Clinical significance of pleural fluid lactate dehydrogenase/adenosine deaminase ratio in the diagnosis of tuberculous pleural effusion.

BACKGROUND: Pleural fluid is one of the common complications of thoracic diseases, and tuberculous pleural effusion (TPE) is the most common cause of pleural effusion in TB-endemic areas and the most common type of exudative pleural effusion in China. In clinical practice, distinguishing TPE from pleural effusion caused by other reasons remains a relatively challenging issue. The objective of present study was to explore the clinical significance of the pleural fluid lactate dehydrogenase/adenosine deaminase ratio (pfLDH/pfADA) in the diagnosis of TPE. METHODS: The clinical data of 618 patients with pleural effusion were retrospectively collected, and the patients were divided into 3 groups: the TPE group (412 patients), the parapneumonic pleural effusion (PPE) group (106 patients), and the malignant pleural effusion (MPE) group (100 patients). The differences in the ratios of pleural effusion-related and serology-related indicators were compared among the three groups, and receiver operating characteristic curves were drawn to analyze the sensitivity and specificity of the parameter ratios of different indicators for the diagnosis of TPE. RESULTS: The median serum ADA level was higher in the TPE group (13 U/L) than in the PPE group (10 U/L, P < 0.01) and MPE group (10 U/L, P < 0.001). The median pfADA level in the TPE group was 41 (32, 52) U/L; it was lowest in the MPE group at 9 (7, 12) U/L and highest in the PPE group at 43 (23, 145) U/L. The pfLDH level in the PPE group was 2542 (1109, 6219) U/L, which was significantly higher than that in the TPE group 449 (293, 664) U/L. In the differential diagnosis between TPE and non-TPE, the AUC of pfLDH/pfADA for diagnosing TPE was the highest at 0.946 (0.925, 0.966), with an optimal cutoff value of 23.20, sensitivity of 93.9%, specificity of 87.0%, and Youden index of 0.809. In the differential diagnosis of TPE and PPE, the AUC of pfLDH/pfADA was the highest at 0.964 (0.939, 0.989), with an optimal cutoff value of 24.32, sensitivity of 94.6%, and specificity of 94.4%; this indicated significantly better diagnostic efficacy than that of the single index of pfLDH. In the differential diagnosis between TPE and MPE, the AUC of pfLDH/pfADA was 0.926 (0.896, 0.956), with a sensitivity of 93.4% and specificity of 80.0%; this was not significantly different from the diagnostic efficacy of pfADA. CONCLUSIONS: Compared with single biomarkers, pfLDH/pfADA has higher diagnostic value for TPE and can identify patients with TPE early, easily, and economically.

Clinical outcomes prediction in kidney transplantation by use of biomarkers from hypothermic machine perfusion.

PURPOSE: The clinical outcomes of kidney transplantation from deceased donors have seen significant improvements with the use of machine perfusion (MP), now a standard practice in transplant centers. However, the use of perfusate biomarkers for assessing organ quality remains a subject of debate. Despite this, some centers incorporate them into their decision-making process for donor kidney acceptance. Recent studies have indicated that lactate dehydrogenase (LDH), glutathione S-transferase, interleukin-18, and neutrophil gelatinase-associated lipocalin (NGAL) could predict post-transplant outcomes. MATERIALS AND METHODS: Between August 2016 and June 2017, 31 deceased-donor after brain death were included and stroke was the main cause of death. Pediatric patients, hypersensitized recipients were excluded. 43 kidneys were subjected to machine perfusion. Perfusate samples were collected just before the transplantation and stored at -80ºC. Kidney transplant recipients have an average age of 52 years, 34,9% female, with a BMI 24,6±3,7. We employed receiver operating characteristic analysis to investigate associations between these perfusate biomarkers and two key clinical outcomes: delayed graft function and primary non-function. RESULTS: The incidence of delayed graft function was 23.3% and primary non-function was 14%. A strong association was found between NGAL concentration and DGF (AUC=0.766, 95% CI, P=0.012), and between LDH concentration and PNF (AUC=0.84, 95% CI, P=0.027). Other perfusate biomarkers did not show significant correlations with these clinical outcomes. CONCLUSION: The concentrations of NGAL and LDH during machine perfusion could assist transplant physicians in improving the allocation of donated organs and making challenging decisions regarding organ discarding. Further, larger-scale studies are required.

A retrospective study: analysis of the relationship between lactate dehydrogenase and castration-resistant prostate cancer based on restricted cubic spline model.

