Cardiopulmonary bypass with low systemic heparinization: an experimental study.
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Animals↗
Biomedical subjects
P Pei
Publications and source records attributed to P Pei.
Isotachophoretic determination of urea-ammonium in plasma: a candidate reference method.
Separation and determination of sample constituents by capillary isotachophoresis are entirely based on physical phenomena. The method has therefore been proposed as a universal reference method for ionic constituents. The present paper shows that even neutral species can be adequately determined after suitable preceding reactions. Urea was completely hydrolysed by urease (EC 3.5.1.5) to ammonia and bicarbonate, followed by direct measurement of the ammonium ion concentration by capillary isotachophoresis. Standard Reference Material No. 912a urea (National Bureau of Standards) was used as a primary standard. The analytical linear range of the method extends to 64 mmol urea per litre. The precision of the method was in the range of 1.05-2.64% (CV) and the analytical recovery of added urea was excellent (99.4%, SD 1.13%). Further proof of accuracy was obtained by analysing the NBS human reference serum (standard reference material 909). The mean result by the capillary isotachophoretic method, 9.52 +/- 0.085 mmol/l, agrees well with the reference value, 9.64 mmol/l. The results obtained by capillary isotachophoresis showed good agreement with those obtained by the coupled-enzyme method (r = 0.995).
Ammonia↗
Simultaneous determination of the most abundant cationic species in human urine by capillary isotachophoresis.
Analytical isotachophoresis has proved to be an excellent method for separation and quantitative measurement of ionic species in biologic fluids. Isotachophoretic separation of cations in presence of a complex-forming nonionic detergent (e.g. Triton X-100) in 98% methanol enables simultaneous quantitative determination of ammonium, sodium, potassium, magnesium, and protonated creatinine in urine samples. For calcium determination in urine, lead acetate was used to precipitate anions that form complexes with calcium. The mean deviation from 100% recovery of ammonium, sodium, potassium, magnesium, calcium and creatinine added to urine samples is 3.1%. The proposed method shows good agreement with chemical (routine) methods.
Cations↗
Simultaneous determination of chloride, sulphate, orthophosphate and organic anions in human urine by capillary isotachophoresis.
The principle of isotachophoresis has been used to develop a simple, specific and sensitive analytical method for the determination of anions in untreated urine. Isotachophoretic separation of anions in the presence of complex-forming counter ions (e.g. Cd2+) enables the quantitative separation and determination of chloride, sulphate and orthophosphate in the same sample and the less accurate measurement of the concentrations of citrate, formate, acetate, hippurate, benzoate and glucuronate. The mean deviation from 100% recovery of chloride, sulphate and orthophosphate added to urine samples is 3.1%. The proposed method shows good agreement with chemical (routine) methods.
Anions↗
[Significance of immunoreactive lipase in the diagnosis of pancreatic diseases].
The diagnostic value of a new enzyme immunoassay for lipase (IRL) was evaluated in controls (n = 65), in acute pancreatitis (n = 11) and in extrapancreatic hyperamylasemia (n = 15) by comparing IRL with serum amylase (TA), pancreatic isoamylase (PA) and lipase (turbidimetrically: TL). IRL and immunoreactive trypsin (IRT) of 60 patients with alcoholic chronic calcified pancreatitis were also studied and correlated with duration of disease and degree of pancreatic insufficiency (based on fecal chymotrypsin test: FCT). IRL was constantly elevated in patients with acute pancreatitis. In extrapancreatic hyperamylasemia IRL was mainly normal, in contrast to PA, which was elevated in 7 patients with macroamylasemia. In 56.7% of all patients with chronic pancreatitis, IRL was pathologically low; in association with advanced insufficiency (FCT less than 20 micrograms/g) this figure was 74%, and after duration of disease of greater than or equal to 15 years 77%. For IRT comparable results were found in 79% and 77% respectively. This new lipase test thus seems to be useful for the diagnosis of acute pancreatitis, the differential diagnosis of extrapancreatic hyperamylasemia and the detection and monitoring of severe chronic pancreatitis.
Acute Disease↗
On the pathogenesis of pancreatic ascites.
The pancreatic ascites of 2 patients and the drainage fluid collected adjacent to the pancreas postoperatively of 1 of them were analyzed for protein composition and enzyme activity. We did not find a proteolytic activity, especially enzymatically active trypsin and chymotrypsin in these fluids. Immunoreactive (inactive) trypsin was, however, present in rather high concentrations. The drainage fluid changed from an inflammatory exudate to a fluid similar in composition to pancreatic juice later on. Our results indicate that pancreatic ascites consist of a combination of enzyme-rich pancreatic fluid and protein-rich exudate from the inflamed pancreas. No evidence of peritonitis or of proteolytic activity capable of inducing peritonitis was found.
Adult↗
[Bedside diagnosis of pancreatitis using the urinary amylase test tape. Preliminary results].
A test strip for rapid detection of alpha-amylase in urine was evaluated in 12 patients with an acute episode of acute or chronic pancreatitis and in 16 patients with hyperamylasemia of varying origin. The test strip was positive in 11 of 12 patients with acute pancreatitis and in 8 of 13 patients with hyperamylasemia. In 3 patients with macroamylasemia the test strip was negative. The specificity was 98% in 100 ambulatory patients without evidence of pancreatic disease.
Acute Disease↗
High amylase content of neoplastic pleural and pericardial effusion probably secondary to amylase producing tumor cells: report of 2 cases.
We report two cases of malignant pleural and pericardial effusion respectively secondary to bronchogenic carcinomas. In both effusions, a significant elevation of the Salivary-type-amylase fraction was found, while the corresponding values were normal in serum and urine. Electronmicroscopy of the malignant tumor cells from the pleural effusion showed typical electron-dense granules, suggesting zymogen granules. It is concluded that the high amylase content of the effusions was due to secretion of S-type-isoamylase by the tumor cells.
