Thiol redox modulation of doxorubicin mediated cytotoxicity in cultured AIDS-related Kaposi's sarcoma cells

The chemotherapeutic, doxorubicin, is currently used empirically in the treatment of AIDS- related Kaposi's sarcoma (AIDS-KS). Although often employed in a chemotherapeutic cocktail (doxorubicin, bleomycin, vincristine) single-agent therapy has recently been attempted with liposome encapsulated doxorubicin. Although doxorubicin's mechanism of action against AIDS-KS is unknown, we hypothesized that doxorubicin's ability to undergo redox cycling is associated with its clinical efficacy. The current study was conducted to investigate the effects of doxorubicin on selected xenobiotic-associated biochemical responses of three cellular populations: KS lesional cells, nonlesional cells from the KS donors, and fibroblasts obtained from HIV- aged matched men. Our results show that during doxorubicin challenge, there are strong positive correlations between cellular glutathione (GSH) levels and viability (r = 0.94), NADPH levels and viability (r = 0.93), and GSH and NADPH levels (r = 0.93), and demonstrate that as a consequence of their abilities to maintain cellular thiol redox pools HIV- donor cells are significantly less susceptible to doxorubicin's cytotoxic effects relative to AIDS-KS cells. Additional studies further supported the contribution of reduced thiols in mediating doxorubicin tolerance. While pretreatment with the GSH precursor, N-acetylcysteine was cytoprotective for all cell groups during doxorubicin challenge, GSH depletion markedly enhanced doxorubicin's cytotoxic effects. Studies to investigate the effects of a hydroxyl scavenger and iron chelator during doxorubicin challenge showed moderate cytoprotection in the AIDS-KS cells but deleterious effects in the HIV control cells. Inactivation of the longer lived membrane generated ROI in the cytoprotective deficient AIDS-KS cells, as well as an impairment of endogenous defenses in the HIV- donor control cells, may account for these scavenger and chelator associated findings. In summary, our findings show that doxorubicin mediates, at least in part, its AIDS-KS cellular cytotoxic effects by a redox related mechanism, and provides a biochemical rationale for doxorubicin's clinical efficacy in AIDS-KS treatment.

Free/total prostate-specific antigen ratio can prevent unnecessary prostate biopsies

OBJECTIVES

To evaluate the ability of free/total prostate-specific antigen (PSA) ratio to improve specificity of prostate cancer detection, compare Diagnostic Products Corporation (DPC) Immulite and Ciba Corning ACS 180 total (t)PSA assay, and define an assay-specific cutoff point and reflex range for DPC PSA ratio (PSAR).

METHODS

In a prospective study, 206 men were enrolled with measurement of both assays. Group 1 consisted of 173 men with a suspicion of prostate cancer (PCA). Thirteen men with known PCA (group 2) and 20 men younger than 32 years (group 3) were used as control groups.

RESULTS

Our results in group 1 (115 with benign prostatic hyperplasia [BPH], 58 with PCA) revealed a sensitivity of 82.7%, a specificity of 45.2%, and an accuracy of 57.8% for the DPC tPSA assay (cutoff point more than 4.0 ng/mL) within the entire PSA range. tPSA values of the ACS 180 assay were 1.97-fold higher. Within the tPSA gray zone of 2.5 to 10 ng/mL (66 BPH, 23 PCA), specificity and accuracy of DPC tPSA can be improved by using the DPC PSAR (cutoff point less than 19%) from 33.3% to 71.2% and 42.7% to 70.8%, respectively, maintaining the same sensitivity level of 69.6%.

CONCLUSIONS

By combining tPSA testing with PSAR within the gray zone, 39.7% (25 of 63) of unnecessary biopsies can be saved, without missing any additional cancers compared with tPSA testing alone. The optimal reflex range for DPC PSAR is 2.5 to 10 ng/mL and the best PSAR cutoff point for biopsy criterion is less than 19% in our high-risk population, with a cancer yield of 34%. Because we still do not have an international PSA standard, it is important to use assay-specific "normal values" and PSAR cutoff points.

