDA), and suppression of CD14 receptors; and (2) to determine if CD14 receptor expression is able to recover with time. An experimental design incorporating RAW 264.7 cells (RAW) was used in order to evaluate our objectives. The cells were plated on 24 well plates and subsequently divided into four groups. The first group was untreated and served as the control. Group two was treated with LPS, group three with 10 uL of cortisol and a combination of LPS and cortisol was used in the treatment of the fourth group. The cells were recovered at 24, 48, and 72 hours. Results showed that there was a significant decrease in the proliferation rate in RAW cells exposed to cortisol and LPS either alone of in combination when compared to the untreated cells. Cell damage was also increased in treated cells. LPS caused receptor expression at all time points. CD14 expression was down regulated at 48 hours in cells pretreated with cortisol, however, this suppression was no longer evident at 72 hours.

Animals↗

PubMed2003

The analysis of the dorsal aorta and renal vessels exposed to sustained delivery of AED, T, and DHT using a rat model.

Studies have shown that endogenous estrogen minimized cellular injury at the organ level; however, very little research was done to determine the effects of endogenous androgens such as Testosterone (T), Dihydrotestosterone, (DHT), and Androstenedione (AED) on the cardiovascular system at the cellular level. Studies targeted at establishing such effects will broaden our understanding of the roles played by these male steroid hormones on the cardiovascular system. Our objective therefore was to (1) Use a Rat model and sustained delivery of physiological levels of these hormones to and (2) evaluate pathophysiological effects on the dorsal aorta and renal vessels. Sprague Dawley rats equally divided into four groups (n = 4) were included in the study. Group 1 animals served as control, groups II, III, and IV were treated with TCPL drug delivery devices containing 40 mg each of T, DHT, and AED, respectively. Animals were sacrificed after 90 days of exposure. Aorta and renal vessels were stained with hemotoxylin and eosin for histopathological evaluation. Results showed that TCPL drug delivery systems released 5 ng/ml/day of T, and 2 ng/ml/day of DHT and AED. After 90 days and evaluating each group, the renal arteries showed that groups exposed to T, DHT and AED showed an increase in the width of the measured arteries compared to the control group. The renal arteries exposed to AED showed the most significant increase in width. Compared to the dorsal aorta of the control group, T treated animals had decreased dorsal aorta width. The results revealed the following: (i) the exposure of sustained levels of androgenic hormones exhibited increased width of the renal arteries compared to the control animals; (ii) animals treated with sustained delivery of T had a decreased aortic width when compared to control animals; and (iii) anabolic receptors may be differentially expressed in the dorsal aorta and renal vessels of adult male rats.

Androgens↗

PubMed2003

Primary rabbit epithelial cells exposed to adrenal, gonadal, and pituitary hormones in culture.

Various studies have investigated the effects of Monkey Kidney Epithelial cells to various agents but there are few studies that are looking at other species to determine the effects these agents may have. Studying other species and their effects may provide valuable information on the differences that are seen between humans and information as to why treatment works for some and not for others. The specific objective of this study was to investigate the effects of cortisol (C), testosterone (T), dehydroepiandrosterone (DHEA), estradiol (E), and Growth Hormone (G) individually and in combination on the proliferation and viability of Primary Rabbit Kidney epithelial cells in culture. In phase I: a total of 30 tubes plated with PRKEC were divided into six equal groups. In-groups 1-5, tubes were treated with physiological doses of hormones individually i.e., C, T, DHEA, E, and G respectively. Data obtained suggests that: (1) PRKEC treated with T for 24, 48, 72, and 96 hours displayed a significant increase in catalase, LDH, as well as MDA, (2) PRKEC treated with DHEA for 48 hours displayed a reduction in cell proliferation (70%) and an increase in MDA, LDH, and catalase. The hormones studied affect Primary Rabbit Kidney Epithelial cell growth, function, and viability, however the data suggests that further study needs to be conducted to determine the full impact of steroids and growth agents on Kidney Epithelial cells.

Adrenal Cortex Hormones↗

PubMed2003

TCPL delivery system as a model for E + P replacement therapy in post-ovariectomized adult rats mimicking a postmenopausal condition.

