RNA Sequencing in COVID-19 patients identifies neutrophil activation biomarkers as a promising diagnostic platform for infections.

Infection with the SARS-CoV2 virus can vary from asymptomatic, or flu-like with moderate disease, up to critically severe. Severe disease, termed COVID-19, involves acute respiratory deterioration that is frequently fatal. To understand the highly variable presentation, and identify biomarkers for disease severity, blood RNA from COVID-19 patient in an intensive care unit was analyzed by whole transcriptome RNA sequencing. Both SARS-CoV2 infection and the severity of COVID-19 syndrome were associated with up to 25-fold increased expression of neutrophil-related transcripts, such as neutrophil defensin 1 (DEFA1), and 3-5-fold reductions in T cell related transcripts such as the T cell receptor (TCR). The DEFA1 RNA level detected SARS-CoV2 viremia with 95.5% sensitivity, when viremia was measured by ddPCR of whole blood RNA. Purified CD15+ neutrophils from COVID-19 patients were increased in abundance and showed striking increases in nuclear DNA staining by DAPI. Concurrently, they showed >10-fold higher elastase activity than normal controls, and correcting for their increased abundance, still showed 5-fold higher elastase activity per cell. Despite higher CD15+ neutrophil elastase activity, elastase activity was extremely low in plasma from the same patients. Collectively, the data supports the model that increased neutrophil and decreased T cell activity is associated with increased COVID-19 severity, and suggests that blood DEFA1 RNA levels and neutrophil elastase activity, both involved in neutrophil extracellular traps (NETs), may be informative biomarkers of host immune activity after viral infection.

Establishing the blood reference interval of pancreatic elastase-1: A prospective study.

BACKGROUND AND AIM: Pancreatic elastase-1 (PE-1) has been investigated in pancreatic disorders. However, the reference interval (RI) of PE-1 in blood remains unconfirmed. We aimed to establish the blood RI of PE-1 in an adult population. METHODS: In this prospective cross-sectional study, we enrolled 400 adults who had received the whole-body physical check-up program between May 1, 2019 and November 20, 2019. The serum and plasma PE-1 levels were measured by latex turbidimetric immunoassay in different storage conditions (fresh, refrigerated, and frozen). The 95% and 99% RI of PE-1 were calculated according to the Clinical & Laboratory Standards Institute guidelines. The correlations between PE-1 and other parameters were analyzed using multivariable regression models. Ultimately, 38 patients with acute pancreatitis were prospectively recruited as the validation cohort. RESULTS: The PE-1 levels in fresh serum were highly correlated with those in refrigerated (R2  = 0.998) or frozen (R2  = 0.942) samples; however, plasma should not be suggested in frozen conditions (plasma vs serum: R2  = 0.185). In the RI study population (202 male & 198 female participants), the median age was 52.6 (25-75% interquartile range: 43.1-61.0). The 95% and 99% RIs of PE-1 were 30.0-221.0 and 22.0-359.0 ng/dL, respectively. Triglycerides (ß = 0.106, P = 0.033), lipase (ß = 0.154, P = 0.007), and CA19-9 (ß = 0.130, P = 0.008) were independent factors associated with PE-1. In the pancreatitis validation cohort, with a cut-off value of 359.0 ng/dL, the sensitivity and specificity were 100% and 99.8%, respectively. CONCLUSION: The RI of PE-1 established in this study can be used for further applications. Serum is the suggested form for frozen sample storage.

The recombinant plant Bauhinia bauhinioides elastase inhibitor reduces rat thrombus without alterations in hemostatic parameters.