[The effect of short-term hyperventilation on the concentration of ionized serum calcium]

BACKGROUND AND OBJECTIVE

Paraesthesias and carpopedal spasms on hyperventilation are explained by a reduction in ionised serum calcium (ISC). We tested whether 5-minute hyperventilation changes the concentration of ISC.

SUBJECTS AND METHOD

Arterial blood samples were obtained via a small plastic catheter introduced into the femoral artery of ten healthy male volunteers (mean age 33 years) before, during and after 5 minutes of hyperventilation, which was achieved by deep and rapid breathing and considered adequate when the end-expiratory pCO2 had fallen to 2.5 kPA within the first minute and remained below this level during the remaining 4 minutes. These criteria were met in nine of the ten patients. The ISC concentration was measured with an ion-selective electrode, the pH, paCO2 and bicarbonate levels with an autoanalyser.

RESULTS

Paraesthesias of the fingers and hand occurred in nine of the volunteers, carpopedal spasms in seven. Despite a definite rise in pH from 7.39 +/- 0.02 to 7.75 +/- 0.045, the concentration of ISC did not change significantly during the hyperventilation.

CONCLUSION

Paraesthesias and carpopedal spasms which occur during hyperventilation are not caused by a fall in ionised serum calcium in arterial blood.

Normothermia versus hypothermia during cardiopulmonary bypass: a randomized, controlled trial

To evaluate the influence of perfusion temperature on systemic effects of cardiopulmonary bypass (CPB), 30 patients undergoing elective coronary artery bypass grafting were randomly assigned to either normothermic (warm, n = 14, 36 degrees C) or hypothermic (cold, n = 16, 28 degrees C) CPB. Serial hemodynamic measurements and blood samples were obtained before, during and after the CPB procedure. During CPB, there were no differences between both groups in the need for vasopressors (norepinephrine, phenylephrine), urinary output, or fluid balance. In the early postoperative period, normothermic CPB patients had significantly lower systemic vascular resistance and higher cardiac index measurements (mean +/- standard error: systemic vascular resistance, 880 +/- 27 versus 1,060 +/- 57 dyne.s.cm-5, p = 0.025; cardiac index, 3.6 +/- 0.1 versus 2.9 +/- 0.1 L.min-1.m-2, p = 0.01) without differences in the administration of vasoactive drugs. Blood loss was significantly higher in patients after hypothermic CPB (median [range] body surface area: 370 [180-560] versus 490 [280-2,120] mL/m2, p = 0.0006), with a greater need for transfusion of erythrocytes and fresh frozen plasma. Plasma levels of tumor necrosis factor and soluble tumor necrosis factor receptors increased during and after CPB, independent of perfusion temperature. This study suggests a significant influence of CPB temperature and respective perfusion management on postoperative hemodynamics and blood loss. Normothermic CPB is not associated with additional systemic adverse effects.

Heparin surface coated hard shell venous reservoirs: experimental evaluation ex vivo

