Immunoablative high-dose cyclophosphamide without stem-cell rescue for refractory, severe autoimmune disease.

BACKGROUND: Immunoablative high-dose cyclophosphamide without stem-cell rescue induces durable, complete remission in most patients with aplastic anemia. OBJECTIVE: To determine the efficacy of high-dose cyclophosphamide in various refractory, severe autoimmune diseases. DESIGN: Prospective phase II study. SETTING: Johns Hopkins University (Baltimore, Maryland) and Hahnemann University (Philadelphia, Pennsylvania). PATIENTS: Eight patients with refractory, severe autoimmune disease. INTERVENTION: Immunoablative high-dose cyclophosphamide (50 mg/kg of body weight per day) for 4 consecutive days. MEASUREMENTS: Clinical and laboratory variables of autoimmune disease. RESULTS: Seven patients improved markedly: Five achieved complete remission and two achieved partial remission. Four patients have remained in continuous complete remission for 3 to 21 months, and two patients in partial remission continue to improve after 14 and 19 months of follow-up. High-dose cyclophosphamide was well tolerated; median times to a neutrophil count of 0.5 x 10(9) cells/L and platelet transfusion independence were 17 and 16 days, respectively. CONCLUSIONS: Immunoablative high-dose cyclophosphamide without stem-cell rescue can induce complete remission in patients with refractory, severe autoimmune disease. Reemergence of marrow function is similar to that seen after autologous transplantation and does not carry the risk for reinfusion of autoaggressive lymphocytes with the autograft.

Diphenylhydantoin inhibits calcification of bovine pericardial implants and myocardium: a preliminary study.

Calcification is a major cause of glutaraldehyde-fixed bioprosthetic valve failure. Recent studies have shown that dystrophic calcification shares basic features with normal bone mineralization, including crystal initiation through the mediation of cell membranes, usually in the form of extracellular vesicles. In this study, we observed that calcification of the myocardium of DBA/2J mice was inhibited or reversed by diets supplemented with 100 mg/kg diet diphenylhydantoin (dilantin) for 70 days, with a calcification incidence of 25% in the dilantin group versus 58% in control. We further studied the effects of dilantin on bioprosthetic valve calcification. Three groups of young male Sprague-Dawley rats (100 g, 9/group) were implanted subcutaneously with 1-cm2 pieces of glutaraldehyde-fixed bovine pericardium. Controls were fed a ground chow for 45 or 90 days postimplantation; experimentals received the same chow for the first 45 days postimplantation and then were fed the same diet supplemented with 1000 mg dilantin/kg for the succeeding 45 days. Calcium content (microgram/mg dry weight) of the implants in the dilantin group was 137 +/- 18.6 versus 214 +/- 34.3 in 90 days control and 79.9 +/- 41.5 in 45 days control (mean +/- SD, P < 0.01 and P < 0.05 respectively, t test). The tibia calcium content of the dilantin group was not significantly different from 90 days control. We conclude that orally administered dilantin inhibits calcification of glutaraldehyde-fixed bovine pericardial implants preferentially. It does not cause decalcification either of implants that have already calcified or of the bones. The anti-calcification effect of dilantin may be associated with its anti-vitamin D effect.

Zone II flexor tendon repair: effects of vitamins A, E, beta-carotene.

Ninety-six adult Leghorn chickens each had the flexor profundus tendon in each middle toe sharply divided in Zone II with immediate repair (pentobarbital, 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 beta-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 postoperative 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. beta-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.

Supplemental vitamin A prevents the tumor-induced defect in wound healing.