Background: Different prostate cancer patients take different amounts of time to progress to castration-resistant prostate cancer (CRPC), and this difference in time determines the patient's ultimate survival time. If the time to progression to CRPC can be estimated for each patient, the treatment can be better individualized. Objective: Castration-resistant prostate cancer is a challenge in attacking prostate cancer, the aim of the paper is to analyze the correlation between lactate dehydrogenase (LDH) and CRPC occurrence based on the restricted cubic spline model, and to provide a theoretical basis for LDH as a prognostic biomarker for prostate cancer patients. Methods: We retrospectively analyzed clinical and follow-up data of patients diagnosed with prostate cancer and treated with Androgen Deprivation Therapy (ADT) in our hospital from October 2019 to August 2022. Investigate the correlation between LDH and CRPC by COX regression, restricted cubic spline model and survival analysis. Results: The initial tPSA concentration, prostate volume, LDH and alkaline phosphatase levels in patients with prostate cancer with rapid progression are higher than those in patients with prostate cancer with slow progression. Multivariate COX regression showed that initial tPSA level and LDH level are independent risk factors for prostate cancer. Restricted cubic spline model further showed that LDH level is linearly correlated with the risk of CRPC in prostate cancer patients (total P < 0.05, nonlinear P > 0.05). Conclusion: LDH was associated with the prognosis of prostate cancer and had a dose-response relationship with the risk of CRPC in prostate caner patients.

Measurement of lactate in pleural fluid rapidly identify infection and guide therapy.

BACKGROUND: Measurements of pleural fluid biomarkers for rapid identification of complicated parapneumonic effusion (CPPE) are crucial for optimal management. Previous studies for biomarker evaluation were however based on pleura culture, not modern DNA technique. Lactate has not been thoroughly studied earlier as a potential biomarker in this regard. OBJECTIVES: To evaluate whether the routine biomarkers pH, glucose, lactate dehydrogenase (LDH) measured in pleural fluid in a microbiological well characterised cohort could differentiate simple parapneumonic effusion (SPPE) from CPPE and if pleural fluid lactate could be of additional use in this discrimination. METHODS: Pleural fluid prospectively collected from adult patients (n = 112) with PPE admitted to the Departments of Infectious Diseases (DIDs) at four Stockholm County hospitals were characterised microbiologically with bacterial culture and 16S rDNA sequencing, and biochemically with pH, glucose, LDH and lactate. RESULTS: Forty and seventy two patients were categorised as SPPE/CPPE. The median values between SPPE/CPPE differed significantly for all biomarkers with varying overlap. Receiver operating characteristics (ROC) curves showed the area under the curve (AUC) for pH 0.905 (CI 0.847-0.963), glucose 0.861 (CI 0.79-0.932), LDH 0.917 (CI 0.860-0.974) and lactate 0.927 (CI 0.877-0.977), corresponding to best cut-off levels and sensitivity/specificity for pH of 7.255, 0.819/0.9, glucose 5.35 mmol/L, 0.847/0.775, LDH 9.8 µcat/L, 0.905/0.825 and lactate 4.9 mmol/L, 0.875/0.85. CONCLUSIONS: To distinguish between SPPE/CPPE, pH and LDH performed well, but optimal cut-off values differed from earlier established recommendations. Pleura lactate had the largest AUC of the investigated biomarkers and may be used in the analyses of PPE-staging.

Adenosine deaminase-based measurement in the differential diagnosis of pleural effusion: a multicenter retrospective study.

INTRODUCTION: The differential diagnosis of pleural effusion is difficult, and studies have reported on the potential role of adenosine deaminase (ADA) in the differential diagnosis of undiagnosed pleural effusion. This retrospective study aimed to investigate the diagnostic role of ADA in pleural effusion. METHODS: 266 patients with pleural effusion from three centers were enrolled. The concentrations of ADA and lactate dehydrogenase (LDH) were measured in pleural fluids and serum samples of the patients. The diagnostic performance of ADA-based measurement for tuberculous pleural effusion (TPE), malignant pleural effusion (MPE), and parapneumonic effusion (PPE) was examined by receiver operating characteristic (ROC) curve analysis. RESULTS: An area under the ROC curve (AUC) value of 0.909 was obtained using the pleural ADA values as the indicator for TPE identification (sensitivity: 87.50%, specificity: 87.82%). The ratio of serum LDH to pleural ADA (cancer ratio) provided the predictive capacity with an AUC of 0.879 for MPE diagnosis (sensitivity: 95.04%, specificity: 67.06%). At a cut-off value of 14.29, the pleural ADA/LDH ratio showed a sensitivity and specificity of 81.13% and 83.67%, respectively, and a high AUC value of 0.888 for the differential diagnosis of PPE from TPE. CONCLUSION: ADA-based measurement is helpful for the differential diagnosis of pleural effusion. Further studies should be performed to validate these results.