The present study was designed for ex vivo evaluation of a heparin coated hard shell venous reservoir in comparison to uncoated control reservoirs. An open chest bovine right heart bypass model (n=9, bodyweight 72 ± 6 kg) with passive blood drainage from the right atrium into the venous reservoir and active retransfusion into the pulmonary artery (roller pump) was selected for this purpose. Clear priming was used for the open perfusion circuit. No heparin was given before or during the evaluation period which was scheduled for 6 hours. Reservoir blood flow was at the beginning 3.5 ± 0.6 I/min for coated versus 3.4 ± 0.3 l/min for uncoated (NS). After 6 hours, blood flow was 3.3 ± 0.1 I/min for coated versus 2.7 ± 0.4 l/min for uncoated (p<0.05). Hematocrit moved from a baseline level of 30 ± 2% for coated versus 28 ± 3% for uncoated (NS) to 28 ± 3% for coated versus 27 ± 5% for uncoated (NS) after 6 hours. Prebypass platelet levels of 100% in both groups moved to 84 ± 3% for coated versus 78± 23% for uncoated (NS) after 6 hours. Activated coagulation time (ACT) before bypass was 148 ± 12 s for coated and 153 ± 6 s for uncoated (NS). After 6 hours, ACT was 160 ± 9 s for coated versus 152 ± 5 s for uncoated (NS). Thrombin time before bypass was 15 ± 2 s for coated versus 16 ± 2 s for uncoated (NS). After 6 hours, thrombin time was 17 ± 2 s for coated versus 18 ± 4 s for uncoated (NS). Baseline antithrombin III levels were 91 ± 25% for coated versus 96 ± 17% for uncoated (NS). After 6 hours antithrombin III levels were 95 ± 23% for coated versus 93 ± 19% for uncoated (NS). Baseline fibrinopeptide A levels were 2.6 ± 0.4 ng/ml for coated versus 2.6 ± 0.8 ng/ml for uncoated (NS). After 10 minutes of perfusion fibrinopeptide A moved to 4.8 ± 0.9 ng/ml for coated versus 8.8 ± 3.2 ng/ml for uncoated and reached 10.7 ± 2.6 ng/ml after 2 hours for coated versus 15.3 ± 0.1 for uncoated (p<0.01). We conclude, that despite the open perfusion mode, the tested heparin surface coated venous hard shell reservoirs have improved thromboresistance. Heparin surface coating increases the reservoir flows and reduces fibrinopeptide A production.

Heparin surface coated hard shell venous reservoirs: experimental evaluation ex vivo

The present study was designed for ex vivo evaluation of a heparin coated hard shell venous reservoir in comparison to uncoated control reservoirs. An open chest bovine right heart bypass model (n = 9, bodyweight 72 +/- 6 kg) with passive blood drainage from the right atrium into the venous reservoir and active retransfusion into the pulmonary artery (roller pump) was selected for this purpose. Clear priming was used for the open perfusion circuit. No heparin was given before or during the evaluation period which was scheduled for 6 hours. Reservoir blood flow was at the beginning 3.5 +/- 0.6 l/min for coated versus 3.4 +/- 0.3 l/min for uncoated (NS). After 6 hours, blood flow was 3.3 +/- 0.1 l/min for coated versus 2.7 +/- 0.4 l/min for uncoated (p < 0.05). Hematocrit moved from a baseline level of 30 +/- 2% for coated versus 28 +/- 3% for uncoated (NS) to 28 +/- 3% for coated versus 27 +/- 5% for uncoated (NS) after 6 hours. Prebypass platelet levels of 100% in both groups moved to 84 +/- 3% for coated versus 78 +/- 23% for uncoated (NS) after 6 hours. Activated coagulation time (ACT) before bypass was 148 +/- 12 s for coated and 153 +/- 6 s for uncoated (NS). After 6 hours, ACT was 160 +/- 9 s for coated versus 152 +/- 5 s for uncoated (NS). Thrombin time before bypass was 15 +/- 2 s for coated versus 16 +/- 2 s for uncoated (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Relation of cyclosporine blood levels to adverse effects on lipoproteins

Hyperlipidemia is common in renal allograft recipients. To elucidate the role of cyclosporine in posttransplant hyperlipidemia, we measured lipids, lipoprotein lipids, and apolipoproteins of thirty-five renal allograft recipients and evaluated their relation to trough cyclosporine blood levels. All patients were on a triple immunosuppressive regimen with equal doses of prednisone and azathioprine, and had stable graft function. Cyclosporine blood levels were significantly correlated to total plasma cholesterol (P = 0.028), low-density lipoprotein cholesterol (P = 0.022), apolipoprotein B (P = 0.017), and the cholesterol/high-density lipoprotein cholesterol ratio (P < 0.002), but not to plasma triglycerides. Significant inverse correlations were found between cyclosporine blood levels and high-density lipoprotein cholesterol (P = 0.034), high-density lipoprotein3 cholesterol (P = 0.025), and apolipoprotein A-1 (P = 0.047), but not high-density lipoprotein2 cholesterol. The independent relation of cyclosporine blood levels to each of the measured lipid parameters was investigated by a stepwise regression model including age, body mass index, interval from transplantation, diabetes mellitus, plasma creatinine, and intake of diuretics and beta-blockers. After correction for these 7 variables, cyclosporine blood levels remained significantly associated with high-density lipoprotein cholesterol, high-density lipoprotein3 cholesterol, apolipoprotein A-1, apolipoprotein B, low-density lipoprotein cholesterol, and the cholesterol/high-density lipoprotein cholesterol ratio. These data suggest that cyclosporine causes atherogenic dyslipidemia.

