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1.
NPJ Vaccines ; 9(1): 99, 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38839821

ABSTRACT

Vaccination has proven to be a valuable tool to combat SARS-CoV-2. However, reports of rare adverse reactions such as thrombosis/thrombocytopenia syndrome after ChAdOx1 nCoV-19 vaccination have caused scientific, public and media concern. ChAdOx1 was vectorised from the Y25 chimpanzee adenovirus, which was selected due to low human seroprevalence to circumvent pre-existing immunity. In this study, we aimed to explore patterns of T-cell activation after SARS-CoV-2 COVID-19 vaccine exposure in vitro using PBMCs collected from pre-pandemic ChAdOx1 nCoV-19 naïve healthy donors (HDs), and ChAdOx1 nCoV-19 and Pfizer vaccinated controls. PBMCs were assessed for T-cell proliferation using the lymphocyte transformation test (LTT) following exposure to SARS-CoV-2 COVID-19 vaccines. Cytokine analysis was performed via intracellular cytokine staining, ELISpot assay and LEGENDplex immunoassays. T-cell assays performed in pre-pandemic vaccine naïve HDs, revealed widespread lymphocyte stimulation after exposure to ChAdOx1 nCoV-19 (95%), ChAdOx-spike (90%) and the Ad26.COV2. S vaccine, but not on exposure to the BNT162b2 vaccine. ICS analysis demonstrated that CD4+ CD45RO+ memory T-cells are activated by ChAdOx1 nCoV-19 in vaccine naïve HDs. Cytometric immunoassays showed ChAdOx1 nCoV-19 exposure was associated with the release of proinflammatory and cytotoxic molecules, such as IFN-γ, IL-6, perforin, granzyme B and FasL. These studies demonstrate a ubiquitous T-cell response to ChAdOx1 nCoV-19 and Ad26.COV2. S in HDs recruited prior to the SARS-CoV-2 pandemic, with T-cell stimulation also identified in vaccinated controls. This may be due to underlying T-cell cross-reactivity with prevalent human adenoviruses and further study will be needed to identify T-cell epitopes involved.

2.
Brain Behav ; 14(5): e3482, 2024 May.
Article in English | MEDLINE | ID: mdl-38715397

ABSTRACT

INTRODUCTION: Chronic adolescent stress profoundly affects prefrontal cortical networks regulating top-down behavior control. However, the neurobiological pathways contributing to stress-induced alterations in the brain and behavior remain largely unknown. Chronic stress influences brain growth factors and immune responses, which may, in turn, disrupt the maturation and function of prefrontal cortical networks. The tumor necrosis factor alpha-converting enzyme/a disintegrin and metalloproteinase 17 (TACE/ADAM17) is a sheddase with essential functions in brain maturation, behavior, and inflammatory responses. This study aimed to determine the impact of stress on the prefrontal cortex and whether TACE/ADAM17 plays a role in these responses. METHODS: We used a Lewis rat model that incorporates critical elements of chronic psychosocial stress, such as uncontrollability, unpredictability, lack of social support, and re-experiencing of trauma. RESULTS: Chronic stress during adolescence reduced the acoustic startle reflex and social interactions while increasing extracellular free water content and TACE/ADAM17 mRNA levels in the medial prefrontal cortex. Chronic stress altered various ethological behavioral domains in the observation home cages (decreased ingestive behaviors and increased walking, grooming, and rearing behaviors). A group of rats was injected intracerebrally either with a novel Accell™ SMARTpool TACE/ADAM17 siRNA or a corresponding siRNA vehicle (control). The RNAscope Multiplex Fluorescent v2 Assay was used to visualize mRNA expression. Automated puncta quantification and analyses demonstrated that TACE/ADAM17 siRNA administration reduced TACE/ADAM17 mRNA levels in the medial prefrontal cortex (59% reduction relative to control). We found that the rats that received prefrontal cortical TACE/ADAM17 siRNA administration exhibited altered eating patterns (e.g., increased food intake and time in the feeding zone during the light cycle). CONCLUSION: This study supports that the prefrontal cortex is sensitive to adolescent chronic stress and suggests that TACE/ADAM17 may be involved in the brain responses to stress.


Subject(s)
ADAM17 Protein , Prefrontal Cortex , Rats, Inbred Lew , Stress, Psychological , Animals , Male , Rats , ADAM17 Protein/metabolism , Behavior, Animal/physiology , Prefrontal Cortex/metabolism , Reflex, Startle/physiology , Stress, Psychological/physiopathology , Stress, Psychological/metabolism , Female
4.
Environ Sci Technol ; 57(33): 12251-12258, 2023 08 22.
Article in English | MEDLINE | ID: mdl-37566763

ABSTRACT

The United States has begun unprecedented efforts to decarbonize all sectors of the economy by 2050, requiring rapid deployment of variable renewable energy technologies and grid-scale energy storage. Pumped storage hydropower (PSH) is an established technology capable of providing grid-scale energy storage and grid resilience. There is limited information about the life cycle of greenhouse gas emissions associated with state-of-the-industry PSH technologies. The objective of this study is to perform a full life cycle assessment of new closed-loop PSH in the United States and assess the global warming potential (GWP) attributed to 1 kWh of stored electricity delivered to the nearest grid substation connection point. For this study, we use publicly available data from PSH facilities that are in the preliminary permitting phase. The modeling boundary is from facility construction to decommissioning. Our results estimate that the GWP of closed-loop PSH in the United States ranges from 58 to 530 g CO2e kWh-1, with the stored electricity grid mix having the largest impact, followed by concrete used in facility construction. Additionally, PSH site characteristics can have a substantive impact on GWP, with brownfield sites resulting in a 20% lower GWP compared to greenfield sites. Our results suggest that closed-loop PSH offers climate benefits over other energy storage technologies.


Subject(s)
Greenhouse Gases , United States , Animals , Global Warming , Renewable Energy , Climate , Life Cycle Stages
5.
bioRxiv ; 2023 Jan 24.
Article in English | MEDLINE | ID: mdl-36747666

ABSTRACT

Childhood traumatic stress profoundly affects prefrontal cortical networks regulating top-down control of eating and body weight. However, the neurobiological mechanisms contributing to trauma-induced aberrant eating behaviors remain largely unknown. Traumatic stress influences brain immune responses, which may, in turn, disrupt prefrontal cortical networks and behaviors. The tumor necrosis factor alpha-converting enzyme / a disintegrin and metalloproteinase 17 (TACE/ADAM17) is a sheddase with essential functions in brain maturation, behavior, and neuroinflammation. This study aimed to determine the role of TACE/ADAM17 on traumatic stress-induced disruption of eating patterns. We demonstrate a novel mechanistic connection between prefrontal cortical TACE/ADAM17 and trauma-induced eating behaviors. Fifty-two (52) adolescent Lewis rats (postnatal day, PND, 15) were injected intracerebrally either with a novel Accell™ SMARTpool ADAM17 siRNA or a corresponding siRNA vehicle. The RNAscope Multiplex Fluorescent v2 Assay was used to visualize mRNA expression. Observation cages were used to monitor ethological behaviors in a more naturalistic environment over long periods. We found that traumatic stress blunts startle reactivity and alter eating behaviors (increased intake and disrupted eating patterns). We also found that the rats that received prefrontal cortical TACE/ADAM17 siRNA administration exhibited decreased eating and increased grooming behaviors compared to controls. These changes were associated with decreased AIF-1 expression (a typical marker of microglia and neuroinflammation). This study demonstrates that prefrontal cortical TACE/ADAM17 is involved in neuroinflammation and may play essential roles in regulating feeding patterns under stress conditions. TACE/ADAM17 represents a promising target to ameliorate inflammation-induced brain and behavior alterations.

