Observation of Vascular Injury After Freezing: Investigating the Response of Normal Skin and Subcutaneous AT-1 Tumor Tissue to Cryosurgery in the Dorsal Skin Flap Chamber

1999 ◽  
Author(s):  
Nathan E. Hoffmann ◽  
David J. Swanlund ◽  
John C. Bischof
Keyword(s):  
Vascular Injury ◽  
Thermal History ◽  
Host Response ◽  
Tissue Injury ◽  
Skin Flap ◽  
Tissue Type ◽  
Crystal Formation ◽  
Dorsal Skin ◽  
Tissue Necrosis

Abstract Two main mechanisms have been explored in an attempt to explain injury to the cells of tissues due to freezing in vivo. The first is direct cellular injury caused by injurious osmotic changes and ice crystal formation that happens as a result of freezing (Mazur, 1984). The second is host response injury caused by the vascular damage and immunologic response in response to freezing (Gage and Baust, 1998). The amount of injury caused by freezing appears to vary with tissue type and thermal history of the freezing protocol. The hypothesis of this study was that host response injury, specifically vascular injury, causes the majority of tissue necrosis at the edge of a frozen region and therefore determines the size of the lesion seen after in vivo freezing. Many investigations have previously made a qualitative correlation between thermal history, vascular injury, and tissue necrosis (e.g. Greene. 1943 and Rabb et al., 1974). We chose the dorsal skin flap chamber (DSFC) implanted in the Copenhagen rat as the cryosurgical model for this study. This in vivo freezing model appears insensitive to the immunologic phenomenon (Hoffmann et al., 1999) and allows us to monitor thermal history and investigate both vascular and tissue injury in response to cryosurgery.

Cryo, Hyper or Both? Investigating Combination Cryo/Hyperthermia in the Dorsal Skin Flap Chamber

2000 ◽  
Author(s):  
Nathan E. Hoffmann ◽  
Bo H. Chao ◽  
John C. Bischof
Keyword(s):  
Combination Therapy ◽  
Thermal History ◽  
Standard Treatment ◽  
Tissue Injury ◽  
Skin Flap ◽  
Dorsal Skin ◽  
Combination Therapies ◽  
Disease Treatment ◽  
Copenhagen Rat

Abstract Combination therapies have been investigated as a mean to increase efficacy of disease treatment. For example, combinations such as radiation and chemotherapy, surgery and chemotherapy, and two different chemotherapies have become standard treatment for most cancers. Current theories suggest that vascular-mediated injury is an important mechanism of cryosurgical (reviewed in Gage and Baust (1998)) and hyperthermic destruction (Badylak et al., 1985; Dudar and Jain, 1984) in the treatment of solid tumors. These techniques appear complementary. Freezing creates vascular damage and promotes stasis within the vessels (Rabb et al., 1974), whereas hyperthermia creates cell and vascular destruction more effectively with a compromised vasculature (Shakil et al., 1999). Thus, in this study, we investigated the effect of combining these therapies on the vascular and tissue injury from the two therapies. We chose the dorsal skin flap chamber (DSFC) implanted in the Copenhagen rat as the cryosurgical model for this study. This in vivo freezing model allowed us to monitor thermal history and investigate both vascular and tissue injury in response to the combination therapy.

Cryosurgery of Normal and Tumor Tissue in the Dorsal Skin Flap Chamber: Part I—Thermal Response

2001 ◽  
Vol 123 (4) ◽  
pp. 301-309 ◽  
Author(s):  
Nathan E. Hoffmann ◽  
John C. Bischof
Keyword(s):  
Blood Flow ◽  
Thermal Properties ◽  
Thermal History ◽  
Tumor Tissue ◽  
Normal Skin ◽  
Skin Flap ◽  
Companion Paper ◽  
Two Dimensional ◽  
Dorsal Skin ◽  
Freezing And Thawing