To test our hypothesis that supplemental vitamin A would mitigate the impaired healing that occurs in tumor-bearing animals, six groups of C3H mice, eight per group, eating a standard commercial mouse chow ad libitum that supports normal growth, reproduction, and longevity were innoculated with 200,000 C3HBA cells. When tumors measured approximately 6 mm in diameter, the mice were anesthesized and wounded (dorsal skin incisions and subcutaneous polyvinyl alcohol sponges). Twenty-four hours later, two groups (one continued on the chow and the other started on the chow supplemented with 150,000 IU vitamin A/kg chow) underwent local tumor irradiation; two groups, one ingesting the chow, the other the vitamin A supplemented chow, were started on cyclophosphamide therapy; two groups, one ingesting the chow, the other the vitamin A supplemented chow, received neither local tumor irradiation nor cyclophosphamide therapy. An additional two groups ingesting the chow, one group neither innoculated with tumor nor wounded, the other wounded by not innoculated, served as controls. Wound breaking strength and sponge reparative collagen accumulation (assessed by hydroxyproline proline measurement) were used as indicators of wound healing. The mice were killed 12 days after wounding. Tumor presence decreased wound breaking strength and sponge hydroxyproline content; these effects were largely negated by supplemental vitamin A. Local tumor irradiation diminished the adverse effect of tumor on sponge reparative collagen content but to a lesser extent than the supplemental vitamin A. Supplemental vitamin A added to the irradiation effect on healing but irradiation did not add to the vitamin A effect. Cyclophosphamide, a systemic radiomimetic anti-tumor agent, did not alter the impaired wound healing of the tumor-bearing mice. Supplemental vitamin A mitigated the impaired wound healing in the cyclophosphamide-treated tumor-bearing mice. Supplemental vitamin A also moderated the effects of wounding, tumor, and tumor therapies (local irradiation and cyclophosphamide) on the increase in adrenal size, leukopenia, thrombocytopenia, and thymic involution (except the last was not moderated in the cyclophosphamide-treated tumor-bearing rats). The splenic enlargement in the untreated tumor-bearing wounded rats and in those treated with cyclophosphamide was lessened by supplemental vitamin A. We hypothesize that these anti-stress effects of vitamin A underlie, in part, its action in mitigating the impaired wound healing of tumor-bearing mice, including those treated by local irradiation or cyclophosphamide. These findings have implications for the care of patients with malignant tumors.

Effect of supplemental vitamin A on colon anastomotic healing in rats given preoperative irradiation.

We studied the effect of dietary supplementation with vitamin A on the healing of colon anastomoses in irradiated bowel. Rats were divided into two groups. Those in the first group were fed a standard chow diet and those in the second group were fed the same diet supplemented with 150 IU vitamin A/g of chow. The rats were maintained on their respective diets throughout the experiment. After 7 days, half the rats in each group underwent abdominal irradiation (200 rads). Seven days later, all of the rats underwent distal colon division and anastomosis under pentobarbital anesthesia. All rats were killed 7 days postoperatively, the colons excised, and bursting strength and hydroxyproline determinations performed on both the anastomotic segment and a normal proximal segment of adjacent colon. There was a significant decrease in the bursting strength at the colon anastomosis (p less than 0.02) and in the collagen content (p less than 0.02) after preoperative irradiation. This effect was mitigated by dietary vitamin A supplementation.

Protective effect of vitamin E in rats with acute liver injury.

We have previously shown that supplemental vitamin E has a cytoprotective effect in the liver of rats with chronic CCL4-induced liver cirrhosis. In this study, we hypothesized that vitamin E would have a protective effect in acute liver injury induced by D-galactosamine. D-Galactosamine-induced injury has been thought to be due to a synergistic direct toxic effect and presence of intestinal bacteria and/or endotoxins. D-Galactosamine was used to induce acute "hepatitis" (1.5-2.0 g/Kg body weight, ip). Rats were placed on either standard chow or the same chow supplemented with vitamin E (300 mg DL-alpha-tocopherol/Kg diet) and 6 days later were given D-galactosamine. There was significantly improved early (5-day) survival and late (14-day) survival in the vitamin E-supplemented group. The vitamin E beneficial effect was manifested also by decreased liver fat and collagen content and decreased SGPT level. Because bacterial endotoxins have been implicated as playing a role in the pathogenesis of D-galactosamine hepatitis, the same experiment was carried out using germ-free and conventional rats. There was significantly improved survival in both the germ-free and conventional vitamin E-supplemented groups both at 5 and 14 days. There was no significant difference between conventional and germ-free rats with or without vitamin E supplementation. In summary (a) vitamin E improves the early fat and collagen accumulation in the liver, decreases SGPT level, and improves survival in the D-galactosamine experimental model of acute liver injury in both conventional and germ-free rats; and (b) D-galactosamine toxicity is probably not mediated through intestinal bacteria and/or endotoxins.

Prevention of duodenal ulcer formation in the rat by dietary vitamin A supplementation.

