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Biomedical subjects

D L Fraker

Publications and source records attributed to D L Fraker.

At least 109 records · Page 6Linked to original sources
PubMed1991

Human recombinant interleukin-1 alpha protection against the lethality of endotoxin and experimental sepsis in mice.

Human recombinant interleukin-1 alpha (IL-1) has a diverse range of physiological activities which may be beneficial or deleterious to the host. Pretreatment with doses of IL-1 has been shown to protect mice against a subsequent lethal bacterial injection; however, the protective effects of a single intravenous (iv) dose of IL-1 have not been well characterized. The current experiments were performed to determine the best dose, timing, and duration of action of a single iv dose of IL-1 against a subsequent lethal challenge with intraperitoneal endotoxin (LPS) or experimental sepsis induced by cecal ligation and puncture (CLP). Female C57B1/6 mice treated with iv IL-1 24 hr prior to 30 mg/kg LPS ip had improved survival compared to saline-treated controls (P less than 0.01). IL-1 was also protective when given 6 to 72 hr, but not 2 or 96 hr, prior to LPS. IL-1 protection against LPS lethality was similar to protection seen with an iv dose of tumor necrosis factor (TNF). After CLP, survival was improved with IL-1 versus saline pretreatment (P = 0.02). Unlike previous work with TNF, no toxicity or lethality was observed at any dose of IL-1 administered. A single iv dose of IL-1 protects against the lethality of LPS and CLP in mice. IL-1 may be a useful treatment strategy in patients at risk for the development of life-threatening sepsis.

Animals↗
PubMed1991

Locally recurrent parathyroid neoplasms as a cause for recurrent and persistent primary hyperparathyroidism.

Between 1982 and 1989, 145 patients underwent operations for persistent or recurrent primary hyperparathyroidism (HPT). At re-exploration, 15 patients (10.3%) were found to have locally recurrent parathyroid tumors (11 patients with adenoma and 4 with carcinoma). These 15 patients had 28 previous operations at outside institutions for HPT. Patients with locally recurrent HPT secondary to adenoma had a longer disease-free interval than patients with locally recurrent carcinoma. At the time of evaluation at the National Institutes of Health (NIH) for recurrent or persistent HPT, each patient was symptomatic and patients with carcinoma had significantly more symptoms and higher serum levels of calcium and parathyroid hormone than patients with adenoma. Locally recurrent parathyroid neoplasm was correctly localized by preoperative testing in 14 of 15 patients. These 15 patients underwent 18 reoperations at NIH for excision of locally recurrent parathyroid tumors. Following the final reoperation (two patients had more than one procedure), each patient had normal serum levels of calcium. In addition each patient remains biochemically cured (based on normal serum calcium level), with a median follow-up interval of 21 months. Local recurrence of parathyroid adenoma comprises a small but significant proportion of cases of recurrent or persistent HPT and can be indistinguishable from parathyroid carcinoma. Findings suggestive of carcinoma include shorter disease-free interval, higher serum levels of calcium and parathyroid hormone, and histologic appearance. Whether the locally recurrent parathyroid neoplasm is benign or malignant, aggressive surgery can control serum levels of calcium in these patients with acceptable rates of morbidity.

Adenoma↗
PubMed1991

Treatment with recombinant human tumor necrosis factor-alpha protects rats against the lethality, hypotension, and hypothermia of gram-negative sepsis.

