ISSN:0894-1939    

DOI:10.3109/08941939109140755

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

This study examines the biochemical changes that occur in argon laser-fused canine veins compared with control segments of vein. Laser fusions were formed using 0.5 W argon laser energy (1100–1500 J/cm2). Immediately following tissue fusion, blood flow was reestablished to test the integrity of the welds, 1-mm3sections of the anastomoses and control sections were minced and protein extraction was performed by solubilizing the tissue in hot SDS Laemmli gel sample buffer. The proteins were separated electrophoretically on 5 and 10% polyacyl-amide SDS gels and silver stained. The analysis demonstrated significant biochemical differences between control and lased veins. We noted increases in several proteins after laser welding: the putative beta chain of type V collagen (5/5 gels), the putative gamma chain of type 1 collagen (4/5 gels), a 156-kDa protein (based on collagen molecular weight standards) (7/7 gels), an 82-kDa protein (8/9 gels), and several proteins of lower molecular weight (3/8 gels). The increases may be due to crosslinking of lower molecular weight proteins, degradation of higher molecular weight proteins, or increased solubility of certain proteins. These findings suggest that laser welding may occur by formation of crosslinks or by denaturalion and reannealment of structural proteins.

ISSN:0894-1939    

DOI:10.3109/08941939109140756

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The in vitro and in vivo corrosion characteristics of two alloys, cast Co-Cr-Mo (ASTM F75) and wrought Ni-Cr-Mo, were evaluated using electrochemical corrosion analysis. Two in vitro electrolytic solutions were utilized, an isotonic saline solution consisting of 0. 9 w/o NaCl in distilled water and an isotonic saline solution with 10 v/o sterile calf serum. The in vivo environment was created by implanting cylindrically shaped specimens of each alloy into the back muscles of New Zealand white rabbits. Cyclic anodic and cathodic polarization curves were generated for the three test conditions and subsequently were compared. Anodic curves conducted using the isotonic saline and isotonic saline plus serum electrolyte solutions were very similar to the anodic curves generated for the implanted alloy specimens for both alloys. The corrosion rates predicted from the in vitro and in vivo cathodic polarization curves were not statistically different for the three test conditions. Overall, the corrosion data generated using the in vitro environmental conditions adequately predicted the in vivo corrosion behavior of the cast Co-Cr-Mo and wrought Ni-Cr-Mo alloys.

ISSN:0894-1939    

DOI:10.3109/08941939109140757

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Early revascularization is critical for the treatment of acute myocardial infarction (AMI) because the ischemic myocardium begins to suffer irreversible damage after 4 h from the onset of symptoms. However, to make a diagnosis, perform coronary angiography, and prepare for operative revascularization usually takes longer than 4 h. Also, once a patient develops severe cardiogenic shock, coronary angiography is often impossible. Without angiography, the patient is no longer a candidate for surgical repair. To circumvent this problem, we designed this experiment to determine whether intraoperative aortic root angiography after cardiopulmonary bypass and cardioplegic arrest could satisfactorily substitute for angiographic examination in the identification of critical coronary lesions. The feasibility of this approach was tested in dog hearts in which one or two of the major coronary arteries were ligated. The ascending aorta was then clamped, contrast material was injected, and continuous real-time fluoroscopic images were obtained and recorded on videotape. The videotape was then analyzed by three physicians independently, each without prior knowledge of the lesion locations. Lesions of the left anterior descending artery, the circumflex coronary artery, and the right coronary artery were identified with 94, 91, and 94% accuracy, respectively, for an overall identification rate of 92%. We conclude that aortic root angiography reliably demonstrates coronary artery lesions, and refinements in this technique may allow certain patients to undergo coronary operations without preoperative catheterization

ISSN:0894-1939    

DOI:10.3109/08941939109140758

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Intraabdominal adhesions continue to pose a potentially serious postoperative clinical problem. Reported here is an experiment designed to study any effect that balanced Ringer's lactate (RL) solution may have on intraabdominal adhesion formation. Surgical trauma was induced in mice by controlled gauze abrasion of one side of the abdominal wall; the opposite side was used as a control. RL irrigation was compared with no irrigation. A dhesions were scored on the basis of incidence (%) and severity (on a 0–10 scale). The abraded right peritoneum exhibited 100% adhesions for both the RL group and the nonirrigated group. However, on the side that was not abraded, the nonirrigated group showed only 30% incidence of adhesions and 1.7±3.3 severity as compared with 100% adhesions and 7.7±2.2 severity for the RL group. These results suggest the need for further studies to establish the extent to which irrigation with solutions such as Ringer's lactate or saline may enhance formation of postoperative adhesions.