We have shown previously that supplemental vitamin A (Vit. A) increases the early inflammatory response to wounding and enhances the collagen content of the intestine of normal and injured rats. We now report the effect of dietary supplementation with Vit. A on the prevention of duodenal ulcer (DU) in rats caused by intragastric administration of cysteamine-HCl. A major way cysteamine-HCl induces DU formation is by enhancing gastric acid secretion. Adult male rats were divided into two groups: (1) rats fed a standard rat Chow (Purina) (15 IU Vit. A/g diet) containing two to three times the National Research Council recommended daily allowance for Vit. A for normal rats; (2) rats fed the same supplemented with 150 IU of Vit. A palmitate per/g Chow. One week later, all rats were given 1 ml of cysteamine-HCl (135 mg) intragastrically. The rats were maintained on their respective diets. Two days later, all rats were killed with ether, the stomach and duodenum excised, and examined for the presence of ulcers. No gastric ulcers were found in either group. There was a statistically significant decrease in the incidence of DUs in the Vit. A-supplemented group when compared to the control group (p less than 0.01) 48 hr following cysteamine-HCl administration; 32% of the Vit. A-supplemented rats developed a DU whereas 74% of rats fed standard Chow had DUs. Most rats had a single DU in the first part of the duodenum, occasionally a second ulcer was noted in the same area. Dietary supplementation with Vit. A had no effect on gastric acid production. In conclusion, our data show that Vit. A dietary supplementation is effective in preventing formation of DUs caused by cysteamine-HCl administration to rats. This effect does not appear to be due to reduction of gastric acid output.

The effect of vitamin E on experimentally induced peritoneal adhesions in mice.

Previous studies in our laboratory demonstrated that dietary supplementation with vitamin A enhances peritoneal adhesion formation in mice. Other researchers have shown that vitamin E antagonizes some effects of vitamin A in various systems, eg, wound healing. We investigated our hypothesis that dietary supplementation with vitamin E would decrease peritoneal adhesion formation. Adult mice were divided into the following groups: group 1, which ate a standard chow containing 65 IU of vitamin E per kilogram diet (twice the National Research Council's recommended daily allowance for normal mice); and group 2, which ate the same chow supplemented with vitamin E at 300 IU/kg diet (a nontoxic level). Following peritoneal ligation, all mice were killed on the tenth postoperative day and their peritoneal cavities examined for the presence and extent of adhesions. There was a statistically significant decrease in the incidence and degree of adhesions in the vitamin E-supplemented animals; these data supported our hypothesis.

Morbidity and mortality reduction by supplemental vitamin A or beta-carotene in CBA mice given total-body gamma-radiation.

Male CBA mice received graded doses (450-750 rad) of total-body gamma-radiation (TBR) from a dual-beam 137Cs irradiator. Commencing directly after TBR, 2 days later, or 6 days later, groups of mice received supplemental vitamin A (Vit A) or beta-carotene (beta-Car), compounds previously found to reduce radiation disease in mice subjected to partial-body X-irradiation. Given directly after TBR, supplemental Vit A decreased mortality, evidenced by increases in the radiation dose required to kill 50% of the mice within 30 days (LD50/30). In one experiment, Vit A increased the LD50/30 from 555 to 620 rad; in another experiment, Vit A increased the dose from 505 to 630 rad. Similarly, in a third experiment, supplemental beta-Car increased the LD50/30 from 510 to 645 rad. Additionally, each compound increased the survival times, even of those mice that died within 30 days. In addition to reduction of mortality and prolongation of survival time, supplemental Vit A moderated weight loss, adrenal gland hyperemia, thymus involution, and lymphopenia--all signs of radiation toxicity. Delaying the supplementation for 2 days after irradiation did not greatly reduce the efficacy of Vit A; however, delaying supplementation for 6 days decreased its effect almost completely.

Supplemental vitamin A prevents the acute radiation-induced defect in wound healing.

