Levels of l-arginine and l-citrulline in patients with erectile dysfunction of different etiology.

Nitric oxide is a physiologic signal essential to penile erection. l-citrulline (l-Cit) is converted into l-arginine (l-Arg), the precursor from which nitric oxide is generated. The level of l-Arg and l-Cit in the field of male sexual function remains relatively underexplored. The aim of the study was to evaluate the level of serum l-Arg and of l-Cit in a group of patients with erectile dysfunction. Diagnosis and severity of erectile dysfunction was based on the IIEF-5 and its etiology was classified as arteriogenic (A-ED), borderline (BL-ED), and non-arteriogenic (NA-ED) with penile echo-color-Doppler in basal condition and after intracaversous injection of prostaglandin E1. Serum l-Arg and l-Cit concentrations were measured by a cation-exchange chromatography system. l-Arg and l-Cit levels of men with A-ED were compared with those of male with BL-ED and NA-ED. Median level of l-Arg and l-Cit in 122 erectile dysfunction patients (41 A-ED, 23 ED-BL, 58 NA-ED) was 82.7 and 35.4 µmol/L, respectively. l-Arg and l-Cit levels in control patients were not significantly different (p = 0.233 and p = 0.561, respectively) than in total erectile dysfunction patients. l-Arg and l-Cit levels in control patients were significantly higher (p < 0.001 and p < 0.018, respectively) than in A-ED patients, but no difference (p > 0.50) was observed in controls and in both BL-ED and NA-ED patients. Patients with severe/complete-erectile dysfunction (IIEF-5 < 10) had l-Arg or l-Cit level significantly lower (-17%, p < 0.03; -13%, p < 0.04) and were more frequent (p < 0.01 and p < 0.04) under the respective median level (82.7 and 35.4 µmol/L) than those with mild-erectile dysfunction (IIEF-5 = 16-20). l-Arg and l-Cit levels in A-ED were significantly lower (p < 0.007 and p < 0.001, respectively) than in NA-ED patients. Penile echo-color-Doppler revealed that A-ED (peak systolic velocity ≤ 25 cm/sec) was more frequent in men with l-Arg under 82.7 µmol/L or l-Cit under 35.4 µmol/L and in the same population, the median peak systolic velocity values were lower in l-Arg deficient (29 vs. 35; p < 0.04) and also in l-Cit deficient (31 vs. 33, p > 0.3) but without reaching the statistical significance. Our study shows that a significant proportion of erectile dysfunction patients have low l-Arg or l-Cit level and that this condition is more frequent in patients with arteriogenic etiology. Low levels of these nitric oxide synthase substrates might increase the erectile dysfunction risk by reducing the concentration of nitric oxide.

Levels of human erythrocyte membrane-bound and cytosolic glycohydrolases are associated with oxidative stress in erectile dysfunction patients.

Oxidative stress (OS) and production of NO, by endothelium nitric oxide synthetase (eNOS), are involved in the pathophysiology of erectile dysfunction (ED). Moreover, OS induces modifications of the physicochemical properties of erythrocyte (RBC) plasma membranes and of the enzyme content of the same membranes. Due to their role in signalling early membrane alterations in OS-related pathologies, several plasma membrane and cytosolic glycohydrolases of human RBC have been proposed as new markers of cellular OS. In RBC, NOS can be activated and deactivated by phosphorylation/glycosylation. In this regulatory mechanism O-ß-N-AcetylGlucosaminidase is a key enzyme. Cellular levels of O-GlcNAcylated proteins are related to OS; consequently dysfunctional eNOS O-GlcNAcylation seems to have a crucial role in ED. To elucidate the possible association between RBC glycohydrolases and OS, plasma hydroperoxides and antioxidant total defenses (Lag-time), cytosolic O-ß-N-AcetylGlucosaminidase, cytosolic and membrane Hexosaminidase, membrane ß-D-Glucuronidase, and α-D-Glucosidase have been studied in 39 ED patients and 30 controls. In ED subjects hydroperoxides and plasma membrane glycohydrolases activities are significantly increased whereas Lag-time values and cytosolic glycohydrolases activities are significantly decreased. These data confirm the strong OS status in ED patients, the role of the studied glycohydrolases as early OS biomarker and suggest their possible use as specific marker of ED patients, particularly in those undergoing nutritional/pharmacological antioxidant therapy.

Performance assessment of a glucose control protocol in septic patients with an automated intermittent plasma glucose monitoring device.

