Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ESTERASES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed1984

[Detection of T lymphocytes with acid alpha-naphthyl acetate esterase. Specificity and use in pleural effusions].

A modified technique for demonstration of acid alpha-naphthylacetate esterase was examined with regard to specificity and application on human T-lymphocytes in peripheral blood and pleural fluids of different genesis. T-lymphocytes of healthy donors showed only in 60% positive findings of acid alpha-naphthylacetate esterase. Positive reactions appear as dot-like reaction products in cytoplasm of lymphocytes. The application of this method on pleural fluids is possible, without technical problems. We found differences in the percentage of positive-reacting lymphocytes in pleural fluids between tuberculosis (= 78% T-cell esterase positive lymphocytes) and tumors (= 65% T-cell esterase positive lymphocytes). Mesotheliomas exhibit very low positive findings (= 32% T-cell esterase positive lymphocytes) in contrast to carcinomas. In this way, acid alpha-naphthylacetate esterase may be helpful in some cases as a diagnostic aid.

Humans↗
PubMed1984

Subunit interactions of 7 S nerve growth factor. Gamma-esterase activity, rates, and conformational changes during reassociation.

The gamma-esterase activity of 7 S nerve growth factor (NGF) is depressed relative to free subunit because of constraints within the oligomer. 4 M urea causes a reversible dissociation of 7 S NGF and concomitant increase in esterase activity. The gamma-esterase activity with tosyl-arginyl-methyl-ester increased between 1 and 4 M urea and was inhibited at higher concentrations. Upon dilution of 7 S NGF from 6 M urea, the esterase activity was initially identical with that of the similarly treated gamma-subunit but decayed rapidly (10 min) to approach that of the native 7 S NGF. In the presence of 100 microM EDTA the activity was higher, but still required the same length of time to reach a constant depressed value. Upon dilution of 7 S NGF from 2 M NaCl the rapid decay was not observed and the activity remained constant at about the same level as the equilibrium values for the urea-treated and renatured 7 S NGF. A red shift in the fluorescence maximum and a concomitant increase in quantum yield occurred for the 7 S in 8 M urea. Dilution into buffer resulted in a rapid decay and return to native 7 S fluorescence but not when EDTA was included. Both the decay in esterase activity and in fluorescence intensity upon dilution from urea were first order reactions with a rate constant of about 8 X 10(-3) s-1 suggesting that both methods were measuring a unimolecular renaturation process. Renaturation from NaCl or recombination of isolated subunits was much more rapid, indicating a simple combination of subunits in a native conformation. The circular dichroism spectra of urea and NaCl-treated 7 S NGF were different, and spectra of the renatured species with and without EDTA differed. Reassociation to a conformationally different 7 S NGF probably occurs in the presence of EDTA. The results emphasize the role of zinc in 7 S NGF formation and the influence of conformational changes in the effect of beta-NGF on the activity of the gamma-esterase in 7 S NGF.

Animals↗
PubMed1982

Nonspecific esterase of B lymphocytes from a case of chronic lymhocytic leukemia and of normal T lymphocytes: similar constellations of isoenzymes.

Lymphocytes from a case of B-cell chronic lymphocytic leukemia (CLL) were obtained in a highly purified state from a therapeutic leukapheresis preparation. The CLL lymphocytes showed a fine, scattered, granular pattern of nonspecific esterase cytochemical reactivity with either alpha-naphthyl acetate (alpha NA) or alpha-naphthyl butyrate (alpha NB) substrate as opposed to the more focal pattern of control (T) lymphocytes. Nonspecific esterase of CLL lymphocytes and normal control lymphocytes was equally resistant to inhibition by fluoride ion. Extractable nonspecific esterases from the CLL lymphocytes and from purified normal T lymphocytes were indistinguishable in regard to specific activity, substrate specificity, pH optima, and zymogram profiles on polyacrylamide gel electrophoresis at pH 9.5 and pH 4.0. Zymograms of alpha NA esterase and alpha NB esterase prepared by isoelectric focusing were also similar, with no unequivocal differences. These results are consistent with recent reports that B lymphocytes contain detectable nonspecific esterase and suggest that the B lymphocytes from this case of CLL contained a constellation of isoenzymes similar to that of normal T lymphocytes. This is interpreted as a reflection of the close kinship of these cells.

