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Biomedical subjects

C W Dunn

Publications and source records attributed to C W Dunn.

11 recordsLinked to original sources
PubMed1995

Alcohol interventions in trauma centers. Current practice and future directions.

Nearly half of all trauma beds are occupied by patients who were injured while under the influence of alcohol. Alcoholism plays such a significant role in trauma that efforts to reduce injury recurrence are unlikely to be successful if it remains untreated. An injury requiring hospitalization creates a unique opportunity to intervene and to motivate patients to alter their drinking behavior, thereby making trauma centers ideal sites to implement an alcohol screening, intervention, and referral program. However, despite emphasis on injury control and prevention, little has been done to incorporate alcohol intervention programs into care of the injured patient. Effective means of intervention exist that are consistent with the time, financial, and staffing constraints of trauma centers, and they should be implemented.

Alcoholism↗
PubMed1993

Role of angiotensin II in neonatal sepsis.

Previous studies in adult animals have indicated that plasma angiotensin converting enzyme (ACE) activity is inhibited by endotoxin. Reduced ACE activity may decrease plasma angiotensin II (AII) levels, contributing to the refractory hypotension we have previously reported in neonatal septic shock. In this study, hemodynamic function, plasma renin activity (PRA), AII, prostacyclin (PGI2), and thromboxane B2 (TxB2) levels were measured in 17-20-day-old dogs before and 1, 2, and 3 hr after endotoxin administration (1 mg/kg, Escherichia coli lipopolysaccharide-B). PRA and AII levels rose significantly 60 min post-endotoxin, returning to baseline values by 180 min; PGI2 and thromboxane B2 levels rose post-endotoxin and remained elevated. Indomethacin or captopril was given by oral gavage 30-35 min before endotoxin. Captopril significantly blunted the rise in PRA and AII, while indomethacin blocked the rise in PGI2 and TxB2. Mean arterial blood pressure and cardiac output fell 60 min after endotoxin challenge without pharmacologic intervention and remained depressed. Our data suggest that renin and AII responses to endotoxin challenge remain intact in the neonatal subject. Maintenance of hemodynamics in indomethacin-pretreated dogs may be due to unopposed stimulation of the peripheral vasculature by AII. Thromboxane B2 in maintenance of vasomotor tone may be minimal in the young.

Angiotensin II↗
PubMed1992

Pheochromocytoma with extension into the inferior vena cava: a case report.

Eleven cases of pheochromocytoma with extension into the inferior vena cava have been reported previously. This report describes a case of a right adrenal pheochromocytoma with extension into the inferior vena cava that was removed with the aid of cardiopulmonary bypass and circulatory arrest.

Adrenal Gland Neoplasms↗
PubMed1991

Effects of relief of biliary obstruction on mononuclear phagocyte system function and cell mediated immunity.

Obstructive jaundice causes depression of immune system function but it is unclear at present how rapidly immune function recovers after relief of biliary obstruction. To address this issue, we studied 218 Sprague-Dawley rats with common bile duct obstruction. Mononuclear phagocyte function, cell mediated immune function, portal-systemic shunt fraction, liver function tests, and liver histology were evaluated in normal (sham) rats, obstructed rats, and at weekly intervals after relief of biliary obstruction. Hepatic uptake of radiolabelled bacteria was 82 per cent in sham rats and 66 per cent in rats 21 days after CBD obstruction (P less than 0.05). Phagocytic activity returned to normal within 7 days after choledochoduodenostomy. Cell mediated immunity, measured by skin graft rejection, was significantly prolonged in the obstructed group (P less than 0.05) but had returned to normal 7 days after biliary diversion. Return of hepatocellular function, as measured by liver function tests, paralleled recovery of immune function. This study demonstrates prompt recovery of the immune system after internal biliary drainage for obstructive jaundice. This finding is in contrast to previous studies that demonstrated persistent immune suppression months after biliary diversion. These data may have implications concerning the usefulness of internal biliary drainage before surgery in patients with obstructive jaundice.

Animals↗
PubMed1991

Contribution of portal systemic shunt to Kupffer cell dysfunction in obstructive jaundice.

Previous animal models of biliary tract obstruction have shown that hepatic phagocytic activity is impaired secondary to Kupffer cell dysfunction. Biliary tract obstruction leads to portal hypertension and an associated portal systemic shunt. Forty-eight Sprague-Dawley rats were studied to determine the contribution of portal systemic shunt to Kupffer cell dysfunction after 21 days of obstructive jaundice or sham operation. Liver uptake of radiolabeled Escherichia coli decreased from 76.1 +/- 1.4% (sham) to 63.1 +/- 6.1% in the common duct ligation (CDL) rats (P less than 0.05); lung uptake increased from 4.0 +/- 0.6% (sham) to 20.2 +/- 4.5 (CDL) (P less than 0.05). Portal systemic shunt, determined using radioactive microspheres, increased from 2.0 +/- 1.0% (sham) to 46.6 +/- 13.1% (CDL), P less than 0.05. Although a significant portal systemic shunt does exist in this 21-day model of obstructive jaundice, it does not appear to be the only mechanism underlying Kupffer cell dysfunction.