The anti-inflammatory effects of the plant protease inhibitor BbCI (Bauhinia bauhinioides cruzipain inhibitor), which blocks elastase, cathepsin G, and L, and proteinase 3 has been demonstrated. Here, we investigated the recombinant rBbCI-His(6) (containing a histidine tail) in an experimental venous thrombosis model of vena cava (VC) ligature in rats, comparing to heparin. We evaluate the effects of the inhibitors (native or recombinant) or heparin on the activated partial thromboplastin time (aPTT) and prothrombin time (PT) in human and rat plasmas. The rats undergoing treatment received a saline solution or increasing concentrations of rBbCI-His(6), heparin, or a mixture of both. After 4 h of ligature VC, thrombus, if present was removed and weighed. aPTT, PT, and cytokines were measured in blood collected by cardiac puncture. aPTT, PT, and bleeding time (BT) were also measured at the time of VC (vena cava) ligature. rBbCI-His(6) (0.45 or 1.40 mg/kg) does not alter aPTT, PT or BT. No differences in coagulation parameters were detected in rBbCI-His(6) treated rats at the time of VC ligature or when the thrombus was removed. There was a significant decrease in the weight of thrombus in the animals of the groups treated with the rBbCI-His(6) (1.40 mg/kg), with the rBbCI-His(6) mixture (1.40 mg/kg) + heparin (50 IU/kg) and heparin (100 IU/kg) in relation to control group (saline). The growth-related oncogene/keratinocyte chemoattractant (GRO/KC) serum levels in rats treated with rBbCI-His(6) (1.40 mg/kg) or heparin (200 IU/kg) were reduced. In the experimental model used, rBbCI-His(6) alone had an antithrombotic effect, not altering blood clotting or bleeding time.

CELA2A mutations predispose to early-onset atherosclerosis and metabolic syndrome and affect plasma insulin and platelet activation.

Factors that underlie the clustering of metabolic syndrome traits are not fully known. We performed whole-exome sequence analysis in kindreds with extreme phenotypes of early-onset atherosclerosis and metabolic syndrome, and identified novel loss-of-function mutations in the gene encoding the pancreatic elastase chymotrypsin-like elastase family member 2A (CELA2A). We further show that CELA2A is a circulating enzyme that reduces platelet hyperactivation, triggers both insulin secretion and degradation, and increases insulin sensitivity. CELA2A plasma levels rise postprandially and parallel insulin levels in humans. Loss of these functions by the mutant proteins provides insight into disease mechanisms and suggests that CELA2A could be an attractive therapeutic target.

Neutrophils Are Dysregulated in Patients with Hereditary Angioedema Types I and II in a Symptom-Free Period.

Neutrophils impact on processes preceding the formation of bradykinin, a major swelling mediator in hereditary angioedema (HAE), yet their potential role in HAE pathogenesis has not been sufficiently studied. We assessed the relative mRNA expression of 10 genes related to neutrophil activation using RNA extracted from the peripheral blood neutrophils of 23 HAE patients in a symptom-free period and 39 healthy donors. Increased relative mRNA expression levels of CD274, IL1B, IL1RN, IL8, MMP9, and TLR4, together with a lack in their mutual correlations detected in HAE patients compared to healthy controls, suggested a preactivated state and dysregulation of patients' neutrophils. Patients' neutrophil-alerted state was further supported by increased CD11b, decreased CD16 plasma membrane deposition, and increased relative CD274+ and CD87+ neutrophil counts, but not by increased neutrophil elastase or myeloperoxidase plasma levels. As CD274 mediates inhibitory signals to different immune cells, neutrophils were cocultured with T-cells/PBMC. The decrease in CD25+ and IFN-γ + T-cell/PBMC ratio in patients indicated the patients' neutrophil suppressive functions. In summary, the results showed neutrophils' alerted state and dysregulation at the transcript level in patients with HAE types I and II even in a symptom-free period, which might make them more susceptible to edema formation. Neutrophils' T-cell suppressive capacity in HAE patients needs to be further investigated.

Serum Elastase 1 Level as a Risk Factor for Postoperative Recurrence in Patients with Well-Differentiated Pancreatic Neuroendocrine Neoplasms.

