Urinary lactic dehydrogenase isoenzyme 5 in the differential diagnosis of kidney and bladder infections

Caspase-like activity is associated with bacterial infection of the urine in urinary tract diseases

Urinary tract infections (UTIs) are a serious public health problem. They can be caused by a number of pathogens, but the most common are Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis and Staphylococcus saprophyticus. Bacterial infection is diagnosed by examining a urine sample. The presence of bacteria or white blood cells is determined under a microscope or a urine culture is performed. In this study, we used a panel of chromogenic substrates for the qualitative determination of specific enzyme activity in the urine of patients with confirmed bacterial infection and/or urinary tract disease. Healthy patients were used as a control group. It turned out that in the case of Escherichia coli infection, we observed the activity of the caspase subunit of the human 20S proteasome. We did not observe similar correlations for infections with other types of bacteria.

Lactate dehydrogenase isoenzymes in patients with acute exacerbation of chronic obstructive pulmonary disease: An exploratory cross-sectional study

We aimed to evaluate differences in serum lactate dehydrogenase (LDH) isoenzymes between patients hospitalized for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and other lower respiratory tract infections (LRTIs). Based on self-reported COPD diagnosis, 71 participants were divided into AECOPD (n = 38, 29 males, mean age 70.5 years) and LRTI (n = 33, 12 males, mean age 70.4 years) groups. Information on demographics, comorbidities, and COPD severity markers, as well as arterial blood gases and laboratory data were collected, while serum LDH electrophoresis was performed to examine the LDH isoenzymes. Adjusting for sex, age, comorbidities, degree of hypoxemia, inflammation markers, muscle and myocardial enzymes, and total serum LDH, the mean differences (95 % confidence intervals) in the ratios of serum LDH isoenzymes to total serum LDH between groups (LDHx_AECOPD - LDHx_LRTI) were statistically significant for LDH1 [4.9 (1.4 to 8.3)], LDH2 [3.0 (0.1 to 5.8)], LDH3 [-4.3 (-6.3 to -2.3)], and LDH4 [-3.2 (-4.9 to -1.5)]. A sum of LDH3 and LDH4 ratios below 29 % had the highest discriminative ability to classify a subject in the AECOPD group (AUC 0.841, sensitivity 76 %, specificity 87 %). Aerobic metabolic adaptive mechanisms in respiratory muscles during AECOPD could explain the above differences.

Usefulness of Dialysate Fibrin Degradation Products and Lactic Dehydrogenase Isoenzyme Patterns in Assessing the Clinical Course of Peritonitis

Objective

To establish the usefulness of fibrin degradation products (FDP) and lactic dehydrogenase isoenzyme patterns (LDH isoenzyme) in assessing the clinical course of peritonitis.

Design

A retrospective study of patients with peritonitis who were divided into three groups according to their clinical course.

Setting

Single dialysis unit of a general hospital.

Interventions

Patients were treated by intraperitoneal and oral antibiotics.

Patients

Twenty-six patients with 34 episodes of peritonitis were studied. Group 1 consisted of 21 patients with 26 recoveries from peritonitis; Group 2 consisted of 5 patients with 5 relapsing episodes of peritonitis, and Group 3 consisted of 3 patients with 3 persistent episodes of peritonitis.

Main Outcome Measures

Concentrations of WBCs, FDP, LDH isoenzyme and microbiological culture of the dialysate were determined.

Results

In most of Group 1, WBCs, FDP, and LDH isoenzyme returned to normal within 2 weeks. In 4 patients of Group 1, who had complications (diverticulitis, cholecystitis, cystitis, and tunnel infection), WBCs, FDP, and LDH isoenzyme returned to normal gradually within 3 weeks. In Group 2, WBCs returned to normal, but FDP remained relatively high and LDH isoenzyme did not normalize. In Group 3, WBCs, FDP and LDH isoenzyme did not normalize.

Conclusions

Failure of normalization of FDP and LDH isoenzyme suggests an incomplete recovery from peritonitis. FDP and LDH isoenzyme are useful in assessing the course of peritonitis.