Diagnostic accuracy and limit of detection of ten malaria parasite lactate dehydrogenase-based rapid tests for Plasmodium knowlesi and P. falciparum.

Background: Plasmodium knowlesi causes zoonotic malaria across Southeast Asia. First-line diagnostic microscopy cannot reliably differentiate P. knowlesi from other human malaria species. Rapid diagnostic tests (RDTs) designed for P. falciparum and P. vivax are used routinely in P. knowlesi co-endemic areas despite potential cross-reactivity for species-specific antibody targets. Methods: Ten RDTs were evaluated: nine to detect clinical P. knowlesi infections from Malaysia, and nine assessing limit of detection (LoD) for P. knowlesi (PkA1-H.1) and P. falciparum (Pf3D7) cultures. Targets included Plasmodium-genus parasite lactate dehydrogenase (pan-pLDH) and P. vivax (Pv)-pLDH. Results: Samples were collected prior to antimalarial treatment from 127 patients with microscopy-positive PCR-confirmed P. knowlesi mono-infections. Median parasitaemia was 788/µL (IQR 247-5,565/µL). Pan-pLDH sensitivities ranged from 50.6% (95% CI 39.6-61.5) (SD BIOLINE) to 87.0% (95% CI 75.1-94.6) (First Response® and CareStart™ PAN) compared to reference PCR. Pv-pLDH RDTs detected P. knowlesi with up to 92.0% (95% CI 84.3-96.7%) sensitivity (Biocredit™). For parasite counts ≥200/µL, pan-pLDH (Standard Q) and Pv-pLDH RDTs exceeded 95% sensitivity. Specificity of RDTs against 26 PCR-confirmed negative controls was 100%. Sensitivity of six highest performing RDTs were not significantly different when comparing samples taken before and after (median 3 hours) antimalarial treatment. Parasite ring stages were present in 30% of pre-treatment samples, with ring stage proportions (mean 1.9%) demonstrating inverse correlation with test positivity of Biocredit™ and two CareStart™ RDTs.For cultured P. knowlesi, CareStart™ PAN demonstrated the lowest LoD at 25 parasites/µL; LoDs of other pan-pLDH ranged from 98 to >2000 parasites/µL. Pv-pLDH LoD for P. knowlesi was 49 parasites/µL. No false-positive results were observed in either P. falciparum-pLDH or histidine-rich-protein-2 channels. Conclusion: Selected RDTs demonstrate sufficient performance for detection of major human malaria species including P. knowlesi in co-endemic areas where microscopy is not available, particularly for higher parasite counts, although cannot reliably differentiate among non-falciparum malaria.

Reducing unnecessary routine laboratory testing for noncritically ill patients with COVID-19.

BACKGROUND: Reducing unnecessary routine laboratory testing is a Choosing Wisely® recommendation, and new areas of overuse were noted during the COVID-19 pandemic. OBJECTIVE: To reduce unnecessary repetitive routine laboratory testing for patients with COVID-19 during the pandemic across a large safety net health system. DESIGNS, SETTINGS AND PARTICIPANTS: This quality improvement initiative was initiated by the System High-Value Care Council at New York City Health + Hospitals (H + H), the largest public healthcare system in the United States consisting of 11 acute care hospitals. INTERVENTION: four overused laboratory tests in noncritically ill hospitalized patients with COVID-19 were identified: C-reactive protein (CRP), ferritin, lactate dehydrogenase (LDH), and procalcitonin. A two-pronged electronic health record intervention was implemented consisting of (1) nonintrusive, informational nudge statements placed on selected order sets, and (2) a forcing function of one consecutive day limit on ordering. MAIN OUTCOME AND MEASURES: The average of excess tests per encounter days (ETPED) for each of four target laboratory testing only in patients with COVID-19. OBJECTIVE: Interdisciplinary System High-Value Care Council identified four overused laboratory tests (inflammatory markers) in noncritically ill hospitalized patients with COVID-19: C-reactive protein (CRP), ferritin, lactate dehydrogenase (LDH), and procalcitonin. Within an 11-hospital safety net health system, a two-pronged electronic health record intervention was implemented consisting of (1) nonintrusive, informational nudge statements placed on selected order sets, and (2) a forcing function of one consecutive day limit on ordering. The preintervention period (March 16, 2020 to January 24, 2021) was compared to the postintervention period (January 25, 2021 to March 22, 2022). RESULTS: Time series linear regression showed decreases in CRP (-17.9%, p < .05), ferritin (-37.6%, p < .001), and LDH (-30.1%, p < .001). Slope differences were significant (CRP, ferritin, and LDH p < 0.001; procalcitonin p < 0.05). Decreases were observed across weekly averages: CRP (-19%, p < .01), ferritin (-37.9%, p < .001), LDH (-28.7%, p < .001), and procalcitonin (-18.4%, p < .05). CONCLUSION: This intervention was associated with reduced routine inflammatory marker testing in non-intensive care unit COVID-19 hospitalized patients across 11 hospitals. Variation was high among individual hospitals.

