Richard L. Gamelli

Treatment of intra-abdominal infection with granulocyte colony-stimulating factor.

Polymicrobial infection is a significant cause of mortality in critically ill patients. Antibiotics and surgical intervention are useful but limited in their effectiveness for combating mixed infections. New prophylactic and therapeutic approaches are required to improve survival in critically ill patients. Neutrophils are a known primary host defense mechanism against bacterial infection. We evaluated the use of a neutrophil growth factor, recombinant human granulocyte colony-stimulating factor (G-CSF), to improve survival in a well-established sepsis model, cecal ligation and puncture (CLP). When administered beginning 4 days before CLP with injections continuing for 14 days after CLP, mice that received 10, 100, or 1000 ng of G-CSF had significantly improved survival compared with the control group. When treatment began at the time of CLP and continued for 7 days after CLP, G-CSF treatment resulted in a dose-dependent improvement in survival in groups that received 100, 500, or 1000 ng. The interaction of G-CSF and conventional antimicrobial therapy was evaluated by administration of G-CSF plus gentamicin. Mice received 100 ng of G-CSF beginning on day 1 before CLP with injections continuing for 3 days after CLP. Gentamicin-treated mice received a single 15 mg/kg injection of gentamicin at the time of CLP. Mice that received G-CSF alone or gentamicin alone had significantly improved survival compared with controls. Mice that received G-CSF plus gentamicin had improved survival compared with control mice and compared with mice that received G-CSF alone but not compared with mice that received gentamicin alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental tumors and aging: local factors that may account for the observed age advantage in the B16 murine melanoma model☆

In the B16 murine melanoma model tumor growth has been shown to be slower in animals of advanced age. One feature associated with this slower growth has been prominent fibrosis demonstrated in biopsies of the tumor in older animals. We have performed experiments to examine the fibrotic response in young and old mice. In non-tumor bearing animals the capacity to regain skin strength after surgical laceration and healing by primary intention was greater in old mice. Histologic preparations suggested a more prominent fibrosis at the wound site. The animals who were injected subcutaneously with B16 melanoma and treated with L 3,4-dehydroproline (an inhibitor of collagen synthesis) local tumor growth was significantly enhanced only for the old animals. Although this inhibition of collagen synthesis produced a differential growth enhancement, there remained a significant difference in tumor volume between young and old animals. We conclude that fibrogenesis is an important host defense for containing local tumor growth and that this mechanism is preserved if not enhanced in mice of advanced age. Nevertheless other factors are needed to account completely for the observed age-advantage in the B16 melanoma model.

Effects of fluid resuscitation on cardiac dysfunction following thermal injury

To test the hypothesis that low cardiac output in burns is secondary to hypovolemia, the effects of resuscitation on isovolumic contracting rat heart following a full-thickness burn were studied. Sprague-Dawley rats were randomly assigned into three groups: (1) Sham burn, (2) 30% body surface area burn nonresuscitated, (3) 30% body surface area burn with 15 cc Ringers lactate/180 g body wt ip at the time of burn resuscitated. Twenty hours postburn, the hearts were mounted on a Lagendorff perfusion apparatus. A balloon-tipped catheter placed in the left ventricle measured pressure and dp/dt. Coronary flow was determined. Myocardial samples for ATP and water were obtained. Left ventricular function was evaluated by recording peak systolic pressure, end diastolic pressure, and maximum +/- dp/dt while balloon volume was increased to 0.3 cc. Results are with end diastolic volume constant at 0.15 cc. Compared to sham burn, burn nonresuscitated generated lower peak systolic pressure +/- dp/dt and higher end diastolic pressure while hearts from burn resuscitated generated the same as sham burn. Coronary flow and tissue water content was similar in all. ATP content was lower in burn nonresuscitated. Our data support that impaired systolic and diastolic function in burn nonresuscitated hearts is associated with lower ATP levels not seen in burn resuscitated and reperfusion of burn nonresuscitated hearts does not reverse the myocardial depressant effect.

Immunomodulators and wound healing

The synthetic immunomodulators muramyl dipeptide (MDP), thymopoietin pentapeptide (TP5), and CP-46,665 were examined for their effects on wound healing in mice. We found no differences in wound disruption strength between immunomodulator-treated animals and saline controls on days 11, 14, and 21. The only exception was with high-dose CP-46,665, which produced weakened wounds on day 14 (p less than 0.05) and 21 (p less than 0.01). CP-46,665 was further studied by injecting high and low doses 48 hours before or after wounding. No differences were seen for these groups compared to controls at 11 and 21 days. Finally, to simulate a common clinical situation, mice were subjected to a 10% total body surface area (TBSA) burn to the right paraspinal region. Twenty-four hours later, a left paraspinal incision was performed with simultaneous injection of saline, Corynebacterium parvum (C. parvum), or low-dose TP-5, MDP, or CP-46,665. At 11 days, no detriment in wound healing was found for burned control or any of the immunomodulator-treated animals except in the C. parvum-treated mice, with significantly weakened skin strips (p less than 0.001). While C. parvum may be detrimental to wound healing, the synthetic modulators tested appear to have little effect on wound healing.

