The Effects of NPY1 Receptor Antagonism on Intervertebral Disc and Bone Changes in Ovariectomized Rats.

STUDY DESIGN: Basic science. OBJECTIVE: To compare the effects of a neuropeptide Y1 receptor antagonist (NPY-1RA) to estrogen on maintaining vertebral bone microarchitecture and disc height in a rat model of menopause. METHODS: This study was an institutional animal care approved randomized control study with 104 ovariectomized rats and 32 intact control animals. Comparison of disc height, trabecular bone, body weights, circulating levels of NPY and estrogen, and distribution of Y1 receptors in the intervertebral disc in an established rodent osteoporotic model were made at baseline and after 2, 4, and 8 weeks after receiving either an implant containing estrogen or an antagonist to the neuropeptide Y1 receptor. Data was compared statistically using One-way analysis of variance. RESULTS: Circulating levels of estrogen increased and NPY decreased following estrogen replacement, with values comparable to ovary-intact animals. NPY-1RA-treated animals had low estrogen and high NPY circulating levels and were similar to ovariectomized control rats. Both NPY-1RA and estrogen administration were able reduce, menopause associated weight gain. NPY-1RA appeared to restore bone formation and maintain disc height, while estrogen replacement prevented further bone loss. CONCLUSION: NPY-1RA in osteoporotic rats activates osteoblast production of bone and decreased marrow and body fat more effectively than estrogen replacement when delivered in similar concentrations. Annulus cells had NPY receptors, which may play a role in disc nutrition, extracellular matrix production, and pain signaling cascades.

The role of the msaABCR operon in implant-associated chronic osteomyelitis in Staphylococcus aureus USA300 LAC.

BACKGROUND: The msaABCR operon regulates several staphylococcal phenotypes such as biofilm formation, capsule production, protease production, pigmentation, antibiotic resistance, and persister cells formation. The msaABCR operon is required for maintaining the cell wall integrity via affecting peptidoglycan cross-linking. The msaABCR operon also plays a role in oxidative stress defense mechanism, which is required to facilitate persistent and recurrent staphylococcal infections. Staphylococcus aureus is the most frequent cause of chronic implant-associated osteomyelitis (OM). The CA-MRSA USA300 strains are predominant in the United States and cause severe infections, including bone and joint infections. RESULTS: The USA300 LAC strain caused significant bone damage, as evidenced by the presence of severe bone necrosis with multiple foci of sequestra and large numbers of multinucleated osteoclasts. Intraosseous survival and biofilm formation on the K-wires by USA300 LAC strains was pronounced. However, the msaABCR deletion mutant was attenuated. We observed minimal bone necrosis, with no evidence of intramedullary abscess and/or fibrosis, along reduced intraosseous bacterial population and significantly less biofilm formation on the K-wires by the msaABCR mutant. microCT analysis of infected bone showed significant bone loss and damage in the USA300 LAC and complemented strain, whereas the msaABCR mutant's effect was reduced. In addition, we observed increased osteoblasts response and new bone formation around the K-wires in the bone infected by the msaABCR mutant. Whole-cell proteomics analysis of msaABCR mutant cells showed significant downregulation of proteins, cell adhesion factors, and virulence factors that interact with osteoblasts and are associated with chronic OM caused by S. aureus. CONCLUSION: This study showed that deletion of msaABCR operon in USA300 LAC strain lead to defective biofilm in K-wire implants, decreased intraosseous survival, and reduced cortical bone destruction. Thus, msaABCR plays a role in implant-associated chronic osteomyelitis by regulating extracellular proteases, cell adhesions factors and virulence factors. However additional studies are required to further define the contribution of msaABCR-regulated molecules in osteomyelitis pathogenesis.

Tracking tidal volume noninvasively in volunteers using a tightly controlled temperature-based device: A proof of concept paper.