Clinical implications of LDH isoenzymes in hemolysis and continuous-flow left ventricular assist device-induced thrombosis

Pump-induced thrombosis continues to be a major complication of continuous-flow left ventricular assist devices (CF-LVADs), which increases the risks of thromboembolic stroke, peripheral thromboembolism, reduced pump flow, pump failure, cardiogenic shock, and death. This is confounded by the fact that there is currently no direct measure for a proper diagnosis during pump support. Given the severity of this complication and its required treatment, the ability to accurately differentiate CF-LVAD pump thrombosis from other complications is vital. Hemolysis measured by elevated lactate dehydrogenase (LDH) enzyme levels, when there is clinical suspicion of pump-induced thrombosis, is currently accepted as an important metric used by clinicians for diagnosis; however, LDH is a relatively nonspecific finding. LDH exists as five isoenzymes in the body, each with a unique tissue distribution. CF-LVAD pump thrombosis has been associated with elevated serum LDH-1 and LDH-2, as well as decreased LDH-4 and LDH-5. Herein, we review the various isoenzymes of LDH and their utility in differentiating hemolysis seen in CF-LVAD pump thrombosis from other physiologic and pathologic conditions as reported in the literature.

Urinary Lactate Dehydrogenase Activity and Its Isozyme Patterns in Kawasaki Disease

Abnormal urinary findings, such as sterile pyuria, proteinuria, and microscopic hematuria, are often seen in the acute phase of Kawasaki disease (KD). We investigated the potential significance of urinary lactate dehydrogenase (U-LDH) activity and its isozyme patterns in KD. Total U-LDH activity and its isozymes (U-LDH1-5) levels were compared among 120 patients with KD, 18 patients with viral infection (VI), and 43 patients with upper urinary tract infection (UTI) and additionally compared between intravenous immunoglobulin (IVIG) responders (n = 89) and nonresponders (n = 31) with KD. Total U-LDH activity was higher in KD (35.4 ± 4.8 IU/L, P < 0.05) and UTI patients (66.0 ± 8.0 IU/L, P < 0.01) than in VI patients (17.0 ± 6.2 IU/L). In the isozyme pattern analysis, KD patients had high levels of U-LDH1 and U-LDH2, while UTI patients had high levels of U-LDH3, U-LDH4, and U-LDH5. Furthermore, IVIG nonresponders of KD had significantly higher levels of total U-LDH activity (45.1 ± 4.7 IU/L, P < 0.05), especially U-LDH1 and U-LDH2 (P < 0.05), than IVIG responders (32.0 ± 2.8 IU/L). KD patients have increased levels of total U-LDH activity, especially U-LDH-1 and U-LDH2, indicating a unique pattern of U-LDH isozymes different from that in UTI patients.

Diagnostic potential of urinary enzymes and beta 2-microglobulin in acute urinary tract infection

Urinary excretions of beta 2-microglobulin (beta 2M), N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase, beta-glucuronidase, acid and neutral alpha-glucosidase as indicators of proximal tubular dysfunction were measured in patients with acute upper and lower urinary tract infection (UTI) and fever of non-renal origin. The sensitivity of beta 2M was 67% and of NAG 49% as assessed in more than 100 episodes of acute pyelonephritis. Combined use of beta 2M and NAG increased the sensitivity to 75%. The degree of beta 2-microglobulinuria and enzymuria was comparable in patients with acute pyelonephritis and fever due to non-renal infections. The excretion of beta 2M and the various enzymes was too variable and unpredictable in individual cases to be useful as diagnostic indicator. In localizing an acute UTI, tests for proximal tubular dysfunction seem to be of no more clinical value than properly measured body temperature.

Proteinuria and Enzymuria in Vesicoureteric Reflux

Vesicoureteric reflux is a common abnormality of the urinary tract leading to significant renal morbidity and premature mortality. No reliable non-invasive method exists for its diagnosis. This study investigated the presence of urinary proteins and enzymes in healthy children and those with reflux. A log normal distribution was found for all analyte/creatinine ratios. Significantly higher tubular protein/creatinine ratios were found in patients with reflux nephropathy. Three enzyme/creatinine ratios (n-acetyl-B-D-glucosaminidase, gamma-glutamyl transferase and lactate dehydrogenase) were higher in children with reflux who had no renal scarring, but the degree of overlap with the normal range was such that it is doubtful whether any will be of use as a urinary marker.