Tumor necrosis factor (TNF) is a peptide secreted by macrophages in response to endotoxin that can produce many of the changes seen in septic shock. After cecal ligation and puncture (CLP) rats gradually develop tachycardia, hypotension, tachypnea, and hypothermia. At 5 h post-CLP, rats have a peak in serum levels of endotoxin and 60% of rats have blood cultures that grow Gram-negative rods (Escherichia coli and Klebsiella pneumonia). At 20 h post-CLP all rats develop positive blood cultures. Serum levels of TNF are not reproducibly measurable in rats following CLP. Rats undergoing CLP have a 50-80% mortality with deaths usually occurring 24-72 h postinjury. Repetitive (twice daily x 6 d) i.p. injection of sublethal doses of recombinant human TNF-alpha (100 micrograms/kg) to rats undergoing CLP 1 d after the treatment period resulted in a significant reduction in mortality compared to control rats previously unexposed to rTNF (P less than 0.03). Animals treated with rTNF had no hypotension or hypothermia after CLP and regained normal food intake faster than control rats. 12 h after CLP the gene expression for manganous superoxide dismutase (MnSOD), an inducible mitochondrial metalloenzyme responsible for cellular resistance to injury from toxic reactive oxygen species, was higher in livers of rats treated with rTNF suggesting that the TNF treatment augmented expression of this protective enzyme. Unlike MnSOD, expression of the gene for copper-zinc SOD was not affected by CLP or rTNF treatment. The results suggest that prior treatment with recombinant TNF can ameliorate the lethality, hypotension, hypothermia, and anorexia of Gram-negative sepsis in rats and that the mechanism may be related to enhanced hepatic expression of the gene for MnSOD. Repeated administration of recombinant TNF may be a strategy to minimize mortality and morbidity of Gram-negative sepsis.

Animals↗
PubMed1991

Splenectomy for the massively enlarged spleen.

The experience at the National Cancer Institute from 1955 to 1988 with 46 cases of splenectomy for massive splenomegaly (greater than or equal to 1,500 grams) was reviewed to assess the indications, pathology, operative, and postoperative course for this procedure. The median age was 51 years. Thirty-one splenectomies (67.4%) were performed for malignancy (chronic lymphocytic leukemia, 11; chronic myelogenous leukemia, 10; lymphoma, 9; hairy cell leukemia, 1), 11 for myeloid metaplasia, and four for other nonmalignant conditions. Indications for splenectomy included hypersplenism (32 patients), symptoms (6), diagnosis (3), and splenic rupture (3). A midline incision (30 patients) was most commonly used. Median operative time was 2 hours, 50 minutes. Median operative blood loss was 1,300 ml (range, 100 ml-60 units). The splenic artery was ligated initially in 16 patients (34.8%) but did not correlate with blood loss or operating time. The median splenic weight was 2,030 grams (range, 1500-5320 gm). The postoperative complication rate was 39.1 per cent (21 complications in 18 patients). This included infection in 10 patients, bleeding in six patients. Six patients required reoperation (bleeding, 4; abscess, 1; small bowel obstruction, 1 patient). The 30-day operative mortality was 19.6 per cent (9 patients). Excluding operative deaths, 35 patients were available for follow-up evaluation. Twenty-nine patients had improvement in parameters for which splenectomy was indicated. Six patients had no change in their course after splenectomy. These findings indicate that many patients with massive splenomegaly benefit from splenectomy, however, the procedure is associated with a high risk for postoperative morbidity and mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Prolonged survival of tumor-bearing rats with repetitive low-dose recombinant tumor necrosis factor.