BACKGROUND & AIMS: The optimal level and modality of glucose control in critically ill patients is still debated. A protocolized approach and the use of nearly-continuous technologies are recommended to manage hyperglycemia, hypoglycemia and glycemic variability. We recently proposed a pato-physiology-based glucose control protocol which takes into account patient glucose/carbohydrate intake and insulin resistance. Aim of the present investigation was to assess the performance of our protocol with an automated intermittent plasma glucose monitoring device (OptiScanner™ 5000). METHODS: OptiScanner™ was used in 6 septic patients, providing glucose measurement every 15' from a side-port of an indwelling central venous catheter. Target level of glucose was 80-150 mg/dL. Insulin infusion and kcal with nutritional support were also recorded. RESULTS: 6 septic patients were studied for 319 h (1277 measurements); 58 [45-65] hours for each patient (measurements/patient: 231 [172-265]). Blood glucose was at target for 93 [90-98]% of study time. Mean plasma glucose was 126 ± 11 mg/dL. Only 3 hypoglycemic episodes (78, 78, 69 mg/dL) were recorded. Glucose variability was limited: plasma glucose coefficient of variation was 11.7 ± 4.0% and plasma glucose standard deviation was 14.3 ± 5.5 mg/dL. CONCLUSIONS: The local glucose control protocol achieved satisfactory glucose control in septic patients along with a high degree of safeness. Automated intermittent plasma glucose monitoring seemed useful to assess the performance of the protocol.

Asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and L-arginine in patients with arteriogenic and non-arteriogenic erectile dysfunction.

The plasma concentration of asymmetrical dimethylarginine (ADMA), an inhibitor of nitric oxide synthase, has been linked to endothelial dysfunction. We investigated the relation between ADMA, symmetric dimethylarginine (SDMA) and L-arginine concentrations and erectile dysfunction. We compared plasma levels of ADMA, SDMA and L-arginine in 61 men in good health with erectile dysfunction of arteriogenic and non-arteriogenic origin. Diagnosis of erectile dysfunction was based on the International Index of Erectile Function Score and its aetiology was classified with penile echo-colour-Doppler in basal condition and after intracavernous injection of prostaglandin E1. The ADMA and SDMA concentrations were significantly higher in men with arteriogenic erectile dysfunction compared with those with erectile dysfunction of non-arteriogenic origin (p < 0.05) and the concentrations in both subgroups were significantly higher than in controls (p < 0.001). There was a negative correlation between ADMA and International Index of Erectile Function Score only in arteriogenic erectile dysfunction subgroup. L-arginine did not differ significantly neither between the two erectile dysfunction subgroups (p > 0.05) nor between each of the two erectile dysfunction subgroups and controls (p > 0.05). The L-arginine/ADMA and the L-arginine/SDMA ratios in arteriogenic erectile dysfunction subgroups were significantly lower than both in controls (p < 0.05) and in non-arteriogenic erectile dysfunction patients (p < 0.05); the two ratios in non-arteriogenic erectile dysfunction patients did not differ from those in the controls (p > 0.05). We conclude that ADMA and SDMA concentrations are significantly higher and L-arginine/ADMA ratio lower in patients who have arteriogenic erectile dysfunction compared with both patients with non-arteriogenic erectile dysfunction and controls. The negative correlation between ADMA and severity of erectile dysfunction is present only in patients with arteriogenic erectile dysfunction. This study supports the importance to always distinguish arteriogenic from non-arteriogenic erectile dysfunction patients to study the complicate erectogenic mechanisms that lead to erectile dysfunction and also to provide potential therapeutic agents for patients with arteriogenic erectile dysfunction.

Daily monitoring of biomarkers of sepsis in complicated long-term ICU-patients: can it support treatment decisions?

