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Biomedical subjects

F Garcia

Publications and source records attributed to F Garcia.

At least 145 records · Page 8Linked to original sources
PubMed1986

Trauma of the extremities: prospective comparison of digital and conventional angiography.

Digital subtraction angiography (DSA) and conventional film angiography (CFA) were compared prospectively in 50 patients with trauma of the extremities. Each patient underwent both procedures with comparable imaging parameters and injections. Three angiographers reviewed the angiograms for the presence of seven angiographic signs of arterial injury. The two modalities showed pseudoaneurysms, arteriovenous fistulas, vessel displacement, occlusion, and focal narrowing equally well. CFA was superior to DSA in delineating intimal dissection; DSA was better for demonstrating extravasation. Clinical follow-up demonstrated that both procedures had a sensitivity of 100%; the specificity was 94% for DSA and 97% for CFA. Neither procedure produced a false-negative result.

Angiography↗
PubMed1986

Atherosclerotic rabbit aortas: expandable intraluminal grafting.

Balloon-expandable intraluminal grafts that ranged in diameter from 2 to 4 mm were placed in the atherosclerotic abdominal aortas of 24 rabbits. The animals were killed 1, 3, 8, or 24 weeks after placement of the graft. All grafts retained patency without altering the luminal diameter. The small degree of neointimal thickening covering the graft's inner surface was not detectable on conventional in vivo arteriograms. Aortic atherosclerotic plaque external to the graft was markedly compressed 1 week after graft placement. The plaque regained full thickness 24 weeks after grafting when the plaque expanded outside the graft as a result of relaxation or atrophy of the surrounding arterial media.

Angioplasty, Balloon↗
PubMed1986

Expandable intrahepatic portacaval shunt stents in dogs with chronic portal hypertension.

A canine experimental model was used to investigate the feasibility of using balloon-expandable portacaval shunts in humans with chronic portal hypertension. Intrahepatic portacaval shunts were created in nine dogs with stable portal hypertension previously induced by intraportal injections of polyvinyl alcohol (Ivalon). Embolic material was injected periodically through a subcutaneous port that allowed repeated access to the portal system. Shunts were placed 14 weeks after the last embolization. A shunt patency rate of 100% was observed up to 48 weeks. Low portacaval pressure gradient and high shunt flow accounted for the good results.

Animals↗
PubMed1986

Expandable intraluminal vascular graft: a feasibility study.

An expandable intraluminal graft mounted coaxially over an angioplasty balloon catheter was used in dog arteries. The graft, a wire mesh tube that has the ability to retain its expanded shape, opposes elastic recoil of the arterial wall after maximum balloon inflation. Eighteen grafts were placed in the abdominal aorta and iliac femoral, renal, superior mesenteric, and carotid arteries of eight dogs through femoral or carotid arteriotomies. Two grafts were placed in areas of artificially induced stenosis, completely restoring the lumen. Overall patency rate at 35 weeks was 77%. Histopathologic examination of patent grafts showed complete endothelialization at 3 weeks. The smaller caliber grafts and those that had outflow obstruction showed significant degrees of intimal hyperplasia.

Angiography↗
PubMed1985

Expandable intrahepatic portacaval shunt stents: early experience in the dog.

Intrahepatic portacaval shunts were established in dogs by the transjugular approach. The shunts extended from the anterior aspect of the inferior vena cava to the portal bifurcation through interposed liver parenchyma. The tissue track was created by a long transjugular needle and enlarged by balloon angioplasty catheter dilatation. The opening was then stented with a specially made, expandable, tubular, woven mesh of stainless steel wire. The stent was introduced mounted in a collapsed fashion around a folded angioplasty balloon. Inflation of the balloon expanded the stent and the tissue track simultaneously, leaving a large side-to-side portacaval shunt. Nine out of 12 animals survived the procedure and eight of them had functioning shunts as long as 9 months after placement. Pathologic examination showed complete endothelialization of the inner surface of the stents.

