Pericardial tissue

Fig 7. Scanning electron micrographs of adhered platelets to (A) Glutaraldehyde fixed bovine pericardial tissue and (B) Polyethylene glycol grafted tissue, on exposure to washed platdets for IS minutes. 

Malm, T Bowald, S. Bylock, A. Saldeen, T and Busch, C. Regeneration of pericardial tissue on absorbable polymer patches implanted into the pericardial sac. An im-munohistochemical, ultrastructural and biochemical study in the sheep. Scandinavian J. Thoracic Cardiovascular Surg. 1992, 26(1), 15-21(b). 

Fixed bovine pericardial tissue is also used to construct heart valves in which design characteristics such as orifice area, valve height, and degree of coaptation can be specified and controlled. Thus, the geometry and flow dynamics past pericardial prostheses mimic those of the natural human aortic valves more closely. Due to the low profile design of pericardial prostheses and increased orifice area, these valves are less stenotic compared to porcine bioprostheses, especially in smaller sizes [Chandran et al., 1984]. In the currently available bioprostheses, the stents are constructed from polypropylene, Acetol homopolymer or copolymer, Elgiloy wire, or titanium. A stainless steel radiopaque marker is also introduced to visualize the valve in vivo. Other biomateriaU, which have been employed in making the bioprostheses, include fascia lata tissue as well as human duramater tissue. The former was prone to deterioration and hence unsuitable for bioprosthetic apphcation, while the latter lacked commercial avahabihty. 

Pericardial Leaflets Porcine pericardial tissue fixed by stebilized gluteraldehyde... 

Pericardial prostheses Heart valve prosthesis made with hxed bovine pericardial tissue. 

The way in which Cherian et al. fabricated the nanobiocomposites was by stacking the cellulose nanofiber mats between polyurethane films and pressing by compression molding. With the addition of 5 wt% cellulose nanofbers into polyurethane the strength and stiffness increased by nearly 300% and 2600%, respectively. The developed composites were utilized to fabricate various versatile medical implants. Cellulose poly-urethanes-based materials are sufficiently durable and blood compatible for potential use in a prosthetic heart valves and effectively showed less mineralization than glutar-aldehyde-fixed bovine pericardial tissue [231]. 

The most commonly used mechanical valves around the world are tilting disk and bileaflet mechanical heart valves. Both valves have similar durability and the need for anticoagulation therapy, but the bileaflet valves have superior hemodynamic performance. The primary advantage of mechanical valves is their durability, which translates to lesser reoperation rates compared to bioprosthetic valves. The most commonly used bioprosthetic valves in clinical practice are made of bovine or porcine pericardial tissue, mounted on either a stented or stentless assembly. Bioprosthetic valves have significantly lower risk of thrombosis, so the patient does not need lifelong anticoagulant therapy. However, structural... 

Occurs as a result of circulatory insufficiency associated with overwhelming infection Occurs when obstruction of blood flow results in inadequate tissue perfusion. Examples include a severe reduction of blood flow as the result of massive pulmonary embolism, pericardial tamponade, restrictive pericarditis, and severe cardiac valve dysfunction Occurs as a result of blockade of neurohum oral outflow. Examples include from a pharmacological source (ie, spinal anesthesia) or direct injury to the spinal cord. This type of shock is rare. 

Nontoxic responses were reported by Chiaretti et al. [90], who investigated the pathological effects of MWNTs on the parenchymal tissues after intraperitoneal administration. Only high doses of MWNTs (20 and 40 mg kg-1) caused death of animals in the first day (20 and 33%, respectively), whereas doses of 5 and 10 mg kg-1 had no effect after 7 days. In addition, repeated administration of 5 mg kg-1 doses did not cause any lesion in the abdominal cavity or in the pleural and pericardial cavities. Only a small irritation was observed at the injection point. It should be emphasized that this study did not address the carcinogenicity risk associated with CNT exposure,... 