[Are the advantages of percutaneous catheterization technique gained by increased blood trauma?]

The development of thin-walled cannulas which can be introduced by percutaneous technique into femoral artery and vein has revived interest in emergency cardiopulmonary support (CPS). To assess possible blood damaging effect due to the small-bore cannulas, 8 in vitro perfusions were performed with two parallel pump circuits: one circuit with a 17 F arterial and a 21 F venous cannula, one circuit without cannulas (control). The circuits were filled with 61 of bovine blood and run for 6 hours at a temperature of 37 degrees C and a flow of 4 l/min. Serial blood samples were taken before and during the experiment. There was a significantly higher level of free plasma haemoglobin (pl Hb) and a decreased number of leukocytes (Lc) after 6 hours of perfusion in the group with percutaneous cannulas as compared with control (pl Hb: 63.2 +/- 0.3 vs. 26.3 +/- 4.1 mumol/l, p < 0.05, Lc: 2.4 +/- 0.6 vs. 4.6 +/- 0.8 x 10(9)/l, p < 0.05, mean +/- se).

CONCLUSION

percutaneous cannulas are associated with an increased blood trauma. If extended cardiopulmonary support is considered (more than several hours), percutaneous cannulas should be replaced by large-bore cannulas.

A new look at the limits of detection (LD), quantification (LQ) and power of definition (PD)

The relationship between the concentration of the analyte and the imprecision of an analytical method can be displayed by the precision profile in which the coefficient of variation (relative standard deviation) is plotted against the concentration of the analyte. The function of the curve of the profile and its confidence limits can easily be assessed by a computer program developed by W.A. Sadler & M.H. Smith (Clin. Chem. 36 (1990), 1346-1350). For the assessment of limits of detection and of quantification the following procedure is proposed: The lower (and upper) limit of the measuring interval is defined by the point at which an acceptable CV-line intersects the confidence limit. If, in the variance function one sets the concentration to zero, the normal distribution of the random errors of the blank will result. The mean of the next adjacent normal distribution, following the variance formula and overlapping the "zero-distribution" by a defined amount, represents the limit of detection. Within the described measuring interval, or within a fraction of it, one might construct overlapping normal distributions in an analogous manner. Their number represents the "power of definition" (PD) (instead of the "analytical sensitivity"), which also depends on the concentration of the determinand according to the variance function. We tested these hypotheses by a comparison of two methods for the determination of cyclosporin A (ciclosporin, INN). Our results demonstrate that the data of the lower limits of the measuring interval and of the limit of detection agree well with data from the literature obtained in extensive interlaboratory surveys.