Current research in cryosurgery is concerned with finding a thermal history that will definitively destroy tissue. In this study, we measured and predicted the thermal history obtained during freezing and thawing in a cryosurgical model. This thermal history was then compared to the injury observed in the tissue of the same cryosurgical model (reported in companion paper (Hoffmann and Bischof, 2001)). The dorsal skin flap chamber, implanted in the Copenhagen rat, was chosen as the cryosurgical model. Cryosurgery was performed in the chamber on either normal skin or tumor tissue propagated from an AT-1 Dunning rat prostate tumor. The freezing was performed by placing a ∼1 mm diameter liquid-nitrogen-cooled cryoprobe in the center of the chamber and activating it for approximately 1 minute, followed by a passive thaw. This created a 4.2 mm radius iceball. Thermocouples were placed in the tissue around the probe at three locations (r=2, 3, and 3.8 mm from the center of the window) in order to monitor the thermal history produced in the tissue. The conduction error introduced by the presence of the thermocouples was investigated using an in vitro simulation of the in vivo case and found to be <10°C for all cases. The corrected temperature measurements were used to investigate the validity of two models of freezing behavior within the iceball. The first model used to approximate the freezing and thawing behavior within the DSFC was a two-dimensional transient axisymmetric numerical solution using an enthalpy method and incorporating heating due to blood flow. The second model was a one-dimensional radial steady state analytical solution without blood flow. The models used constant thermal properties for the unfrozen region, and temperature-dependent thermal properties for the frozen region. The two-dimensional transient model presented here is one of the first attempts to model both the freezing and thawing of cryosurgery. The ability of the model to calculate freezing appeared to be superior to the ability to calculate thawing. After demonstrating that the two-dimensional model sufficiently captured the freezing and thawing parameters recorded by the thermocouples, it was used to estimate the thermal history throughout the iceball. This model was used as a basis to compare thermal history to injury assessment (reported in companion paper (Hoffmann and Bischof, 2001)).

Cryosurgery of Normal and Tumor Tissue in the Dorsal Skin Flap Chamber: Part II—Injury Response

2001 ◽  
Vol 123 (4) ◽  
pp. 310-316 ◽  
Author(s):  
Nathan E. Hoffmann ◽  
John C. Bischof
Keyword(s):  
Vascular Injury ◽  
Normal Tissue ◽  
Tumor Tissue ◽  
Skin Flap ◽  
Hold Time ◽  
Companion Paper ◽  
Temperature History ◽  
Dorsal Skin ◽  
Tissue Lesion ◽  
Cellular Destruction

It has been hypothesized that vascular injury may be an important mechanism of cryosurgical destruction in addition to direct cellular destruction. In this study, we report correlation of tissue and vascular injury after cryosurgery to the temperature history during cryosurgery in an in vivo microvascular preparation. The dorsal skin flap chamber, implanted in the Copenhagen rat, was chosen as the cryosurgical model. Cryosurgery was performed in the chamber on either normal skin or tumor tissue propagated from an AT-1 Dunning rat prostate tumor, as described in a companion paper (Hoffmann and Bischof, 2001). The vasculature was then viewed at 3 and 7 days after cryoinjury under brightfield and FITC-labeled dextran contrast enhancement to assess the vascular injury. The results showed that there was complete destruction of the vasculature in the center of the lesion and a gradual return to normal patency moving radially outward. Histologic examination showed a band of inflammation near the edge of a large necrotic region at both 3 and 7 days after cryosurgery. The area of vascular injury observed with FITC-labeled dextran quantitatively corresponded to the area of necrosis observed in histologic section, and the size of the lesion for tumor and normal tissue was similar at 3 days post cryosurgery. At 7 days after cryosurgery, the lesion was smaller for both tissues, with the normal tissue lesion being much smaller than the tumor tissue lesion. A comparison of experimental injury data to the thermal model validated in a companion paper (Hoffmann and Bischof, 2001) suggested that the minimum temperature required for causing necrosis was −15.6±4.3°C in tumor tissue and −19.0±4.4°C in normal tissue. The other thermal parameters manifested at the edge of the lesion included a cooling rate of ∼28°C/min, 0 hold time, and a ∼9°C/min thawing rate. The conditions at the edge of the lesion are much less severe than the thermal conditions required for direct cellular destruction of AT-1 cells and tissues in vitro. These results are consistent with the hypothesis that vascular-mediated injury is responsible for the majority of injury at the edge of the frozen region in microvascular perfused tissue.

