Jacques Padawer

Impaired wound healing in streptozotocin diabetes. Prevention by supplemental vitamin A.

Goodson and Hunt showed that wound healing is impaired in streptozotocin (Sz) diabetic rats; we speculated that this impairment results from defective early inflammatory responses to wounding. Because we had shown that supplemental vitamin A stimulates the early inflammatory response to wounding in nondiabetic rats, we studied the effect of supplemental vitamin A on wound healing in rats with Sz-induced diabetes. Male Sprague-Dawley rats were fed a commercial rat chow containing twice the amount of vitamin A recommended by the NRC for healthy rats. The rats ate and drank (tap water) ad libitum. Two-thirds of the rats were injected (intravenously) with Sz 60 mg/kg body weight. All of these rats became diabetic (hyperglycemia greater than 350 mg/dl, hyperphagic, polydipsic, polyuric, glycosuric greater than 2%). Seven days later, half of the Sz-injected rats were continued on the chow (Group 2) while the other half (Group 3) were switched to the chow supplemented with 150,000 units of vitamin A/kg chow. The next day, all were wounded (7 cm skin incisions and s.c. polyvinyl alcohol sponge implants). Similarly wounded saline injected nondiabetic rats ingesting the unsupplemented chow served as controls (Group 1). The wounds of Group 2 rats healed poorly compared to Group 1 (breaking strength of skin incisions, 308 +/- 19 g vs 584 +/- 23 g, p less than 0.001; hydroxyproline of the sponge reparative tissue, 0.87 mg vs 2.40 mg/100 mg sponge p less than 0.001). Supplemental vitamin A (Group 3) did not affect the hyperglycemia, hyperphagia, polydipsia or glycosuria, but increased the breaking strengths of the incisions of the diabetic rats (468 +/- 40 g, p less than 0.001), and the sponge hydroxyproline (2.38 mg/100 mg sponge, p less than 0.001). In another experiment, in which the wounding and start of supplemental vitamin A were delayed until 28 days after streptozotocin administration (50 mg/kg body weight), similar results were obtained. Streptozotocin diabetes also caused a decrease in the cross-linking of reparative collagen as judged by the ratio of breaking strengths of skin incisions before and after formalin fixation. Supplemental vitamin A did not influence this defect. Sz also caused peripheral lymphocytopenia, adrenal hypertrophy and thymic involution which responded to the supplemental vitamin A. Based upon experimental data and theoretical considerations we conclude Sz diabetes causes two defects in wound healing: a) quantitatively (reduction in reparative collagen accumulation) and b) qualitative reduction in the degree of cross-linking of reparative wound collagen. The action of supplemental vitamin A in correcting the impaired wound healing, adrenal enlargement, thymic involution and lymphocytopenia of Sz-diabetic rats is independent of an effect on their disturbed carbohydrate metabolism.

QUANTITATIVE STUDIES WITH MAST CELLS

The field of mast cell research has experienced a dramatic expansion over the last few years. This has extended into several disciplines, some closely, others less closely related, as is evident from the broad scope now possible for a conference on mast cells and basophils. This interdisciplinary approach has been invaluable in most respects, but it also has led to some confusion, because each discipline has its own approach, terminology, and standards. Research on mast cells has developed to the point where these various factors can and should be standardized, and where a strictly quantitative approach can now be applied meaningfully to many of the problems at hand. In this paper, several aspects of mast cell physiology will be examined, with special emphasis on quantitative methods. With the benefit of hindsight, it seems pertinent to underline any weakness in our conceptual approach and methodology. We must reach in new directions, even at the risk of learning at a later time that we have erred again. If this approach stimulates us either to prove or to disprove a point it will have served its function.

Mast cells: Extended lifespan and lack of granule turnover under normal in vivo conditions☆

Abstract Rat mast cell granules, tagged with an indigestible marker (thorium dioxide), are still present 10 months after marker injection. It is concluded that mast cells are long-lived elements and that their function does not depend on degranulation. Thus, degranulation may rather be indicative of cellular injury or pathology.

Zone II flexor tendon repair: Effects of vitamins A, E, β-carotene

Abstract Ninety-six adult Leghorn chickens each had the flexor profundus tendon in each middle toe sharply divided in Zone II with immediate repair (pentabarbital, ketamine anesthesia). Animals were then randomly assigned to receive unsupplemented standard chick chow or the chow supplemented with vitamin A (150,000 IU/kg chow), Vitamin E (1000 IU/kg chow), or β-carotene (90 mg/kg chow). Eight animals from each of the four groups were examined at 7, 30, or 45 days post repair. After sacrifice, in situ composite wound breaking strength was measured in the amputated toe by constant speed tensiometry. Vitamin A-supplemented animals demonstrated breaking strength more than double that of control at each post-operative test day, while those animals receiving supplemental Vitamin E had breaking strength less than half that of control at Day 7 and Day 45. These results are statistically significant. Tensiometry curves differed markedly at all time points among the groups: Vitamin A curves being broader, higher, and having more spikes. These differences in the tensiometry curves, both qualitative and quantitative, may be due to differences in intrinsic tendon healing or to differences in adhesion formation or a combination of both. β-Carotene supplementation had modest effect. We conclude that supplemental dietary vitamin A increases the breaking strength of composite tendon wounds and that supplemental dietary vitamin E decreases it.