6.
Sports Med Arthrosc Rev ; 26(1): 31-39, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29300225

ABSTRACT

Articular cartilage injury and degeneration is a frequent occurrence in synovial joints. Treatment of these articular cartilage lesions are a challenge because this tissue is incapable of quality repair and/or regeneration to its native state. Nonoperative treatments endeavor to control symptoms, and include anti-inflammatory medication, viscosupplementation, bracing, orthotics, and activity modification. Techniques to stimulate the intrinsic repair (fibrocartilage) process include drilling, abrasion, and microfracture of the subchondral bone. Currently, the clinical biologic approaches to treat cartilage defects include autologous chondrocyte implantation, periosteal transfer, and osteochondral autograft or allograft transplantation. Newer strategies employing tissue engineering being studied involve the use of combinations of progenitor cells, bioactive factors, and matrices, and the use of focal synthetic devices. Many new and innovative treatments are being explored in this exciting field. However, there is a paucity of prospective, randomized controlled clinical trials that have compared the various techniques, treatment options, indications and efficacy.


Subject(s)
Cartilage Diseases/therapy , Cartilage, Articular/injuries , Orthopedic Procedures/methods , Cartilage, Articular/surgery , Humans , Orthopedic Procedures/instrumentation
7.
IEEE Trans Vis Comput Graph ; 23(11): 2378-2388, 2017 11.
Article in English | MEDLINE | ID: mdl-28809700

ABSTRACT

This paper presents the results of two cognitive load studies comparing three augmented reality display technologies: spatial augmented reality, the optical see-through Microsoft HoloLens, and the video see-through Samsung Gear VR. In particular, the two experiments focused on isolating the cognitive load cost of receiving instructions for a button-pressing procedural task. The studies employed a self-assessment cognitive load methodology, as well as an additional dual-task cognitive load methodology. The results showed that spatial augmented reality led to increased performance and reduced cognitive load. Additionally, it was discovered that a limited field of view can introduce increased cognitive load requirements. The findings suggest that some of the inherent restrictions of head-mounted displays materialize as increased user cognitive load.


Subject(s)
Cognition/physiology , User-Computer Interface , Virtual Reality , Adult , Computer Graphics , Equipment Design , Female , Humans , Male , Middle Aged , Reaction Time/physiology , Young Adult
8.
Blood Press ; 22(3): 131-7, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23244451

ABSTRACT

It is well established that hypertension and obesity appear to be associated. The exact mechanism by which they are linked is unclear and remains a topic of a great deal of research. Current NICE guidelines recommend that patients with a BMI in excess of 35 kg/m(2) should be considered for bariatric surgery if they have a concomitant obesity-associated condition, of which hypertension is one. The commonest bariatric procedure in the UK is the Roux-en-Y gastric bypass, which has been shown to result in long-standing remission of hypertension in up to 93% of patients. This paper summarizes the existing literature on the main theories as to how obesity leads to hypertension as well as the literature concerning the effects of gastric bypass surgery on hypertension.


Subject(s)
Gastric Bypass/methods , Hypertension/etiology , Obesity/complications , Obesity/surgery , Body Mass Index , Gastric Bypass/adverse effects , Humans
9.
Knee ; 19(4): 422-30, 2012 Aug.
Article in English | MEDLINE | ID: mdl-21620711

ABSTRACT

The aim of this study was to evaluate a new collagen-GAG-calcium phosphate biphasic scaffold for the repair of surgically created osteochondral defects in goats. Comparison of morphological, histological and mechanical performance of the repair tissue was made with defects repaired using a synthetic polymer scaffold. Defects were created in the medial femoral condyle (MFC) and lateral trochlear sulcus (LTS) of Boer Cross goats and evaluated at 12 and 26 weeks. It was found that the total histology score of the collagen-GAG based biomaterial (23.8; SD 1.7) provided a significant improvement (p<0.05) over the biphasic PLGA material (19;3) and the empty control defect (17.3;1.2) in the LTS. The overall trajectory of histological and morphological improvement between 12 and 26 weeks was found to be higher for the collagen-GAG scaffold compared to the PLGA material. The occurrence of sub-chondral bone cysts was lower for the collagen-GAG scaffold with an incidence of 17% of defects, compared to 67% for the PLGA material at 26 weeks. The cartilage repair tissue for both materials evaluated was superior after 26 weeks implantation than the empty control with 75% of the collagen-GAG-treated defects showing markedly more hyaline-like cartilage and 50% of the PLGA sites exhibiting hyaline-like appearances, compared to 17% for the empty control. These early stage data indicate biphasic scaffolds based on collagen-GAG and PLGA both provide indications of satisfactory development of a structural repair to surgically prepared osteochondral defects. Furthermore, the biomaterial composition of the collagen-GAG may provide a more favourable environment for osteochondral repair.