N-acetyl-beta-D-glucosaminidase in the localisation of urinary tract infection in patients with spinal cord injury

This study evaluates the pattern of urinary N-acetyl-beta-D-glucosaminidase (NAG) isoenzyme excretion in patients with spinal cord injury (SCI) and its use as a diagnostic tool in localising the site of urinary tract infection (UTI). NAG-B excretion in 27 control SCI patients (mean 207.78 units) was significantly higher than in 10 normal controls (mean 12.6 units) p less than 0.001). The relative isoenzyme distribution as represented by NAG-B/Total NAG percentage is however similar in both groups, 24.27 and 20.38% respectively. NAG-B excretion in 6 SCI patients with upper UTI was not significantly higher than in 12 SCI patients with lower UTI. NAG-B/Total NAG percentage was significantly different between these two groups (35.3% and 24.98% respectively, p less than 0.05). There was no significant difference in NAG-B excretion or NAG-B/Total NAG percentage between control SCI patients and those with lower UTI. The results indicate that there is a non-selective increase in urinary NAG excretion in control SCI patients and those with lower UTI. In SCI patients with upper urinary UTI there is a selective increase in NAG-B excretion. The overlap in enzyme values between the different groups suggests that the test may not be clinically useful in localising the site of UTI.

Urinary lactic dehydrogenase isoenzyme analysis in children with spinal lesions

In 48 children with spinal lesions and micturition problems urinary lactic dehydrogenase (LDH) isoenzymes were analyzed. They had higher total LDH activities (716.8 +/- 1,050.2 nkat/I), isoenzymes V percents (22.2 +/- 13.0%) and isoenzyme V activities (203.4 +/- 308.4 nkat/I) than those of healthy children (150.0 +/- 83.4 nkat/I, 1.9 +/- 1.0%, 5.0 +/- 3.3 nkat/I). Many subjects had an isoenzyme V-dominant LDH isoenzyme pattern. Among 48 subjects the patients with pyuria, bacteriuria or abnormal pyelograms had markedly high total LDH activities, isoenzyme V percents and isoenzyme V activities. The rise in LDH isoenzyme V levels may reflect the renal damage in the patients with neurogenic bladders.

The relationship of lactic dehydrogenase to epithelial cells in the urine of normal neonates

Urinary lactic dehydrogenase (LDH) isoenzyme assays in 20 female and 15 male normal newborn infants during the first 3 days of life revealed higher levels than in older populations and a tendency toward a "slow zone pattern" (predominance of isoenzymes 4 and 5). Total LDH and LDH-5 activities were higher in the female (33.2 +/- 5.2 and 12.4 +/- 2.8 mU/mL, respectively), than in the male population (9.7 +/- 2.2 and 1.0 +/- 0.3 mU/mL, respectively). The amount of LDH correlated with the presence of epithelial cells in the urine that also were prominent in female patients and were apparently derived from the vagina. Separation of epithelial cells by centrifugation and filtration decreased total LDH and isoenzyme activities in the remaining sample, while sonification of the resuspended cells increased TLDH and LDH-5 activities by 6- and 12-fold respectively. Saline washings of the perineum and vagina revealed large numbers of epithelial cells and similar LDH isoenzyme patterns suggesting that contamination of the urine with these cells is a frequent occurrence during collection of voided and/or bag urine samples, and that these cells are responsible for much of the LDH activity found in the urine. We conclude that epithelial cells can increase both total LDH and isoenzyme activity in voided urine samples from otherwise normal female neonates. In this age group, urine collected by other methods (catheterization or suprapubic aspiration) must be studied to minimize the possibility of contamination of the sample with epithelial cells from the vagina or the perineum or both.

Lactate dehydrogenase isoenzymes

The analytical procedures for LD isoenzymes include electrophoresis, chromatography, immunochemical and kinetic methods. Electrophoretic methods are generally preferred because the resulting patterns are directly observable and all five isoenzymes are resolved in a single procedure. Chromatographic methods, with the introduction of HPLC, have recently been perfected in terms of speed, resolution, precision and accuracy. Immunochemical methods and kinetic methods are attractive because of their speed and simplicity. Therefore, the latter methods are used mainly for assaying acute myocardial infarction, where generally the determination of LD-1 and LD-2 is sufficient. In all other instances, however, electrophoretic separation is currently preferred. Ion-exchange high-performance procedures are useful prospects, particularly in view of their velocity in comparison with electrophoresis. In general, the LD isoenzymes assay contributes considerably to diagnosis, but the results must be used with an adequate knowledge of biochemistry, physiology and the advantages and drawbacks of the different assay methods used.

Chromatographic profiles of urinary isoenzymes in healthy children

Urinary excretion of alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase was studied in a carefully selected group of 155 healthy children, 83 females and 72 males. Enzyme activity was assayed in randomly collected urine samples after gel filtration of the urine specimens. On chromatograms, urinary enzymes of alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase were separated into 4, 2 and 5 isoenzymes, respectively. Mean values of alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase activity were 4.59, 21.6 and 10.0 U/g creatinine. There were no sex-related differences besides lactate dehydrogenase which showed a higher excretion in females than in males. The excretion of urinary enzymes clearly decreased with increasing age.

Alterations of urinary carbon dioxide tension, electrolyte handling and low molecular weight protein excretion in acute pyelonephritis

Renal tubular function tests were performed in 45 children suffering from upper and lower urinary tract infections. Determinations were made of the urinary carbon dioxide tension in maximally alkaline urine as an index of distal tubular H+-ion secretion, of urinary protein excretion, and of urinary sodium and phosphate handling. Urinary PCO2 was low (2.7 +/- 13.9 mmHg) in acute pyelonephritis compared to values in healthy children (52 +/- 32 mmHg) or those with cystitis (48 +/- 34 mmHg). At the onset of pyelonephritis an elevated fractional excretion of sodium (1.38 +/- 0.38 vs. 0.50 +/- 0.20%) and decreased phosphate reabsorption (69.2 +/- 7.1 vs. 90.4 +/- 4.9%) were also observed. Significantly elevated urinary low molecular weight protein excretion was also found in pyelonephritis. These data indicate the existence of proximal and distal tubular dysfunction at the onset of acute bacterial pyelonephritis.

Correlation of symptoms and results of direct bacterial localization in patients with urinary tract infections

During the last 8 years we localized 725 urinary tract infections in 213 patients via the bladder washout test. With this test the infections were located in the upper urinary tract in 11.9 per cent of the patients without vesicoureteral reflux, 27.1 per cent with reflux and 25.3 per cent without reflux after a successful antireflux operation. Of all supravesical and vesical bacteriuric episodes 57.6 and 67.1 per cent, respectively, were asymptomatic. The presence of symptoms differed only slightly among patients with and without reflux, and with and without pyelonephritic scars. Vesical symptoms, such as dysuria and frequency, were seen in 18.8 per cent of the patients with supravesical and 26.2 per cent with vesical infections, while fever and/or loin pain occurred in 23.6 and 6.7 per cent, respectively. However, urinary tract infections with loin pain and/or fever were localized evenly between the bladder and upper urinary tract. We conclude that factors other than the site of infection determine the presence or absence of symptoms.

Differentiation of upper and lower urinary tract infections: how and when?

The principal purpose of differentiating upper and lower urinary tract infections is to prevent renal damage by determining which patients require long-term antibiotic treatment and follow-up. This article takes a critical look at the method now in use for differentiation of these infections. Special attention is given to the problems of locating a urinary tract infection in a child, both because this is exceptionally difficult in this population and because kidney infections in children carry a high risk of permanent damage including renal failure and hypertension.

Urine lactic dehydrogenase--an aid in the management of patients with spinal cord injury

Urine lactic dehydrogenase (LD) and urinary LD isoenzyme determinations were performed for 59 adult afebrile patients with spinal cord lesions. Twenty-eight were found to have a predominance of LD 1 and 2. Thirteen had positive urine cultures and 12 also had positive antibody coated bacteria (ACB). Twenty were found to have a predominance of LD 4 and 5, with a mean total urine LD activity of 175.7 mU/ml. Sixteen of this group had positive urine cultures and 12 also ACB positive. Eleven had no demonstrable LD isoenzyme with a mean total urine LD activity of 17.5 mU/ml. Eight had positive urine cultures and four were also ACB positive. Forty-six normal controls had a mean LD activity of 15.1 mU/ml. In the study population changes in U-LD occurred in the absence of bacteriuria most frequently in patients who were appliance-free or used catheterization. In the absence of bacteriuria bladder overdistention may contribute to changes in LD isoenzyme patterns.