The specific aim of this investigation was to utilize TCPL delivery system as a model for estrogen (E) plus progesterone (P) replacement therapy in post-ovariectomized adult rats mimicking a postmenopausal condition. A total of 20 adult female rats were used in this study. The animals were randomly divided into four different groups: groups II, III and IV were ovariectomized (OVX), OVX plus E (40 mg loaded TCPL), and OVX plus E (TCPL, 40 mg) plus P (TCPL, 80 mg) treatment. Group I animals (n = 5) served as intact control group. Blood samples were collected biweekly for 30 days. Vaginal smears were taken and screened daily during the entire investigation. The total serum levels of E, P, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were measured by means of radioimmunoassay procedure. Data obtained from this study suggest the followings: (I) OVX resulted in an increase in total serum levels of LH and FSH within 2 days post-ovariectomy, (II) TCPL were capable of releasing sustained levels of E (10-40 pg/ml) and P (2.30-3.75 ng/ml) at the end of second day and continued until the 30th day, (III) the sustained levels of E plus P were able to suppress the post ovariectomy rise of LH and FSH to almost physiological levels, (IV) sustained delivery of E resulted in maturation of vaginal epithelium and the smears exhibited the estrus phase throughout the investigational period, and (V) sustained delivery of E + P induced no estrus and the epithelial changes resembled the OVX group.

Animals↗

PubMed2002

Investigating initial cell-seeding density and culture period of fibroblast growing on biodegradable tricalcium phosphate lysine disks.

"Tissue engineering" uses implanted cells, scaffolds, DNA, protein, and/or protein fragments to replace or repair injured or diseased tissues and organs. Recently, biocompatible materials, such as hydroxyapatite and tricalcium phosphate, have been associated with cellular migration, exposure, and an increase in inflammatory mediators. Complications are less likely after the implants have become integrated. A model was sought to study the influence of multiple cell densities on the rate of fibroblast in-growth into porous implants. Fibroblasts were seeded at three different densities (50, 100, 200 x 10(6) cells/well) onto the surface of a 24 well tissue culture plate in the presence of porous tricalcium phosphate lysine ceramic disks. Cell number, viability, and morphology were evaluated after 1, 2, and 3 days. The results show a linear 2-fold increase in cell number during the first two days in culture. By day 3, the cells initially seeded at 200 x 10(6) cells no longer exhibited linear growth. This suggests that the tissue culture wells were confluent. Interestingly, the cells growing in wells containing TCPL disks showed slightly more cell numbers than cells growing on plastic alone for each density. The results also revealed no significant differences between the groups for parameters of cell function such as protein concentration and markers of cellular damage. Evaluation of cellular morphology indicated changes in cellular appearance with time in culture. Overall, initial cell seeding is important for faster in-growth, but with time the cells seeded at lower cell numbers will also become confluent. In conclusion, this study provides a novel approach for the study of fibroblast in-growth into implants with time. This work is important for understanding functional tissue engineering and ultimately result in safer and more efficacious repairs and replacements for the surgeon and patient.

Biodegradation, Environmental↗

PubMed2002

Cytopathological changes in early stages of benign prostatic hyperplasia upon exposure to sustained delivery of androgens.

The objective of this study was to assess the possible morphological changes that occur in the columnar epithelial cells of the prostate peripheral zone during early development of benign prostatic hyperplasia. In this study benign prostatic hyperplasia (BPH) was encouraged by the continuous delivery of androgens using TCPL drug delivery devices. A total of 16 adult male rats were randomly divided into four groups (n = 4). Group 1 served as an intact control and Groups 2-4 were implanted with tricalcium phosphate lysine (TCPL) capsules designed to deliver continuous physiologic (40 mg) doses of specific androgens as follows: Group 2, testosterone (Test); Group 3, dihydrotestosterone (DHT); Group 4, androstenedione (AED), respectively. Upon completion of the study, the columnar epithelial cells were targeted for morphometric analysis. The means number of cells per high power field, cell length, cell area, nuclear area and nuclear to cytoplasmic ratio were measured using image analysis techniques. The results of this study showed that (1) the number of cells per high power field were not changed with treatment, (2) the cell length was decreased with treatment of all androgens, (3) the cell area was decreased with treatment, (4) the nuclear area was increased with treatment of Test and DHT, and (5) the N/C ratio was increased with all three androgens. These results suggest that very early in the development of BPH, remarkable changes occur in the nucleus of the columnar epithelial cells. These changes may indicate a specific physiological response to irritation arising from the continuous delivery of androgens.