BACKGROUND: Diagnosis/grading of infection and the systemic response to infection may be difficult on admission to the intensive care unit, but it is even more complicated for severely ill patients with long intensive care stays. The ACCP-SCCM criteria are difficult to apply for such patients, and objective, validated biomarkers would be of great use in this setting. METHODS: Long-term (>6 days) critically ill patients in the general ICU of University Hospital were prospectively enrolled in the study. All patients were assessed daily by the attending physician using the ACCP-SCCM classification. C-reactive protein (CRP, mg/dL), procalcitonin (PCT, ng/mL), and interleukin-6 (IL-6, pg/mL) of daily stored sera were measured after each patient's discharge. After discharge, an independent, overall clinical evaluation and an a posteriori ACCP-SCCM classification were chosen as the reference standard for all comparisons. The assessor was aware of the patient's clinical course but was blinded to levels of biomarkers. RESULTS: We studied clinical variables and biomarkers of 26 patients over a total of 592 patient days. The day-by-day ACCP-SCCM classification of the attending physician overestimated the severity of the inflammatory response to infection. The diagnostic discriminative ability of severe-sepsis/septic-shock for PCT was high (ROC area 0.952 [0.931-0.973]) and had a best threshold value of 1.58 (83.7% sensitivity, 94.6 % specificity). IL-6 had better discriminative ability than CRP, but both were worse than PCT. CONCLUSION: PCT > 0.43 ng/mL could add to the clinical propensity for sepsis vs. SIRS not related to infection. Values higher than 1.58 ng/mL may support the bedside clinical diagnosis of severe-sepsis. PCT between 0.5 and 1.0 suggest tight daily monitoring of clinical conditions and re-evaluation of PCT.

Intra-operative testing for parathyroid hormone: the Central Laboratory option.

BACKGROUND: Intra-operative PTH testing in the operating theatre has proven to be an accurate way to verify the removal of all pathological parathyroid tissue in primary hyperparathyroidism. Its limitation is the high cost. An alternative, more cost-effective procedure is proposed: intra-operative PTH dosage at the Central Laboratory. PATIENTS AND METHODS: Fifty-four patients underwent parathyroidectomy with intraoperative dosage of PTH at the Central Laboratory. Three blood samples were taken from each patient: just after the induction of anesthesia, 5 and 10 min after parathyroidectomy. The samples were sent to the Central Laboratory and analysed simultaneously. The results were phoned back to the theatre. The procedure was considered effective when PTH drop was >/=50% from basal value, 10 min after parathyroidectomy. RESULTS: 98.1% of patients proved recovered (average follow- up 31.1 months). The procedure had 3 false negatives, 1 false positive, with sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 94.0%, 75.0%, 92.6%, 97.9%, and 50.0%, respectively. DISCUSSION AND CONCLUSION: The main disadvantage of the presented procedure is the long waiting time. Nevertheless this time is the same as that required for results from intra-operative histological examination, the only alternative to determine surgery effectiveness in centres where portable instrumentation for intra-operative PTH dosage in the operating theatre is not available. The advantage of intra-operative PTH at the Central Laboratory is the very low cost. If results in terms of sensitivity, specificity, accuracy, and cost are taken into consideration, intra-operative dosage of PTH at the Central Laboratory may be deemed a viable alternative to the operating theatre.

Multiple sclerosis and celiac disease: is there an increased risk?

Multiple sclerosis and celiac disease are both considered immune-mediated diseases. Recently, improved serological screening methods provided a higher prevalence of celiac disease (CD) in the general population worldwide and also demonstrated gastrointestinal symptoms may be lacking. The aim of this study was to determine the prevalence of (CD) in an unselected group of 95 adults with multiple sclerosis using transglutaminase antibodies. No patients showed pathological values. Different immune and genetic basis between the two diseases may represent crucial insights to explain our results.

Serum cardiac troponin I after conventional and minimal invasive coronary artery bypass surgery.

We evaluated myocardial release of cardiac troponin I (cTnI) in patients treated with conventional coronary artery bypass grafting (CABG), which employs extracorporeal circulation, and different kinds of minimal invasive coronary artery bypass grafting (MICABG), a surgical technique where the operation is performed without extra-corporeal circulation. Furthermore, we evaluated the usefulness of serum cTnI measurement to detect perioperative myocardial infarction (PMI) after coronary artery bypass surgery. Thirty-one patients were included: sixteen underwent CABG, fifteen underwent different MICABG and five patients had PMI. Blood specimens for cTnI measurements were collected up to 72 hours after opening the graft. Aortic cross-clamping time was a minor determinant of myocardial damage; on the other side, the trauma during surgery correlated with the number of involved arteries and with the manoeuvre employed to obtain heart dislocation, and appeared a more important determinant of myocardial damage. In patients with PMI, the cumulative release of cTnI was higher than in patients free from PMI; however, only after 24-72 hours we observed significant differences in serum cTnI values, because the increased perioperative values of cTnI complicated the interpretation of the myocardial status and a single cut-off could not be used to exclude PMI.

Biological variability of myoglobin in healthy elderly and younger subjects.