Tumor necrosis factor may be a mediator of the syndrome of cancer cachexia. Tachyphylaxis or tolerance to the cachectic effects of recombinant tumor necrosis factor (rTNF) has been previously described. In this study, we investigate whether repetitive exposure to rTNF can induce similar tolerance in tumor-bearing (TB) rats and ameliorate cachexia induced by the tumor. In experiment 1, non-tumor-bearing (NTB) and TB rats were randomized to either escalating low doses of rTNF or saline i.p. twice daily for 9 consecutive days. NTB rats treated with rTNF demonstrated a significant decline in food intake and weight change (P less than 0.00001) but soon developed tolerance to the cachectic effects of rTNF; they consumed significantly more food than on the first day of treatment and had weight change similar to NTB rats treated with saline. TB rats treated with rTNF showed a similar significant decline in food intake and weight change (P less than 0.0001) and also demonstrated similar tolerance to the cachectic effects of rTNF with continued treatment. Following treatment, TB rats that had been treated with rTNF ate significantly more and lost less weight than TB rats that had been treated with saline (P less than 0.00001). rTNF treatment of TB rats also demonstrated antineoplastic activity, as estimated tumor weight of tumors from rats treated with rTNF were significantly less than controls (P = 0.003). The anticachexia and antineoplastic effects of rTNF resulted in prolonged survival of TB rats treated with rTNF compared to control TB rats (P = 0.015). Experiment 2 utilized two different rTNF treatment regimens in TB rats: one group received 12 days of escalating doses of rTNF, and another group received 15 days of rTNF treatment. TB rats treated with rTNF again had a significantly greater food intake (P less than 0.00001) and delayed weight loss (P = 0.0001) posttreatment that was further augmented by additional doses of rTNF. Antineoplastic activity of rTNF was less clear, and overall tumor growth curves were not affected by rTNF treatment. Survival of TB rats treated with rTNF was again significantly increased in a dose-dependent manner (P = 0.006). Repeated administration of low doses of rTNF to TB rats induces mild reduction in tumor growth, tolerance to the cachectic effects of rTNF that results in tolerance to the cachectic effects of tumor, and prolongation of survival.

Animals↗
PubMed1990

Cachectic effects of recombinant human tumor necrosis factor in rats.

Treatment of rats with either intermittent bolus i.v. injections or continuous i.v. infusions of the same sublethal daily dose of tumor necrosis factor (TNF) results in decreased food intake and decreased nitrogen balance compared to saline-treated control rats. After 4 days of treatment, rats treated with intermittent bolus doses of TNF develop tolerance to the nutritional effects and consume normal amounts of food and have nitrogen balance similar to those of saline treated rats. Rats receiving the continuous infusion of TNF do not. Rats treated with both routes of TNF lose more weight than pair fed rats who eat the same mean amount as the continuous TNF treated group. In addition, 56% of rats receiving continuous infusion TNF die during the 8-day experimental period while rats receiving either intermittent bolus TNF or similar food intake (pair fed) do not. Body composition studies of rats that completed the 8 days of treatment indicate that rats receiving either continuous infusion or intermittent bolus TNF have increased percentages of body water and reduced percentages of body solid compared to saline treated control rats. Rats pair fed to the food intake of continuous TNF treated rats also had increased percentages of body water and reduced percentages of body solid, but changes were significantly less than those observed in continuous TNF infused rats. Continuous TNF infusion reduced total body nitrogen and potassium while pair feeding did not reduce potassium and reduced nitrogen to a lesser degree. Pair feeding and continuous TNF infusion reduced total body fat to a similar extent. Twice a day administration of TNF resulted in lesser changes in carcass water, solid, nitrogen, lipid, and potassium than continuous infusion of the same dose of TNF. The results indicate that continuous infusion of TNF can produce anorexia, weight loss, edema, loss of body protein, lipid and cell mass, and lethality which is markedly ameliorated with bolus doses of TNF. The findings are consistent with the hypothesis that slow continuous secretion of sublethal amounts of TNF may mediate cancer cachexia.

Animals↗
PubMed1990

Impact of tolerance on antitumor efficacy of tumor necrosis factor in mice.