Androgens↗

PubMed2002

Effect of TCP sintering temperatures on MRC-5 fibroblast proliferation and viability.

Calcium/Phosphate ceramics have recently been used as orthopaedic implants, drug delivery systems, and models for studies on bone remodeling. Although their use has been very successful, problems such as aseptic loosening, coagulation, fibrous tissue formation, and inflammation have been noted. The objective of the study was to investigate the effects of tri-calcium Phosphate (TCP) ceramics sintered at different temperatures on the proliferation of MRC-5 fibroblasts. This was accomplished by light microscopy morphologic analysis, measurements of MDA (a measure of cell damage) and total protein, and cell counts. The experimental design consisted of four experimental groups and one control group. 96 TCP ceramics were divided into 4 groups of 24, with each group being assigned a different sintering temperature of 800, 1000, 1200 or 1400 degrees celcius. Each temperature group was then further divided into 8 ceramics per phase of 24, 48 and 72 hours. All data were analyzed using Sigma Stat software. The data collected from this study provided useful information pertaining to the optimum manufacturing conditions that produce high proliferation rates with minimal cellular damage. At 72 hours (the phase simulating chronic conditions), cell counts and MDA analysis showed that the cells incubated with the TCP sintered at 1200 degrees C had the greatest proliferation and least damage when compared to the other groups. Morphological, MDA and protein analysis showed the cells incubated with the 1400 degrees C TCP capsules to have undergone lysis or other extreme cellular alterations. Overall, the data collected revealed a marked alteration in cellular function and morphology over the range of sintering temperatures that were tested.

Biocompatible Materials↗

PubMed2002

Interrelationship between sex steroid hormones and cardiovascular disease using MRC-5 cell line as a model.

Increasing evidence reveals that low-density lipoproteins (LDL) and gender are significant risk factors in the development of cardiovascular disease (CVD). The long-term objective of this investigation is to determine the possible relationship between sex hormones, LDL, and the development of CVD. The specific aims of this investigation include: (1) to evaluate the effect of estrogen (E) and testosterone (T) on the proliferation of MRC-5 cells, (2) to investigate the role of E and T on the viability of MRC-5 cells exposed to physiological and supraphysiological levels of LDL, and (3) to evaluate the morphological changes associated with E, T, and LDL, alone or in combination, on MRC-5 cells. Proliferation rates, biochemical marker analysis, and morphological evaluations were performed following standard laboratory procedures. The results of the investigation revealed that physiological and supraphysiological levels of LDL, alone, or in combination with E and T, induced significant changes in the functional and structural capacities of MRC-5 fibroblasts throughout the experimental phases (24, 48, and 72 hours) in comparison to the control groups. MRC-5 cells exposed to T and LDL resulted in increased proliferation rates and remarkable cellular damage. In contrast, E exposure induced decreased levels of MDA compared to T exposure. Results from this investigation suggest the development of collagen matrix post cardiovascular necrosis can be attributed to the presence of T. This response could be triggered directly at the fibroblast level or by altering the physiochemical characteristics of LDL.

Cardiovascular Diseases↗

PubMed2002

The effects of TCP fabricated with amino acid binders on the proliferation and viability of fibroblast cells.