Aged↗
Variations with age of immunoreactive serum trypsin: higher reference ranges in "healthy" elderly people.
According to the literature, the mean values of immunoreactive serum trypsin (IRT) (RIA-gnost Hoechst) in controls vary considerably between 150 and 283 ng/ml. The reasons for these variations are unknown. The purpose of the present investigation was to study the variations of IRT in relation to age in adults. We studied 124 hospital controls, who were without evidence of pancreatic disease or renal insufficiency and who varied in age between 17 and 84 years. Utilizing the kit of Hoechst, IRT was determined in fasting serum specimens. The mean (+/- SD) in patients over 60 years was 469.6 +/- 197.4 ng/ml, in contrast to 309.1 +/- 118.9 ng/ml (30-59 years) and 209.7 +/- 80.7 (less than 30 years). Of cases over 60 years 36.5% had elevated IRT levels above 500 ng/ml. In 25 cases over 60 years no correlation was found between IRT levels and creatinine clearance and in eight of ten cases of this group with high IRT (greater than 500 ng/ml) the serum pancreatic isoamylase levels were normal. The data indicate that in the diagnosis of pancreatic disease the higher reference ranges in the elderly people have to be taken into account. The age-related higher reference ranges seem not to be due to subclinical renal disease nor to clinically evident pancreatic disease.
Adolescent↗
Comparative diagnostic accuracy of four tubeless pancreatic function tests in chronic pancreatitis.
The comparative sensitivity of 4 tubeless pancreatic function tests was evaluated in 125 patients with proved chronic pancreatitis associated with various degrees of pancreatic insufficiency. NBT-PABA, immunoreactive trypsin (IRT), and pancreatic isoamylase (P-iso) were studied in relation to the fecal chymotrypsin test (FCT) and steatorrhea. In advanced insufficiency (steatorrhea or FCT less than 20 micrograms/g) PABA, IRT, and P-iso were pathologically low in only 70-85% of patients. In less severe pancreatic insufficiency (FCT 21-120 micrograms/g) these tests yielded pathological results in 35-53% of patients. Thus the sensitivity of the three tests was comparable and rather low. IRT values (and P-iso) were constantly low or progressively decreasing in 64% of patients (30/47) studied repeatedly over an average of 17 months. The serum enzyme tests seem, therefore, to be valuable for monitoring pancreatic insufficiency, like the FCT. This is particularly important for the differential diagnosis of acute (reversible) and chronic (progressive) pancreatitis.
4-Aminobenzoic Acid↗
Neoral drug monitoring in stable kidney allotransplant recipients: C(0) versus C(2).
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Administration, Oral↗
Controlled-release of doxorubicin from poly(lactide-co-glycolide) microspheres significantly enhances cytotoxicity against cultured AIDS-related Kaposi's sarcoma cells.
Subsequent to the introduction of highly active antiretroviral therapy (HAART), there has been a reduction in HIV viral titers and a concomitant decrease in AIDS-related Kaposi's sarcoma. However, as failure rates of HAART approach 30%, concerns arise regarding resurgence in AIDS-KS. Current AIDS-KS therapies fail to provide sustained remissions and yet also result in significant morbidity. Although partially effective, systemic chemotherapy is particularly debilitating to AIDS patients. In this report, we examined the co-incubation of AIDS-KS cells with doxorubicin which was slowly delivered from biodegradable, locally injectable, controlled-release poly(lactide-co-glycolide) (PLGA) microspheres. Local drug delivery systems such as PLGA microspheres can sustain therapeutic intralesional concentrations while minimizing deleterious systemic side effects, providing a pharmacologic advantage at the treatment site. Our data show that controlled release from PLGA microspheres augments doxorubicin cytotoxicity towards AIDS-KS cells without increasing toxicity in nonlesional cells from the AIDS-KS donors. Electron microscopic analysis revealed that PLGA microspheres possess a strong affinity for cell membranes, facilitating doxorubicin delivery to redox-sensitive cell membrane sites. Consistent with their speculated endothelial cell lineage, some of the AIDS-KS cells appeared to engulf microspheres via phagocytosis. Our results suggest that PLGA controlled-release doxorubicin microspheres have potential clinical applicability in management of AIDS-KS.
Acquired Immunodeficiency Syndrome↗
Effects of 10-hydroxycamptothecin, delivered from locally injectable poly(lactide-co-glycolide) microspheres, in a murine human oral squamous cell carcinoma regression model.
This study investigated whether local delivery of 10-hydroxycamptothecin provides effective inductive chemotherapy as assessed by significant tumor reduction. Established tumorigenic human oral squamous cell carcinoma cells were used for these experiments. The experimental groups were comprised of: control (blank (no drug) poly(lactide-co-glycolide) (PLGA) microspheres), intraperitoneal 10-hydroxycamptothecin delivery + blank microspheres, local bolus 10-hydroxycamptothecin + blank microspheres, and PLGA controlled-release microspheres. The 10-hydroxycamptothecin dose administered was 12 mg/kg (bolus-intraperitoneal, local) or controlled-release over 10 days. Regardless of delivery route, 10-hydroxycamptothecin significantly reduces tumor volume. However, PLGA microspheres provide significantly higher intratumor-drug concentrations (approximately 10 and 100 fold higher) relative to local bolus and intraperitoneal routes, respectively. Also, only the PLGA microspheres significantly reduced tumor weights. Camptothecin clinical applications are limited by drug inactivation at physiological pH and the need for sustained infusions. However, due to their acidic, camptothecin-stabilizing microclimate, PLGA microspheres could provide a novel delivery system for camptothecin-based induction chemotherapy.
Animals↗