James A. Owen

Identification of the depth of burn injury by collagen stainability.

Heat-denatured collagen in burned skin stains red instead of blue in Massons trichrome stain. This change in stainability corresponds to the loss of birefringence in slides examined in polarized light. The depth of the abnormal staining of the skin slices was proportional to the time and temperature of the heat exposure. It is concluded that the change in collagen stainability from blue to red relates to the loss of crystallinity or parallel alignment of the collagen fibers. It is further proposed that change in the stainability of collagen in the burns could be used to delineate the depth of the thermal skin injury or the effectiveness of the surgical excision or debridement of the wound by dressing materials.

Studies on nonoxynol-9. II. Intravaginal absorption, distribution, metabolism and excretion in rats and rabbits

Some pharmacological aspects of Igepal CO-630, used by some pharmaceutical companies as the source of nonylphenoxypoly (ethyleneoxy) ethanol (Nonoxynol-9, N-9) in various spermicidal formulations, were studied. It was found that Igepal CO-630 contains at least 13 components, 70% having molecular weights near that of N-9. After intravaginal administration, the detergent is rapidly and quantitatively absorbed through the vaginal wall into the systemic circulation. The rate of vaginal absorption of N-9 depends on the vehicle in which the detergent is carried. Once in the blood, N-9 is excreted by liver-bile-feces and the kidney-urine routes, the first being more effective in rats, the latter in rabbits. Following intravaginal or intraperitoneal injection of radioactive N-9, the highest content of radioactivity was found in the liver and kidney. The detergent was detected in the milk of lactating rats and the serum of their pups within two hours after the intravaginal dose.

Effect of zinc on acute and chronic isoproterenol induced heart injury.

Abstract Hypertensive male rats were injected with single or multiple injections of isoproterenol. Some of the rats were administered zinc parenterally. A significant increase in serum zinc concentration occurred after administration of zinc but not in zinc content of the heart. Acute isoproterenol injection induced a 5-fold increase in calcium content of the heart. Zinc treatment significantly reduced calcium content and increased zinc content of the injured heart. When isoproterenol was injected in rats pretreated and simultaneously administered zinc for a period of 14 days, zinc significantly reduced calcium content, collagen content and size of the necrotic area in the heart. Histopathology of heart of rats treated with both zinc and isoproterenol showed only foci of necrosis replaced with less organized granulation tissue, while isoproterenol alone induced confluent circumferential subendocardial necrosis with mature granulation tissue. The weight of the heart (wet, dry, relative) was not affected by zinc treatment. The weight of the adrenal, significantly increased by isoproterenol, was significantly less in zinc-treated animals. It is concluded that parenteral administration of zinc partially protects the heart against isoproterenol induced myocardial necrosis. Although the mechanism of this effect is still not quite clear, we propose that zinc decreases the isoproterenol-induced influx of calcium into the myocardium, thus lowering the imbalance between heart work and O 2 -supply to the cardiac muscle.

A standardized animal model for evaluation of hemostatic effectiveness of various materials

Two anatomic sites of bleeding injuries were selected in dogs to evaluate the hemostatic effectiveness and handling properties of various hemostatic materials. Split-thickness skin excisions inflict a wound of 90 cm2 area with regular spotted bleeding, which allows gravimetric quantitation of blood loss and of ease of removal of the agent. Excision of a wedge of the spleen 0.5 cm deep and 4 cm wide induced reproducible and moderate bleeding in pentobarbital-anesthesized dogs. Three to four similar injuries could be inflicted in the same spleen with comparable blood flow. In this model of bleeding injury only the highly effective hemostatic agents based on collagen and with a sheet-like structure successfully stopped the bleeding within 3 minutes. Powder-like collagen was effective only when pressed against the wound. Gelatin sponge or oxidized cellulose materials were less effective.

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; Duoderms 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.

Early Changes in the Chemical Composition of the Rat Lung after Silica Administration

A group of 200 g male Sprague-Dawley rats was injected with 75 mg of quartz (less than 5 mu particle size) and changes in lung DNA, noncollagenous protein, total lipids, and collagen were studied after 6, 24, 72, 96, and 144 hr. Another group of rats received 10, 30, 59, and 75 mg quartz and the above lung analysis was performed 6 days later. Control rats received saline only. Both sets of experiments indicate that striking changes in the above parameters occur very early. The sequence of statistically significant changes was: lung weight (24 hr), DNA (24 hr), noncollagenous proteins (72 hr), total lipids (72 hr), collagen (144 hr). At the dose of 30 mg quartz/lung all the above parameters were significantly increased within 6 days after the lung injury. It is proposed that in early stages of experimental silicosis an excessive amount of collagen accumulates in the lung. Later, some of the deposited collagen is resorbed. This indicates that in the course of the silicotic fibroproliferative inflammation, the balance between collagen deposition and degradation varies.

Laboratory and clinical testing of an intravaginal contraceptive collagen sponge.

