Laboratory investigation of the cryosurgical lesion

Cryosurgery denotes the therapeutic ablation of tissues by cold. Its use was first described by Arnott in 1851 for the treatment of carcinoma of the cervix, but never attained clinical prominence due to lack of a simple controlled means of applying cold to tissues. The introduction, 100 years after Arnott's original treatise of cryogenic apparatus based on the circulation of liquid nitrogen³⁰ reawakened interest in this form of treatment. Despite its widespread application in many of the surgical specialities over the last eight years, little experimental effort has been made to quantitate the destructive effect of low temperatures used in this way. From the surgeon's point of view it is essential to know what factors determine the quantity of tissue water frozen under any given conditions, to what extent this phase change of water produces cellular death and how he can best control his freezing to produce optimal destruction.This paper is a study of:-(1) The macroscopic and microscopic changes which occur in tissue after single and repetitive freeze -thaw cycles. (Repetitive freeze -thaw cycles indicate successive freezing and thawing at the same site as opposed to multiple freeze -thaw cycles where the successive applications are at different sites.)(2) Those variable factors which determine the size of the cryolesion (the spherical zone of ice surrounding a cryoprobe in tissue) and these may be subdivided as being: -(a) Related to the environment. (b) Related to the cryoprobe. (c) Related to the tissues.These three aspects of the problem will be considered separately.The cryogenic apparatus used throughout these experiments was the Linde-Cooper Cryosurgery Unit CE 2A (Union Carbide Corporation) which utilises circulating liquid nitrogen (- 196 °C) through a partially insulated operating cryoprobe. Two standard probes whose freezing tips approximated to hemispheres 2.5 mm and 5 mm respectively were used.A second prototype instrument, supplied by the Hymatic Company, was used which generates cold by the Joule Thomson effect involving rapid expansion of pressurised Argon (2,500 p.s.i.) through a tight nozzle. The cooling probe of this machine carried four microthermocouples embedded at 0.14 cm intervals in a non -heat conducting plastic extension.The resultant frozen tissue was measured through an operating microscope incorporating an eye -piece graticule scale permitting measurements with an accuracy up to 0.02 cm.The macroscopic and microscopic changes which follow the freezing of tissues resemble ischaemic infarction and are productive of a fibrous scar within six weeks of freezing. Histological death of tissue extends throughout the whole frozen volume and is considered the result of ischaemia rather than crystal formation.Absolute prediction of the volumes of tissue frozen in vivo by consideration of the variable physical factors involved will not be possible until more information is available regarding local tissue blood flows and the thermal properties of human tissues.At present, thermocouples provide the most accurate means of control available and the ways in which an analysis of the thermal gradients in frozen and unfrozen tissue can aid in their intelligent use has been outlined

Regenerated soleus muscle shows reduced creatine kinase efflux after contractile activity in vitro

Date of Acceptance: 07/10/2014 Acknowledgements We are very grateful to Petras Jeneckas and Audrius Capskas for technical assistance. The study was supported by a grant (No. MIP-067/2012) from the Research Council of Lithuania.Peer reviewedPostprin

Ultrasonographic Guidance and Characterization of Cryoanalgesic Lesions in Treating a Case of Refractory Sural Neuroma

The recurrent pain of a neuroma following surgical excision and burial of nerve endings can be clinically challenging to manage. Cryoanalgesia in conjunction with ultrasound guidance was used successfully to manage this type of pain. Furthermore, ultrasound provided visualization of the cryolesions, as well as the relationships of the ice ball to the surrounding tissue. Following the completion of the freeze cycle, the tissue can be monitored for return to its usual morphology during the thaw period

Increased circulating leukocyte numbers and altered macrophage phenotype correlate with the altered immune response to brain injury in metallothionein (MT) -I/II null mutant mice

<p>Abstract</p> <p>Background</p> <p>Metallothionein-I and -II (MT-I/II) is produced by reactive astrocytes in the injured brain and has been shown to have neuroprotective effects. The neuroprotective effects of MT-I/II can be replicated <it>in vitro </it>which suggests that MT-I/II may act directly on injured neurons. However, MT-I/II is also known to modulate the immune system and inflammatory processes mediated by the immune system can exacerbate brain injury. The present study tests the hypothesis that MT-I/II may have an indirect neuroprotective action via modulation of the immune system.</p> <p>Methods</p> <p>Wild type and MT-I/II^-/-mice were administered cryolesion brain injury and the progression of brain injury was compared by immunohistochemistry and quantitative reverse-transcriptase PCR. The levels of circulating leukocytes in the two strains were compared by flow cytometry and plasma cytokines were assayed by immunoassay.</p> <p>Results</p> <p>Comparison of MT-I/II^-/-mice with wild type controls following cryolesion brain injury revealed that the MT-I/II^-/-mice only showed increased rates of neuron death after 7 days post-injury (DPI). This coincided with increases in numbers of T cells in the injury site, increased IL-2 levels in plasma and increased circulating leukocyte numbers in MT-I/II^-/-mice which were only significant at 7 DPI relative to wild type mice. Examination of mRNA for the marker of alternatively activated macrophages, Ym1, revealed a decreased expression level in circulating monocytes and brain of MT-I/II^-/-mice that was independent of brain injury.</p> <p>Conclusions</p> <p>These results contribute to the evidence that MT-I/II^-/-mice have altered immune system function and provide a new hypothesis that this alteration is partly responsible for the differences observed in MT-I/II^-/-mice after brain injury relative to wild type mice.</p