Repetitive sublethal doses of tumor necrosis factor (TNF) can induce tolerance or tachyphylaxis to the toxic effects of TNF. Because tumor-bearing (TB) mice are more sensitive to the toxic effects of TNF, this study investigates whether similar tolerance occurs in TB mice and whether it affects the antitumor response of TNF. Nontumor-bearing C3H/Hen mice were treated with twice daily i.p. sublethal escalating doses of human recombinant TNF (2, 2, 3, 3, 4, and 4 micrograms i.p. every 12 h for 6 days) and were challenged 2 days later with a lethal i.v. dose (40 micrograms) of TNF. TNF-pretreated mice had 100% survival as compared to 0% survival in control mice previously treated with saline (P less than 0.01). Tumor-bearing C57BL/6 mice bearing an MCA-106 or MCA-102 sarcoma were treated with an identical TNF-tolerizing regimen (2, 2, 3, 3, 4, and 4 micrograms i.p. every 12 h for 6 days) beginning 3 days following tumor inoculation and were similarly more resistant to a subsequent 100% lethal i.v. treatment dose of TNF than control TB mice. A significantly greater percentage of TNF-pretreated mice bearing the MCA-106 sarcoma survived treatment doses of 8, 12, and 16 micrograms of TNF i.v. than control TB mice. Similarly, a significantly greater percentage of TNF-pretreated mice bearing the MCA-102 sarcoma survived treatment doses of 6 and 9 micrograms of TNF i.v. than control TB mice. However, the ability to administer higher doses of TNF i.v. to TNF-pretreated TB mice did not improve therapeutic efficacy. In mice bearing the MCA-106 tumor the most efficacious treatment responses were seen in animals that were previously naive to TNF, and treatment toxicity (lethality) correlated directly with antitumor efficacy such that larger treatment doses of TNF in tolerant mice resulted in similar antitumor effects as smaller treatment doses in control TB mice. In mice bearing the MCA-102 tumor, equitoxic treatment doses of TNF produced similar antitumor effects in both control and tolerant TB mice. There were no differences in cure rate for TNF-tolerant or control TB mice bearing either tumor. The results suggest that TNF tolerance occurs in TB mice and reduces the toxicity as well as the therapeutic efficacy of TNF.

Animals↗
PubMed1990

Localization and surgical treatment of occult insulinomas.

Management of patients with biochemical evidence of insulinoma and negative preoperative imaging studies (occult) tumors is controversial, varying from primarily medical management to aggressive, blind nearly total pancreatectomy to extirpate the tumor. Since 1982, 12 consecutive patients with occult insulinoma underwent preoperative portal venous sampling (PVS) for insulin followed by surgical exploration with intraoperative ultrasound (IOUS). Eleven of twelve patients (92%) had insulinoma removed and were cured. Portal venous sampling correctly predicted the location of the insulinoma in 9 patients (75%) and that no tumor would be found in another patient. A fourfold insulin gradient in the pancreatic tail of one patient correctly predicted that a distal pancreatectomy would remove the insulinoma despite the fact that neither palpation nor IOUS identified any tumor. Intraoperative ultrasound was the single best method to identify occult tumors because it correctly identified 10 of 11 insulinomas that were found, including five pancreatic head tumors that were not palpable. Palpation identified five insulinomas. Of the 10 tumors that were identified during operation by palpation or ultrasound, IOUS identified significantly more (100% versus 50%, p = 0.03) and guided the successful enucleation of each. The results support the strategy of preoperative PVS and operation with IOUS to localize and remove insulinoma in patients with occult tumors. Most tumors (75%) will be correctly localized to a specific pancreatic region by preoperative PVS and identified by IOUS (83%), allowing simple enucleation and biochemical correction of hypoglycemia. Morbid blind pancreatic resections are no longer indicated and long-term medical management of hypoglycemia should be reserved for the occasional patient (8%) who fails preoperative PVS and operation guided by IOUS.

Adult↗
PubMed1989

Passive immunization against tumor necrosis factor partially abrogates interleukin 2 toxicity.

Passive immunization against TNF allowed non-tumor-bearing C3H/HEN mice and tumor-bearing C57BL/6 mice to tolerate significantly more doses of IL-2 before death (p less than 0.005 and p less than 0.001, respectively). The antitumor effect of IL-2 against both 3-d and 10-d pulmonary metastases was maintained in mice treated concurrently with neutralizing antibodies to TNF. In one experiment with 10-d pulmonary metastases, increased administration of IL-2 made possible by passive immunization against TNF significantly improved the antitumor response compared to equitoxic doses of IL-2 and control antibody. The results indicate that TNF is a mediator of IL-2 toxicity but contributes minimally to the antitumor effects of IL-2. Strategies to inhibit TNF may improve the therapeutic index of IL-2 as a neoplastic agent.