Abstract The efficacy of collagen sponge (CS) used as intravaginal contraception barrier depends largely on the continuous retention of CS in the upper vault of the vagina, prompt absorption of ejaculate into CS and inactivation of sperm by acidity of the sponge. All three factors were tested in in vitro studies, and retention was also evaluated in human volunteers. Retention seems to depend on adequate resilience of the CS. This can be controlled by the degree of crosslinking of collagen fibers. With adequate resilience the expulsion rate, originally 33%, was reduced to 2.5%. Our tests were conducted by 30 volunteers who tested eight types of CS in a total of 213 insertions. The rate of fluid absorption by the CS could be significantly increased by treating the sponge with a surfactant, such as Triton X-100 (0.1%). It was found that prewetted sponge absorbs fluid instantaneously; thus, modification of CS with surfactant is not necessary. CSs were equilibrated to various pHs (4 to 7). Extracts from these were applied to fresh human spermatozoa to test the effects on sperm motility. At pH 5.0 the motility stopped after 4 min. while at pH 7.0 the cells were still active after 30 min. observation. This is one of the reasons why CSs used as contraceptive should have acidity around 5.0. The various methods of insertion and removal of CS were tested by five volunteers for 5 consecutive days. Both digital and applicator insertion were found acceptable. Removal of CS was facilitated by a loop or strand of umbilical tape fixed to the CS.

The importance of the liver in normal and silicotic lung-lipid homeostasis: 2. Cholesterol☆

Abstract We studied the total content, concentration, and rate of synthesis of cholesterol in the lung, liver, and serum of rats intratracheally injected with quartz or saline. Intact rats served as controls. The animals were sacrificed at four time intervals ranging from 6 to 144 hr after the treatment. The presented data are based on analyses of 87 rat lungs. Instillation of silica into rat lung results in a prompt and significant increase in cholesterol content in the lung amounting to a three- to fourfold increase over the control values within 3 to 6 days after the instillation. These changes, when correlated with cholesterol changes in the serum and liver, indicate that the lung injury initiates synthesis of cholesterol in the liver. This lipid species (as well as other lipids) is then transported into the serum and deposited in the lung. The results indicate that some of the cholesterol in silica-treated rats is synthesized directly in the injured lung. The dynamics of the changes in the above indicators of cholesterol synthesis and deposition in the three tissue standards indicate that the early changes are a part of the nonspecific stress reaction (surgical trauma) and the later changes are specific to the silica related injury in the lung. Thus, the injured lung mediates the liver cholesterolgenesis and cholesterol transport into the serum and accumulation in the lung.

Healing of skin incision wounds treated with topically applied BAPN free base in the rat.

beta-Aminopropionitrile as free base (BAPN) was applied onto the incised or intact skin of rats at the dose of 5, 20, 100, and 200 microliters for 9 days, twice daily. Breaking strength of the skin wound or intact skin was significantly reduced at doses of 20 microliters and higher; body weight growth was significantly retarded at the two highest dosages. It is concluded that at a given dose (20 microliters) collagen polymerization (evaluated by reduced breaking strength and increased extractability of collagen) was specifically inhibited by BAPN. Furthermore, no evidence of topical or general toxic effects were observed, as reflected in histology, body weight growth, and behavior of the rats. Acute LD50 of BAPN base and fumarate, administered either ip or topically, was determined in mice. While BAPN base in ip administration shows LD50 of 1.15 g/kg, in cutaneous application it is more than 12.8 g/kg. It is suggested that topically applied BAPN base is percutaneously absorbed and affects collagen polymerization in the skin and adjacent tissues.

Ultrastructure of the Vaginal Tissue of Rabbits Treated With Collagen Sponge Alone and Medicated with Zinc and Copper Salts and Copper Wire

We tested the reaction of rabbit vaginal epithelium to inserted collagen sponges which have been proposed for human use as intravaginal contraceptive barriers. Some collagen sponges were medicated with zinc and copper sulfate and oher (untreated) sponges were wrapped loosely with copper wire. Scanning and transmission electron microscopy was performed on vaginal tissue after 10days of intravaginal contact with the sponges. The characteristic longitudinal rugate arrangement of polygonal, flat epithelial cells with a dense, even covering of microvilli seen in intact vaginas was not changed by the presence of a collagen sponge for 10days. In the presence of zinc sulfate in the sponge, the microvilli were in general shorter; however, the cells remained flat and continuous, forming visible, longitudinally oriented folds. Sponges containing copper sulfate induced marked changes in the epithelial lining of the rabbit vagina. Cells of differing sizes protruded above the plane of the surface. These cells had a hypertrophic appearance with narrow neck and widening at the top. Microvilli in these cells were very short and widely spaced, in contrast to the profuse microvillous projections in other vaginal samples. Copper wire induced definite abnormalities which were classified into three categories: (1) altered appearance similar to that caused by copper sulfate; (2) localized complete denudation of cells; (3) necrotic changes with penetration of the continuity of epithelial lining and excessive leukocytic infiltration of the lesion at the site of direct contact of the vaginal mucosa with the wire.