Animals↗
PubMed1985

Histochemical and cellular changes induced in the rabbit knee joint by an intraarticular implantation of a sheet of polyethylene.

Implantation of a sterile rigid sheet of polyethylene into the right patellofemoral rabbit joint caused changes that resemble those found in human osteoarthritis. Initial synovial proliferation resulted in the isolation of the implant. Marginal osteophytes developed from soft cellular tissue which later underwent chondrification and finally became ossified. Articular cartilage under the area in contact with the implant showed early cell necrosis and diffuse loss of metachromasia. Focal superficial fibrillation followed and later developed into deep erosions and bone exposure. The first clefts appeared tangentially to the surface within an acellular electron-dense material. In spite of numerous mitotic divisions of viable chondrocytes, mainly in clusters or clones, cell density progressively decreased in every layer of articular cartilage beneath the implant. The present study suggests that necrosis of chondrocytes, and the later failure of viable cells to respond adequately to the altered environment, can lead to cartilage fibrillation and then to more severe lesions.

Animals↗
PubMed1983

[The annular scotoma and jack-in-the-box phenomenon in aphakia corrected with eyeglasses. Experimental approach].

An experimental study of "annular scotoma" was conducted. Variations in prismatic effects at the boundary of the lens with respect to incidence were evaluated with the aid of a laser beam. The use of an arc-perimeter and an artificial aphakic eye allowed reconstruction of light beam paths from the outside to the inside of the eye. The results obtained enabled a more rigorous analysis of this optical phenomenon. A straightforward formula obtained from the experiment (tan theta = b/a) provided better understanding of the variations generated by certain parameters. This same formula can be applied to the mechanism of the "Jack-in-the-box" phenomenon.

Aphakia, Postcataract↗
PubMed1982

[Response of the joint tissues to the presence of a foreign body implanted into the rabbit knee. A new model of experimental arthrosis].

The joint tissues (synovium, articular cartilage and bone), respond rapidly and consistently to the presence of a piece of polypropylene surgically implanted into the Rabbit knee joint. In the contact of a foreign body, a synovium proliferates in an attempt to isolate and exclude the intruder from the joint cavity. The articular cartilage degenerates at the sites of maximal pressure. Its superficial layer undergoes cell necrosis and fibrillation and is progressively destroyed in the process of mechanical grinding. At the sites of lower pressure, the chondrocytes proliferate and form the metabolically hyperactive clones which have increased capacity to incorporate tritiated thymidine and radioactive sulfate. The glycosaminoglycan content of articular cartilage, compared to the shamoperated control side, rapidly decreases after operation as suggested by a loss of metachromatic staining and lower per unit weight concentration of uronic acid and hexosamine. In addition to the above changes, the osteophytes quickly develop at the articular margins from the proliferating synovial tissue while underlying bone become thicker and eburnated. These foreign body induced changes in articular morphology and metabolism resemble closely those observed in osteoarthrosis. The present model therefore may prove useful in studying the latter condition.

Animals↗
PubMed1982

Fever, antipyretics and serum iron levels in rabbits.

The intracerebroventricular (i.c.v.) injection of bacterial endotoxin (Shigella dysenteriae) produces a rise in deep-body temperature in rabbits. The increase in body temperature was partially inhibited by polymyxin B (P), and completely suppressed by ketoprofen (K). The systemic injection of bacterial endotoxins (Shigella dysenteriae or Salmonella typhosa) elicited an elevation of body temperature in rabbits which was partially blocked by polymyxin B and completely antagonized by ketoprofen. Serum iron concentration fell in rabbits treated with Salmonella typhosa endotoxin and rose after injections of ketoprofen, polymyxin B, indomethacin and ketoprofen plus endotoxin (En). However, the total increases in serum iron levels were higher after antipyretics than after ketoprofen plus endotoxin treatment. These results show that the antipyretics antagonized the rise in body temperature and the fall in serum iron concentration induced by bacterial endotoxin and all the drugs used in this study to induce antipyresis increased serum iron levels.

Animals↗