Animals↗
PubMed1989

Cachectin activity in the serum of cachectic, tumor-bearing rats.

Cachectin/tumor necrosis factor has been postulated to be a possible mediator of cancer cachexia. Using a sensitive bioassay, we attempted to detect circulating cachectin activity in the serum of sarcoma-bearing rats and to correlate levels with measurements of cachexia and the extent of disease. In addition, we resected the tumor to determine the time course of reversal of cachexia and the disappearance of cachectin activity in the serum. Circulating cachectin activity was not detectable in the serum of non-tumor-bearing rats or in tumor-bearing rats until 28 days after implantation. With evidence of food intake and body weight decline, cachectin activity became detectable in the serum and levels increased as cachexia and tumor burden increased. Serum cachectin activity levels correlated directly with tumor burden and inversely with food intake and body weight change. After resection of the tumor, food intake and body weight increased and serum cachectin activity became undetectable. Serum triglyceride levels were higher in cachectic tumor-bearing rats than in pair-fed non-tumor-bearing controls, and levels decreased after tumor resection as cachectin activity decreased. The results suggest that cachectin is a humoral mediator of cachexia in this rat-tumor model.

Animals↗
PubMed1989

Altered macrophage activity and tumor necrosis factor: tumor necrosis and host cachexia.

Tumor necrosis factor (TNF) may be a mediator of cancer cachexia. This study evaluates the activity of macrophages from non-tumor-bearing (NTB) and tumor-bearing (TB) rats by measuring TNF production in response to endotoxin (LPS), both in vitro and in vivo, and correlates macrophage activity with tumor burden and parameters of host cachexia. Isolated macrophages from rats with small tumors, normal food intake, and weight gain secreted more TNF in response to 10 micrograms/ml LPS than macrophages from control NTB rats and behaved similar to activated macrophages from rats previously treated with thioglycollate. Heightened macrophage activity (increased production of TNF in response to LPS) in TB rats increased further as tumor burden increased (r = 0.889, P less than 0.001). Tumor resection reversed the heightened macrophage activity as LPS-induced levels of TNF secreted by macrophages from resected TB rats were not different from those of sham-operated NTB control rats. TB rats had serum levels of TNF activity following an iv bolus of 10 mg/kg LPS greater than those of NTB rats (P less than 0.05). In addition, peak serum TNF activity levels following iv LPS increased directly as tumor burden increased (r = 0.91, P less than 0.001). Supernatants from tissue cultures of the tumor (MCA sarcoma) failed to have any detectable TNF activity. However, large tumors in vivo had increased amounts of necrosis (78 +/- 8%), increased numbers of infiltrating macrophages, and increased levels of TNF (480 +/- 68 U/ml) compared to small tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Reversal of the toxic effects of cachectin by concurrent insulin administration.

Rats treated with recombinant human tumor necrosis factor-cachectin, 100 micrograms/kg ip twice daily for 5 consecutive days, had a 56% decrease in food intake, a 54% decrease in nitrogen balance, and a 23-g decrease in body weight gain vs. saline-treated controls. Concurrent neutral protamine hagedorn insulin administration of 2 U/100 g sc twice daily reversed all of these changes to control levels without causing any treatment deaths. The improvement seen with insulin was dose independent. Five days of cachectin treatment caused a severe interstitial pneumonitis, periportal inflammation in the liver, and an increase in wet organ weight in the heart, lungs, kidney, and spleen. Concurrent insulin treatment led to near total reversal of these histopathologic changes. Cachectin treatment did not significantly change blood glucose levels from control values of 130-140 mg/dl, but insulin plus cachectin caused a significant decrease in blood glucose from 1 through 12 h after injection. Administration of high-dose insulin can near totally reverse the nutritional and histopathologic toxicity of sublethal doses of cachectin in rats.

Animals↗
PubMed1989

The role of surgery in the management of islet cell tumors.