Pericardial effusion Pericardial effusion, occasionally with tamponade, has occurred in approximately 3% of treated patients not on dialysis, especially those with inadequate or compromised renal function. Many cases were associated with connective tissue disease, the uremic syndrome, CHF or fluid retention, but were instances in which these potential causes of effusion were not present. Observe patients closely for signs of pericardial disorder. Perform echocardiographic studies if suspicion arises. More vigorous diuretic therapy, dialysis, pericardiocentesis, or surgery may be required. If the effusion persists, consider drug withdrawal. 

In adults, the signs and symptoms of hypothyroidism include somnolence, slow mentation, dryness and loss of hair, increased fluid in body cavities (e.g., the pericardial sac), low metabolic rate, tendency to gain weight, hyperlipidemia, subnormal temperature, cold intolerance, bradycardia, reduced systolic and increased diastolic pulse pressure, hoarseness, muscle weakness, slow return of muscle to the neutral position after a tendon jerk, constipation, menstrual abnormalities, infertility, and sometimes myxedema (hard edema of subcutaneous tissue with increased content of proteoglycans in the fluid). A goiter (i.e., enlargement of the thyroid gland) may be present. 

When the heart can no longer pump an adequate supply of blood to meet the metabolic needs of the tissues or in relation to venous return, cardiac failure may ensue. The causes of cardiac failure are complex, but stem from mechanical abnormalities (e.g., pericardial tamponade), myocardial failure (e.g., cardiomyopathy and inflammation), and arrhythmias. In high-output failure, the cardiac output, which may be normal or even higher than normal, is not sufficient to meet the metabolic requirement of the body. Cardiac failure may predispose a patient to congestive heart failure, which is a state of circulatory congestion. Toxic injury, caused by agents such as doxorubicin, the alkaloid emetine in ipecac syrup, cocaine, or ethyl alcohol, is another way by which the functional integrity of the heart may also be compromised. 

Cephalosporins distribute into most body fluids and tissues, including pleural fluid, synovial fluid, pericardial fluid and urine. Cephalosporins distribute into milk, but therapeutic concentrations are not reached following systemic administration at accepted dose rates. Cephalosporins cross the placenta but do not appear to cause adverse effects in the fetus. Their penetration into cortical and cancellous bone is usually adequate. Most cephalosporins penetrate poorly into the aqueous humor, accessory sex glands and CSF. Cephalosporins have typically low values in horses 0.191/kg for cefazolin, 0.151/kg for cefa-lotin, 0.171/kg for cefapirin, 0.41/kg for cefradine and 0.121/kg for cefoxitin. 

Many errors can occur during the collection, processing, and transport of biological specimens. Minimizing these errors win result in more reliable information for use by healthcare professionals. Examples of biological specimens that are analyzed in clinical laboratories include whole blood serum plasma urine feces saliva spinal, synovial, amniotic, pleural, pericardial, and ascitic fluids and various types of solid tissue. The National Committee for CMnical Laboratory Standards (NCCLS) has published several procedures for collecting many of these specimens under standardized conditio ns.In addition, the NCCLS has published documents related to sample collection and analysis for specialized tests, such as sweat chloride (see also Chapter 27). 

Figure 2. The function of tinman in the formation of mesodermal tissues. The (eft column shows wild-type embryos and the right column tinman mutant embryos of the same stage and stained with the same markers. (A, B) Neither cardioblasts nor pericardial cells are formed in tin mutants (embryos stained as in Figure 1 ). (C, D) The midgut musculature (stained for flCal expression from an enhancer trap insertion is completely m ssing in tinman mutants. (E, F Dorsal muscles (stained for [iCa expression from a .cZ reporter insertion Yin and Frasch, 1998) are not properly specified in tinman mutants. (G, H) Earlv stage 12. The muscle founders of the S59 cluster I (as detected with an S59 antibody), which give rise to muscles 5 and 25, are not specified in tinman mutants. By contrast, the founder cells of S59 cluster II are formed normally and will develop into muscles 26, 2(r, and 29, (I, J) Stage 11. huttonlesi niRN.A expression in the DM cell precursors (arrow) is absent in tin mutants and DM cells are not formed. (The bilateral pairs of nuclei are Eve-stained neuronal precursors).. Abbreviations DM dorsal median cell precursors dsm dorsal somatic muscles mgv m midgut visceral mesoderm pc pericardial precursors.

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