Acute radiation injury leads to thymic involution, adrenal enlargement, leukopenia, thrombocytopenia, gastrointestinal ulceration, and impaired wound healing. The authors hypothesized that supplemental vitamin A would mitigate these adverse effects in rats exposed to acute whole-body radiation. This hypothesis was based on previous experiments in their laboratory that showed that supplemental vitamin A is thymotropic for normal rodents and lessens the thymic involution, lymphopenia, and adrenal enlargement that follows stress, trauma, and neoplasia, largely obviates the impaired wound healing induced by the radiomimetic drugs streptozotocin and cyclophosphamide, lessens the systemic response (thymic involution, adrenal enlargement, leukopenia, lymphocytopenia) to local radiation, and shifts the median lethal dose (LD50/30) following whole-body radiation to the right. To test their hypothesis, dorsal skin incisions and subcutaneous implantation of polyvinyl alcohol sponges were performed in anesthetized Sprague-Dawley rats at varying times following sham radiation or varying doses of whole-body radiation (175-850 rad). In each experiment, the control diet [which contains about 18,000 IU vit. A/kg chow (3 X the NRC RDA for normal rats)] was supplemented with 150,000 IU vit. A/kg diet beginning at, before, or after sham radiation and wounding or radiation and wounding. The supplemental vitamin A prevented the impaired wound healing and lessened the weight loss, leukopenia, thrombocytopenia, thymic involution, adrenal enlargement, decrease in splenic weight, and gastric ulceration of the radiated (750-850 rad) wounded rats. This was true whether the supplemental vitamin A was begun before (2 or 4 days) or after (1-2 hours to 4 days) radiation and wounding; the supplemental vitamin A was more effective when started before or up to 2 days after radiation and wounding. The authors believe that prevention of the impaired wound healing following radiation by supplemental vitamin A is due to its enhancing the early inflammatory reaction to wounding, including increasing the number of monocytes and macrophages at the wound site; possible effect on modulating collagenase activity; effect on epithelial cell (and possible mesenchymal cell) differentiation; stimulation of immune responsiveness; and lessening of the adverse effects of radiation.

Effect of supplemental vitamin A on the healing of colon anastomosis.

The effect of dietary supplementation with vitamin A on the healing of colon anastomoses was studied. Fifty adult male Sprague-Dawley rats were divided into two groups: (1) rats fed a standard chow which contains the equivalent of about 15 IU vitamin A/g diet; (2) rats fed the chow supplemented with an additional 150 IU vitamin A/g diet. Rats were prefed for 5 days; on Day 6 under ether anesthesia the colon was divided 1-in. distal to the ileocecal junction and then reanastomosed. The rats were maintained on the above diets for 5 days and killed on the sixth postoperative day with ether and the segment of colon containing the anastomosis was resected. In 15 rats of each group, the breaking strength of the anastomosis was measured. In the remaining 10 rats of each group, the bursting strength of the anastomotic site and a segment of normal distal colon was measured. Samples of colon from the anastomotic site and the normal segment were analyzed for hydroxyproline. There was a significant decrease in hydroxyproline content at the anastomotic site when compared to the normal distal colon segment in each group of rats (P less than 0.01). The hydroxyproline content of both normal colon and the anastomotic site was significantly higher in the vitamin A-supplemented rats than in the control diet rats (P less than 0.01). There was also a significant increase in bursting strength in the vitamin A-supplemented rats both of the anastomotic site (P less than 0.01) and of the normal colon segment (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of vitamin A and beta carotene on intra-abdominal sepsis.

Vitamin A may play a role systemically and locally in controlling intra-abdominal sepsis. Adult male rats were divided into three groups. Group 1 ate a standard rat laboratory chow (not vitamin A deficient), group 2 ate the same chow supplemented with vitamin A, and group 3 ate the chow supplemented with beta carotene. All animals underwent cecal ligation, and the cecum was perforated either with a 27-gauge or an 18-gauge needle. Vitamin A dietary supplementation had a significant protective effect, which was manifested by improved survival in the animals whose cecum was perforated with an 18-gauge needle, prevention of postoperative hypothermia, maintenance of peripheral WBC counts at normal or above-normal values, and better localization of the intra-abdominal inflammatory process. Dietary supplementation with beta carotene had a lesser protective effect.

Regression of C3HBA mouse tumor due to X-ray therapy combined with supplemental beta-carotene or vitamin A.

Male CBA/J mice, ingesting a vitamin A- and beta-carotene-sufficient laboratory chow, were inoculated in a hind limb with 2 X 10(5) C3HBA adenocarcinoma cells. When the mean tumor size was 6.2 mm, the mice were divided randomly into groups; some groups received supplemental vitamin A or beta-carotene, some received 3,000 rad local radiation to the tumor, and others received both radiation and one of the supplements. All mice that received only radiation or one of the dietary supplements died within 3 months. When local irradiation and supplemental vitamin A or beta-carotene were coupled, "complete" tumor regression occurred in every case (12/12), and tumor regrowth in and death of the mice occurred in only 1 of 12 in each of these groups during the succeeding 12 months. One year after irradiation and dietary supplementation, half the surviving mice were switched back to the control chow. During the next year, none of the mice remaining on the vitamin A or beta-carotene supplements developed tumors; however, of 6 mice switched from vitamin A, 5 had tumors that reappeared. In contrast, tumors recurred in only 2 of 6 mice after they were switched from beta-carotene. A second experiment yielded similar results. These results show that both vitamin A and beta-carotene supplementation added remarkably to the antitumor effect of local irradiation. beta-Carotene supplementation produced a greater residual antitumor action than vitamin A supplementation after the supplements were discontinued, which may have been due to greater tissue storage of beta-carotene.