B-Lymphocytes↗
PubMed1982

Enzymologic classification of acute leukemias: nonspecific esterase markers distinguish myeloid and lymphoid varieties.

Nonspecific esterase zymograms of purified leukemic cells from a case of acute myelomonocytic leukemia (AMML) and from a case of acute non-B, non-T lymphocytic leukemia (ALL) were produced by isoelectric focusing and staining with alpha-naphthyl acetate (alpha NA) or alpha-naphthyl butyrate (alpha NB) substrate. A "myeloid" zymogram was found with AMML cells, which closely matched control monocyte and granulocyte zymograms. On the other hand, nonspecific esterase of ALL showed a striking departure from the zymogram pattern of control B lymphocytes and T lymphocytes. An intense reactivity with a very low isoelectric point accounted for most of the ALL nonspecific esterase activity. No corresponding reactivity or relatively small amounts thereof were seen in other zymograms. Conversely, few of the isoenzymes that were prominent in zymograms of control lymphocytes were apparent above trace levels in ALL zymograms. Thus, zymogram analysis of nonspecific esterases clearly differentiated the myeloid leukemia from the lymphoid leukemia and provided a potential marker for each. The AMML cells appeared well enough differentiated with respect to nonspecific esterases as to be similar to mature cells of like lineage. It is plausible that the ALL cells, however, were arrested at an earlier stage of esterase expression as reflected by the associated atypical species.

Acute Disease↗
PubMed1977

The role of an activatable esterase in immune-dependent phagocytosis by human neutrophils.

Diisopropylphosphofluridate, cyclohexyl alkylphosphonofluoridates, and cyclohexyl phenylalkylphosphonofluoridates, which are potent, irreversible inactivators of serine esterases, inhibit the phagocytosis of opsonized sheep erythrocytes by human neutrophils. Two types of inhibition were observed: a) 'cell-dependent' inhibition, which is determined by measuring the ingestion of neutrophils pre treated with the esterase inhibitors and washed; and b) 'phagocytosis-dependent' inhibition, which is due to the presence of the inhibitors during phagocytosis. With the cyclohexyl alkylphosphonofluoridates, phagocytosis-dependent inhibition was always greater than cell-dependent inhibition. Cell-dependent inhibition was irreversible and dependent on the duration of the incubation of neutrophils with inhibitor. Both types of inhibition were dependent on the concentration of the inhibitor. Poorly or non-phosphorylating analogues of the cyclohexyl alkylphosphonofluoridates of DFP were not inhibitory; nor did fluoride, the hydrolysis product of these inhibitors, inhibit ingestion under either condition. In addition, neither method of treating the neutrophils resulted in a decrease in neutrophil viability. Furthermore, pretreating the EAC1423 with the inhibitors did not decrease ingestion. We conclude that cell-dependent inhibition is due to the inactivation of an esterase required for phagocytosis which is in or on the neutrophil in an active form, and thus is susceptible to inhibition by the esterase inactivators before contact of the neutrophil with the phagocytic stimulus. Phagocytosis-dependent inhibition is interpreted as being due to inactivation of an esterase required for phagocytosis which is normally in an inactive precursor proesterase form that is activated by the interaction of the neutrophil with the phagocytic stimulus. The distinctly different inhibition profiles of the active and activatable esterases indicate that they are two different activities.

Cell Adhesion↗
PubMed1998

Purification of two rat hepatic proteins with A-esterase activity toward chlorpyrifos-oxon and paraoxon.

A-esterases are calcium-dependent hydrolases that can detoxify the active metabolites (oxons) of organophosphorus insecticides such as chlorpyrifos and parathion. A-esterases from rat liver have previously been shown to hydrolyze chlorpyrifos-oxon but not paraoxon at low substrate concentrations. Two A-esterases were extracted by ammonium sulfate fractionation from solubilized rat liver microsomes followed by gel filtration chromatography and preparative scale isoelectric focusing. The proteins displayed similar characteristics and were difficult to separate; both had similar high molecular mass and isoelectric point range and exhibited A-esterase activity toward high and low concentrations of chlorpyrifos-oxon and high concentrations of paraoxon. Sufficient amounts of the higher molecular mass protein were obtained for kinetic studies, which yielded a Km of 0.93 mM toward high concentrations of chlorpyrifos-oxon and a Vmax of 369 nmoles product formed/mg protein-min. The protein hydrolyzed phenyl acetate, chlorpyrifos-oxon and paraoxon, suggesting that arylesterase and A-esterase activities are attributable to the same liver protein(s). Assays of purified protein and kinetic studies of microsomes suggested that the activity toward high (320 microM) and low (</=10(-5) M) concentrations of chlorpyrifos-oxon are due to the same protein(s), and that the activity toward low concentrations of chlorpyrifos-oxon is attributable to both a higher affinity and a higher Vmax (but primarily the latter) for chlorpyrifos-oxon than for paraoxon, which is not detectably hydrolyzed at low concentrations. The higher A-esterase activity with chlorpyrifos-oxon than paraoxon may be a major determinant in the observed lower acute toxicity of chlorpyrifos than parathion.