Calcium phosphate (CaP) biomaterials were produced, by fusing individual crystals together at 1200 degrees C. This ceramic material has the ability to interact with and bond to the surrounding tissue. Therefore, ceramics can serve as scaffolds for tissue growth. The objective of this study was to determine if ceramics formulated with amino acid binders can enhance and support cell growth. A total of 147 tubes containing 1 x 10(5) MRC5 cells were divided into seven equal groups. Group I served as control, Groups II-VI were incubated with ceramics containing amino acid binders (ASP, CYS, HIS, LYS, or SER, respectively) and Group VII served as ceramic without binder control. Equal numbers of tubes were terminated from each group at 24, 48 and 72 hours. Cell numbers, morphology and markers of cell damage were determined at each time point. Results indicated: 1) Total cell numbers at 24 hours were increased in all experimental groups when compared with control. Increased levels of MDA were associated with control cells. 2). At 48 hours the total cell numbers in comparison to the control cells were increased in all groups with the exception of HIS. In addition to cell number, cellular adhesion was also increased in the experimental groups compared with the control. Significant increases in MDA levels were detected at 24 hours in the CYS treated cells. 3). Cellular adhesion in the experimental groups was increased over the control, but the total cell number was only increased in the ceramic material groups containing CYS and LYS. Cells exposed to ceramics with SER as a binder showed decreased cell numbers as well as increased MDA levels at this time point in comparison to control and other binders. Morphological evaluation of the cells showed amino acid binders with acidic side chains caused an increase in the presence of spindled shaped cells. Neutral side chains resulted in cells with elongated appearances, and basic side chains caused the cells to be less elongated. In conclusion, amino acid binders are able to induce the cells to adhere, proliferate and affect their morphological appearance as early as 24 hours.

Amino Acids↗

PubMed2002

The effects of vitamin E on the proliferation and viability of irradiated fibroblast-like cells.

Few studies have indicated the use of antioxidants in the protection against cancers. The goal of this study was to develop a tissue culture model using MRC-5 cells, which would allow for rapid testing of treatments for skin damage, mediated by exposure to ultraviolet radiation (UVR). Overall the specific aims were to evaluate the morphological and pathophysiological responses of MRC-5 fibroblast cells exposed to UVR and antioxidant supplementation. In the first phase, MRC-5 cells were exposed to UVR for 30, 45 or 60 minute time intervals, and cellular damage was assessed biochemically and morphologically. In the second phase, cells were treated for 45 minutes in the presence or absences of physiological levels of vitamin E. The cells were evaluated after 24, 48, and 72 hours for biochemical and morphological changes. Structural changes were noted throughout the experimental phase among the UVR exposed groups compared with native control. However, treatment with vitamin E pre and post exposure provided a protective role by demonstrating lower levels of MDA (p < 0.05) as well as normal structural appearance.

Cell Count↗

PubMed2002

Localization of cytokines in heart ventricular and apex tissues exposed to sustained delivery of AED, T, and DHT using a rat model.

Studies have shown that endogenous estrogen minimized cellular injury at the organ level; however, very little research was done to determine the effects of endogenous androgens such as Testosterone (T), Dihydrotestosterone, (DHT), and Androstenedione (AED) on the cardiovascular system at the cellular level Studies targeted at establishing such effects will broaden our understanding of the roles played by these male steroid hormones on the cardiovascular system. Our objective therefore was to (1) Use a Rat model and sustained delivery of physiological levels of these hormones to (1) evaluate pathophysiological effects on the cardiovascular system; and (2) localized cytokines such as IL-1, IL-6 and TNF on these tissues. Four groups of Sprague Dawley rats were included in the study. Group 1 animals served as control, groups II, III, and IV were treated with TCPL drug delivery devices containing 40 mg each of T, DHT, and AED, respectfully. Animals were sacrificed after 90 days of exposure. The ventricles and apex were immunostained for IL-1, IL-6, TNF and were also stained with Hemotoxylin and Eosin for histopathological evaluation. Results showed that TCPL drug delivery systems released 5 ng/ml/day of T, and 2 ng/ml/day of DHT and AED. IL-6 was expressed in the control heart ventricle and T, DHT, and AED reduced expression of the cytokine significantly after 90 days. Very small number of cells from the apex responded to IL-6 than cells within the ventricles. The results revealed that (i) the exposure of sustained levels of androgenic hormones exhibited myocardial hypertrophic condition compared to the control animals, (ii) the control animals had a two-fold increase in the ventricles IL-6 production over T treated animals and approximately five-fold increase over DHT and AED treated animals, and (iii) other inflammatory cytokines IL-1 and TNF were not differentially expressed in the ventricles of experimental animals when compared with the control; and (iv) In the apex tissue, animals treated with AED exhibited cells with increased response to IL-6 and a decrease cells responding to TNF and IL-1. IL-6 production in the ventricles decreased in animals exposed to sustained androgenic steroids and this decrease could possibly lead to increased blood flow, resulting in better oxygenation of the myocardium and improved cardiac function.

Androstenedione↗