PURPOSE: This study was designed to assess the potential role of the preoperative serum level of elastase 1 as a risk factor for recurrence in patients with resectable well-differentiated pancreatic neuroendocrine neoplasms (PanNETs). METHODS: Preoperative serum elastase 1 levels were measured in 53 patients with PanNETs who underwent complete tumor resection in two tertiary referral centers between January 2004 and June 2017. The preoperative elastase 1 levels were correlated with clinicopathological characteristics, including tumor recurrence and recurrence-free survival. RESULTS: The median elastase 1 level was 96 ng/dL (range: 21-990 ng/dL). Preoperative serum elastase 1 levels were significantly higher in those with tumors ≥ 20 mm in diameter (vs. < 20 mm, P = 0.018), WHO grade 2 (vs. grade 1, P = 0.035), and microscopic venous invasion (vs. without venous invasion, P = 0.039). The median preoperative serum level of elastase 1 was higher in patients with recurrence than in those without recurrence (251 vs. 80 ng/dL, P = 0.004). Receiver operating characteristic analysis of elastase 1 levels showed that a cutoff level of 250 ng/dL was associated with postoperative recurrence, with 63% sensitivity, 100% specificity, and 94% overall accuracy. Patients with higher elastase 1 levels showed significantly worse recurrence-free survival than that of those with lower levels (2-year recurrence-free survival rate: 25% and 92%, respectively, P < 0.001). CONCLUSIONS: Our data provide the first evidence that high preoperative elastase 1 levels may be a risk factor for postoperative recurrence in patients with resectable PanNETs.

Nbeal2 Deficiency Increases Organ Damage but Does Not Affect Host Defense During Gram-Negative Pneumonia-Derived Sepsis.

Objective- Nbeal2-/- mice, a model of human gray platelet syndrome, have reduced neutrophil granularity and impaired host defense against systemic Staphylococcus aureus infection. We here aimed to study the role of Nbeal2 deficiency in both leukocytes and platelets during gram-negative pneumonia and sepsis. Approach and Results- We studied the role of Nbeal2 in platelets and leukocytes during murine pneumonia and sepsis by Klebsiella pneumoniae. Apart from platelet α-granule deficiency and reduced neutrophil granularity, also monocyte granularity was reduced in Nbeal2-/- mice, whereas plasma levels of MPO (myeloperoxidase), elastase, NGAL (neutrophil gelatinase-associated lipocalin), and MMP-9 (matrix metalloproteinase 9), and leukocyte CD11b expression were increased. Nbeal2-/- leukocytes showed unaltered in vitro antibacterial response and phagocytosis capacity against Klebsiella, and unchanged reactive nitrogen species and cytokine production. Also during Klebsiella pneumonia and sepsis, Nbeal2-/- mice had similar bacterial growth in lung and distant body sites, with enhanced leukocyte migration to the bronchoalveolar space. Despite similar infection-induced inflammation, organ damage was increased in Nbeal2-/- mice, which was also seen during endotoxemia. Platelet-specific Nbeal2 deficiency did not influence leukocyte functions, indicating that Nbeal2 directly modifies leukocytes. Transfusion of Nbeal2-/- but not of Nbeal2+/+ platelets into thrombocytopenic mice was associated with bleeding in the lung but similar host defense, pointing at a role for platelet α-granules in maintaining vascular integrity but not host defense during Klebsiella pneumosepsis. Conclusions- These data show that Nbeal2 deficiency-resulting in gray platelet syndrome-affects platelets, neutrophils, and monocytes, with intact host defense but increased organ damage during gram-negative pneumosepsis.

Canine Neutrophil Extracellular Traps Enhance Clot Formation and Delay Lysis.