Extracellular Nucleotides ATP and UTP Induce a Marked Acute Release of Tissue-type Plasminogen Activator In Vivo in Man

2001 ◽  
Vol 85 (05) ◽  
pp. 875-881 ◽  
Author(s):  
Thórdís Hrafnkelsdóttir ◽  
David Erlinge ◽  
Sverker Jern
Keyword(s):  
Vascular Endothelium ◽  
Adenosine Receptors ◽  
Healthy Subjects ◽  
Tissue Injury ◽  
Extracellular Nucleotides ◽  
Tissue Type ◽  
Type Plasminogen Activator ◽  
Ischemic Tissue ◽  
Stimulation Of

SummaryExtracellular nucleotides such as ATP and UTP are released by activation of platelets and ischemic tissue injury. The aim of the present study was to investigate whether ATP and UTP can induce acute tPA release from the vascular endothelium in vivo. Nine healthy subjects were studied in a perfused-forearm model during stepwise intraarterial infusions of ATP and UTP (10-200 nmol/min), and UTP during inhibition of prostanoid and NO synthesis by indomethacin and L-NMMA. ATP and UTP induced a similar and marked stimulation of forearm tPA release which increased 11- and 18-fold above baseline (p ≤ 0.01 for both) in conjunction with pronounced vasodilation. Neither the acute tPA release nor the vasodilation could be abrogated by NO and prostanoid synthesis inhibition. The similar effect of ATP and UTP suggests that P2Y rather than adenosine receptors mediate the response. Release of extracellular nucleotides in ischemic tissue may induce a pronounced activation of the endogenous fibrinolytic system.

1108: Treatment Strategy Improves the in Vivo Stone Comminution Efficiency and Reduces Renal Tissue Injury During Shock Wave Lithotripsy

2005 ◽  
Vol 173 (4S) ◽  
pp. 300-301
Author(s):  
Michaella E. Maloney ◽  
Pei Zhong ◽  
Charles G. Marguet ◽  
Yufeng F. Zhou ◽  
Jeffrey C. Sung ◽  
...  
Keyword(s):  
Shock Wave ◽  
Treatment Strategy ◽  
Shock Wave Lithotripsy ◽  
Tissue Injury ◽  
Renal Tissue

Comparison of Specific Antibody, D-Phe-Pro-Arg-CH2Cl and Aprotinin for Prevention of In Vitro Effects of Recombinant Tissue-Type Plasminogen Activator on Haemostasis Parameters

1987 ◽  
Vol 58 (03) ◽  
pp. 921-926 ◽  
Author(s):  
E Seifried ◽  
P Tanswell
Keyword(s):  
Specific Antibody ◽  
Plasma Concentrations ◽  
Fibrinolytic Therapy ◽  
Tissue Type ◽  
Control Value ◽  
Type Plasminogen Activator ◽  
In Vitro Effects ◽  
Fibrinolytic Parameters

SummaryIn vitro, concentration-dependent effects of rt-PA on a range of coagulation and fibrinolytic assays in thawed plasma samples were investigated. In absence of a fibrinolytic inhibitor, 2 μg rt-PA/ml blood (3.4 μg/ml plasma) caused prolongation of clotting time assays and decreases of plasminogen (to 44% of the control value), fibrinogen (to 27%), α2-antiplasmin (to 5%), FV (to 67%), FVIII (to 41%) and FXIII (to 16%).Of three inhibitors tested, a specific polyclonal anti-rt-PA antibody prevented interferences in all fibrinolytic and most clotting assays. D-Phe-Pro-Arg-CH2Cl (PPACK) enabled correct assays of fibrinogen and fibrinolytic parameters but interfered with coagulometric assays dependent on endogenous thrombin generation. Aprotinin was suitable only for a restricted range of both assay types.Most in vitro effects were observed only with rt-PA plasma concentrations in excess of therapeutic values. Nevertheless it is concluded that for clinical application, collection of blood samples on either specific antibody or PPACK is essential for a correct assessment of in vivo effects of rt-PA on the haemostatic system in patients undergoing fibrinolytic therapy.

Turnover of Human Extrinsic (Tissue-Type) Plasminogen Activator in Rabbits

1981 ◽  
Vol 46 (03) ◽  
pp. 658-661 ◽  
Author(s):  
C Korninger ◽  
J M Stassen ◽  
D Collen
Keyword(s):  
Plasminogen Activator ◽  
Intravenous Injection ◽  
Active Site ◽  
Half Life ◽  
Degradation Products ◽  
Gel Filtration ◽  
Tissue Type ◽  
Organ Distribution ◽  
Small Rise