Combined treatment with radioestradiol-lucanthone in mouse C3HBA mammary adenocarcinoma and with estradiol-lucanthone in an estrogen bioassay

Abstract C3H female mice bearing transplantable estrogen-nondependent adenocarcinomas were treated subcutaneously with either estradiol, tritiated ( 3 H)estradiol, lucanthone, 3 H-estradiol followed by lucanthone, or lucanthone followed by 3 H-estradiol. Tumor growth and host survival were ascertained. As single agents, lucanthone or 3 H-estradiol had slight tutor-inhibiting effects with small tumors. Combined treatment with radioestrogen followed by htcatlthone 4 hrs later blocked early tumor growth for several days and permanently reduced the growth rate thereafter; it also lengthened survival by some 67%. On the other hand, combined treatment with lucanthone followed 1 hr later by 3 H-estradiol did not have the same effect. The increase in adrenal gland weight that occurs as this tumor grows was significantly reduced by treatment with lucanthone, and more so by 3 HE2…..+Lu; both of these treatmelnts also depressed the lymphatic system. It is suggested that the antitumor effects observed may be mediated-systemically via the adrenal. None of the treatments were effective against advanced tumors. Lucantbone was also administered subcutaneously to w female Swiss mice in conjunction with estradiol. Evidence showed that lucanthone interferes with the immature mouse uterine weight response to estrogen, especially what given 1 hr before the hormone. Although an estrogen dose-response relationship was demonstrated for all groups, the hormone and the DNA intercalating agent interfered with each other in a way that suggests possiblle steric or competitive inhibition. Thus lucanthone modulates two estrogen effects, namely, the effect of estrogen out an estrogen-response tissue (uterine weight, especially when given prior to the hormone), and the effect of radioestrogen on an estrogen-nondependent antonomous tumor (when given after the hormone). A novel antitumor strategy, here called radiocytochemotherapy , is described, and possible applications to human tumors are discussed.

Ingestion of colloidal gold by mast cells.

Summary Rat peritoneal fluid mast cells can phagocytize colloidal gold. This foreign participate rapidly becomes localized within the specific cytoplasmic granules of the cell. With the previously demonstrated uptake of zymosan and of Thorotrast particles by mast cells, the demonstrated phagocytosis of a third particulate substance by mast cells suggests that uptake of substances from the tissue environment may be a process with broad significance with respect to mast cell function.

Some studies on the fluorescence of mast cells after paraformaldehyde treatment

SummaryAir dried peritoneal fluid and tissue spreads from rat, mouse, hamster, rabbit, guinea pig, cat, chicken, and frog were treated with paraformaldehyde (pCHO) at 80 ° C for 1 hr. Only rat and mouse mast cells fluoresced. In the rat, mast cells fluoresced whether present in vascular or avascular areas of mesentery, in fat depots, or in peritoneal fluid. Photographs were obtained by fluorescence microscopy, the preparations were then stained and the same fields rephotographed in white light. Comparison of the photographs showed that every fluorescent rat mesentery mast cell also stained with acidified toluidine blue and with Astrablau; a few fluorescent cells did not stain with toluidine blue and an occasional cell that did not fluoresce stained with this dye or with Astrablau. Paraformaldehyde depressed somewhat toluidine blue, inhibited strongly Astrablau, and abolished Alcian blue binding. It had no effect on the staining of purified heparin in model experiments.Reserpine administration in the rat did not prevent visualization of mast cells by the pCHO method.These experiments indicate that all rat mast cells contain serotonin, regardless of cell size (age ?) or site and suggest that no massive, cyclic release of this amine occurs either physiologically or in response to reserpine treatment.

Supplemental arginine increases thymic cellularity in normal and murine sarcoma virus-inoculated mice and increases the resistance to murine sarcoma virus tumor.

Arginine supplements were given to 6 week old CBA mice beginning 3 days prior to inoculation with a murine sarcoma virus, the Moloney Sarcoma Virus (MSV). Although the basal diet contained 1.8% arginine and was therefore not arginine-deficient, supplementation of the diet and the drinking water with 0.5% arginine HCl reduced tumor incidence, lengthened the latency period, decreased tumor size, and hastened tumor regression. Arginine also increased thymic weight and cellularity in normal and in MSV-inoculated mice. The antitumor action of arginine may be related to its effect on the thymus.

Mast Cell Degranulation in Fixed Preparations.

Summary The present study indicates that significant morphological changes in mast cell size, shape, and granule size can occur following conventional fixation, and that these fixed cells are also particularly prone to damage by mechanical manipulations inherent in standard histological techniques. In all cases where mast cell degranulation has been described, these factors deserve serious consideration to differentiate fact from artifact.

Scanning electron microscopy: Identification of mast cells by indirect cathodoluminescence

SummaryMast cells of rat peritoneal fluid deposited on glass and stained selectively with Acridine Orange can be detected in the SEM by cathodoluminescence. Model experiments with dyes suggest that the stained cells block the radiation emitted by the substrate (glass slide support). This approach may be useful for SEM identification of other cell types or for histo- and cytochemical purposes.