[Value of the assay of 4 urinary enzyme activities in the diagnosis of the infectious or toxic (aminoglycosides) origin of a renal disease. Preliminary results]

Occurrence of a renal failure in an infected patient may be referred to various causes: infection, renal toxicity of drugs (for instance aminoglycosides), shock . . . Determination of some urinary enzymatic activities might be helpful in unravelling the mechanism involved in such cases. Therefore a prospective study of the specificity of some urinary enzymatic activities was performed. The whole LDH activity, the LDH isoenzyme 5 (LDH 5), and two lysosomal enzymes, N-acetyl-beta-D-glucosaminidase (NAG) and beta-glucuronidase (beta-GLU) were dosed systematically, in several groups of patients: I (n = 34): healthy control, with normal renal function; II (n = 24): renal impairment, without recent upper urinary-tract infection (UTI) or aminoglycoside treatment; III (n = 27): upper UTI without aminoglycoside treatment, IV (n = 22): patients treated with aminoglycosides (without upper UTI); V (n = 16): upper UTI treated with aminoglycosides. Results showed a rather good specificity of whole LDH and LDH 5 for infectious kidney damage, and of NAG for tubular injury due to aminoglycoside treatments. Values of urinary beta-glucuronidase varied over a wide range; they were little increased in group III, without a great discriminative value. No significant difference was noted between group I and group II, for any enzyme whatever.

Urinary lactic dehydrogenase and serum C-reactive protein as means of localizing the site of urinary tract infection in patients with ileal conduits

Many patients with ileal conduit urinary diversion have infected urine but far fewer have clinical pyelonephritis. A noninvasive diagnostic test to distinguish renal bacteriuria from conduit colonization in these patients would seem desirable. Urine total lactic dehydrogenase and lactic dehydrogenase isoenzymes, and serum C-reactive protein have been useful to distinguish pyelonephritis from cystitis in patients with intact urinary tracts. We used these tests in patients with ileal conduits who had urine containing more and less than 10(5) organisms per ml. All patients had elevated urine total lactic dehydrogenase-5 isoenzyme, and serum C-reactive protein. No statistically significant difference in any of these parameters existed between the groups. These results may indicate that all patients with conduits have pyelonephritis but only intermittently demonstrate bacteriuria, or that the conduit mucosa contributes lactic dehydrogenase to the urine. However, it does not appear that these tests alone can distinguish accurately renal bacteriuria from conduit colonization.

The length of antimicrobial therapy in upper vs. lower urinary tract infection of childhood

235 infants and children were randomized to a 10-day and 42-day treatment group and followed-up for 12 months after their first urinary tract infection. The anatomical level of each symptomatic infection was determined using simple laboratory criteria. The two regimens prescribed were equally effective in eradicating the infection, but after the discontinuation of the 10-day treatment with sulfafurazole, 17 (23%) of 73 patients with their upper urinary tract infection experienced a recurrence within one month, as compared to only one (1) of 76 subjects in the 42-day therapy group. After the phase of early recurrence, there was no difference in recurrence rate between these groups. The early recurrences were associated with the patient's early age and a short duration of symptoms before therapy. The recurrence rate of first lower UTI after 10-day therapy was significantly lower than that after 42-day treatment. The duration of antimicrobial therapy for childhood urinary tract infection should be adjusted according to the patient's age and the anatomical level of the infection. 10-day treatment may not be sufficient to prevent early recurrence of pyelonephritic infections in infants under 6 months of age.

[Antibody coated bacteria in the urine: a specific test for pyelonephritis (author's transl)]

Three groups of subjects have been studied: the first group with sterile urine, the second with significant bacteriuria without antibody-coated bacteria and the third with significant bacteriuria with antibody-coated. IgG, IgA, IgM and transferrin were determined by immunological methods (partigen plates). The antibody coating was determined by immunofluorescence. Subcultures were prepared from the urine samples containing bacteria. The bacteria obtained from the subcultures were then incubated with the original urine which had been sterilised by passing through a filter. These were then treated with AH-IgG containing fluorescein. Serum was taken from several patients and incubated with the bacteria from the subcultures. These were also treated with AH-IgG fluorescein. In no case could specific antibodies against the infecting organisms be found, although IgG in the urine were elevated and specific antibodies were present in the serum. This leads to the conclusion that specific antibodies are formed by direct tissue contact of the bacteria and that coating is not established in the urine itself.