SummaryThe turnover of highly purified human extrinsic plasminogen activator (EPA) (one- and two-chain form) was studied in rabbits. Following intravenous injection, EPA-activity declined rapidly. The disappearance rate of EPA from the plasma could adequately be described by a single exponential term with a t ½ of approximately 2 min for both the one-chain and two-chain forms of EPA.The clearance and organ distribution of EPA was studied by using 125I-labeled preparations. Following intravenous injection of 125I-1abeled EPA the radioactivity disappeared rapidly from the plasma also with a t ½ of approximately 2 min down to a level of 15 to 20 percent, followed by a small rise of blood radioactivity. Gel filtration of serial samples revealed that the secondary increase of the radioactivity was due to the reappearance of radioactive breakdown products in the blood. Measurement of the organ distribution of 125I at different time intervals revealed that EPA was rapidly accumulated in the liver, followed by a release of degradation products in the blood.Experimental hepatectomy markedly prolonged the half-life of EPA in the blood. Blocking the active site histidine of EPA had no effect on the half-life of EPA in blood nor on the gel filtration patterns of 125I in serial plasma samples.It is concluded that human EPA is rapidly removed from the blood of rabbits by clearance and degradation in the liver. Recognition by the liver does not require a functional active site in the enzyme. Neutralization in plasma by protease inhibitors does not represent a significant pathway of EPA inactivation in vivo.

Factors Influencing Leukocyte Adherence in Microvessels

1977 ◽  
Vol 38 (04) ◽  
pp. 0823-0830 ◽  
Author(s):  
Mayrovttz N. Harvey ◽  
Wiedeman P. Mary ◽  
Ronald F. Tuma
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Tissue Injury ◽  
Threshold Value ◽  
In Vivo Studies ◽  
Leukocyte Adherence ◽  
Rolling Velocity ◽  
Subsequent Behavior ◽  
Flow Stasis

SummaryIn vivo studies of the microcirculation of an untraumatized and unanesthetized animal preparation has shown that leukocyte adherence to vascular endothelium is an extremely rare occurrence. Induction of leukocyte adherence can be produced in a variety of ways including direct trauma to the vessels, remote tissue injury via laser irradiation, and denuding the epithelium overlying the observed vessels. The role of blood flow and local hemodynamics on the leukocyte adherence process is quite complex and still not fully understood. From the results reported it may be concluded that blood flow stasis will not produce leukocyte adherence but will augment pre-existing adherence. Studies using 2 quantitative measures of adherence, leukocyte flux and leukocyte velocity have shown these parameters to be affected differently by local hemodynamics. Initial adherence appears to be critically dependent on the magnitude of the blood shear stress at the vessel wall as evidenced by the lack of observable leukocyte flux above some threshold value. Subsequent behavior of the leukocytes as characterized by their average rolling velocity shows no apparent relationship to shear stress but, for low velocities, may be related to the linear blood velocity.

An Experimental Multiple-Organ Model for the Study of Regional Net Release/Uptake Rates of Tissue-type Plasminogen Activator in the Intact Pig

1997 ◽  
Vol 78 (03) ◽  
pp. 1150-1156 ◽  
Author(s):  
Christina Jern ◽  
Heléne Seeman-Lodding ◽  
Bjӧrn Biber ◽  
Ola Winsӧ ◽  
Sverker Jern
Keyword(s):  
Plasminogen Activator ◽  
Multiple Organ ◽  
Tissue Type ◽  
Hepatic Veins ◽  
Plasma Flows ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Uptake Rates ◽  
Net Release

SummaryExperimental data indicate large between-organs variations in rates of synthesis of tissue-type plasminogen activator (t-PA), which may reflect important differences in the capacity for constitutive and stimulated t-PA release from the vascular endothelium. In this report we describe a new multiple-organ experimental in vivo model for simultaneous determinations of net release/uptake rates of t-PA across the coronary, splanchnic, pulmonary, and hepatic vascular beds. In eleven intact anesthetized pigs, blood samples were obtained simultaneously from the proximal aorta, coronary sinus, pulmonary artery, and portal and hepatic veins. Plasma flows were monitored separately for each vascular region. Total plasma t-PA was determined by ELISA with a porcine t-PA standard. Regional net release/uptake rates were defined as the product of arteriovenous concentration gradients and local plasma flows. The net release of t-PA across the splanchnic vascular bed was very high, with a mean output of 1,919 ng total t-PA X min-1 (corresponding to 90 ng per min and 100 g tissue). The net coronary t-PA release was 68 ng X min-1 (30 ng X min-1 X 100 g"1)- Pulmonary net fluxes of t-PA were variable without any significant net t-PA release. The net hepatic uptake rate was 4,855 ng X min-1 (436 ng X min-1 X 100 g-1). Net trans-organ changes of active t-PA mirrored those of total t-PA. The results demonstrate marked regional differences in net release rates of t-PA in vivo. The experimental model we present offers new possibilities for evaluation of regional secretion patterns in the intact animal.

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