Management of pineal non-germinoma germ cell tumor with residual teratoma and normal alpha-fetoprotein.

A 16-year-old white male presented with multiple abnormal extraocular movements secondary to an enhancing pineal tumor. Subtotal resection of the lesion revealed a mixed malignant germ cell tumor. The preoperative serum alpha-fetoprotein (AFP) was markedly elevated at 155 IU/L. The patient subsequently received radiotherapy and adjuvant chemotherapy consisting of cisplatin rotating monthly with vincristine and cyclophosphamide, with dramatic tumor regression and return of AFP to normal. Eighteen months later the persistence of a substantial tumor mass despite a normal AFP raised concern for residual active tumor. Histological examination of the resected lesion revealed benign teratoma and fibrous tissue. Repeat management of mixed malignant germ cell tumors, which demonstrate a persistent mass following an initial response to treatment.

Cisterna magna microdialysis of 22Na to evaluate ion transport and cerebrospinal fluid dynamics.

Microdialysis is used in vivo for measuring compounds in brain interstitial fluid. The authors describe another application of this technique to the central nervous system, namely microprobe dialysis in the cisterna magna to study the dynamics of ion transport and cerebrospinal fluid (CSF) formation in the rat. The choroid plexus is the major source of CSF, which is produced by active transport of Na from blood into the cerebral ventricles. Formation of CSF is directly proportional to the blood-to-CSF transport of Na. By injecting 22Na into the systemic circulation and quantifying its movement into CSF by microdialysis, one can reliably estimate alterations in the rate of CSF formation. The sensitivity of this system was determined by administering acetazolamide, a standard inhibitor of CSF production. Because acetazolamide is known to decrease CSF formation by 40% to 50%, the cisternal microdialysis system in animals treated with this drug should detect a corresponding decrease in the amount of 22Na dialyzed. This hypothesis is supported by the 22Na uptake curves for control versus treated animals: that is, by the acetazolamide-induced average diminution of about 45% in both the rate and extent of tracer accession to dialysate. Bumetanide, a loop diuretic, reduced by 30% the 22Na entry into dialysate. Microprobe dialysis of fluid in the cisterna magna is thus a minimally invasive and economical method for evaluating effects of drugs and hormones on the choroid plexus-CSF system.

Effects of bombesin on fasting bile formation.

Adult dogs were previously prepared by cholecystectomy, ligation of the lesser pancreatic duct, and insertion of cannulae into the duodenum and stomach. After a 2-week period of postoperative recovery and an overnight fast, bile ducts were cannulated, gastric cannulae placed to open drainage and sodium taurocholate 500 mg hr-1 was administered to replace bile acids lost from the interrupted enterohepatic circuit. Bombesin was infused IV for 1 hour over the dose range, 0.625-10 ng kg-1 min-1. In control experiments 0.15 N NaCl was infused. Bombesin caused a significant increase in fasting bile flow, 3.0 +/- 0.2 ml/15 min to 4.2 +/- 0.3 ml/15 min (40%). Bile acid and phospholipid outputs were unchanged during bombesin. Bile cholesterol output decreased significantly during bombesin, 1029 +/- 142 micrograms/15 min to 856 +/- 109 micrograms/15 min (17%). The increase in bile flow was linearly related to the logarithm of the bombesin dose. In dogs with pyloric occlusion, to prevent acid from reaching the duodenum, bombesin increased bile flow and bicarbonate output but had no effect on 14C erythritol biliary clearance. Bombesin stimulated ductular bile acid independent bile formation in a dose-dependent manner. Bombesin also inhibited bile cholesterol output.

Effects of serotonin on canine bile formation.

Long-term studies were performed on dogs previously prepared by cholecystectomy, ligation of the lesser pancreatic duct, and insertion of a duodenal cannula. After an overnight fast, bile duct cannulation and stabilization of bile flow with intravenous (IV) sodium taurocholate, serotonin, 10 micrograms/kg/min, or 0.15 N NaCl was infused. In similar experiments, animals were fed a standard meal, and serotonin or 0.15 N NaCl was infused IV beginning simultaneously with or 30 minutes after the meal. Short-term experiments were performed on dogs anesthetized with pentobarbital and prepared by abdominal evisceration, cholecystectomy, and bile duct cannulation. Serotonin caused significant inhibition of fasting bile formation (3.8 +/- 0.3 ml/15 min to 3.2 +/- 0.3 ml/15 min), meal-stimulated choleresis (4.0 +/- 0.3 ml/15 min to 3.5 +/- 0.3 ml/15 min), and bile flow in eviscerated animals (1.6 +/- 0.1 ml/15 min to 1.1 +/- 0.2 ml/15 min). Bile acid output and 14C erythritol clearance were stable while bile bicarbonate output was decreased during serotonin infusion. A similar inhibitory effect was demonstrated with serotonin, 5 micrograms/kg/min, but the inhibition was not statistically significant with 2.5 micrograms/kg/min. These studies demonstrate that serotonin inhibits bile acid-independent bile formation, possibly at the ductular level, and the inhibition occurs independently of endogenous gastrointestinal tract hormone secretion.

Apoprotein C effect on triglyceride transport in tandem-perfused rat hind end and liver.

The metabolism of double-labeled triglyceride in a synthetic emulsion was defined in an in vitro perfusion system of rat hind end and liver described previously [Am. J. Physiol. 245 (Gastrointest. Liver Physiol. 8): G106-G112, 1983]. The metabolism of [3H]glycerol-[14C]triolein was defined in the absence of added apoproteins and with additions of human CII and both CII and CIII. Without apoprotein, a pronounced lipolysis of the triglyceride was recognized by high concentrations of radiolabeled glycerol and free fatty acid in the perfusate. The removal of an aliquot of hind-end venous effluent 5 min after adding the labeled triglyceride emulsion to the arterial inflow demonstrated a brisk lipolysis of the substrate when incubated outside the perfusion system. The addition of CII protein to the emulsion before its introduction into the tandem system eliminated perfusate lipolysis, both within the perfusion system and in incubations of aliquots withdrawn from the system. Intravascular lipolysis was not seen with triglyceride emulsions containing both CII and CIH or when an aliquot of hind-end venous effluent was incubated with triglycerides that had not been exposed to the perfusion system. The intravascular lipolysis observed for the [14C]triglyceride added to the tandem system without apoproteins was associated with relatively greater recoveries of 14C-fatty acyl in liver, fat, and muscle and relatively greater recoveries of 14CO2 than when CII alone or both CII and CIII were added with the triglyceride. The addition of CIII to CII in a 1:1 molar ratio increased the recovery of 14C-fatty acyl in muscle and the recovery as 14CO2.(ABSTRACT TRUNCATED AT 250 WORDS)