Autoimmune diseases increase the risk of thrombosis. Neutrophil extracellular traps (NETs) are webs of DNA and protein that may mediate thrombosis in autoimmune diseases. Human and murine studies show NET-releasing neutrophils within a thrombus promote its growth, but it is unclear to what extent NET fragments released into circulation during inflammation are prothrombotic. This study hypothesized that canine NETs promote clot formation and impair lysis even in the absence of neutrophils. NETs were prepared from PMA-stimulated neutrophils and added to fibrinogen and thrombin or to recalcified pooled canine platelet-poor plasma, tissue factor, and tissue plasminogen activator. Clot formation and lysis were measured spectrophotometrically. NETs did not alter fibrin clot formation, but NETs increased maximum clot formation velocity ( P = .001) and delayed lysis ( P = .009) of plasma clots compared with supernatants from nonstimulated neutrophils. DNase digestion of NETs reduced their effect on clot lysis but not maximum clot formation velocity. This suggested impaired lysis was principally mediated by DNA within NETs but that NET proteins were principally responsible for increased speed of clot formation. Previous reports suggested elastase or histones might be responsible for the effect of NETs on clot formation. Elastase activity was greatly reduced by plasma, and addition of histones to plasma did not increase formation velocity, suggesting these proteins were not responsible for increasing maximum formation velocity. This study showed that NETs enhanced clot formation and impaired clot lysis in canine platelet-poor plasma. These in vitro findings suggest both NET proteins and DNA may contribute to thrombosis in inflammatory disease.

Levels of Matrix-Degrading Enzymes and Lubricin in Patients With Degenerative Joint Disease Requiring Arthroplasty.

Total joint arthroplasty (TJA) of the hip or knee (THA and TKA) is the primary surgical intervention for individuals with degenerative joint disease (DJD). Although it is commonly thought that shear force on the joint causes the degradation of articular cartilage, it is possible that there are other factors that contribute to the progression of DJD. It is plausible that specific enzymes that degrade the joint are upregulated, or conversely, there is downregulation of enzymes critical for joint lubrication. The aim of this study is to profile collagenase-1, elastase, heparanase, and lubricin levels in patients undergoing TJA in order to determine potential preexisting dysregulation that contributes to the pathogenesis of DJD. Deidentified blood samples were obtained from patients undergoing TJA 1 day pre- and 1 day postoperatively. Plasma samples were analyzed using enzyme-linked immunosorbent assay kits for elastase, collagenase-1, heparanase, and lubricin. In comparison to healthy controls, there were significant increases in circulating collagenase-1, elastase, and lubricin levels in both the preoperative and postoperative samples. There were no significant differences in heparanase levels in the preoperative or postoperative samples. Comparing the preoperative versus postoperative patient samples, only lubricin demonstrated a significant change. The results of this study confirm that patients undergoing TJA have preexisting alterations in the levels of matrix-degrading enzymes and lubricin. The alterations observed in this study may provide insight into the pathogenesis of DJD.

Potential biomarkers in patients with systemic sclerosis.

AIM: Reduced capillary density is considered the hallmark of systemic sclerosis (SSc) leads to tissue hypoxia, a condition that usually induces angiogenesis. The objective of our study is to investigate mediators regulating angiogenesis in SSc and to correlate their levels with serological and clinical parameters. METHODS: vascular endothelial growth factor, fibroblast growth factor-2, endostatin, thrombospondin-1 and soluble vascular cell and intracellular adhesion molecules (sICAM-1 and sVCAM-1) were measured in sera of SSc and normal subjects by enzyme-linked immunosorbent assay. RESULTS: Among the pro- and anti-angiogenic mediators, endostatin was significantly higher in SSc than in the control subjects. Out of the proteases involved in endostatin production, elastase but not cathepsin-L, was significantly increased in SSc patients. The soluble adhesion molecules sICAM-1 and sVCAM-1 were significantly increased and they occur in parallel. sICAM-1, but not sVCAM-1 positively correlates with the inflammatory markers C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). CONCLUSIONS: Endostatin, elastase and the soluble adhesion molecules (sICAM-1 and sVCAM-1) are potentially involved in the pathogenesis of SSc. Moreover, the significant correlation observed between sICAM-1 and CRP and ESR indicates that sICAM-1 might be a useful biomarker of the inflammatory state of the disease.