INTRODUCTION: There is a paucity of noninvasive respiratory monitors for patients outside of critical care settings. The Linshom respiratory monitoring device is a novel temperature-based respiratory monitor that measures the respiratory rate as accurately as capnography. OBJECTIVES: Determine whether the amplitude of the Linshom temperature profile was an accurate, surrogate and qualitative metric of the tidal volume (VT ) that tracks VT in healthy volunteers. METHODS: Forty volunteers breathed room air spontaneously through a tight-fitting continuous positive airway pressure mask with a Linshom device mounted in the mask. VT was measured contemporaneously using a standalone Maquet Servo-i ICU ventilator. The amplitudes of the Linshom temperature profiles were paired with the contemporaneous VT measurements using least squares linear regression analysis and the coefficient of variation (R2 ) was determined. RESULTS: Forty volunteers completed the study. The data from 30 of the volunteers were analysed and are presented; data from 10 volunteers were not included due to protocol violations and/or technical issues unrelated to Linshom. The fluctuations in the amplitude of the Linshom temperature profiles mapped closely with the measured VT using least squares linear regression analyses yielding a mean R2 (95% CI) value of 0.87 (0.84-0.90). CONCLUSION: These results support the notion that the Linshom temperature profile is an accurate and reliable surrogate that tracks changes in VT in healthy volunteers. Further studies are warranted in patients in clinical settings to establish the effectiveness of this monitor.

Pre-medication before dental procedures: A randomized controlled study comparing intranasal dexmedetomidine with oral midazolam.

BACKGROUND: This study aimed to determine if intranasal dexmedetomidine is a superior pre-medication to oral midazolam in older, difficult children. METHODS: This was conducted as a prospective, single-blind randomized control trial in a tertiary care center. Seventy-five children, age >5 years and weight >20 kg, who needed general anesthesia for dental procedures were randomly assigned to be pre-medicated with either oral midazolam at a dose of 0.5 mg/kg (max 15 mg) or intranasal dexmedetomidine at a dose of 2 mcg/kg (max 100 mcg). The primary outcome studied was the patients' level of sedation when separated from their parents, which was assessed using a 5-point University of Michigan Sedation Scale. Secondary outcome studied was the level of anxiolysis assessed by the acceptance of mask induction using a 4-point scale. All assessments were made by one research person blinded to the study drug. RESULTS: The two groups were similar in age, sex, weight, pre-anesthetic behavior, time from pre-medication to anesthesia induction, and surgical time. A significantly higher proportion of patients who received dexmedetomidine had satisfactory sedation at separation from parents (69.4% vs 40.5%, P = .03) compared to those who received midazolam. There were no significant differences in the rate of acceptance of mask induction (80.6% vs 78.4%, P = 1.00). Intranasal dexmedetomidine was tolerated well when administered using a mucosal atomizer and without any clinically significant effect on heart rate or systolic blood pressure. CONCLUSIONS: Intranasal dexmedetomidine provides higher success rate in sedation and parental separation compared to oral midazolam, in older, difficult children.

Sustained Release of Demineralized Bone Matrix Protein in Osteoporotic Rats.

Demineralized bone matrix protein (DBM) was considered highly effective in stimulating bone healing. The objective of the study was to explore the use of tricalcium phosphate (TCP) delivery system to continuously deliver DBM in an osteoporotic condition and to evaluate changes in bone density and preservation of the spine. Ovariectomized Sprague Dawley rats were divided into three equal groups (n=16 per group). Animals in group I served as control, animals in groups II and III were surgically implanted with either empty (SHAM) or DBM filled TCP implants adjacent to L4/L5. Eight animals from each group were euthanized at 2 and 8 weeks post implantation. Femurs were evaluated for changes in density, and the lumbar spine was evaluated for changes in the endplate. Results of this study revealed (1) TCP implants were capable of delivering DBM for long duration, (2) use of sustained delivery of DBM did not induce untoward effects in the vital organs or in the uterus, fallopian tubes, or vaginal tissues, (3) DBM had no effect on chondrocyte differentiation in the spine, and (4) DBM did not increase bone density in osteoporotic female rats.