Field performance of Plasmodium falciparum lactate dehydrogenase rapid diagnostic tests during a large histidine-rich protein 2 deletion survey in Ethiopia.

BACKGROUND: Malaria rapid diagnostic tests (RDTs) have expanded diagnostic service to remote endemic communities in Ethiopia, where 70% of malaria services per annum are reliant on them. However, diagnostic strategies are threatened by Plasmodium falciparum parasites with deletions of the histidine-rich protein 2 and/or 3 (pfhrp2/3) genes. Studies have reported pfhrp2/3 gene deletion prevalence in Ethiopia that exceeds the WHO recommended threshold to switch to non-HRP2 targeted RDTs for detection of P. falciparum. Therefore, RDTs that target alternative antigens, such as P. falciparum lactate dehydrogenase (PfLDH) are increasingly in programmatic use. METHODS: Malaria suspected patients visiting health facilities of Amhara, Tigray, Gambella, and Oromia regions of Ethiopia were screened by community health workers using Carestart Pf/Pv (HRP2/Pv-LDH) and SD-Bioline Pf (HRP2 for Pf/LDH for Pf) RDTs. Dried blood spot (DBS) samples were collected from selected patients for molecular and serological analysis. The clinical data and RDT results were recorded on standard forms, entered into EpiInfo, and analysed using STATA. The Pf-LDH detecting RDT results were compared with real-time PCR and bead-based immunoassay to determine their diagnostic performance. RESULTS: The 13,172 (56% male and 44% female, median age of 19 years ranging from 1 to 99 year) study participants were enrolled and tested with PfHRP2 and PfLDH detection RDTs; 20.6% (95% CI: 19.6 to 21.6) were P. falciparum RDT positive. A subset of samples (n = 820) were previously tested using P. falciparum lactate dehydrogenase (pfldh) quantitative real-time PCR, and 456 of these further characterized using bead-based immunoassay. The proportion of samples positive for P. falciparum by the PfHRP2 Carestart and SD-Bioline RDTs were 66% (539/820) and 59% (481/820), respectively; 68% (561/820) were positive for the PfLDH band on the SD-Bioline RDT. The sensitivity and specificity of the PfLDH RDT band were 69% and 38%, respectively, versus pfldh qPCR; and 72% and 36%, respectively, versus PfLDH detection by immunoassay. Among samples with results for RDT, qPCR, and immunoassay, higher proportions of P. falciparum were recorded by pfldh qPCR (90%, 411/456) and PfLDH immunoassay (88%, 363/413) compared to the PfLDH band on the SD-Bioline RDT (74.6%, 340/456). CONCLUSION AND RECOMMENDATION: Both PfHRP2 RDTs detected fewer P. falciparum cases than PfLDH, and fewer cases than qPCR or immunoassay. The poor sensitivity and specificity of the PfLDH RDT compared to qPCR and to immunoassay in this study raises concern. Continuous operator training and RDTs quality assurance programme to ensure quality diagnostic services are recommended.

Comparison of two malaria multiplex immunoassays that enable quantification of malaria antigens.

BACKGROUND: Immunoassay platforms that simultaneously detect malaria antigens including histidine-rich protein 2 (HRP2)/HRP3 and Plasmodium lactate dehydrogenase (pLDH), are useful epidemiological tools for rapid diagnostic test evaluation. This study presents the comparative evaluation of two multiplex platforms in identifying Plasmodium falciparum with presence or absence of HRP2/HRP3 expression as being indicative of hrp2/hrp3 deletions and other Plasmodium species. Moreover, correlation between the malaria antigen measurements performed at these platforms is assessed after calibrating with either assay standards or international standards and the cross-reactivity among Plasmodium species is examined. METHODS: A 77-member panel of specimens composed of the World Health Organization (WHO) international Plasmodium antigen standards, cultured parasites for P. falciparum and Plasmodium knowlesi, and clinical specimens with mono-infections for P. falciparum, Plasmodium vivax, and Plasmodium malariae was generated as both whole blood and dried blood spot (DBS) specimens. Assays for HRP2, P. falciparum-specific pLDH (PfLDH), P. vivax-specific pLDH (PvLDH), and all human Plasmodium species Pan malaria pLDH (PanLDH) on the Human Malaria Array Q-Plex and the xMAP platforms were evaluated with these panels. RESULTS: The xMAP showed a higher percent positive agreement for identification of hrp2-deleted P. falciparum and Plasmodium species in whole blood and DBS than the Q-Plex. For whole blood samples, there was a highly positive correlation between the two platforms for PfLDH (Pearson r = 0.9926) and PvLDH (r = 0. 9792), moderate positive correlation for HRP2 (r = 0.7432), and poor correlation for PanLDH (r = 0.6139). In Pearson correlation analysis between the two platforms on the DBS, the same assays were r = 0.9828, r = 0.7679, r = 0.6432, and r = 0.8957, respectively. The xMAP HRP2 assay appeared to cross-react with HRP3, while the Q-Plex did not. The Q-Plex PfLDH assay cross-reacted with P. malariae, while the xMAP did not. For both platforms, P. knowlesi was detected on the PvLDH assay. The WHO international standards allowed normalization across both platforms on their HRP2, PfLDH, and PvLDH assays in whole blood and DBS. CONCLUSIONS: Q-Plex and xMAP show good agreement for identification of P. falciparum mutants with hrp2/hrp3 deletions, and other Plasmodium species. Quantitative results from both platforms, normalized into international units for HRP2, PfLDH, and PvLDH, showed good agreement and should allow comparison and analysis of results generated by either platform.

Diagnostic Accuracy of Salivary Biomarkers including Lactate Dehydrogenase and Hemoglobin A1c for Screening Chronic Periodontitis.

Aims: Periodontitis is one of the most common chronic bacterial infections in humans involving the tooth-supporting tissue. The present study aimed to evaluate and compare salivary biomarkers, including lactate dehydrogenase (LDH) and hemoglobin A1c (HbA1c), between patients with severe chronic periodontitis and healthy individuals. Methods: This study was performed on 29 patients with severe chronic periodontitis and 30 healthy individuals at Zahedan University of Medical Sciences, Zahedan, Iran, in 2021. Salivary samples were taken, and clinical parameters, including the clinical attachment loss (CAL) and probing pocket depth (PPD), were measured. Besides, the levels of LDH and HbA1c were measured using ELISA kits. The sensitivity, specificity, and positive and negative predictive values of HbA1c and LDH were examined for chronic periodontitis diagnosis. Results: Based on the present results, the levels of LDH and HbA1C did not show adequate sensitivity or specificity for screening chronic periodontitis. Conclusion: According to the present findings, salivary biomarkers, including LDH and HbA1c, cannot be used with certainty for screening chronic periodontitis.

[Analysis of lactate dehydrogenase gene polymorphisms and prediction of B cell epitopes in four human Plasmodium species].

OBJECTIVE: To analyze the polymorphism of Plasmodium lactate dehydrogenase (pLDH) gene and predict B-cell epitopes in pLDH peptides in four species of human malaria parasites. METHODS: The blood samples and epidemiological characteristics were collected from malaria cases in Yunnan Province registered in the National Notifiable Disease Report System. The pLDH genes of four human Plasmodium species were amplified using nested PCR assay and sequenced. The polymorphisms of pLDH genes was analyzed using the software MEGA version 7.0.26 and DnaSP version 5.10, and the B-cell epitopes were predicted in pLDH peptides using the Immune Epitope Database (IEDB). RESULTS: The sequences of P. vivax LDH (PvLDH), P. falciparum LDH (PfLDH), P. ovale LDH (PoLDH) and P. malariae LDH (PmLDH) genes were obtained from 153, 29, 17 and 11 blood samples from patients with P. vivax, P. falciparum, P. ovale and P. malariae malaria, respectively, which included 15, 2, 4 and 2 haplotypes and had a nucleotide diversity (π) of 0.104. A high level of intra-species differentiation was seen in the PoLDH gene (π = 0.012), and the π values were all < 0.001 for PvLDH, PfLDH and PmLDH genes. Active regions of B-cell antigen were predicted in the pLDH peptide chain of four human malaria parasites, of 4 to 5 in each chain, and the activity score was approximately 0.430. Among these peptide chains, the "86-PGKSDKEWNRD-96" short-peptide was a B-cell epitope shared by all four species of human malaria parasites, and the "266-GQYGHS (T)-271" short-peptide was present in PvLDH and PoLDH peptide chains, while "212-EEVEGIFDR-220" was only found in the PvLDH peptide chain, and "208-LISDAE-213" was only seen in the PfLDH peptide chain. CONCLUSIONS: The PoLDH gene polymorphism may be derived from the weak negative purification selection, while PvLDH, PfLDH and PmLDH genes may maintain a relatively conservative state. There may be two B-cell epitopes "212-EEVEGIFDR-220" and "208-LISDAE-213" in the proximal region of the C terminal in the pLDH peptide chain, which is feasible to differentiate between P. vivax and P. falciparum infections.