Low molecular weight heparin may benefit nephrotic remission in steroid­sensitive nephrotic syndrome via inhibiting elastase.

Low molecular weight heparin (LMWH) has a structure similar to heparan sulfate, which exerts anti­inflammatory effects via inhibiting elastase (Ela) activity. Release of Ela along the glomerular capillary wall may induce glomerular injury and proteinuria. The present study aimed to investigate the influence of LMWH on steroid­sensitive nephrotic syndrome (SSNS) and the potential underlying mechanism. A total of 40 SSNS patients and 20 healthy controls were recruited. SSNS patients were treated with LMWH and prednisone simultaneously (LMWH+pred group) or with prednisone alone (pred group). Proteinuria, urinary glycosaminoglycans (GAGs), serum Ela and urinary creatinine levels were measured. The nephrotic period of SSNS was 15.93±5.78 days. The nephrotic period of SSNS in LMWH+pred group was significantly reduced compared with the pred group (14.13±4.56 vs. 18.63±6.49 days; P<0.05). At the follow­up of the SSNS patients, there was no statistically significant difference in number of relapses between the LMWH+pred and pred groups. Proteinuria (2.51±0.97 g/24 h), urinary GAG levels (4.92±0.87 mg/mmol creatinine) and serum Ela levels (77.64±10.99 ng/l) were significantly greater in the nephrotic period of SSNS compared with the remission period (0.107±0.026 g/24 h, 1.53±0.27 mg/mmol Cr and 41.92±7.81 ng/l, respectively) and the healthy control group (0.098±0.027 g/24 h, 1.40±0.26 mg/mmol creatinine and 38.43±9.83 ng/l, respectively; P<0.05). During the remission period, urinary GAG and serum Ela levels in the LMWH+pred group were significantly reduced compared with the pred group (P<0.05), whereas proteinuria did not differ between these groups (P>0.05). Positive correlations were revealed between urinary GAG excretion and proteinuria (r=0.877; P<0.05), proteinuria and serum Ela levels (r=0.844; P<0.05) and serum Ela levels and urinary GAG excretion (r=0.881; P<0.05). The results of the present study indicated that elevated serum Ela levels may induce proteinuria by degrading GAGs in the glomerular basement membrane in children with SSNS. LMWH may benefit nephrotic remission of SSNS via inhibiting Ela.

Septic Complications after Resection for Middle or Low Rectal Cancer: Role of Gut Barrier Function and Inflammatory Serum Markers.

BACKGROUND: The focus of this study was to understand the relationship between the failure of gut barrier function, inflammatory markers and septic complications after resection for extraperitoneal rectal cancer. METHODS: One hundred seven patients were enrolled into this prospective observational study and underwent open colorectal resection for extraperitoneal cancer. All patients underwent an assessment of intestinal permeability (L/M ratio), endotoxemia, interleukin-1ß (IL-1ß), interleukin-6 (IL-6), C-reactive protein (CRP) and elastase levels before surgery and on postoperative days 1, 3, and 7. RESULTS: Septic complications developed in 23.3% of patients. There were no significant differences in preoperative L/M ratio, endotoxine, CRP, interleukin-1 (IL-1), IL-6, and elastase levels between septic and non-septic groups. All patients showed a significant increase in intestinal permeability, endotoxemia, IL-1, IL-6, CRP, and elastase on the first postoperative day. At postoperative day 7, the septic group continued to demonstrate an increase in intestinal permeability, endotoxemia and elastase and significant difference was observed between the 2 groups (p < 0.05), whereas there was no significant difference in IL-1, IL-6, and CRP levels. CONCLUSION: The pattern of change in the postoperative period of intestinal permeability, systemic endotoxemia and elastase concentration is significantly higher in patients in whom sepsis develops, while the concentration of IL-1ß, IL-6, and CRP does not permit to distinguish infection from inflammation.

Neutrophil function in children following allogeneic hematopoietic stem cell transplant.

HSCT is a lifesaving procedure for children with malignant and non-malignant conditions. The conditioning regimen renders the patient severely immunocompromised and recovery starts with neutrophil (PMN) engraftment. We hypothesize that children demonstrate minimal PMN dysfunction at engraftment and beyond, which is influenced by the stem cell source and the conditioning regimen. Peripheral blood was serially collected from children at 1 to 12 months following allogeneic HSCT. PMN superoxide (O2-) production, degranulation (elastase), CD11b surface expression, and phagocytosis were assessed. Twenty-five patients, mean age of 10.5 yr with 65% males, comprised the study and transplant types included: 14 unrelated cord blood stem cells (cords), seven matched related bone marrow donors, three matched unrelated bone marrow donors, and one peripheral blood progenitor cells. Engraftment occurred at 24 days. There were no significant differences between controls and patients in PMN O2- production, phagocytosis, CD11b surface expression, and total PMN elastase. Elastase release was significantly decreased <6 months vs. controls (p < 0.05) and showed normalization by six months for cords only. The conditioning regimen did not affect PMN function. PMN function returns with engraftment, save elastase release, which occurs later related to the graft source utilized, and its clinical significance is unknown.

Diabetes and Pancreas: Why So Difficult? Potential Mechanisms of Elevated Serum Pancreatic Enzymes.

Diabetes mellitus has been associated with a higher risk of exocrine pancreas disorders despite inconsistencies among studies, presumably due to the presence of several (often unmeasured) confounding factors. As a direct consequence of this uncertainty, the relationship between anti-diabetic therapies and pancreatic adverse reactions is difficult to evaluate and remains far from being clarified. Indeed, the on going debate on the safety of incretin-based therapies does not lie in any definite conclusion. Serum level of amylases and lipase reflects the balance between production from different tissues and clearance, but it may be also influenced by numerous molecular, cellular, and systems mechanisms. The present review tries to provide an overview of potential biochemical pathways that may underlie pancreatic hyperenzymemia in health and diabetes mellitus.

Practical Interpretation and Application of Exocrine Pancreatic Testing in Small Animals.

The pancreas remains a difficult organ to evaluate using laboratory methods alone. No single laboratory test is diagnostic of pancreatitis (chronic or acute) without other diagnostic modalities concurring with the diagnosis or ruling out other diseases. The diagnosis of pancreatitis is particularly difficult in cats, and pancreatitis often occurs with other diseases. The use of pancreatic cytology may be useful in diagnosing both inflammation and neoplasia. Exocrine pancreatic insufficiency (EPI) can be relatively easily diagnosed when clinically manifested by the measurement of trypsinlike immunoreactivity. Diagnosis is more difficult when EPI is subclinical.

A new methodology for the determination of enzyme activity based on carbon nanotubes and glucose oxidase.

In this research, a novel enzyme activity analysis methodology is introduced as a new perspective for this area. The activity of elastase enzyme, which is a digestive enzyme mostly of found in the digestive system of vertebrates, was determined by an electrochemical device composed of carbon nanotubes and a second enzyme, glucose oxidase, which was used as a signal generator enzyme. In this novel methodology, a complex bioactive layer was constructed by using carbon nanotubes, glucose oxidase and a supporting protein, gelatin on a solid, conductive substrate. The activity of elastase was determined by monitoring the hydrolysis rate of elastase enzyme in the bioactive layer. As a result of this hydrolysis of elastase, glucose oxidase was dissociated from the bioactive layer, and following this the electrochemical signal due to glucose oxidase was decreased. The progressive elastase-catalyzed digestion of the bioactive layer containing glucose oxidase decreased the layer's enzymatic efficiency, resulting in a decrease of the glucose oxidation current as a function of the enzyme activity. The ratio of the decrease was correlated to elastase activity level. In this study, optimization experiments of bioactive components and characterization of the resulting new electrochemical device were carried out. A linear calibration range from 0.0303U/mL to 0.0729U/mL of elastase was reported. Real sample analyses were also carried out by the new electrochemical device.