Subject(s)
Cartilage, Articular/pathology , Collagen , Glycosaminoglycans , Tissue Scaffolds , Animals , Goats , Male , Materials Testing , Polymers
10.
Cartilage ; 3(3)2012 Jul 01.
Article in English | MEDLINE | ID: mdl-24224069

ABSTRACT

OBJECTIVE: The articular cartilage of autologous osteochondral grafts is typically different in structure and function from local host cartilage and thereby presents a remodeling challenge. The hypothesis of this study was that properties of the articular cartilage of trochlear autografts and adjacent femoral condyle are associated with the 3-D geometrical match between grafted and contralateral joints at 6 and 12 months after surgery. DESIGN: Autografts were transferred unilaterally from the lateral trochlea (LT) to the medial femoral condyle (MFC) in adult Spanish goats. Operated and contralateral Non-Operated joints were harvested at 6 and 12 months, and analyzed by indentation testing, micro-computed tomography, and histology to compare (1) histological indices of repair, (2) 3-D structure (articular surface deviation, bone-cartilage interface deviation, cartilage thickness), (3) indentation stiffness, and (4) correlations between stiffness and 3-D structure. RESULTS: Cartilage deterioration was present in grafts at 6 months and more severe at 12 months. Cartilage thickness and normalized stiffness of Operated MFC were lower than Non-Operated MFC within the graft and proximal adjacent host regions. Operated MFC articular surfaces were recessed relative to Non-Operated MFC and exhibited lower cartilage stiffness with increasing recession. Sites with large bone-cartilage interface deviations, both proud and recessed, were associated with recessed articular surfaces and low cartilage stiffness. CONCLUSION: The effectiveness of cartilage repair by osteochondral grafting is associated with the match of 3-D cartilage and bone geometry to the native osteochondral structure.

11.
Tissue Eng Part B Rev ; 16(1): 65-79, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19728790

ABSTRACT

The aging human population is experiencing increasing numbers of symptoms related to its degenerative articular cartilage (AC), which has stimulated the investigation of methods to regenerate or repair AC. However, the seemingly inherent limited capacity for AC to regenerate persists to confound the various repair treatment strategies proposed or studied. Animal models for testing AC implant devices and reparative materials are an important and required part of the Food and Drug Administration approval process. Although final testing is ultimately performed in humans, animal testing allows for a wider range of parameters and combinations of test materials subjected to all the biological interactions of a living system. We review here considerations, evaluations, and experiences with selection and use of animal models and describe two untreated lesion models useful for testing AC repair strategies. These created lesion models, one deep (6 mm and through the subchondral plate) the other shallow (to the level of the subchondral bone plate) were placed in the middle one-third of the medial femoral condyle of the knee joints of goats. At 1-year neither the deep nor the shallow full-thickness chondral defects generated a repair that duplicated natural AC. Moreover, progressive deleterious changes occurred in the AC surrounding the defects. There are challenges in translation from animals to humans as anatomy and structures are different and immobilization to protect delicate repairs can be difficult. The tissues potentially generated by proposed cartilage repair strategies must be compared with the spontaneous changes that occur in similarly created untreated lesions. The prevention of the secondary changes in the surrounding cartilage and subchondral bone described in this article should be addressed with the introduction of treatments for repairs of the articulating surface.


Subject(s)
Cartilage, Articular/physiology , Regeneration/physiology , Wound Healing/physiology , Animals , Disease Models, Animal , Translational Research, Biomedical
12.
Sports Med Arthrosc Rev ; 16(2): 62-6, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18480724

ABSTRACT

Computer-assisted orthopedic surgery and navigation applications have a history rooted in the desire to link imaging technology with real-time anatomic landmarks. Although applications are still evolving in the clinical and research setting, computer-assisted orthopedic surgery has already demonstrated in certain procedures its potential for improving the surgeon's accuracy, reproducibility (once past the learning curve), and in reducing outlier outcomes. It is also being used as an educational tool to assist less experienced surgeons in interpreting measurements and precision placements related to well defined anatomic landmarks. It also can assist experienced surgeons, in real-time, plan their bony cuts, tunnel placement, and with ligament balancing. Presently, the additional time, the expense to acquire the needed software and hardware, and restricted reimbursement have slowed the widespread use of navigation. Its current applications have been primarily in joint replacement surgery, spine surgery, and trauma. It has not been widely used in the clinical setting for sports medicine procedures. Sports medicine applications such as individualizing tunnel placement in ligament surgery, opening wedge osteotomy with and without accompanying ligament reconstruction, and balancing and tensioning of the ligaments during the procedure (allowing real-time corrections if necessary) are currently being evaluated and being used on a limited clinical basis.


Subject(s)
Anterior Cruciate Ligament/surgery , Orthopedics/methods , Plastic Surgery Procedures/instrumentation , Sports Medicine/history , Surgery, Computer-Assisted/instrumentation , History, 20th Century , History, 21st Century , Humans , Orthopedics/history , Surgery, Computer-Assisted/history
13.
Sports Med Arthrosc Rev ; 14(3): 146-54, 2006 Sep.
Article in English | MEDLINE | ID: mdl-17135961

ABSTRACT

Articular cartilage injury and degeneration is a frequent occurrence in synovial joints. Treatment of these articular cartilage lesions are a challenge because this tissue is incapable of quality repair and/or regeneration to its native state. Nonoperative treatments endeavor to control symptoms, and include anti-inflammatory medication, viscosupplementation, bracing, orthotics, and activity modification. Techniques to stimulate the intrinsic repair (fibrocartilage) process include drilling, abrasion, and microfracture of the subchondral bone. Currently, the clinical biologic approaches to treat cartilage defects include autologous chondrocyte implantation, periosteal transfer, and osteochondral autograft or allograft transplantation. Newer strategies employing tissue engineering being studied involve the use of combinations of progenitor cells, bioactive factors, and matrices, and the use of focal synthetic devices. Many new and innovative treatments are being explored in this exciting field. However, there is a paucity of prospective, randomized controlled clinical trials that have compared the various techniques, treatment options, indications and efficacy.


Subject(s)
Cartilage, Articular/injuries , Cartilage, Articular/physiopathology , Osteoarthritis/physiopathology , Osteoarthritis/therapy , Regeneration/physiology , Arthroplasty, Replacement , Biological Factors , Cartilage, Articular/physiology , Cartilage, Articular/transplantation , Humans , Osteoarthritis/diagnosis , Prostheses and Implants , Surgical Flaps
15.
Clin Colon Rectal Surg ; 18(4): 255-60, 2005 Nov.
Article in English | MEDLINE | ID: mdl-20011291

ABSTRACT

Office procedures are an important part of colon and rectal surgery. Patients often present with urgent conditions that can be handled quickly and easily in the office setting. On the other hand, the surgeon must make an accurate assessment regarding which situations are appropriate to manage in the office and which are not. To avoid complications, the office must be equipped with staff familiar with the procedures and instruments/supplies to perform the procedure. The surgeon must also establish a rapport with patients to facilitate completion of each procedure with minimal patient, surgeon, and staff anxiety. With thoughtful preparation one can accomplish many procedures in the office effectively and safely.