To study the effect of age on serum myoglobin more clearly, the analytical, intra-individual and inter-individual components of variation were estimated from duplicate analyses of specimens collected from 18 healthy elderly subjects [ages 74-97 years; 9 men (EM)], and 14 healthy younger subjects [ages 25-31 years; 7 men (YM)] over a period of 6 weeks. The mean values (microgram/L) were EM: 53.7; EW: 44.9; YM: 34.2; YW:24.8. Estimated analytical (CVA), intra- (CVI) and inter-individual (CVG) variations as CV% were: CVA: 2.2. CVI: EM: 13; EW: 9.9; YM: 12.4; YW: 9.6. CVG: EM: 37.6; EW: 28; YM: 18.5; YW: 13.4. The data obtained were used to derive the desirable analytical goal for imprecision (i.e., < or = 6.5% in EM; < or = 4.9% in EW and < or = 6.2% in YM; < or = 4.8% in YW); inaccuracy (i.e., < or = 9.9% in EM; < or = 7.7 in EW and < or = 5.5% in YM; < or = 4.12% in YW); the change required for serial results to be significantly different (i.e., 36% in EM; 28% in EW and 34% in YM; 27.2% in YW), the numbers of specimen collections required to produce a more precise estimate of the homeostatic set point of an individual within 5% (i.e., 26 in EM; 16 in EW and 24 in YM; 15 in YW), and the index of individuality (i.e., 0.34 in EM; 0.35 in EW and 0.67 in YM; 0.71 in YW). This study shows that intra-individual biological variation of myoglobin in healthy elderly subjects is not different from that in young subjects. Inter-individual variation, instead, is greatly influenced by differences in age and sex.

Serum amyloid A, procalcitonin, and C-reactive protein in early assessment of severity of acute pancreatitis.

Amyloid A (SAA) and procalcitonin (PCT) have been reported as useful indicators of inflammation. Our aim was to assess the utility of SAA and PCT in establishing the severity of acute pancreatitis in comparison to C-reactive protein (CRP): Thirty-one patients with acute pancreatitis enrolled within 24 hr from the onset of pain and 31 healthy subjects were studied. Nineteen patients had mild acute pancreatitis, and 12 had severe pancreatitis. Serum SAA, PCT, and CRP were measured in all subjects at admission and, in acute pancreatitis patients, during the following five days. Patients with acute pancreatitis had serum concentrations of SAA, PCT, and CRP significantly higher (P < 0.001) than those of healthy subjects during the entire study period. Using cutoff values ranging from 240 to 250 mg/liter for SAA, from 0.252 to 0.255 ng/ml for PCT, and from 12.8 to 12.9 mg/dl for CRP, the sensitivity (calculated on patients with severe pancreatitis), the specificity (calculated on patients with mild pancreatitis), and the efficiency (calculated as the percentage of correct classifications) were 76.8%, 69.3%, and 72.4% for SAA; 21.7%, 83.2%, and 58.2% for PCT; and 60.9%, 89.1%, and 77.6% for CRP. In conclusion, the sensitivity of SAA is significantly higher than that of PCT and CRP in assessing the severity of pancreatitis, whereas PCT and CRP had a specificity significantly higher than SAA. The accuracy and efficiency were similar for SAA and CRP, and both these markers had an accuracy and efficiency significantly higher than those of PCT.

Mechanistic aspects of the relationship between low-level chemiluminescence and lipid peroxides in oxidation of low-density lipoprotein.

In this study oxidation of low-density lipoprotein (LDL) induced by different Cu2+ concentrations was investigated. Lipid peroxidation was assessed by monitoring low-level chemiluminescence (LL-CL), conjugated diene hydroperoxide (CD) and alpha-tocopherol (TocOH), the major lipophilic antioxidant in LDL. At high Cu2+ concentration, LDL oxidation was characterised by CD formation, LL-CL emission and TocOH consumption. At low Cu2+ concentration, CD formation was independent of LL-CL and occurred in the presence of TocOH. Thus, two different mechanisms lead to lipid peroxide formation in LDL. The combination of CD assay and LL-CL monitoring makes it possible to distinguish the autocatalytic mechanism of CD formation and that associated with TocOH, found at a high and a low rate of initiation, respectively.

Macroamylase detection in serum using selective precipitation: a rapid and reliable assay.