[DIAGNOSTIC MARKERS FOR CHRONIC PANCREATITIS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS WITH DIFFERENT PHENOTYPE].

UNLABELLED: The purpose--to study the relationships between levels of apelin, elastase-1 and tumor necrosis factor-α (TNF-α) in patients with chronic pancreatitis (CP), type 2 diabetes mellitus (T2DM) and with combined course of its with a different phenotype. MATERIALS AND METHODS: The investigation involved of 114 patients with CP, type 2 diabetes mellitus and with combined course of its with a different phenotype. The control group consisted of 20 healthy individuals. RESULTS: It was found that patients with combined course of CP and type 2 diabetes with overweight had significantly higher hyperapelinemia and hyper-TNF-α-emia (p < 0.05). Patients of all study groups revealed a close correlation between apelin and TNF-α (p < 0.05), a significant correlation between apelin and elastase-1 (p < 0.05). As a result of analysis of variance identified significant contribution of study diseases and different phenotypes in levels of apelin, TNF-α and elastase-1. CONCLUSIONS: The results of the study suggest that the levels of apelin, TNF-α and elastase-1 are important diagnostic markers of CP in patients with type 2 diabetes mellitus.

[State of homeostasis links in the children with intestinal colic].

The state of homeostasis links in the children with intestinal colic is represented by the following parameters and clinical characteristics. The data of investigated children's contingent with intestinal colic prevailed by following comorbidities: SARS--12 (18.18% ± 4.78%), protein-energy malnutrition--9 (12.85% ± 3.82%), pneumonia--6 (8.57% ± 3.57%), atopic dermatitis--7 (10.00% ±.3.57%). All children have a next complaints: flatulence (100%), in the 62 children (88.57% ± 3.82%) were identificated frequent regurgitation, in the 48 (80.33%)--hyperbilirubinemia. ALT levels were elevated in 25 children (41%) and 31 (51.66%) children had increased levels of AST. IL8 level were elevated in the 40 children (71.42%). The level of antibodies to elastase was greatly increased in all 56 (100%) children.

[Clinical and biochemical analysis of ligature-induced periodontitis in rats].

The most common experimental model of periodontitis is a "ligature" model. However due to the complexity connected with performing on rats, modification of existing model is proposed, which differs by fixture of cotton ligature around the central incisor and not around the second molar. The purpose of research - a comparative evaluation of "peroxide" and modified by us, "ligature" models of periodontitis in rats. 2 series of experiments on 36 white Wistar rats were conducted. The animals were divided into two groups: intact rats (control) and rats with a "peroxide" model of periodontitis, which was reproduced by the addition to the diet of rats overoxidized sunflower oil (5% by weight of the feed), daily, for 45 days. "Ligature" model in rats was reproduced by applying a cotton ligature on the central incisor of the upper jaw for 14 days. Elastase activity, malondialdehyde content and catalase activity in the gums and in the blood serum was measured by biochemical methods. The degree of atrophy of the alveolar bone of the mandible was determined by morphometric method. It is found that in both models of periodontitis in rats, changes in the periodontal tissues and in the organism as a whole, is common for periodontal disease in humans. Clinically apparent inflammation of the periodontal tissues is observed, metabolic disorders in the gums, change of biochemical parameters in serum and progressive decline in the alveolar bone are determined. A comparative analysis of the two models showed that the modified "ligature" model of periodontitis in rats has several advantages over the "peroxide" model: shorter term of modeling, more pronounced clinical inflammation of periodontal tissues and faster resorption of alveolar bone.