16.
Dis Colon Rectum ; 46(10): 1325-31, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14530669

ABSTRACT

PURPOSE: The purpose of this study is to discuss indications, technical approach, and morbidity of laparoscopic approaches to major bowel resection in the pediatric/adolescent population with inflammatory bowel disease and familial polyposis. METHODS: Retrospective review of laparoscopic-assisted bowel procedures between May 1991 and January 2002 was performed. Laparoscopic-assisted bowel resection is defined as complete intracorporeal mobilization and devascularization of a segment of colon or rectum. The indications for extracorporeal vs. intracorporeal anastomosis will be discussed. Clinically unstable, septic, or massively bleeding patients were not candidates for this technique. The decision to attempt the laparoscopic approach was based on the experience of the consulting surgeon. There were 31 patients, including 14 females. Five patients had undergone prior surgery. Twenty-nine patients had inflammatory bowel disease, one had familial polyposis, and one had a cavernous hemangioma. We included all pediatric/adolescent patients in our practice undergoing laparoscopic resection. RESULTS: Twenty-nine patients had 33 laparoscopic operations, including proctocolectomy with ileal pouch-anal anastomosis (n = 14), proctocolectomy with ileostomy (n = 3), ileocolectomy with ileocolic anastomosis (n = 13), and small-bowel obstruction (n = 1). Average operating time was 158 (range, 30-400) minutes, with average blood loss of 159 ml. Average wound length was 4.9 cm. The complication rate was 16 percent (n = 5), with one anastomotic leak. The rate of conversion to open operations was 5.8 percent. Liquid diet was begun on Day 3, and the average length of stay was 5.9 days. CONCLUSION: Major laparoscopic bowel surgery can be performed safely in the pediatric/adolescent population, with reasonable operative times, low conversion to open operations, and low morbidity.


Subject(s)
Colectomy , Inflammatory Bowel Diseases/surgery , Laparoscopy , Rectum/surgery , Adolescent , Child , Female , Humans , Intraoperative Complications , Male , Postoperative Complications , Retrospective Studies
17.
J Orthop Res ; 21(3): 470-80, 2003 May.
Article in English | MEDLINE | ID: mdl-12706020

ABSTRACT

An autograft of periosteal tissue containing cambium cells has potential to become chondrogenic or osteogenic depending on the regeneration repair strategies. The potential number of harvestable cambium cells diminishes with age. Other factors may be associated with a reduction in the number or variable yields of cambium cells including harvest technique, harvest site location, and the time interval from harvest to implantation. Attempts to increase the number of cambium cells have included improvements in harvesting and handling technique, and expansion of the cells in tissue culture. An "in situ" stimulation and proliferation technique would offer the potential for increasing the number of cambium cells in a cost-effective manner for transplantation without the need for expansion in tissue culture. The hypothesis tested was that surgical release of the periosteum and its deep inner underlying cambium layer by sharply incising through the superficial periosteal fibrous layer down to and scoring the cortical bone surface would increase the number of cambium cells that could be harvested at a later time period. Two techniques for periosteal release were used to stimulate a proliferation of the underlying cambium layer and increase the cambium cells for harvest in skeletally mature goats: (1) sharply scoring all four-sides of the tissue test site perimeter, and (2) sharply scoring only two sides of the tissue test site. The two-sided and four-sided release scoring of the periosteum induced stimulatory responses in the number of cambium cells. In addition, a marked increase in mRNA expression for BMP-2 (p<0.001) was observed within 24 h and remained elevated over baseline values for up to 96 h after this stimulation to the cambium layer.


Subject(s)
Periosteum/cytology , Periosteum/transplantation , Transforming Growth Factor beta , Animals , Bone Morphogenetic Protein 2 , Bone Morphogenetic Proteins/analysis , Cell Division , Chondrocytes/cytology , Female , Goats , Periosteum/surgery , Stem Cells/chemistry , Stem Cells/cytology , Tibia
18.
Microsc Res Tech ; 58(1): 25-33, 2002 Jul 01.
Article in English | MEDLINE | ID: mdl-12112419