Wound healing and thymotropic effects of arginine: a pituitary mechanism of action.

Supplemental dietary arginine HCl (ARG-HCl) minimizes immediate post-wounding weight loss, accelerates wound healing, and is thymotropic for uninjured and wounded rats. The present experiments were to determine if arginine-pituitary interactions underlie these effects because arginine is a growth hormone secretagogue. Effects of 1% dietary ARG-HCl supplements (0.5% added to a regular commercial rat diet containing 1.8% ARG, 0.5% in drinking water) were studied in (a) hypophysectomized (hypox) rats supplemented with ACTH, L-thyroxine, testosterone propionate, (b) such hypox rats additionally supplemented with bovine growth (hypox + bGH) hormone, (c) intact rats (Int), and (d) intact rats supplemented with growth hormone (Int. bGH). Group (a) hypox rats healed their wounds as rapidly as intact rats (dorsal skin incision breaking strength, accumulation of reparative collagen in sc polyvinyl alcohol sponges). Group (b) hypox, bGH rats showed increased wound breaking strength and accumulation of reparative collagen in the sc sponges to levels significantly greater than those of intact controls; bGH given to intact controls did not affect these indices of wound healing. Supplemental ARG-HCl given intact rats significantly minimized immediate postoperative weight loss, increased wound breaking strength and sponge reparative collagen accumulation, and increased thymic weight. None of these effects of supplemental ARG-HCl were observed in group (a) hypox rats or group (b) hypox + bGH rats. We conclude that an intact hypothalamic-pituitary axis is necessary for these beneficial effects of supplemental ARG-HCl given wounded rats.

Prophylactic and therapeutic actions of supplemental beta-carotene in mice inoculated with C3HBA adenocarcinoma cells: lack of therapeutic action of supplemental ascorbic acid.

Decreased tumor incidence, increased latent period, and increased survival time were observed in C3H/HeJ mice fed supplemental beta-carotene for 3 days and then inoculated with 10(4) C3HBA (syngeneic) tumor cells. In addition, C3H/HeJ, C3H/He, and CBA/J mice, fed supplemental beta-carotene beginning immediately after they were inoculated with 2 X 10(5) C3HBA tumor cells, showed decreased tumor growth and increased survival time. When beta-carotene was fed to mice in which palpable tumors were already present, it similarly slowed tumor growth and extended animal survival time. Ascorbic acid supplementation (5 g/kg diet), introduced into the experiment as a possible synergist for beta-carotene's antitumor action, was without therapeutic action when tested in the presence or absence of beta-carotene supplements. The basal diet, a standard commercial mouse chow, contains more vitamin A than the National Research Council's recommended dietary allowance for normal rodents and supports normal growth, reproduction, and longevity of normal mice. The work reported here is the first demonstration of the antitumor action of beta-carotene in animals with a transplanted tumor.

Moloney murine sarcoma virus tumors in CBA/J mice: chemopreventive and chemotherapeutic actions of supplemental beta-carotene.

Decreased tumor frequency, increased latent period, and increased rate of tumor regression were observed in male inbred CBA/J mice fed supplemental beta-carotene before and/or after they were inoculated with the Moloney sarcoma virus. When beta-carotene feeding was begun after tumors were already present, it markedly increased the rate of tumor regression. beta-Carotene minimized the virus-induced thymus gland involution that accompanies tumor growth, and this action on the thymus gland was believed to underlie part of beta-carotene's antitumor activity. The basal diet, a standard commercial mouse chow containing more vitamin A than the National Research Council recommends as a daily allowance for rodents, supported normal growth, reproduction, and longevity of normal mice. The work reported here is the first demonstration of the antitumor action of beta-carotene in mice inoculated with an oncogenic virus.

Arginine stimulates thymic immune function and ameliorates the obesity and the hyperglycemia of genetically obese mice.