The Physiological Mechanisms of Effect of Vitamins and Amino Acids on Tendon and Muscle Healing: A Systematic Review

© 2018 Human Kinetics, Inc.To evaluate the current literature via systematic review to ascertain whether amino acids/vitamins provide any influence on musculotendinous healing and if so, by which physiological mechanisms. Methods: EBSCO, PubMed, ScienceDirect, Embase Classic/Embase, and MEDLINE were searched using terms including "vitamins," "amino acids," "healing," "muscle," and "tendon." The primary search had 479 citations, of which 466 were excluded predominantly due to nonrandomized design. Randomized human and animal studies investigating all supplement types/forms of administration were included. Critical appraisal of internal validity was assessed using the Cochrane risk of Bias Tool or the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias Tool for human and animal studies, respectively. Two reviewers performed duel data extraction. Results: Twelve studies met criteria for inclusion: eight examined tendon healing and four examined muscle healing. All studies used animal models, except two human trials using a combined integrator. Narrative synthesis was performed via content analysis of demonstrated statistically significant effects and thematic analysis of proposed physiological mechanisms of intervention. Vitamin C/taurine demonstrated indirect effects on tendon healing through antioxidant activity. Vitamin A/glycine showed direct effects on extracellular matrix tissue synthesis. Vitamin E shows an antiproliferative influence on collagen deposition. Leucine directly influences signaling pathways to promote muscle protein synthesis. Discussion: Preliminary evidence exists, demonstrating that vitamins and amino acids may facilitate multilevel changes in musculotendinous healing; however, recommendations on clinical utility should be made with caution. All animal studies and one human study showed high risk of bias with moderate interobserver agreement (k = 0.46). Currently, there is limited evidence to support the use of vitamins and amino acids for musculotendinous injury. Both high-quality animal experimentation of the proposed mechanisms confirming the physiological influence of supplementation and human studies evaluating effects on tissue morphology and biochemistry are required before practical application.Peer reviewe

An investigation into the effects of two bioceramics on rat mandibular bone

The aim of this study was to evaluate the effects of both dense hydroxyapatite and ß tricalcium phosphate on mandibular bone, in an attempt to offer guidelines for their use. The importance of these guidelines is that although both of these bioceramics have been used in clinical studies there are no established guidelines to indicate which clinical situation is best served by either dense hydroxyapatite or ß tricalcium phosphate. This is evidenced by the fact that many materials have been used as dental implants and that many shapes and forms of implants have been used in an attempt either to stabilise dentures or to restore facial form.In vitro and in vivo investigations are included in this study. The in vivo investigation, on 231 male Sprague-Dawley rats contained controlled studies on weakened and unweakened mandibular bone; cryosurgery was used to weaken bone in this investigation as previous studies demonstrated significant reduction in bone strength after cryosurgery. The in vivo studies were assessed in two ways; first, mechanical assessments of fracture strengh were determined by three-point bending tests. Second, histological examination of mandibular bone was performed in parallel to the mechanical evaluation, in an attempt to interpret fracture test results from histological findings.The investigations in this thesis indicated, for the first time, that both materials result in significant increased fracture strength of mandibular bone. The histological findings indicated that these increases in fracture strength were biologically significant.The results presented in this thesis suggest that both materials are biocompatible and that g tricalcium phosphate is more ideally used in unweakened bone whereas dense hydroxyapatite, gives its optimal effect on weakened bone, although it gives more rapid early increases in strength than does g tricalcium phosphate. It is suggested that those biomaterials may be of benefit in those clinical situations where surgery on mandibular bone may render it prone to fractur

Metallothionein (MT) -I and MT-II Expression Are Induced and Cause Zinc Sequestration in the Liver after Brain Injury

Experiments with transgenic over-expressing, and null mutant mice have determined that metallothionein-I and -II (MT-I/II) are protective after brain injury. MT-I/II is primarily a zinc-binding protein and it is not known how it provides neuroprotection to the injured brain or where MT-I/II acts to have its effects. MT-I/II is often expressed in the liver under stressful conditions but to date, measurement of MT-I/II expression after brain injury has focused primarily on the injured brain itself. In the present study we measured MT-I/II expression in the liver of mice after cryolesion brain injury by quantitative reverse-transcriptase PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) with the UC1MT antibody. Displacement curves constructed using MT-I/II knockout (MT-I/II−/−) mouse tissues were used to validate the ELISA. Hepatic MT-I and MT-II mRNA levels were significantly increased within 24 hours of brain injury but hepatic MT-I/II protein levels were not significantly increased until 3 days post injury (DPI) and were maximal at the end of the experimental period, 7 DPI. Hepatic zinc content was measured by atomic absorption spectroscopy and was found to decrease at 1 and 3 DPI but returned to normal by 7DPI. Zinc in the livers of MT-I/II−/− mice did not show a return to normal at 7 DPI which suggests that after brain injury, MT-I/II is responsible for sequestering elevated levels of zinc to the liver. Conclusion: MT-I/II is up-regulated in the liver after brain injury and modulates the amount of zinc that is sequestered to the liver