The Effect Of Selective Serotonin Reuptake Inhibitors and Antidiabetic Drugs on Cardiomyocytes.

Recent reports in the literature show an increase in the risk of heart related events in patients treated with tricyclic antidepressants. There is also evidence that serotonin reuptake inhibitors (SSRIs) are negatively associated with heart failure. The objective of our study is to determine if cardiomyocytes in culture can be used as a tool to mimic clinical scenarios and to evaluate therapeutic concentrations of SSRIs (fluoxetine) and antidiabetic (troglitazone) medication. Cardiomyocytes were grown in a tissue culture environment and challenged with therapeutic concentrations of SSRIs alone or a combination of SSRIs and antidiabetic drugs. Intracellular markers for stress and cytomorphometric analysis indicated SSRIs and SSRIs in combination with antidiabetic drugs negatively impact the health of the cardiomyocytes with time in culture. Analysis of the nuclear area and cytoplasmic changes are sensitive enough to use a cell-based model for determination of adverse effects associated with co-administration of drugs.

The effects of sustained delivery of estrogen on bone strength and cardiovascular panels in osteoporotic female rats.

Osteoporosis and cardiovascular disease (CVD) are common age-related conditions, which are major public health problems leading to an increase in mortality, morbidity, and disability. There have been several connections found between CVD and osteoporosis such as common genetic factors, risk factors, and pathological mechanisms. There is a direct effect of estrogen on CVD and osteoporosis that is demonstrated by the manifestation of estrogen receptors on osteoblasts, osteoclasts, and vascular endothelial and smooth muscle cells. Loss of estrogen has been found to be involved in the pathogenesis of atherosclerosis and bone loss through modulation of other factors including cytokines and oxidized lipids. The goal of this proposed research was to determine if sustained delivery of estrogen is capable of regulating bone cell function while improving cardiovascular panels. Ovariectomized Sprague Dawley rats were administered estradiol at a rate of 5ng/day over an eight-week period. Body weights, estradiol levels, cholesterol levels, and bone strength were determined at 2, 4, and 8 weeks following sustained delivery of estradiol and compared with intact control and ovariectomized control animals. Estrogen replacement resulted in improved cholesterol panels without significant changes in bone flexural strength or improvements in bone porosity. Additional long term studies are needed to determine if the benefits of estrogen replacement outweigh the inherent risks associated with hormone replacement therapies.

The effects of thymoquinone and Doxorubicin on leukemia and cardiomyocyte cell lines.

Acute Lymphoblastic Leukemia remains the most common cancer for children, and if left untreated is rapidly fatal. The gold standard for treatment of ALL in children is with a class of drugs known as the antracyclines. Long term outcomes following treatment of leukemia with antracylines can result in cardiac abnormalities including arrhythmias, congestive heart failure, myocardial infarction, hypertension and left ventricular failure. Thymoquinone is a natural product that has demonstrated anti-proliferative, anti-inflammatory, anti-cancer, and chemo-protective effects in control trials as well as a reduction in cardiotoxicity in antracyline treated rats. The aims of the study were to determine if thymoqunione could be used to reduce leukemia cell viability without injuring primary cardiomyocyte, and to determine its effects if used in conjunction with a known chemotherapeutic agent. Cellular viability and morphological changes were observed in the, RAW leukemia cells and cardiac myocytes following treatment with thymoquinone, antracyline (doxorubicin), alone and in combination for 24, 48 and 72 hours. The results suggest that thymoquinone treatment in RAW leukemia cells reduced the cell number without altering the morphology, while doxorubicin reduced cell number and induced spindle cell formation and increased cellular damage. Findings also suggest RAW cell apoptosis increased in combination therapy with thymoquinone and doxorubicin. Thymoquinone administered to cardiomyocytes showed similar morphological changes as control over time in culture; whereas doxorubicin treated cells showed evidence of loss of connectivity and disruption of cell membranes. Combination treatment with doxorubicin and thymoquinone demonstrated significant cardiac myocyte survival at concentrations when used alone were able to reduce the leukemia cells. Overall, the data is promising and may provide a treatment regime to protect the heart tissue. Additional work is warrant to understand the mechanisms involved to reduce cardio toxicity by combining thymoquinone with doxorubicin.