Extracellular Vesicles Derived from Young Neural Cultures Attenuate Astrocytic Reactivity In Vitro.

Extracellular vesicles (EVs) play an important role in intercellular communication and are involved in both physiological and pathological processes. In the central nervous system (CNS), EVs secreted from different brain cell types exert a sundry of functions, from modulation of astrocytic proliferation and microglial activation to neuronal protection and regeneration. However, the effect of aging on the biological functions of neural EVs is poorly understood. In this work, we studied the biological effects of small EVs (sEVs) isolated from neural cells maintained for 14 or 21 days in vitro (DIV). We found that EVs isolated from 14 DIV cultures reduced the extracellular levels of lactate dehydrogenase (LDH), the expression levels of the astrocytic protein GFAP, and the complexity of astrocyte architecture suggesting a role in lowering the reactivity of astrocytes, while EVs produced by 21 DIV cells did not show any of the above effects. These results in an in vitro model pave the way to evaluate whether similar results occur in vivo and through what mechanisms.

A Novel Malaria Lateral Flow Assay for Detecting Plasmodium falciparum Lactate Dehydrogenase in Busia, Uganda.

Rapid diagnostic tests (RDTs) for Plasmodium falciparum commonly detect histidine-rich protein 2 (HRP-2), but HRP-2 deletions are increasingly recognized. We evaluated a prototype test detecting parasite lactate dehydrogenase (pLDH) and compared it to commercially available RDTs at a health facility in Uganda, using quantitative polymerase chain reaction as a gold standard. The prototype pLDH test had a high sensitivity for infections with at least 100 parasites/µL (98%), comparable to HRP-2, and greater than an existing pLDH RDT (89%). Specificity for the prototype test was 99.5%, which is greater than the HRP-2 tests (93-95%). Therefore, the prototype pLDH test may be an attractive alternative malaria diagnostic.

Diagnostic utility of measuring lactate dehydrogenase levels and its isoenzyme activities for the evaluation of malignancy in feline pleural effusion and ascitic fluid.

Background: Lactate dehydrogenase (LDH) isoenzymes may be useful in the differential diagnosis of pleural effusion (PE) and ascitic fluid (AF) etiologies in cats since tissue damage induces their release, changing the pattern of their activity. Aim: This study aimed to determine the diagnostic utility of measuring LDH levels and isoenzyme activities in PE or AF in cats with malignancy. Methods: LDH levels and isoenzyme activities in the serum, PE, and AF were compared among cats in the malignant, infectious, and non-malignant, non-infectious groups. A receiver operating characteristic (ROC) analysis was performed to assess the accuracy in diagnosing feline malignancy. Results: Significant differences in LDH level and LDH isoenzyme activities in the PE and AF were observed among the three groups. The combination of LDH level and LDH-1 activity in PE or AF had the highest area under the ROC (AUC) values for discriminating malignant effusion from non-malignant effusion. The AUC of the combination of LDH level and LDH-1 activity in PE or AF was 0.874. The sensitivity and specificity of using the combination of LDH level (cut-off: <2,269 U/l) and LDH-1 activity (cut-off: <4.8%) in PE or AF for predicting malignancy with the highest AUC value were 94.4% and 72.7%, respectively. Conclusion: Our results suggest that the combination of LDH level and LDH-1 activity in PE or AF is a potential factor for diagnosing malignancy. Considering that LDH isoenzymes can be measured inexpensively and easily, LDH tests can be readily accommodated in veterinary clinical practice.

Combined immune score predicts the prognosis of newly diagnosed multiple myeloma patients in the bortezomib-based therapy era.