ISSN:0894-1939    

DOI:10.3109/08941939109140759

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Models for the study of prosthetic vascular graft infection have been studied frequently in the dog and rabbit. We have developed a reproducible swine model to study this problem and its treatment. The cardiovascular system, healing characteristics, and the bloodstream clearance of bacteria in swine more closely resembles those of humans than do other animal models. The low cost and availability of the swine is an additional attractive aspect. One hundred fifty-six farmbred pigs have undergone infrarenal aortic replacement with a 3-cm segment of 6-mm prosthetic graft over the past two years. Graft infection was produced by (1) direct inoculation of 106Staphylococcus aureus at the time of the surgery or (2) intravenous infusion of bacteria (102-106organisms/mL) immediately after surgery. All animals were sacrificed 1 to 4 weeks later, depending on the study design. Cultures, histology, and electron microscopy were performed on each graft. Anesthetic complications were rare (2.5%). Postoperative complications leading to animal death decreased with increasing experience (11.5%). but included graft thrombosis, bleeding, sepsis, intussusception, and colonic ischemia. Wound infection was the most common cause of morbidity. The swine model is an attractive alternative to that of other animals for the study of prosthetic vascular graft infections. Further details of the operative technique and the comparison to the human and other animal models is discussed.

ISSN:0894-1939    

DOI:10.3109/08941939109140760

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The susceptibility of different species to bacteremia may influence the results of studies on vascular graft infection. The present study compares prosthetic graft infection in canine and porcine models. Thirty-four mongrel dogs and 38 Yorkshire pigs underwent replacement of the infrarenal aorta with a 3-cm segment of a woven Dacron prosthesis. At the lime of closure, each animal received an intravenous inoculum of 102to 108Staphylococcus aureus (S. aureus) Graft cultures at 1 week produced a predictable infection rate in dogs, while pigs developed only random infections (dogs: 23/34; pigs: 7/38: p = 0001). The median infective dose (ID50) in dogs was 102.9but pigs did not develop enough infections to determine this value. Electron microscopy revealed a smooth fibrin surface in grafts explanted from pigs, while grafts from dogs demonstrated bacteria enmeshed in an irregular fibrinous lining. Prosthetic vascular grafts in dogs are more susceptible to hematogenous infection than those in pigs. Because hematogenous infection in humans is a rare event, the swine model may be a more appropriate representation of the clinical situation.

ISSN:0894-1939    

DOI:10.3109/08941939109140761

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Studies on vascular graft infections may be influenced by species differences in bacteria clearance. The present study compares the bloodstream elimination of Staphylococcus aureus (S. aureus,) in dogs and pigs. Four mongrel dogs and four Yorkshire pigs received a 20-min infusion of 106S. aureus labeled with in-dium-131. Through a catheter placed in the infrarenal aorta, blood samples were removed at intervals for 5 h after infusion. The liver, spleen, and lungs were biopsied at 5 h. Blood and tissue samples were then counted in a gamma counter. The calculated phagocytotic index, k, for dogs was 8.6×10−4, while for pigs it was 1.5×10−3, indicating significantly faster bacterial clearance in pigs (p =. 009). After 21/2h, significantly fewer counts were present in pigs at most time points (p>. 05). Organ counts indicated higher counts in the dog liver and spleen and in the lungs of pigs (p>. 0001). This study indicates that S. aureus bacteremia is cleared faster by pigs, primarily by the lungs, compared to dogs, in which liver-spleen clearance predominated. These differences should be considered when the results of graft infection studies are compared.

ISSN:0894-1939    

DOI:10.3109/08941939109140762

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The critical shortage of available donor organs is the major limit to current allogeneic transplantation. Xenografting has the potential to overcome this difficult problem. Suppressing the vigorous rejection response remains a major obstacle to the clinical application of xenografting. 15-Deoxyspergiialin (DOSP), a potent new immunosuppressive agent has been shown to be effective in allogeneic and xenogeneic experimental models. This study tests DOSP in combination with rabbit anlithymocyte globulin (RA TG) in the hamster-to-rat cardiac xenograft. Results show that combination therapy with DOSP/RA TG was superior to treatment with either agent alone (p>05). Optimal graft prolongation (20.9 days versus control of 3.1 days, p>. 05) was achieved with combination therapy of RATG and DOSP 2.5 mg/kg day by continuous infusion.

ISSN:0894-1939    

DOI:10.3109/08941939109140763

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The experimental model reported here was developed initially to examine the possibility of in utero coverage of congenital soft tissue defects using several types of reconstructive techniques. To pursue this, full-thickness skin grafts, pedicle flaps, and skin“islands”were fashioned on the backs of fetal rabbits; equivalent adult control wounds were also created. While all pedicle flaps and skin islands remained viable, none of the full-thickness grafts survived in the fetus. All adult control flaps, skin islands, and skin grafts were viable. Angiogenesis is crucial to full-thickness skin graft survival. These observations suggest that the death of full-thickness fetal skin grafts may be related to a failure of neovascularization in the graft bed. Further analysis using this model may help elucidate the factors involved in fetal angiogenesis. Additionally, this model may permit testing of putative angiogenic factors applied under a full-thickness skin graft; graft survival offers an easy, objective, and quantifiable means of data analysis.

ISSN:0894-1939    

DOI:10.3109/08941939109140764

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor