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Biomedical subjects

D Pappert

Publications and source records attributed to D Pappert.

41 records · Page 3Linked to original sources
PubMed1993

Time-course and dose-response of nitric oxide inhalation for systemic oxygenation and pulmonary hypertension in patients with adult respiratory distress syndrome.

Inhalation of nitric oxide (NO), an endogenous vasodilator, was recently described to reduce pulmonary vascular resistance, and to improve arterial oxygenation by selective vasodilation of ventilated areas in patients with adult respiratory distress syndrome (ARDS). We describe the time-course and dose-response of initial short-term NO inhalation in 12 patients with ARDS. Enhanced oxygenation was achieved within 1-2 min after starting NO inhalation; after inhalation, baseline conditions were re-achieved within 5-8 min. Effective doses for improvement of oxygenation [baseline: PaO2 = 10.2 +/- 2.5 KPa (76.4 +/- 18.7 mmHg)] were low: ED50 was about 100 ppb--a concentration similar to the atmosphere. NO doses of more than 10 ppm [10 ppm NO: PaO2 = 17.3 +/- 3.3 KPa (129.4 +/- 25.1 mmHg)] re-worsen the arterial oxygenation. The ED50 for reduction of mean pulmonary artery pressure was 2-3 ppm. This indicates that inhalation of NO for improvement of oxygenation in severe ARDS should be performed using lower doses, with lower risk of toxic side effects.

Administration, Inhalation↗
PubMed1993

[Experiences with simultaneous exploration of the bile ducts in surgical therapy of gallstone ileus].

During the last 16 years, 14 patients with a gallstone ileus were treated at our institution. In 11 cases we performed in addition to the enterolithotomy, a cholecystectomy and a resection of the fistula as one-stage repair. Despite the high average age (74.3 years) and the presence of various other serious morbidity in our patient population, we only observed a hospital mortality of 7.1%. Serious postoperative complications, such as sepsis and/or shock were not observed. Utilizing today's advanced anesthesia and proper intensive-care therapy, as well as early operative intervention and safe surgical technique, we believe that enterolithotomy with cholecystectomy and fistula resection as one-stage operation, should primarily be considered before performing enterolithotomy alone.

Aged↗
PubMed1993

Increased blood levels of methyl tert-butyl ether but not of ethyl propionate during instillation with contact gallstone dissolution agents in the pig.

We performed experiments in anesthetized piglets with two cholesterol gallstone solvents, methyl tert-butyl ether and ethyl propionate, to determine whether blood levels of either solvent would increase during gallbladder instillation of these solvents under conditions simulating gallstone dissolution. The solvent was oscillated rapidly in and out of the gallbladder with a computer-controlled syringe pump; intraluminal pressure was set below the leakage pressure, and oscillating volume was set below the leakage volume to decrease loss of solvent into the intestine. Blood levels were measured with gas chromatography. Six piglets received methyl tert-butyl ether, and six piglets received ethyl propionate. During 2 hr of instillation with methyl tert-butyl ether, blood levels increased steadily to concentrations averaging 0.3 ml/L blood at 2 hr; during a 6-hr period of instillation, blood levels rose to above 0.4 ml/L blood. Replacement of methyl tert-butyl ether with saline solution in the gallbladder caused blood levels to decline gradually; plasma levels decreased by half in 90 min. In contrast, when ethyl propionate was infused for 2 or 6 hr, blood levels remained below the detection limit, probably because of high first-pass hepatic extraction. We conclude that, under conditions simulating those likely present in patients undergoing contact dissolution of gallbladder stones, the two solvents differ: Ethyl propionate is removed so rapidly from blood that its levels remain undetectable, whereas methyl tert-butyl ether levels in blood (and, presumably, peripheral tissues) increase continuously.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Radiolabeling of the hydrophobic components of lung surfactant with 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine.

Studies of the metabolism and distribution of lung surfactant are aided by use of radiolabeled surfactant or surfactant components. These studies have often made use of [3H]- or [14C]phosphatidylcholine. Analysis of the lung content of surfactant containing these beta-emitting labels usually requires tissue digestion, use of scintillation fluids, and significant correction for quenching of photon production. Because use of a gamma-emitting isotope would obviate these requirements, we have investigated the use of 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine ([125I]TID), a lipophilic photoactivatable compound, to radiolabel pulmonary surfactant. Our results indicate that, during photoactivation, products of [125I]TID are produced that result in radiolabeling of both the lipid and protein components of extracted porcine surfactant. Separation of radiolabeled surfactant from hydrophobic nonlabelling photolysis products was accomplished by gel chromatography. Exposure of surfactant (34 mumol/ml) to [125I]TID under labeling conditions resulted in incorporation of 45.3 +/- 5.1% of the radiolabel. Incorporation of radiolabel in the various phospholipids of lung surfactant was approximately equivalent. Lipophilic surfactant apoproteins were also radiolabeled. Finally, both in vitro and in vivo testing of radiolabeled surfactant (0.1 microCi/mg) revealed full retention of surface tension lowering ability.

Animals↗