ABSTRACT

The specific cells within ligaments and tendons are important to maintain the unique structural and material properties of these tissues. The use of tendon and ligament allografts with living cells for ligament reconstruction would be desirable assuming that these cells would survive after transplantation and continue to function. We assessed the fate of donor cells in fresh allografts of the patellar and anterior cruciate ligaments after transplantation. The cells in these allografts used to reconstruct the anterior cruciate ligament did not survive. This was demonstrated using a DNA probe technique that clearly distinguished donor cells from host cells in the Spanish goat model. The donor cells were replaced by host cells in a rapid manner. The host cells that repopulated the allografts assumed the histologic similarity to the fibroblasts they replace. Simultaneous full-thickness skin transplants in the same animals were not rejected during the interval of rapid loss of donor DNA from the allografts. The absence of rejection of the skin grafts at the one-week interval suggests that no pre-existing antibody associated with an immune reaction was responsible for the rapid loss of DNA in the allografts. The clinical basis for utilizing intra-articular allografts with living donor cells needs further justification to account for their increased expense, more complicated surgical logistics, and higher potential risk of disease transmission.


Subject(s)
Cartilage, Articular/cytology , Graft Survival , Ligaments, Articular/cytology , Ligaments/cytology , Ligaments/transplantation , Tendons/cytology , Tendons/transplantation , Animals , Cartilage, Articular/metabolism , Cartilage, Articular/pathology , Cartilage, Articular/surgery , Cell Survival , DNA/analysis , DNA/chemistry , Goats , Knee Joint/cytology , Knee Joint/metabolism , Knee Joint/pathology , Knee Joint/surgery , Ligaments/metabolism , Ligaments, Articular/metabolism , Ligaments, Articular/pathology , Ligaments, Articular/surgery , Models, Animal , Molecular Weight , Skin Transplantation , Tendons/metabolism , Transplantation, Autologous
19.
Pancreas ; 24(4): 380-5, 2002 May.
Article in English | MEDLINE | ID: mdl-11961491

ABSTRACT

INTRODUCTION: Exogenous insulin inhibits secretin-stimulated pancreatic bicarbonate output via a dose-dependent mechanism; this effect is prevented by pancreatic denervation. AIMS: To investigate possible cholinergic mediation, we examined the effect of bethanechol on secretin-stimulated pancreatic secretion during euglycemic, hyperinsulinemic clamp. METHODOLOGY: In four dogs with chronic pancreatic fistulas, euglycemic, hyperinsulinemic clamp (1.25 mU/kg/min) was begun after a 30-minute basal period; computer-assisted glucose administration maintained euglycemia. Control studies were performed with volume-matched and rate-matched vehicle infusion. After 1 hour, secretin infusion was begun at a dosage of 16 ng/kg/h; the dose was doubled every 30 minutes. The studies were then repeated during background bethanechol infusion (90 microg/kg/h) begun 30 minutes after clamp initiation. Pancreatic juice was analyzed for bicarbonate and protein; serum samples were analyzed for glucose and insulin. RESULTS: Exocrine outputs and serum glucose and insulin levels did not differ in the basal period. Insulin levels were significantly elevated during the euglycemic, hyperinsulinemic clamp (62 microU/mL versus 12 microU/mL; p < 0.01); glucose levels did not differ. As before, secretin-induced bicarbonate output was inhibited by euglycemic, hyperinsulinemic clamp. The inhibitory effect of insulin was reversed by bethanechol. Despite the euglycemic, hyperinsulinemic clamp, secretin-induced bicarbonate output was potentiated by bethanechol at higher secretin doses (p < 0.05). CONCLUSION: These data confirm that cholinergic mechanisms mediate insulin's inhibition of secretin-induced pancreatic bicarbonate output.


Subject(s)
Bicarbonates/metabolism , Hypoglycemic Agents/pharmacology , Insulin/pharmacology , Pancreas/metabolism , Secretin/pharmacology , Animals , Bethanechol/pharmacology , Blood Glucose , Cholinergic Agonists/pharmacology , Dogs , Drug Interactions , Glucose Clamp Technique , Hypoglycemic Agents/blood , Insulin/blood , Pancreas/drug effects , Parasympathomimetics/pharmacology
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