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Biomedical subjects

T A Chvapil

Publications and source records attributed to T A Chvapil.

9 recordsLinked to original sources
PubMed1991

Effects of electrocautery on midline laparotomy wound infection.

This study compared the healing of midline fascial incisions made with either scalpel or electrocautery and inoculated with Escherichia coli in 57 Sprague-Dawley rats. At 7 days, tensile strength was significantly less when incisions were made with electrocautery than with a scalpel. Additionally, would strength was inversely related to the concentration of the inoculum of E coli. The use of electrocautery was also associated with more frequent bacteremia at 48 hours and higher mortality at 7 days. Our results suggest that the technique used to incise the abdominal fascia influences subsequent wound healing, particularly in contaminated wounds.

Animals↗
PubMed1990

Occlusion of the vas deferens in dogs with a biocompatible hydrogel solution.

The surgically exposed vasa deferentia of 21 dogs were injected, under visual inspection, with Hypan N-90 acrylic hydrogel (50-150 microL). The hydrogel was deposited inside the vas lumen via a 22-gauge Teflon intercatheter. The solution gelled within 120 seconds. Semen was collected by manual collection and analyzed for volume, sperm count and viability. After occlusion with 150 microL of the polymer in the distal direction (direction of the testis), the volume of ejaculate (2.2 mL) did not change. Subsequent samples showed no viable or dead spermatozoa. The stained smears of the ejaculate showed the presence of cell debris, granulocytes and few epithelial cells. When the vas was injected with 50 microL of the polymer in either a distal or proximal direction, the occlusion effectiveness was 75% and 25%, respectively. In the proximal direction, granulomas were noticed in the vas wall where semen leaked through the injection port. Histology of successfully occluded vasa (with Hypan) showed no cellular reaction or fibrotic changes in the proximity of the polymer. For less than or equal to 20 weeks after vas occlusion, no evidence of abnormal morphology was found in the epididymal and testicular tissue. This highly biocompatible polymer solution, when gelled in contact with tissue fluid, offers safe and effective occlusion of the vas with the promise of reversibility.

Animals↗
PubMed1988

An optimal morphometric method for quantitating wound epithelization.

A new, inexpensive method for quantitative evaluation of reepithelization of shallow split thickness wounds in piglets is described. Wounds, 2.2 X 2.2 cm and 0.4 mm depth are inflicted by an electro-keratome knife in domestic piglets. At a specific time after wounding, the wound area is excised and processed for histology. A computer simulation, based on a randomized systematic sectioning of an entire wound, was used to conclude that only eight sections from the 2.2 X 2.2 cm wound are needed for the final evaluation. The results showed that the above method allows for determination of the epithelization magnitude within +/- 5% at a 95% confidence limit. It was found that in 15 kg piglets 50% epithelization of the above wounds was achieved in 65 hr; however, there exists a great interindividual variability. The rate of epithelization is age dependent and significantly faster in 7 kg body weight piglets than in those weighing 40 kg. The epithelization rate was the same at both the wound edge and the center of the wound, stressing the importance of hair follicles as a source of epithelization.

Animals↗
PubMed1988

STM imaging of molecular collagen and phospholipid membranes.

The application of STM to biological materials has been limited by poor conductivity, sample geometry and stability of biological materials. In this paper we describe an STM study of the monomeric helical forms of collagen, a stable, conductive and widely prevalent structural protein. We have also used STM to image artificial Langmuir DPE (dipalmitoyl phosphatidyl ethanolamine) phospholipid membranes. Both molecular collagen and the phospholipid membranes were dried in air on highly oriented pyrolytic graphite (HOPG). Our STM images of collagen dried on HOPG reveal strands 15 A in diameter with a periodicity of about 30 A which correlates with that known to occur in collagen. Spikes which periodically protrude from strands in our STM images of collagen appear to represent pyrrolidine ring structures in the amino acids proline and hydroxyproline. Thus, we report the first STM imaging of native biomolecules revealing intramolecular details and what appear to be specific amino acids. STM imaging of phospholipid membranes show a lattice pattern with densities spaced approximately 4.5 A apart. These are thought to represent individual phospholipid molecules in an artificial membrane formed on the HOPG. We believe STM and its related technologies will have great future utility in biomolecular studies.

Animals↗
PubMed1987

Comparative study of four wound dressings on epithelization of partial-thickness wounds in pigs.

Sixteen shallow wounds were inflicted in each of five Yorkshire white female piglets, 18-20 kg body weight, by a 2-cm diameter, fast-rotating abrasive disc. The injury is similar to a second-degree burn. The wounds were dressed with one of four dressings: Duoderm (Squibb), Op-Site (Smith & Nephew) [corrected], and collagen sponge, covered with either occlusive or semiocclusive polyurethane film (Datascope Corp.). The last two dressings were moistened with saline before application. The rate of epithelization by planimetric quantitation after 3 to 5 days was the same regardless of the dressing used, although the epithelium layer was thicker in wounds treated with Duoderm. Wounds dressed by either of the collagen sponge materials showed a better appearance when visually scored. Wounds dressed with Duoderm or Op-Site were often macerated; Duoderm's paste-like material remained on the wound and was difficult to remove without inflicting discomfort to the patient. Duoderm, and also Op-Site, adhered much more strongly to the intact skin than either type of collagen sponge dressing.

Animals↗
PubMed1979

Reaction of vaginal tissue of rabbits to inserted sponges made of various materials.

Sponges of the same size made of collagen (CS), polyurethane (PU), polyvinylalcohol (PVA) and acetylcellulose (AC) were inserted for 10 days in the vaginas of 22 rabbits. Light and scanning electron microscopy of the vaginal wall and its mucosal lining showed signs of cytotoxicity only with PU and AC while CS and PVA picture did not differ from sham controls. In order to explain the reasons for the toxic effects, all sponges were extracted into aqueous or organic solvent media and analyzed by gas liquid chromatography. Only several minute peaks in organic solvents were found. Extracts of all sponges tested for cytotoxicity in fibroblast cultures showed significant inhibition of H3-thymidine uptake. Nevertheless, extract of collagen sponge was significantly less cytotoxic than the extracts of all other sponges.

Animals↗