ABSTRACT: To investigate the effect of a combined immune score including the lymphocyte-to-monocyte ratio (LMR) and uninvolved immunoglobulin (u-Ig) levels on the prognosis of newly diagnosed multiple myeloma (NDMM) patients treated with bortezomib.Clinical data of 201 NDMM patients were retrospectively analyzed. Patients with LMR ≥ 3.6 and LMR < 3.6 were scored 0 and 1, respectively. Patients with preserved u-Ig levels, suppression of 1 u-Ig, and suppression of at least 2 u-Igs were scored 0, 1, and 2, respectively. The immune score, established from these individual scores, was used to separate patients into good (0-1 points), intermediate (2 points), and poor (3 points) risk groups. The baseline data, objective remission rate (ORR), whether receive maintenance treatment regularly and overall survival of patients before treatment were analyzed.The ORR of the good-risk group was significantly higher than that of the intermediate-risk group (75.6% vs 57.7%, P = .044) and the poor-risk group (75.6% vs 48.2%, P = .007). The multivariate analysis results showed that age ≥ 65 years, International Staging System stage III, platelet count ≤ 100 × 109/L, lactate dehydrogenase (LDH) > 250 U/L, serum calcium > 2.75 mmol/L, no receipt of regular maintenance treatment, LMR < 3.6, suppressed u-Igs = 1, suppressed u-Igs ≥ 2, intermediate-risk group and poor-risk group were independent predictors of poor overall survival.In the bortezomib era, the LMR, u-Ig levels, and the immune score play an important role in the prognosis of NDMM patients. Among them, the immune score showed the strongest prognostic value, and it could be a beneficial supplement for the early identification of high-risk patients.

Lactate Dehydrogenase Levels in the Saliva of Cigarette and E-Cigarette Smokers (Vapers): A Comparative Analysis.

BACKGROUND: We examined the lactate dehydrogenase (LDH) enzyme levels in the saliva of vapers (e-cigarette users) and compared the data with cigarette smokers and a control group of non-smokers and non-vapers. METHODS: Subjects were recruited among those responding to a social media announcement or patients attending the SEGi Oral Health Care Centre between May and December 2019, and among some staff at the centre. Five ml of unstimulated   whole saliva was collected and salivary LDH enzyme activity levels were measured with a LDH colorimetric assay kit. Salivary LDH activity level was determined for each group and compared statistically. RESULTS: Eighty-eight subjects were categorized into three groups (control n=30, smokers n=29, and vapers n=29). The mean ± standard deviation (SD) values for salivary LDH activity levels for vapers, smokers, and control groups were 35.15 ± 24.34 mU/ml, 30.82 ± 20.73 mU/ml, and 21.45 ± 15.30 mU/ml, respectively. The salivary LDH activity levels of smoker and vaper groups were significantly higher than in the control group (p = 0.031; 0.017). There was no significant difference of salivary LDH activity level in vapers when compared with smokers (p= 0.234). CONCLUSION: Our findings showed higher LDH levels in the saliva of vapers when compared with controls, confirming cytotoxic and harmful effects of e-cigarettes on the oral mucosa.

Constitutive transgenic α-Klotho overexpression enhances resilience to and recovery from murine acute lung injury.

Normal lungs do not express α-Klotho (Klotho) protein but derive cytoprotection from circulating soluble Klotho. It is unclear whether chronic supranormal Klotho levels confer additional benefit. To address this, we tested the age-related effects of modest Klotho overexpression on acute lung injury (ALI) and recovery. Transgenic Klotho-overexpressing (Tg-Kl) and wild-type (WT) mice (2 and 6 mo old) were exposed to hyperoxia (95% O2; 72 h; injury; Hx) then returned to normoxia (21% O2; 24 h; recovery; Hx-R). Control mice were kept in normoxia. Renal and serum Klotho, lung histology, and bronchoalveolar lavage fluid oxidative damage markers were assessed. Effects of hyperoxia on Klotho release were tested in human embryonic kidney cells stably expressing Klotho. A549 lung epithelial cells transfected with Klotho cDNA or vector were exposed to cigarette smoke; lactate dehydrogenase and double-strand DNA breaks were measured. Serum Klotho decreased with age. Hyperoxia suppressed renal Klotho at both ages and serum Klotho at 2 mo of age. Tg-Kl mice at both ages and 2-mo-old WT mice survived Hx-R; 6-mo-old Tg-Kl mice showed lower lung damage than age-matched WT mice. Hyperoxia directly inhibited Klotho expression and release in vitro; Klotho transfection attenuated cigarette smoke-induced cytotoxicity and DNA double-strand breaks in lung epithelial cells. Young animals with chronic high baseline Klotho expression were more resistant to ALI. Chronic constitutive Klotho overexpression in older Tg-Kl animals attenuated hyperoxia-induced lung damage and improves survival and short-term recovery despite an acute reduction in serum Klotho during injury. We conclude that chronic enhancement of Klotho expression increases resilience to ALI.