Animals↗
PubMed1988

Immunocytochemical localization of a kallikrein-like serine protease (esterase A) in rat salivary glands.

Light and electron microscopic (EM) immunocytochemical methods have been used to localize arginine esterase A, a kinin-generating enzyme immunologically similar to tissue kallikrein, in rat salivary glands. Both polyclonal and monoclonal antibodies to arginine esterase A were used in these studies. By means of a polyclonal antiserum, esterase A was found in granular tubules of submandibular glands and in striated ducts of all three major salivary glands, in a distribution similar to that of tissue kallikrein. With recently developed specific monoclonal antibodies to esterase A, this enzyme was localized in the granules of some (but not all) granular convoluted tubule cells (GCT) and along the basal membranes (but not in apical granules) of striated ducts. By an EM immunoperoxidase method, esterase A was localized subcellularly in granules of some GCT cells and along the basal cell membranes of the tubule and duct system. Thus, this enzyme is found in some sites (GCT granules) shared with tissue kallikrein, but in some unique sites, i.e., basal membranes of striated ducts. The polyclonal antibody used in the present study cross-reacted with tissue kallikrein, but when absorbed with kallikrein, it gave the staining pattern characteristic of monoclonal antibody to esterase A.

Animals↗
PubMed1994

Juvenile hormone esterase purified by affinity chromatography with 8-mercapto-1,1,1-trifluoro-2-octanone as a rationally designed ligand.

Trifluoromethyl ketones are potent inhibitors of a variety of serine hydrolases. Based on this chemistry improved affinity chromatography procedures were developed for juvenile hormone esterase from insects. New affinity gels were prepared by binding rationally designed ligands to epoxy-activated Sepharose. One ligand is 8-mercapto-1,1,1-trifluoro-2-octanone which has a methylene group replacing a sulfide sulfur beta to the carbonyl of the trifluoromethyl ketone of the previously reported ligand, 3-(4-mercaptobutylthio)-1,1,1-trifluoro-2-propanone. With many loading levels and esterases, the original gel bound enzymes too tightly, resulting in elution difficulties. This replacement of the sulfur beta to the ketone thought to interact with the catalytic serine decreases the binding capacity of the gel at similar loading by approximately 56% compared to the affinity gel with the thioether. However, elution of the enzyme from the column can be accomplished with less potent inhibitors such as 3-n-butylthio- or 3-n-pentylthio-1,1,1-trifluoro-2-propanone, which can easily be removed from the enzyme by dialysis in the presence of the detergent n-octyl beta-D-glucopyranoside. An alternative approach allowing elution with less potent inhibitors involved varying concentrations of the previous high-affinity ligand to optimize the concentration of ligand on the column. Low concentrations of the high-affinity ligand also allowed the use of less potent eluting agents. These two improved affinity chromatography systems have been successfully used to purify juvenile hormone esterase of Heliothis virescens to near homogeneity with a 30-90% recovery of recombinant esterase secreted into the cell media in a baculovirus expression system. The purity of the esterase after affinity chromatography with newly prepared gel was comparable to that produced using the original affinity system based on analyses by SDS-PAGE and isoelectric focusing. A library of affinity gels with ligands of different affinities used at several loading levels and a library of eluting inhibitors of varying potency facilitate the rational selection of conditions for the affinity purification of esterases.

Animals↗
PubMed1988

Human esterase D gene: complete cDNA sequence, genomic structure, and application in the genetic diagnosis of human retinoblastoma.