Refeeding differentially affects tumor and host cell proliferation

Tumor and host tissue DNA synthesis in C3H female mice with MA16/C tumors were examined for the effects of starvation and refeeding. Animals with subcutaneously implanted tumors were randomized to either regular diet or starvation for 48 hr followed by refeeding for 6, 12, 24, 48, or 72 hr. With starvation, both tumor and host tissues demonstrated a decrease in DNA synthetic activity. After refeeding, resumption in DNA tumor synthesis preceded that of host tissues and was greatest within the first 6-12 hr. Host tissue DNA synthetic activity resumed at different times in the various tissues examined with bone marrow being earlier than spleen or liver. The differential time course between induction of tumor and host DNA synthesis could allow a more precise modeling in studies dealing with the interaction of nutritional repletion and antitumor therapy.

Symptomatic biliary obstruction associated with juxtapapillary duodenal diverticulum

SummaryWe describe a 56-year-old woman with symptomatic biliary obstruction associated with a duodenal diverticulum. Cholangiography revealed a dilated common bile duct with prominent distal obstruction of unusual configuration. Liver function tests were normal. Pain has not recurred since choledochojejunostomy.

Inhibition of wound healing by Corynebacterium parvum

Abstract Corynebacterium parvum (C. parvum) , an immunostimulant, was examined for its effects on wound healing in mice. Animals injected intraperitoneally with C. parvum , 1400 μg 48 hr prior to wounding had significantly decreased wound strength at 5, 7, 11, 14, and 21 days after wounding compared to saline-injected controls ( P P C. parvum at 48 or 2 hr before wounding, synchronous with wounding and 2 or 48 hr after wounding had significantly decreased wound disruption strength of 11-day-old wounds ( P P C. parvum -treated animals were consistently weaker than similarly treated wound strips from controls ( P P C. parvum -treated animals revealed decreased amounts of wound collagen and increased inflammatory reaction compared to saline-injected animals. While C. parvum can improve survival following injury or septic challenge, the potential for marked alterations in wound healing may limit its clinical application in surgical and trauma patients.

Do nutritional alterations contribute to adriamycin-induced impaired wound healing?

Adriamycin-impaired wound healing in mice was found to be related to the degree of weight loss which in turn was dependent on the dose given. Treated animals had an initial decrease in food consumption that correlated with initial weight loss. After approximately 7 days, food consumption returned to normal but the weight loss persisted. Both Adriamycin-treated mice and animals pair fed the amount of food consumed by drug-treated mice had wounds significantly weaker than control animals at 7 and 11 days. The Adriamycin-treated animals had 11-day wound strengths equal to or weaker than the pair fed group. By Day 14, the pair fed animals had wounds similar to those of controls but the Adriamycin-treated animals remained significantly weaker than the other groups. We feel that initially Adriamycin produces a short-term nutritional deficit that contributes to early wound healing impairment. Later, the toxicity of the drug predominates in altering wound repair.

Nutritional modulation of tumor growth

The relationship between tumor and host tissue proliferation as a function of protein calorie deficiency followed by balanced nutritional repletion was examined in a series of C3H female mice with MA16/C tumors. Tumor and host tissue DNA synthesis was determined in animals with subcutaneously implanted tumors who were randomized to either regular diet (RD) or a totally protein-free diet (PFD) for 5 days followed by refeeding for 4, 8, 12, 24, 36, 48, or 72 hr. Animals maintained on a protein-free diet demonstrated a decrease in DNA synthetic activity in both tumor and host tissues. Following refeeding of a regular diet to animals fed the protein-free diet, resumption of DNA synthesis in tumor preceded that of liver and was greatest by four hours of refeeding. In the liver, return of DNA synthetic activity was delayed but exceeded control levels by 36 hr. Compared to our previous studies examining the effects of starvation, we found that an isocaloric protein-free diet caused a smaller decrease in tumor DNA synthetic activity and an earlier resumption in tumor proliferation with the reinstitution of a normal protein diet. These studies suggest a nutrient-specific response for tumor and host tissues with nutritional deprivation and refeeding.

The effect of disulfiram on cyclophosphamide-mediated myeloid toxicity

SummaryWe have previously shown that disulfiram (DSF) blocks the urotoxicity of cyclophosphamide (CYT) in mice and increases the oncolytic effect of CYT in the L1210 murine leukemia. However, mice treated with CYT and DSF appeared to have longer-lasting neutropenia than animals treated with CYT alone. To determine whether DSF uroprotection of CYT-treated mice was associated with increased myeloid toxicity, we examined the effects of DSF plus CYT treatment on the bone marrow granulocyte/macrophage progenitor cell (GM-CFC). Marrow cellularity and GM-CFC numbers were analyzed at 1, 2 and 3 days after injection of CYT (62.5 or 125 mg/kg) or CYT plus DSF (200 mg/kg). CYT alone caused a decrease in total marrow cellularity varying from 20% to 50% of control. Animals given CYT plus DSF had a somewhat greater decrease in total marrow cellularity than those treated with CYT alone. However, in mice treated with CYT plus DSF, the GM-CFC were relatively well preserved and the recovery of the GM-CFC was not prolonged by DSF. It appears from these studies that the acute toxic effect of CYT on the granulocyte/macrophage progenitor cells is not enhanced by DSF.