Endocrine tumors of the pancreas are rare disorders that can cause life-threatening symptoms related to the excessive hormonal secretion and the malignant nature of the neoplasm. In addition, these neoplasms can present as part of familial endocrinopathy syndromes, especially multiple endocrine neoplasia type 1 (MEN-1). The initial step in evaluation of a patient with an islet cell tumor is definitive diagnosis of the hormonal syndrome that usually can be achieved biochemically. The next step is to reverse the life-threatening hormonal syndrome medically to allow radiographic localization of the islet cell neoplasm and to prepare the patient for elective surgery. In general, the goal of surgery is to accurately stage the extent of disease and to totally resect the tumor resulting in complete correction of the excessive hormonal condition and freedom from malignant progression of the tumor. Resection of the neoplasm should encompass metastatic disease in select individuals in whom complete or nearly complete resection can be achieved. Surgery must be performed with acceptable morbidity and mortality because the medical management of the excessive hormonal secretion in most patients is adequate and the progression rate of malignant islet cell carcinomas is usually slow. Patients with MEN-1 should be identified during evaluation by careful history and should be managed differently. These patients always have multiple islet cell tumors and may have malignant islet cell carcinomas. Large (3 cm) imageable pancreatic neoplasms in patients with MEN-1 should be resected because nearly 50 per cent are malignant. Zollinger-Ellison syndrome in patients with MEN-1 and primary hyperparathyroidism is best managed initially by surgery directed at the hyperparathyroidism. It may be impossible to correct the biochemical abnormalities of Zollinger-Ellison syndrome by islet cell tumor resection in patients with MEN-1. However, insulinoma or VIPoma syndromes can often be corrected by islet cell tumor resection. Portal venous sampling for hormones may be helpful in determining what hormone a specific tumor is secreting.

Adenoma, Islet Cell↗
PubMed1989

Prevention and treatment of endotoxin and sepsis lethality with recombinant human tumor necrosis factor.

Tumor necrosis factor (TNF) is a macrophage product released in response to endotoxin that has been implicated as a cause of the toxicity and lethality seen in septic shock. Previous work suggests that tolerance to nutritional and lethal effects of TNF occur after repeated exposure to recombinant tumor necrosis factor (rTNF). In this study pretreatment of rats with a single low intravenous dose of rTNF prevented subsequent death when a lethal dose of rTNF was administered 24 hours later (tolerance or tachyphylaxis). Pretreatment with rTNF also afforded protection against the lethal effects of either endotoxin or cecal ligation and puncture when rats were challenged 24 hours later. Recombinant TNF injected 6 hours after cecal ligation and puncture initially resulted in a significant survival advantage for treated animals. When this experiment was repeated with a different lot of rTNF, however, the therapeutic benefit of rTNF was not obtained until the dose was decreased by a factor of 10. Protection against the lethal effects of cecal ligation and puncture did not occur when rTNF was given 24 hours after the insult. A single low dose of rTNF can result in tolerance or tachyphylaxis to the lethal effects of TNF. The results suggest that the early administration of low-dose rTNF may be useful in the prevention and treatment of the lethality of sepsis.

Animals↗
PubMed1988

Cachectin/tumor necrosis factor: a possible mediator of cancer anorexia in the rat.