The gene encoding human esterase D (EsD), a member of the nonspecific esterase family, is a useful genetic marker for retinoblastoma (RB) and Wilson's disease. Previously we identified a cDNA clone from this gene and determined its chromosomal location. In this report, we present the complete cDNA sequence of the human EsD gene. A long open reading frame encoded a predicted protein of 282 amino acids with molecular weight of 30 kD. A computer-assisted search of a protein sequence data base revealed homology with two other esterases, acetylcholinesterase of Torpedo and esterase-6 of Drosophila. Homologous region were centered around presumptive active sites, suggesting that the catalytic domains of the esterases are conserved during evolution. Three genomic clones of this gene were also isolated and characterized by restriction mapping. At least ten exons were distributed over a 35-kb (kilobase pair) region; each exon contained an average of 100 basepairs (bp). A polymorphic site for Apa I, located within an intron of the esterase D gene, can be used to identify chromosome 13 carrying defective RB alleles within retinoblastoma families.

Amino Acid Sequence↗
PubMed1992

Identification of two distinct amplifications of the esterase B locus in Culex pipiens (L.) mosquitoes from Mediterranean countries.

Two new highly active esterases were detected by starch electrophoretic studies in Culex pipiens mosquitoes from the area of Montpellier (France) and from Cyprus. We demonstrate here that both the French and the Cyprus esterases B are overproduced due to amplification of the coding gene. The production of the esterase B is approximately 50- and 500-fold higher in mosquitoes from France and Cyprus, respectively, than in susceptible insects, whereas the number of gene copies is about 25 and 250. Differences of about 7- and 95-fold were also found in the degree of chlorpyrifos resistance. RFLP comparison of the amplified region containing the esterase B gene revealed large differences between French and Cyprus mosquitoes. It thus appears that two distinct haplotypes with an esterase B gene coding an enzyme with identical electrophoretic mobility have been amplified. We therefore named the haplotypes in mosquitoes from France and Cyprus B4 and B5, respectively. The estimated genetic distance between these two haplotypes is not smaller than those observed in all pair comparisons of other known esterase B haplotypes. These results are discussed in the context of amplification phenomena.

Animals↗
PubMed2003

Acute upper airway angioedema secondary to acquired C1 esterase inhibitor deficiency: a case report.

PURPOSE: Adverse reactions to local anesthetics are widely reported. We report a case of acute upper airway angioedema presumed to be due to the local anesthetic articaine, which was subsequently diagnosed as acquired C1 esterase inhibitor deficiency. CLINICAL FEATURES: A 54-yr-old woman presented with a history of progressive facial and periorbital edema 24 hr after receiving articaine local anesthetic for a dental procedure. She was in mild respiratory distress but was not stridorous. After inhalational induction with sevoflurane in the operating room, direct laryngoscopy revealed marked edema of supraglottic structures including epiglottis, uvula and aryepiglottic folds and the larynx was not visualized. The patient's trachea was intubated under direct laryngoscopy. Seventy-two hours later, the endotracheal tube was removed and she made an uneventful recovery. Initially, the angioedema was thought to be caused by a hypersensitivity reaction to articaine. Later investigations showed normal C3 complement level, very low C4 complement and C1 esterase inhibitor levels confirming a diagnosis of C1 esterase inhibitor deficiency. Subsequently, the patient was started on androgen therapy. Her C1 esterase inhibitor level normalized and she remained symptom free nine months after initial presentation. CONCLUSION: We report a case of acute upper airway angioedema secondary to C1 esterase inhibitor deficiency requiring emergency airway management. Anesthesiologists should consider C1 esterase inhibitor deficiency in the differential diagnosis of patients with airway edema and be familiar with the acute and prophylactic treatment of patients with this diagnosis.

Acute Disease↗
PubMed2001

The effect of community-acquired pneumonia on plasma esterases in older people.