BACKGROUND AND AIM: Available assays for measurement of pancreatic isoamylase in serum based on specific immunoinhibition of salivary fraction are unable to detect macroamylase. We combined a polyethylene glycol test which identifies macroamylase by selective precipitation with an automated assay for total amylase and pancreatic isoamylase measurement. METHODS: We analysed 24 sera proven positive for macroamylase using gel filtration chromatography and 80 negative sera. Precipitation of macroamylase with polyethylene glycol, colourimetric measurement of total amylase activity and immunoinhibition for the determination of pancreatic isoamylase were carried out. RESULTS: Macroamylasaemic sera showed precipitation of at least 71% of the amylase activity, while sera with normal-sized amylase exhibited a maximum of 61%. In all the macroamylasaemic sera but two, the immunoinhibition test showed a rise in pancreatic isoamylase, which was found to be the prevalent fraction in 16. In 21 out of 24 sera with macroamylase and 67 out of 80 with normal-sized amylase, the precipitated amylase activity was also measured after immunoinhibition of non pancreatic activity. In macroamylasaemic sera, the percentage of precipitated pancreatic isoamylase activity ranged from 75% to 98%, while in samples with normal-sized amylase it was less than 71%. CONCLUSIONS: Polyethylene glycol precipitation can easily be combined with automated assays for the determination of pancreatic isoamylase and should be carried out whenever dealing with hyperamylasaemia of unclear origin.

Altered oxidative stress in healthy old subjects.

To understand the magnitude of oxidative phenomena during senescence, we evaluated, as antioxidant, the activity of glutathione peroxidase (GSH-Px) in erythrocytes and plasma uric acid (UA) levels together with the malondialdehyde (MDA) levels in plasma, as an index of lipid peroxidation, in 46 apparently healthy elderly subjects (87 +/- 6 years old; mean +/- SD), and 49 young subjects (29 +/- 4 years old). The elderly subjects had lower erythrocyte GSH-Px activity (15.7 +/- 4.8 vs 20.2 +/- 7.0 U/g Hb, p < 0.001; mean +/- SD) and plasma UA levels (192 +/- 46 vs 240 +/- 54 mmol/L, p < 0.001), but higher MDA levels (5.3 +/- 0.8 vs 4.1 +/- 0.8 mmol/L, p < 0.001) than the young subjects. Of additional interest was the finding of a positive correlation between age and erythrocyte GSH-Px activity (r = 0.74, p < 0.001), and a negative correlation between age and plasma MDA levels (r = -0.83, p < 0.001) in the elderly group. Although erythrocyte (GSH-Px activity was significantly less in the elderly than in the young group, the oldest subjects showed the greatest erythrocyte GSH-Px activity and had lower MDA levels.

Fibrinolytic parameters in patients undergoing total hip replacement: relationship with the development of asymptomatic deep vein thrombosis and diagnostic usefulness of venous occlusion.

BACKGROUND AND OBJECTIVE: It has been suggested that impaired fibrinolytic activity contributes to deep vein thrombosis in orthopedic surgery. Studying the fibrinolytic system following venous occlusion has been proposed as a good method of detecting the risk of this postoperative complication. The objective of this work was to verify whether venous occlusion represents a reliable method of detecting an impaired fibrinolytic response after total hip replacement. METHODS: Thirty-two consecutive patients undergoing total hip replacement were studied. Citrated blood samples were taken from each patient the day before surgery and on postoperative days 1, 3, and 7, before and after venous occlusion, in order to evaluate plasma levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1). All patients underwent bilateral phlebography 10 days after surgery. RESULTS: Seven out of 32 patients (21.9%) developed deep venous thrombosis (DVT) according to the venographic test. After surgery, an increase in t-PA antigen levels was detected both in patients who developed DVT and in those who did not, with a significant increase on the first and seventh days after surgery only in the non-DVT group. After 10-min venous occlusion, t-PA antigen levels increased at all postoperative recordings in both groups of patients, but most significantly on days 1 and 7 after surgery. PAI-1 antigen plasma levels, when measured before venous occlusion, increased only in non-DVT patients on the seventh postoperative day. After venous occlusion, a difference was found between the two groups only postoperatively on day 7 with regard to PAI-1 levels. INTERPRETATION AND CONCLUSIONS: According to our results, no impaired fibrinolytic response was found in DVT patients. In addition, venous stasis seems to give no further information with respect to basal values in the early detection of postoperative thromboembolic complications in orthopedic patients.

Reference values of neuroactive amino acids in the cerebrospinal fluid by high-performance liquid chromatography with electrochemical and fluorescence detection.