Multicentre evaluation of the Boehringer Mannheim/Hitachi 747 analysis system

Analytical performance and practicability of the new Boehringer Mannheim/Hitachi 747 analysis system were assessed in a multicentre evaluation involving four laboratories. The analytical performance was evaluated according to a protocol similar to the ECCLS guidelines and comprised 13 analytes including enzymes, substrates and electrolytes. About 65,000 results were obtained within three months. The evaluation was planned and supported by a program system called "Computer Aided Evaluation". Acceptance criteria have been established for judging the results. The median of the within-run coefficients of variation (CVs) in control sera of all methods was below 1%, being far below the acceptance limit of 2%. The median of CVs of between-days imprecision was below 2% (acceptance criterion 3%). The high degree of precision prompted us to set up a biometrical model suitable for the differentiation between deviant points, outliers and measurements that can still be explained by the system performance. No relevant drift effects were observed during eight hours. The methods were linear over a wide range, avoiding rerun analysis in most cases. No sample-related carry-over was found. Reagent-dependent carry-over outside the acceptance limits was measured from uric acid to phosphorus to a slight extent, and from triacylglycerols to lipase, as well as from total protein to bilirubin to a perceptible degree. It can be avoided by separating these reagent combinations in the channel arrangement. Taking a systematic deviation of more than 10% as unacceptable, four of the 13 analytes suffered from interference by haemoglobin, one by bilirubin and one by turbidity. The Boehringer Mannheim/Hitachi 747 analysis system is capable of determining serum indices which in combination with the interferogram allow an assessment of the interference. With the exception of chloride the recovery of the assigned values for all control sera showed values between 95 and 105%. Out of 40 method comparison studies for enzymes and substrates, 31 yielded regression equations with less than 5% proportional errors and less than 5% constant errors. Deviations exceeding these acceptance criteria can be explained by differences in the reagent formulation, in the method employed or in calibration. The agreement of the ISE method comparisons was within a +/- 5% deviation over a wide analytical range. Practicability of the Boehringer Mannheim/Hitachi 747 analysis system was assessed with the help of a questionnaire, in which properties of the instrument were quantified, thus permitting a relatively objective rating. The 190 questions were placed in 14 groups, each dealing with an attribute of the instrument.(ABSTRACT TRUNCATED AT 400 WORDS)

[Evaluation of enzymatic methods for the determination of plasma sodium and potassium using the Hitachi 747 analytic system]

In the hospital clinical laboratory, plasma potassium and sodium are usually determined by using a flame photometer or ion-selective electrodes, for which special equipment is required. The new enzymatic methods of sodium and potassium can be used as a routine chemical method. We evaluated the new enzymatic methods for the determination of sodium and potassium in human plasma on the Hitachi 747. The sodium and potassium assay kits were purchased from Boehringer Mannheim, Germany. Precision studies were performed using three levels of pool plasma. The coefficients of variation (CV) of sodium and potassium determination were less than 1.0% and less than 2.2% by intraassay and interassay respectively. The recoveries of the assigned values of the ten control sera were 97-102%. Comparisons with results either from flame photometry and from ion-selective electrodes showed no clinically relevant differences for 100 patient samples. Performance of the enzymatic methods for Na+ and K+ is clinically comparable to flame photometry or ion-selective electrodes in the routine clinical chemistry laboratory.

Experimental evaluation of heparin-coated cardiopulmonary bypass equipment with low systemic heparinization and high-dose aprotinin

Cardiopulmonary bypass (n = 8 calves) with heparin-coated perfusion equipment, low-dose systemic heparinization (activated clotting time: ACT greater than 180 s) and high-dose aprotinin administration was evaluated in comparison to standard perfusion equipment with full-dose systemic heparinization (ACT greater than 480). All animals were perfused for 6 hours and similar values were observed for blood gases and mixed venous oxygen saturation in both groups. The heparin doses given in the study group before and during the 6 hours of perfusion totalized 14660 +/- 2553 IU as compared to 60833 +/- 5137 IU for the control group. No protamin was given in the study group whereas an equivalent of 27000 +/- 5805 IU was necessary to reverse heparin in the control group. There was no difference for prebypass hematocrit versus postbypass hematocrit in the two groups. Prebypass plasma hemoglobine was 8.4 +/- 2.1 mumol/L in the study group versus 10.0 +/- 3.8 mumol/L in the control group. After mixing with the priming volume, plasma hemoglobine was 8.6 +/- 2.5 mumol/L in the study group versus 6.7 +/- 1.6 mumol/L in the control group. The highest value was observed in the study group after 2 hours of perfusion (8.2 +/- 2.1 mumol/L) versus 5 hours of perfusion in the control group (7.4 +/- 3.6 mumol/L). Prebypass LDH levels of 1610 +/- 150 IU in the study group versus 1740 +/- 210 IU in the control group moved to 1870 +/- 200 IU in the study group at 24 hours after perfusion versus 2650 +/- 400 IU in the control group at 24 hours and decreased thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

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).

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.

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.

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.

[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.

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.

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.

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.