INTRODUCTION: Pneumonia is a major cause of morbidity and mortality in older people. The poor outcome of older pneumonia patients despite treatment is still not understood. OBJECTIVE: The aim of this study was to examine the effect of community-acquired pneumonia on enzymes of drug metabolism in older people. METHODS: Fifteen patients (median age 67 years) with a clinical and radiological diagnosis of community-acquired pneumonia and 14 healthy volunteers matched for age and gender (median age 75 years) were recruited. Plasma activities of benzoylcholinesterase, butyrylcholinesterase, acetylcholinesterase and aspirin esterase were determined spectrophotometrically at three time points in pneumonia patients--within 24 h of admission to hospital, 2 days later and 10 days later. Monocyte aryl hydrocarbon hydroxylase (AHH) activity was determined spectrofluorimetrically at the same time points. Enzyme activities were measured at one time point in healthy controls. RESULTS: Mean plasma benzoylcholinesterase activity was significantly lower in pneumonia patients on admission to hospital (mean +/- SEM 848 +/- 100) and after 10 days of treatment (mean +/- SEM 925 +/- 114) than in healthy controls (mean +/- SEM 1333 +/- 84, P < 0.05). Similarly, plasma acetylcholinesterase activity was significantly lower in pneumonia patients on admission (P = 0.007) and after 10 days of treatment (P = 0.01) than in controls. Butyrylcholinesterase activity was lower in pneumonia patients on admission (P = 0.029) than in healthy controls, but improved slightly after treatment so there was no longer a significant difference at 10 days compared with controls (P = 0.077). In contrast there were no significant differences in plasma aspirin esterase activity or induced monocyte AHH activity between pneumonia patients and healthy controls. The activities of benzoylcholinesterase (r = -0.536, P = 0.04), butyrylcholinesterase (r = -0.638, P = 0.01), acetylcholinesterase (r = -0.583, P = 0.022) and aspirin esterase (r = -0.624, P = 0.013) correlated inversely with the British Thoracic Society pneumonia poor prognostic index. CONCLUSION: The activities of several esterases are reduced in older pneumonia patients. Other enzymes including aspirin esterase and induced monocyte AHH activity are unaltered in pneumonia. There was a significant inverse relationship between the activities of all esterases studied and the British Thoracic Society pneumonia poor prognostic index.

Acetylcholinesterase↗
PubMed1983

Partial purification and properties of sheep serum "A'-esterases.

Using paraoxon and pirimiphos-methyl as substrates, much of the "A'-esterase activity of sheep serum was found to be in the high-density lipoprotein (HDL) fraction. A method was developed for the partial purification of "A'-esterases by the preparation of a lipoprotein fraction, followed by preparative polyacrylamide gel electrophoresis. The properties of the partially purified preparations of "A'-esterase were studied. Although four different preparations all contained a major protein unit, which resembled the core protein of HDL, there was evidence of differences between preparations with regard to substrate specificity, suggesting the existence of multiple enzyme forms. Gel filtration of serum samples indicated that paraoxonase activity is expressed by proteins with mol. wts greater than 200,000, strongly suggesting that the "A'-esterase activity of the lipoprotein fraction is present in one or more forms of HDL2. The dependence of "A'-esterase activity upon Ca2+ and the problem of esterase classification are discussed.

Animals↗
PubMed1996

Identification and isolation of two rat serum proteins with A-esterase activity toward paraoxon and chlorpyrifos-oxon.

The active metabolites (oxons) of phosphorothionate insecticides can be detoxified via A-esterase hydrolysis. Two enzymes with A-esterase activity have been isolated from rat serum. Whole serum was applied to anion exchange gel (DEAE Sepharose Fast Flow) and incubated (1 hr). Tris-HCl buffer (0.05 M; pH 7.7, at 5 degrees) containing 0.25 M NaCl was added to the slurry and incubated. The decant, containing low A-esterase activity but a high protein concentration, was discarded. Further displacement of A-esterase from DEAE gel was achieved with 1.0 M NaCl in 0.05 M Tris-HCl buffer (Ph 7.7 at 5 degrees). Following desalting and concentration, further separation was achieved by gel filtration (Sephacryl S-100 HR) and two sequential preparative scale isoelectric focusings. Final fractions contained two proteins of high molecular mass (one about 200 kDa and one between 137 and 200 kDa). The apparent range of isoelectric points for the two enzymes was 4.5 to 5.6. Following native-PAGE analysis, activity stains with beta-naphthyl acetate and Fast Garnet GBC in the presence of paraoxon (10-5 M) verified that A-esterase activity was associated with both proteins. Spectropho-tometric assay detected A-esterase activity toward paraoxon, chlorpyrifos-oxon, and phenyl acetate in the final preparation.

Acetylcholinesterase↗
PubMed1984

Temporal variations of hemolymph esterase activity and juvenile hormone titers during ovocyte maturation in Acheta domesticus (Orthoptera).