Animals↗
PubMed1990

Muramyl dipeptide improves mononuclear phagocyte system function in obstructive jaundice.

Previous studies have demonstrated depression of the mononuclear phagocyte system (MPS) of which the liver comprises 80-85% in animals subjected to 21 days of obstructive jaundice. This study examined the ability of a macrophage stimulant, muramyl dipeptide (MDP), to reverse MPS dysfunction in an obstructive jaundice rat model. Sixty-two male Sprague-Dawley rats underwent sham (n = 29) laparotomy or common duct ligation (CDL) (n = 33) and were studied after 21 days. Animals were injected with 1-3.5 X 10(6) Escherichia coli via a lateral tail vein, and colony-forming units (CFU) of the liver, lung, and spleen were determined at two time intervals: 30 min postinjection to determine the phagocytic activity of MPS (sham, n = 16; CDL, n = 20) and 24 hr postinjection to determine cytotoxic activity of MPS (sham, n = 13; CDL, n = 13). MDP (3 micrograms/g) was administered subcutaneously 24 hr prior to E. coli injection in 6 sham and 10 CDL rats studied at the 30-min time interval and 7 sham and 7 CDL rats studied at the 24-hr time interval. Pretreatment with MDP appeared to reverse the impairment of phagocytic activity in the liver of CDL rats returning it to the level of sham animals (P less than 0.05). However, pretreatment with MDP did not enhance the cytotoxic activity of the MPS as evidenced by higher CFU of E. coli in the liver, lung, and spleen of CDL animals pretreated with MDP as compared to CDL animals that did not receive MDP pretreatment. This increase was only significant in the spleen.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1989

Hypertonic saline-dextran resuscitation of acute canine bile-induced pancreatitis.

In this study, we examined the effects of hypertonic saline-dextran resuscitation (2,400 mOsm of sodium chloride, 6 percent dextran 70) on cardiopulmonary function and extravascular lung water in acute canine pancreatitis. Acute pancreatitis was induced in 21 dogs by injecting 0.5 ml/kg of autologous bile into the pancreatic duct. In 10 dogs, resuscitation was begun with a 4 ml/kg bolus of hypertonic saline-dextran solution; 11 dogs received no bolus. Lactated Ringer's solution was infused in all dogs to maintain mean arterial pressure and cardiac output at baseline values. Pulmonary hypertension accompanied by a significant increase in pulmonary vascular resistance and a decrease in lung blood flow occurred in those dogs resuscitated with lactated Ringer's solution alone. By contrast, dogs in the hypertonic saline-dextran group maintained pulmonary artery pressure and pulmonary vascular resistance at baseline values while nutritive blood flow to the lung decreased progressively. Our data suggest that hypertonic saline-dextran resuscitation effectively restores cardiac function while it significantly reduces fluid requirements, as well as the pulmonary hypertension and pulmonary edema that frequently accompany lactated Ringer's resuscitation of acute pancreatitis.

Acid-Base Equilibrium↗
PubMed1989

Additive effect of an immunomodulator and broad-spectrum antibiotic in fecal peritonitis.

We examined the effect of muramyl dipeptide (3 micrograms/g body weight) and a broad-spectrum antibiotic cefoxitin (15 mg/kg) on survival and systemic bacteremia in rats with peritonitis. When muramyl dipeptide given 24 hours prior to placement of the bacterial inoculum was combined with a single prophylactic dose of cefoxitin, survival was 100 percent (p less than 0.001) and systemic bacteremia at 4 hours postinoculation was significantly decreased. Twenty-four hour pretreatment with either muramyl dipeptide alone or cefoxitin alone was associated with survival rates of 43 percent and 56 percent, respectively. When muramyl dipeptide was given with cefoxitin at the time of administration of the bacterial inoculum, no survival advantage was seen over the use of cefoxitin alone. There were no significant differences among groups in quantitative bacteremia at 24 hours postinoculation or in the number of intraabdominal abscesses. This study clearly demonstrates an additive effect of muramyl dipeptide pretreatment given with a prophylactic dose of cefoxitin in a human fecal peritonitis rat model.

Acetylmuramyl-Alanyl-Isoglutamine↗