Sampling and HPLC analysis procedures for CSF amino acid determinations were evaluated. In order to increase sensitivity, a precolumn derivatization of amino acids by o-phthalaldehyde-mercaptoethanol reagent was used. By using fluorimetric and electrochemical detection in series, positive peak identification can be obtained in a single chromatographic run. It is recommended to analyze freshly collected CSF. Amino acids are stable for short periods over a wide range of temperature, but storage at -80 degrees C is recommended. The CSF samples for the calculation of the reference values were taken from 40 healthy subjects, hospitalized for lumbar disk herniation, placed on the same diet and kept drug-free for at least 1 week. The mean values (mumol/l) and the ranges (in parentheses) were: 0.27 (0.09-0.63), 0.62 (0.18-1.15), 5.32 (3.05-11.50), 6.16 (2.90-13.30), 0.16 (0.03-0.22) for aspartic acid, glutamic acid, glycine, taurine and gamma-aminobutyric acid respectively.

Determination of illicit drugs and related substances by high-performance liquid chromatography with an electrochemical coulometric-array detector.

A general method for the simultaneous determination of fifteen common drugs (6-acetylmorphine, 3,4-methylenedioxymetamphetamine, buprenorphin, cocaine, codeine, dihydrocodeine, ethylmorphine, heroin, hydrocodone, lidocaine, methadone, morphine, naloxone, procaine and thebaine) was developed using reversed-phase HPLC and electrochemical detection. The separation of the drugs was achieved by using as the mobile phase 20 mM monobasic sodium phosphate-acetonitrile (90:10) with a gradient to 50% of the organic modifier, on a silica based C18 column (150 x 4.6 mm I.D.) of 3 microns particle size and by the selectivity supplied by an array of eight coulometric electrodes at increasing potential. It was possible to identify and to determine fifteen different drugs in the same chromatographic run in 50 min. The method was tentatively applied to the determination of drugs in extracts of human hair.

Increased urinary N-acetyl-beta-glucosaminidase (NAG) excretion in young insulin-dependent diabetic patients.

We evaluated urinary N-acetyl-beta-glucosaminidase (NAG) excretion in overnight and in second morning urine in 50 young diabetic patients, aged 7.4-25 years with a disease duration from 2-19.6 years. In all patients we evaluated urinary NAG and creatinine excretion, in both overnight and second morning urine, glycosuria, fasting blood glucose and HbA1c levels, insulin requirement, blood pressure, and the presence of microangiopathic complications. Urinary NAG excretion was also evaluated in 69 age- and sex-matched controls. NAG was determined using 3-cresolsulfonphtaleinyl-beta-N-acetylglucosaminide as substrate (Boehringer Mannheim, Germany). In the diabetic patients NAG/Cre ratios were significantly higher than in controls both in overnight and second morning urine (P < 0.0005, respectively). We observed significantly higher NAG/Cre ratio levels in the second morning than in overnight urine, both in controls and in diabetics (P < 0.0005, respectively). Elevated (above 2 S.D. of the mean) NAG/Cre ratios were found in 17/50 patients (34%) in overnight urine and in 29/50 (58%) in second morning urine. No correlation was observed between NAG/Cre ratio levels and age, duration of disease, pubertal stage, body mass index, fasting blood glucose, glycosuria, insulin requirement and blood pressure. The patients with one or more complications did show NAG/Cre ratio levels significantly higher than those without complications (P < 0.005) in second morning urine, but not in overnight urine. Our study has demonstrated an increased rate of urinary NAG excretion in young IDDM patients, in particular in those with microangiopathic complications.

Clinical evaluation of a new rapid assay for serum lipase determination.

We evaluated a new continuous colorimetric method for serum lipase determination based on the use of a 1,2-diglyceride as substrate and a specific 2-monoglyceride lipase. This test was compared with a turbidimetric assay and also with serum alpha-amylase and pancreatic isoamylase determinations. We studied 32 patients with acute pancreatitis, 27 with chronic pancreatitis in acute painful relapse, 19 with pancreatic cancer, 44 with other digestive diseases, 53 with end-stage renal disease, and 102 healthy controls. The results of the new test were closely correlated with those of the turbidimetric method (r = 0.96). Sensitivity of the new method was elevated (100%): it was the same as that of the turbidimetric method, but slightly higher than that of alpha-amylase and pancreatic isoamylase determinations (93.7 and 96.9%, respectively). Specificity was 95.5%, i.e. higher than that observed using the other tests (86.4, 84.1 and 88.6% for lipase turbidimetric assay, amylase, and pancreatic isoamylase determinations, respectively). The results demonstrate that this new lipase assay is a sensitive, specific test for the diagnosis of acute pancreatitis.