Using in vitro methods, juvenile hormone (JH) esterase activity and alpha-naphthylacetate esterase activity were determined in the hemolymph during the first reproductive cycle of the house cricket, Acheta domesticus. Biochemical properties of the hemolymph JH esterase were studied. alpha-Naphthylacetate esterases increased during the first gonotrophic cycle: peaks of their activity could be observed concomitant with peaks of JH esterase activity. The fluctuations in JH esterase activity correlated with those of hemolymph JH titers. The results are discussed.

Animals↗
PubMed1993

Transcriptional regulation of dog prostate arginine esterase gene by androgens.

These studies were designed to define the molecular events involved in the modulation of dog prostate arginine esterase gene expression following short castration intervals and androgen treatment. Arginine esterase enzymatic activity and protein levels decreased about 50% 24 h after castration. Thereafter, a more progressive decrease was observed, resulting in 2-4-fold lower levels in 12-day castrates than in the intact controls. Total prostatic arginine esterase mRNA levels slowly decreased during the first five days after castration but more abruptly thereafter and were about 150-fold lower in 12-day castrated animals. By contrast, in isolated prostatic nuclei, levels of arginine esterase RNA precursors and mature transcripts rapidly fell following orchiectomy, with a 50-70% decrease 24 h after castration. Nuclear run-on experiments confirmed that the latter effects were the result of decreased arginine esterase gene transcription. All these changes could be at least partially reversed by administration of testosterone cypionate. Furthermore, no striking modifications in the proportion of epithelial/stromal cells in the prostatic tissue were observed following orchiectomy. These results show that castration and androgens exert very rapid effects on the gene expression of arginine esterase, and that the regulation occurs at the transcriptional level.

Androgens↗
PubMed2005

Butyrylcholinesterase, paraoxonase, and albumin esterase, but not carboxylesterase, are present in human plasma.

The goal of this work was to identify the esterases in human plasma and to clarify common misconceptions. The method for identifying esterases was nondenaturing gradient gel electrophoresis stained for esterase activity. We report that human plasma contains four esterases: butyrylcholinesterase (EC 3.1.1.8), paraoxonase (EC 3.1.8.1), acetylcholinesterase (EC 3.1.1.7), and albumin. Butyrylcholinesterase (BChE), paraoxonase (PON1), and albumin are in high enough concentrations to contribute significantly to ester hydrolysis. However, only trace amounts of acetylcholinesterase (AChE) are present. Monomeric AChE is seen in wild-type as well as in silent BChE plasma. Albumin has esterase activity with alpha- and beta-naphthylacetate as well as with p-nitrophenyl acetate. Misconception #1 is that human plasma contains carboxylesterase. We demonstrate that human plasma contains no carboxylesterase (EC 3.1.1.1), in contrast to mouse, rat, rabbit, horse, cat, and tiger that have high amounts of plasma carboxylesterase. Misconception #2 is that lab animals have BChE but no AChE in their plasma. We demonstrate that mice, unlike humans, have substantial amounts of soluble AChE as well as BChE in their plasma. Plasma from AChE and BChE knockout mice allowed identification of AChE and BChE bands without the use of inhibitors. Human BChE is irreversibly inhibited by diisopropylfluorophosphate, echothiophate, and paraoxon, but mouse BChE spontaneously reactivates. Since human plasma contains no carboxylesterase, only BChE, PON1, and albumin esterases need to be considered when evaluating hydrolysis of an ester drug in human plasma.

Acetylcholinesterase↗
PubMed2003

A preliminary evaluation of the interaction between urine specific gravity and leukocyte esterase results using Bayer Multistix and the Clinitek 500.

OBJECTIVES: To determine the sensitivity of the leukocyte esterase (LE) pad to predict microscopically quantified white blood cells in urine sediment and to assess the interaction of urine specific gravity (SG) on leukocyte esterase sensitivity. METHODS: Microscopic quantification of white blood cells in urine sediment was performed manually and automated chemical urinalysis was performed using the Bayer Clinitek 500 and Multistix 8 SG strips on 422 random urine specimens. RESULTS: The sensitivity of the leukocyte esterase pad to predict white blood cells in centrifuged urine was 58% (61/106). There was a weak but statistically significant negative correlation between SG and LE pad performance, r = -0.12, p < 0.05. CONCLUSIONS: The 58% sensitivity of the Multistix leukocyte esterase detection of white blood cells in urine sediment was consistent with previous reports. The negative correlation of specific gravity and leukocyte esterase provides partial explanation for the lack of sensitivity of the leukocyte esterase test.

Adolescent↗