The effects of sustained delivery of estrogen and demineralized bone matrix proteins on bone in ovariectomized female rats - biomed 2013.

Osteoporosis affects over ten million persons within the United States and is estimated to cost the healthcare system $18 billion dollars a year. Approximately 1.5 million persons will be diagnosed with an osteoporotic fracture and the epidemiological data reflects that prevalence of the osteoporotic fractures is four times more common than having a stroke. The current treatments strategies for osteoporosis are geared toward inhibiting the osteoclast cell resorption of bone, and not on the osteoblast bone formation. The use of demineralized bone matrix proteins (DBM) has been shown to be effective in healing osteoporotic bone fractures within a four week time period. Our goal was to deliver in a sustained manner DBM over an eight week period and compare bone strength and bone histology to osteoporotic untreated animals, osteoporotic animals given sustained delivery of physiological estrogen, as well as naïve control (animals with ovary intact). Our results showed estrogen administered in a sustained fashion was able to reverse the decline in bone strength and re-establish the bone quality similar to ovary intact controls. DBM administered in a sustained manner showed similar bone quality and strength to osteoporotic control animals. Administration of DBM to mature bone in a sustained fashion may be ineffective in inducing osteoblast function or reversing osteoclast activity. It is possible that DBM may be more effective on immature bone cells.

The effects of sustained delivery of corticosterone on the adrenal gland of male and female rats - biomed 2013.

Glucocorticoids have long been recognized to have beneficial effects in rheumatoid arthritis and asthma. Numerous clinical trials show the efficacy of short term low dose treatment to resolve inflammation. Despite the success of short term use, there is concern regarding chronic use of glucocorticoids because of the development of exogenous Cushing’s syndrome. Chronic variable stress models have detailed the effects of chronic stress exposure on body weight, plasma corticosteroid levels, ACTH levels, and adrenal weights, but limited studies detail the effects of the body systems induced by continuous exposure to glucocorticoids similar to that seen in exogenous Cushing’s syndrome. The present study uses a TCPL drug delivery system to administer corticosterone (CS) continuously in male and female animals for 24 days and evaluates long term chronic use effects on body weight, adrenal weight, and adrenal ultrastructure. Continuous release of CS resulted in slight decreases in body weight in both male and female rats and decreases in adrenal wet weight in the female rats. Ultrastructural changes were seen in the adrenal histology in both female and male rats. Male rat adrenal glands showed atrophy of the zona glomerulosa and hypertrophy of the adrenal medulla. Female rats showed disorganization of all zones within the adrenal gland and an increase in fat around the gland. The information is important for understanding physiological differences in males and females during stress. The continuous release of CS may provide insight into the pathology of exogenous Cushing’s syndrome.

Reproductive system behavior following exposure of sustained delivery of npy antagonist in ovariectomized (ovx) rats.