LDHA is enriched in human islet alpha cells and upregulated in type 2 diabetes.

The lactate dehydrogenase isoform A (LDHA) is a key metabolic enzyme that preferentially catalyzes the conversion of pyruvate to lactate. Whereas LDHA is highly expressed in many tissues, its expression is turned off in the differentiated adult ß-cell within the pancreatic islets. The repression of LDHA under normal physiological condition and its inappropriate upregulation under a diabetogenic environment is well-documented in rodent islets/ß-cells but little is known about LDHA expression in human islet cells and whether its abundance is altered under diabetic conditions. Analysis of public single-cell RNA-seq (sc-RNA seq) data as well as cell type-specific immunolabeling of human pancreatic islets showed that LDHA was mainly localized in human α-cells while it is expressed at a very low level in ß-cells. Furthermore, LDHA, both at mRNA and protein, as well as lactate production is upregulated in human pancreatic islets exposed to chronic high glucose treatment. Microscopic analysis of stressed human islets and autopsy pancreases from individuals with type 2 diabetes (T2D) showed LDHA upregulation mainly in human α-cells. Pharmacological inhibition of LDHA in isolated human islets enhanced insulin secretion under physiological conditions but did not significantly correct the deregulated secretion of insulin or glucagon under diabetic conditions.

Effect of pH on the Quantification of Common Chemistry Analytes in Body Fluid Specimens Using the Roche cobas Analyzer for Clinical Diagnostic Testing.

OBJECTIVES: To determine the influence of pH on recovery of analytes in body fluids (BFs), investigate the mechanism of pH interference, measure the frequency of abnormal-pH BFs received, and compare pH measured by meter and paper. METHODS: We performed pH titration in residual BFs. A low-pH BF was spiked and neutralized to investigate pH interference. We measured analytes on a Roche cobas c501 analyzer (Roche Diagnostics) and calculated the percent recovery. Measurement of pH using a meter and paper was conducted on 122 BF samples received in the laboratory. RESULTS: Enzyme activity in BFs was unaffected when pH = 7.4-8.5 lactate dehydrogenase, pH = 7.3-10.2 amylase, pH = 6.0-9.9 lipase, and pH = 1.3-11.7 all other analytes. BFs had mean (range) pH of 8.0 (5.1-8.9), with a mean (range) difference (paper ‒ meter) of ‒0.4 (‒0.6 to 1.1). CONCLUSIONS: Irreversible loss of enzyme activity occurs in BFs at low pH. Few clinical BFs have pH < 7.0, but laboratories should incorporate pH measurement in BF workflows.

Factors associated with negative pleural adenosine deaminase results in the diagnosis of childhood pleural tuberculosis.

BACKGROUND: Until now, the influential factors associated with pleural adenosine deaminase (ADA) activity among children remain unclear. This retrospective study was therefore conducted aiming to investigate the factors associated with negative pleural ADA results in the diagnosis of childhood pleural tuberculosis (TB). METHODS: Between January 2006 and December 2019, children patients with definite or possible pleural TB were recruited for potential analysis. Then, patients were stratified into two categories: negative pleural ADA results group (experimental group, ≤40 U/L) and positive pleural ADA results group (control group, > 40 U/L). Univariate and multivariate logistic regression analyses were performed to estimate risk factors for negative pleural ADA results. RESULTS: A total of 84 patients with pleural TB were recruited and subsequently classified as experimental (n = 17) and control groups (n = 67). Multivariate analysis (Hosmer-Lemeshow goodness-of-fit test: χ2 = 1.881, df = 6, P = 0.930) revealed that variables, such as chest pain (age-adjusted OR = 0.0510, 95% CI: 0.004, 0.583), pleural total protein (≤45.3 g/L, age-adjusted OR = 27.7, 95% CI: 2.5, 307.7), pleural lactate dehydrogenase (LDH, ≤505 U/L, age-adjusted OR = 59.9, 95% CI: 4.2, 857.2) and blood urea nitrogen (≤3.2 mmol/L, age-adjusted OR = 32.0, 95% CI: 2.4, 426.9), were associated with negative pleural ADA results when diagnosing childhood pleural TB. CONCLUSION: Our findings demonstrated that chest pain, pleural total protein, pleural LDH, and blood urea nitrogen were associated with a negative pleural ADA result for the diagnosis of pleural TB among children. When interpreting pleural ADA levels in children with these characteristics, a careful clinical assessment is required for the pleural TB diagnosis.