Heterologous Material Research Articles

Healing of experimental defects on the stomach: Influence of autologous and heterologous materials

This study was undertaken to evaluate the influence of various autologous and heterologous structures on gastric defect healing. In 210 rats, standard gastric defects were closed using the following structures as patches: (1) pedicled colonic patches, (a) mucosal layer to lumen, and (b) peritoneal surface to lumen; (2) leiomuscular colonic buttons; and (3) lyophilized bovine tendon collagen sponges. The specimens were removed from the defect areas at standard time intervals ranging from 2 to 12 months after surgery; the samples were then examined by light microscopy (hematoxylin-eosin; Azan Mallory; Grimelius methods) and by trasmission and scanning electronmicroscopy. The colonic mucosa appeared to be the most resistant of the structures to gastric secretions; it showed no mucosal disruption during the entire period of observation and also underwent a progressive gastric-like morphological transformation. In all the other cases, the healing process involved the initial development of granulation tissue followed by scar tissue with gastric mucosa growing over the scar tissue to fill the defects.

Light and electron microscopic studies of rat kidney after administration of inhibitors of the citric acid cycle in vivo. A morphological and histochemical study of the pars recta during malonate poisoning.

Extensive conglomerations of smooth endoplasmic reticulum (SER) formed in pars recta proximal tubules of rat kidney 15 to 30 minutes after single subcutaneous injections of malonic acid (0.5 M given at 1.0 ml per 100g body weight). Simultaneously rough endoplasmic reticulum (RER) disappeared but within 4 hours the normal ER pattern was restored. During this period numerous large multivesicular bodies (MVB) accumulated. In addition to vesicles many MVB contained mitochondria, cytoplasm and even smaller MVB. Apparent fusion of thinner SER membrane with thicker membrane limiting MVB was observed rarely in both perfusion and immersion fixed tissues. Histochemical studies on altered ER, labelled with thiamine pyrophosphatase and unbuffered osmium staining, failed to demonstrate that MVB vesicles were ER derived or that ER was incorporated into MVB by fusion with the limiting membrane. This must be considered a fixation artifact. Horseradish peroxidase, a pinocytotic tracer, showed MVB to have pinocytotic origin. The vesicles apparently formed by budding of cytoplasm into MVB matrices. Acid phosphatase activity was acquired by MVB as they moved towards mid-cell and the enclosed organelles underwent digestion. It is clear that MVB of pars recta are ambilysosomes digesting both autologous and heterologous materials but there was no evidence that altered ER underwent digestion within them and it is likely that rapid alterations in ER resulted from rearrangements of existing membrane moieties. MVB have been implicated in autophagy in other cell types but their autophagic role in sublethally injured kidney tubules has received little attention.

Experimental tympanic membrane closure with collagen film.

THE CONVENIENCE of having a packaged, commercially available material suitable for closure of tympanic membrane defects is attractive indeed. Interest in homologous and heterologous tissues for closure of drum perforations is increasing. Such materials can be obtained, sterilized, and stored for future usage, thus lending themselves to the possibility of preparation on a large scale. Homologous cornea,¹peritoneum,²pericardium,³vein,^4-6and dura⁷have been used. Tympanic membrane homotransplant^8,9has been carried out. Few reports of tympanic closure with heterologous materials are extant. Cargile's membrane (sheep mesentery) has been used.^10,11 Recent evidence¹²indicates that dehydrated temporalis fascia, as used for tympanic membrane grafting, is nonviable. This lends support to the hope that an exogenous biological material may be found which is suitable for drum closure. The desire to find such a material motivated this study. <h3>Materials and Methods</h3> The collagen film utilized in

Wound-Stimulating Effect of Homologous and Heterologous Cartilage

IT has been firmly established that bovine tracheal cartilage powder will speed the early healing of sutured, incised wounds and open, granulating wounds in normal rats, guinea pigs and mice. 1-5 Additional studies from this laboratory have shown a more dramatic effect in the wounds of diabetic rats. 6,7 To date, only heterologous cartilage powder has been investigated. Because McKhann 8 found that animals whose immune mechanisms had been stimulated healed less rapidly than did normal animals, it seemed appropriate to test the effect of homologous cartilage on wound healing and to compare this effect with that brought on by heterologous material. For completeness, autologous material should also have been tested, but practical factors limited such an investigation. Methods Male albino Wistar rats weighing from 140 to 200 gm (.03 to.04 lb) were housed in individual cages and maintained on a standard laboratory diet. Under intraperitoneal pentobarbital anesthesia, the animals

Attempts to Produce Immunity to Transplantable Rat Tumors with Chicken Blood

It has been recently claimed by Gardner and Hyde (1) that the injection of heparinized, fresh, whole blood from normal chickens would induce in rats resistance to transplantable tumors. In his comprehensive review of the subject of immunity, Woglom (2), however, found that it was the general experience that resistance to transplantable tumors could be elicited only by homologous tissues. That resistance could be induced by the injection of heterologous material such as chicken blood seemed very improbable, but in view of Gardner9s and Hyde9s definite statements, the experiment seemed worth repeating. Gardner and Hyde injected the heparinized blood intraperitoneally, and also subcutaneously at the base of the tail; by both methods of administration it was claimed that resistance was produced to the growth of Walker sarcoma No. 1, as well as Walker carcinoma No. 256. When heat-devitalized chicken blood was used, a similar but much less marked resistance was produced. Injections of dried chicken blood had no immunizing effect, nor did the rats become immune when fed on chicken blood. Since Walker rat carcinoma No. 256 is under cultivation in this laboratory and Walker rat sarcoma No. 1 is not, the former tumor was used in the repetition of the experiment. It seemed advisable to at tempt to duplicate one of Gardner9s and Hyde9s experiments only, but to carry out this one experiment on at least three separate series of animals. Since the experiment in which the chicken blood was injected intraperitoneally had given the most striking results, it was the one selected for repetition.

FURTHER EXPERIMENTS WITH THE INTRADERMAL PNEUMOCOCCUS INFECTION IN RABBITS

1. The continuation of our experiments with intradermal Type I pneumococcus infection in rabbits has furnished further evidence of the marked analogies between this condition and that of human lobar pneumonia. 2. It has been found that the amount of antiserum necessary for successful therapy increases as the disease progresses, and that this progression has a definite mathematical character. Such a condition, it seems, can only be caused by a progressive accumulation of some toxic or antagonistic substance, the exact nature of which is not known. 3. Various lots of antipneumococcus sera have been tested for their therapeutic properties. The results from seven such sera show that this therapeutic value does not parallel the mouse-protective value. It is suggested that the rabbit technic may prove useful for the routine comparison and standardization of antipneumococcus sera since it represents a simple method for determining that property for which the serum is to be utilized. 4. The effect of non-specific therapy in this condition has been determined to be a transient disappearance from the blood stream of circulating organisms. This result was obtained with such heterologous materials as normal horse serum and typhoid vaccine but not with the homologous normal rabbit serum. 5. Rabbits recovering from the intradermal disease without treatment or with such inadequate treatment that the disease runs its normal course, were shown to have a definite though not permanent immunity. Cases in which the disease had been arrested at 24 hours by effective therapy with heterologous immune serum showed no immunity after the early disappearance of the passively administered elements. Cases which were brought to early recovery with immune homologous serum did show a definite immunity comparable to that which was developed in other animals as the result of an untreated course of the disease. 6. The immunity conferred by single and multiple vaccination is reported. The possibility of the application of such methods in the pneumonias of man is discussed and a method for such an application is suggested.