Several investigations have documented that sustained delivery of estrogen can modulate or sustain normal female reproductive functions. However, the literature is lacking scientific evidence regarding the mechanism of estrogen and neuropeptide Y antagonist (NPY) effect on the hypothalamic-pituitary-gonadal axis. The objective of this study was to explore the role of sustained delivery of estrogen and its effects on reproductive unction compared to an antagonist such as NPY. A total of twenty adult female rats (OVX, n=15; intact control, n=5) were divided into five groups (intact control, OVX, sham, OVX + estrogen, and OVX + NPY). Animals in two groups were surgically implanted with a TCP delivery device loaded with estrogen or NPY. Vaginal smears and body weights (BW) were evaluated at baseline and at two weeks post implantation. At the end of two weeks, all animals were euthanized and vital and reproductive organs were retrieved for histopathological evaluation. The results revealed differences in BW between intact control and OVX animals. Furthermore, there was statistical difference (P<0.05) in BW between OVX and OVX + NPY animals. Vaginal smear evaluation revealed that estrogen exposure induced estrus cyclic activities as compared to OVX and sham animals. The animals exposed to sustained delivery of NPY triggered moderate cyclic activities compared to intact control animals. There were no significant differences (P<0.5) in vital organ wet weights among and between animals in all groups. Overall this study proved the capability of TCP to release estrogen and NPY at sustained levels, which resulted inpathophysiological changes in female reproductive organs.

The effects of sugar phosphates in reducing hif-1? Under hypoxic conditions.

Preliminary research has shown evidence of the presence of connective tissue growth factor CTGF in the tenosynovium of patients with carpal tunnel syndrome, a finding which supports the fibrotic pathophysiological progression of the disease. Connective tissue growth factor (CTGF) expression is regulated through the actions of two distinct molecular signals; transforming growth factor-beta (TGF-ß) and hypoxia inducible factor-1 alpha (HIF-1a). Mannose-6 phosphate is a natural inhibitor of TGF-ß and can also is converted to fructose 6 phosphate which we have shown is capable of reducing HIF-1 a. The goal of this experiment was to determine if mannose 6 phosphate is capable of reducing HIF-1a reducing both components of the CTGF pathway. Fibroblast cells were subjected to 5µM or 50µM concentration of either fructose 1,6 diphosphate (F6P) or mannose 6 phosphate (M6P) for a period of 24 hours in either ambient or hypoxic conditions. After the incubation period, cell viability, cell damage, morphology, and concentration of HIF-1a were determined. Cell numbers were reduced by approximately 50% in hypoxic conditions compared with ambient control. Intracellular glutathione concentration was increased significantly under hypoxic conditions compared with control. The concentration of reduced glutathione in both F6P and M6P were similar to ambient air values indicating a protection against oxidative stress. Hypoxia inducible factor-1 alpha was increased in cells under hypoxic conditions compared to base line levels in normoxic treated cells. Interestingly, only 5µM F6P was able to reduce HIF-1a back toward control normoxic values. The data suggest that the HIF-1a pathway leading to fibrosis is not the primary pathway for reductions in CTGF following MP6 treatments. This information is important in terms of developing compounds which decrease adhesion while not decreasing cell viability or impairing cellular function.

The effects of demineralized bone matrix proteins, estrogen, and an antagonist to neuropeptide y on osteoblast and osteoclast viability and function related to osteoporosis.

Currently, osteoporosis affects over half of our population beyond the age of 50, and hip fractures related to osteoporosis accounted for direct costs of $18 billion in 2002 ("About Osteoporosis: Fast Facts", 2006). The average length of a hospital stay for a primary fracture diagnosis is nearly one week, and approximately 25% of previously independent older patients who sustain hip fractures remain in long-term care for over a year. In response to the necessity for improved fracture care and shortened healing time, the field of orthopaedic surgery has begun to turn toward cellular and molecular biology research for the next answer. The goal of the proposed research is to determine if current treatment and potentially new therapeutic compounds are capable of regulating bone cell function. Osteoblast and osteoclast cells were treated for periods of 24, 48 and 72 hours in the presence of estrogen, demineralized bone matrix proteins, or an antagonist to neuropeptide Y. Following the incubation, cell viability, cell function, and morphology were determined. The results indicated a significant increase in osteoblast proliferation and alkaline phosphate production in cells treated with estrogen and DBM without evidence of cellular damage. DBM and estrogen did not affect osteoclast cell numbers, while neuropeptide Y antagonist reduced osteoclast numbers. The data shows Y antagonist may be a useful and safe compound that could be used in the treatment of osteoporotic fractures.