Cachectin/tumor necrosis factor (TNF) is a macrophage product which may have a role in cancer cachexia. Recombinant human cachectin/TNF (Cetus Corporation) was administered i.p. twice daily to male F344 rats at varying, nonlethal dosages for either 5 or 10 days, and daily rat food intake and body weight were measured. There was a dose-dependent cachectin/TNF-induced decline in food intake and body weight gain over the treatment period. However, after 1 day rats became tolerant to these effects and increased food intake and gained body weight despite receiving cachectin/TNF. Rats were subsequently inoculated with a transplantable methylcholanthrene-induced sarcoma, and survival was measured. Rats previously treated with high-dose (either 100 or 200 micrograms/kg/day) cachectin/TNF survived significantly longer following tumor inoculation than did control rats given saline or rats given 10 micrograms/kg/day of cachectin/TNF. Analysis of tumor growth curves and tumor weight indicated that high-dose cachectin pretreatment did not retard tumor growth. Analysis of food intake and tumor burden following tumor inoculation indicated that high-dose cachectin pretreatment decreased the reduction in food intake associated with progressive tumor growth and allowed rats to withstand a greater tumor burden at death. Rats immunized with low-dose human cachectin/TNF developed high IgG titers against human TNF, but failed to demonstrate the same protection against a methylcholanthrene-induced tumor challenge as rats made tolerant with repetitive twice daily high-dose cachectin/TNF. The observation of reduced cancer-associated anorexia and increased survival of tumor-bearing rats associated with previous tolerance to exogenous cachectin/TNF strengthens the contention that endogenously produced cachectin may be a factor in the pathogenesis of cancer anorexia in the tumor-bearing rat. The mechanism of this tolerance is unclear but does not appear to be a humoral immune response.

Animals↗
PubMed1988

Tolerance to tumor necrosis factor in rats and the relationship to endotoxin tolerance and toxicity.

Treatment of rats with recombinant human TNF initially causes a marked decrease in food intake, a loss of body weight, and a negative nitrogen balance. These alterations normalize with continued twice daily intraperitoneal injections of the same dose. Rats tolerized to TNF in this manner are refractory to a lethal dose of TNF. Also, TNF-pretreated and -tolerized rats have prolonged survival and reversed histopathologic changes after injection of a lethal dose of endotoxin compared with control animals. The TNF-tolerant state is dependent on the dose of TNF used and the length of TNF pretreatment. TNF-induced tolerance is relatively short lived, being present 2-4 d after TNF pretreatment and dissipating by 2 wk. Rats made tolerant to endotoxin are also tolerant to a lethal dose of TNF. A bidirectional crossreacting tolerance exists between TNF and endotoxin. The mechanism of TNF tolerance is unclear, but it does not appear to be due to a humoral immune response or a perturbation of the uptake and clearance of injected TNF.

Animals↗
PubMed1988

A prospective study of perioperative and postoperative control of acid hypersecretion in patients with Zollinger-Ellison syndrome undergoing gastrinoma resection.

Fifty-five consecutive patients with Zollinger-Ellison syndrome who underwent exploratory laparotomies for gastrinoma resection were evaluated prospectively to determine the effect of gastrinoma resection on acid secretion and to establish criteria for safe and effective perioperative management of gastric acid hypersecretion. In 15 patients (27%) no tumor was found and postoperative serum gastrin, basal acid output (BAO), and maximal acid output (MAO) were unchanged. Twenty-one patients (38%) had gastrinomas resected and were biochemically cured. Median fasting gastrin, median delta secretin, mean BAO, and mean MAO decreased 89%, 94%, 80%, and 43%, respectively, at 3-month follow-up in these patients. In 19 patients gastrinomas were resected, but patients were not cured, and median fasting gastrin, median delta secretin, mean BAO, and mean MAO decreased 47%, 10%, 26%, and 25%, respectively. Forty percent of patients with gastrinoma resected and cured and 81% of patients with gastrinoma resected but not cured continued to hypersecrete acid (BAO greater than 10 mEq/hr) at 3- to 6-month follow-up. Acid control was managed perioperatively during gastrinoma resection by continuous intravenous infusion of H2 receptor antagonists at a dose established by preoperative titration to decrease acid output to less than 10 mEq/hr. Thirty patients were treated with cimetidine at a mean dose of 3.2 mg/kg/hr for a mean of 13.8 days. Twenty-one patients were treated with ranitidine at a mean dose of 1.1 mg/kg/hr for a mean of 8 days. No patients suffered any complications related to acid hypersecretion or side effects of the H2 antagonists. Patients undergoing gastrinoma resection can be managed safely by continuous infusion of H2 antagonists. Successful gastrinoma resection can reduce acid output, but even 40% of biochemically cured patients will continue to hypersecrete acid at short-term follow-up and will require continuation of antisecretory medication.

Adult↗