The effect of 6-day dietary arginine supplementation on the weight gain, blood glucose, thymus weight, thymic lymphocyte content, and in vitro thymic lymphocyte immune reactivity was studied in obese (C57BL/6J-OB/)B) and heterozygous lean mice. Control mice were fed a commercial laboratory chow (1.8% arginine content) and drank tap water, while supplemented mice were given 0.5% arginine in the chow and 0.5% arginine solution for drinking. All mice ate and drank ad libitum. Supplemental arginine significantly decreased the weight gain (1.2 g vs. 2.2 g, p less than 0.01) and blood glucose levels (303 mg% vs 236 mg%, p less than 0.02) of the OB/OB mice; no such effects were noted in the lean heterozygotes, all of which had normal blood glucose levels. OB/OB mice had thymus glands which weighed less and contained significantly fewer lymphocytes than their lean littermates. In vitro mitogen-stimulated thymic lymphocyte protein synthetic rates were equal in chow-fed lean and OB/OB mice. In both groups, supplemental arginine significantly increased thymus weight, the number of thymic lymphocytes per gland, and thymic lymphocyte immunoreactivity in vitro. The hormonal secretagogue activity of arginine on the pituitary may explain its beneficial effects on the rate of weight gain, hyperglycemia, and depressed thymic immune function of OB/OB mice.

Chemical debridement of burns: mercaptans.

Experiments were conducted using non-enzymatic chemical agents (with emphasis on certain mercaptans), alone, in conjunction with enzymatic agents and/or other nonenzymatic chemicals for debridement of burns. Both in vitro (rats, pigs, humans) and in vivo (rats, pigs) tests were carried out. N-acetylcysteine, penicillamine and cysteine ethyl ester in low to moderate concentrations accelerate the debriding action of bromelain (an enzymatic preparation from pineapple stems) and in higher concentrations, N-acetylcysteine and penicillamine (cysteine ethyl ester was not tested) cause ready separation of the burn eschar from the underlying tissue before solubilization of the eschar is complete (rat) or has occurred (pig). Debridement of 3 degree burns of rats is complete within 4-6 hours; the take of immediately applied syngeneic skin grafts is complete and permanent. This is first time rapid debridement of 3 degree burns permitting immediate successful skin grafting has been accomplished with known defined chemicals. In pigs there is softening of the 3 degree burn eschar by N-acetylcysteine but little, if any, dissolution of the eschar. However, mechanical separation of the eschar from the underlying tissue is accomplished readily with a wooden throat stick with no bleeding. There is a change in color of the superficial layer of the underlying subcutaneous tissue from yellow-light brown to dark brown-black. The debrided areas begin to granulate promptly. The healing of deep dermal burns of pigs is hastened by the application of N-acetylcysteine for a day (beginning 24 hours after burning) while the healing of moderately deep dermal burns is not modified. Unburned skin is not damaged. There is no apparent systemic toxicity associated with the use of N-acetylcysteine for debridement of 10-15% b.s.a. 3 degree burns of rats or 15-20% b.s.a. 3 degree burns of pigs. Major emphasis has been on N-acetylcysteine because of the potential adverse secondary effect of penicillamine and cysteine ethyl ester; N-acetylcysteine is readily metabolized. The use of a keratolytic agent prior to the application of N-acetylcysteine hastens the latter's action. Sulfamylon and sulfadiazine can be used with N-acetylcysteine without interfering with its debriding action. The effects of the mercaptans are likely due largely to their ability to depolymerize connective tissue proteoglycans and proteins, especially at the interface between living and dead tissue.

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.

Vitamin A inhibits some aspects of systemic disease due to local x-radiation.

We have previously reported that supplemental vitamin A ameliorates the stress response to a wide variety of noxious agents. The present study was carried out to determine how supplemental vitamin A influences the course of radiation sickness in C3H female mice subjected to 3000 R irradiation of one lower hind limb. All mice ingested a chow diet containing about 13,000 units of vitamin A/kg diet (about half as preformed vitamin A and half as beta-carotene) which supports normal growth, development, and reproduction of normal mice. One hundred fifty thousand units of vitamin A/kg chow was added for the vitamin A supplemented mice. All mice ate and drank ad libitum. The supplemental vitamin A feeding was begun either 3 days before radiation or immediately after radiation. There were no significant differences in the effects of these two regimens. The supplemental vitamin A prevented the weight loss, moderated the adrenal hypertrophy, prevented the thymic involution, and lessened the lymphopenia due to radiation. We conclude that supplemental vitamin A has both prophylactic and therapeutic benefits in radiation-induced disease.