Biochemical study and in vitro insect immune suppression by a trypsin‐like secreted protease from the nematode Steinernema carpocapsae

A trypsin‐like serine protease was purified by gel filtration and anion‐exchange chromatography from the excretory‐secretory products of parasitic phase Steinernema carpocapsae. The purified protease exhibited a molecular mass of about 29 kDa by SDS–PAGE and displayed a pI of 6·3. This protease exhibited high activity with trypsin‐specific substrate N‐Ben‐Phe‐Val‐Arg‐p‐nitroanilide and was highly sensitive to aprotinin and benzamidine. The purified trypsin protease digested the chromogenic substrate N‐Ben‐Phe‐Val‐Arg‐p‐nitroanilide with K_m, V_max and k_cat values of 594·2 μm , 0·496 μm /min and 22·8/s, respectively. The optimal pH and temperature for protease activity were 9 and 30°C, respectively. Internal amino acid sequencing yielded 150 amino acids and these were homologous to other trypsin sequences. In vitro investigation was carried out to monitor prophenoloxidase suppression in Galleria mellonella by the purified protease; about 38·9–52·6% suppression of prophenoloxidase was observed. The purified protease affected insect haemocyte spreading, causing cells to become spherical or round. Protease‐treated actin filaments were highly disorganized in haemocytes. In vitro, G. mellonella haemocytes recognized infective juveniles of Heterorhabditis bacteriophora; however, S. carpocapsae and Steinernema glaseri were not recognized. We provide experimental evidence that the purified trypsin has the potential to alter host haemocytes, actin filaments and to inhibit host haemolymph melanization.     

Association between CD226 polymorphism and soluble levels in rheumatoid arthritis: Relationship with clinical activity

Objective: To study the relation between CD226 rs763361 gene polymorphism and CD226 serum level and to evaluate their role in susceptibility and disease activity of RA in a cohort of Egyptian individuals.

Methods: The serum level of CD226 was measured using a suitable ELISA kit and the CD226 rs763361 gene polymorphism was typed by PCR-RFLP for 112 RA patients and 100 healthy controls.

Results: Significant association with RA was found with CD226 T allele (OR (95%CI) = 1.6 (1.04–2.4), P = 0.032), and higher CD226 serum level (P = 0.001). Higher CD226 levels were associated with higher ESR values (P = 0.035), positive CRP (0.048), increased number of tender joints (P = 0.045), and higher DAS score (P = 0.035). Serum CD226 is an independent risk factor for the prediction of RA (P = 0.001). No correlations were found between the serum level of CD226 and different CD226 genotypes and also between them and RA activity grades.

Conclusion: The CD226 T allele may be susceptibility risk factors for the development of RA and the higher serum level of CD226 may be involved in the pathogenesis of RA in Egyptian patients. The serum level of CD226 and not CD226 genotypes could be considered as an independent risk factor for the prediction of RA within healthy individuals and also for RA disease activity.     

Comparison of immunoblot analysis of emergent multidrug-resistant Salmonella typhimurium definitive phage type 104 with a non-multidrug-resistant definitive phage type 104 strain.

BACKGROUND AND PURPOSE: The emergent multidrug-resistant (MDR) Salmonella typhimurium definitive phage type 104 (DT104) is a public and veterinary health problem not only due to its wide host range and potential for enhanced virulence, but also the difficulty associated with its control. There is thus a need to investigate possible antigens of MDR DT104. METHODS: Using standard protocols, whole cell lysates, outer membrane extracts and cell-free ultracentrifuge supernatants of selected isolates of MDR DT104 were prepared, electrophoretically separated and tested for their antigen-antibody reactivity in comparison with a non-MDR DT104 strain. RESULTS: Protein antigens of both strain types were recognized by antibodies in chick serum in a similar manner for all methods of antigen preparation used. CONCLUSIONS: This study did not find differences between the antibody recognition of MDR DT104 and that of the non-MDR DT104 strain tested. This observation should strengthen the quest for the possible use of vaccines to control this emergent strain in poultry.     

Distribution of complement receptor subtypes in non-Hodgkin's lymphomas of B-cell origin

Surface receptors specific for either the C4b (CR1) or C3d (CR2) component of complement were examined on the neoplastic cells from 30 cases of non-Hodgkin's lymphoma of B-cell origin and on cells derived from 9 normal lymphoid tissues. Lymphocyte suspensions from non- neoplastic peripheral blood, tonsils, and lymph node contained three categories of complement receptor lymphocytes (CRL): cells with receptors for both C4b and C3d (CR1+, CR2+); cells with receptors for C4b but not C3d (CR1+, CR2-), and cells with receptors for C3d but not C4b (CR1-, CR2+). The mean of the proportion of total CRL expressing receptors only of C3d (CR1-, CR2+) was 0.35 for non-neoplastic tissues and 0.28 for malignant lymphomas of follicular center cell (FCC) origin. However, the proportion of cells with this phenotype was significantly higher in well differentiated lymphocytic lymphomas (WDL) and chronic lymphocytic leukemia (CLL) (0.65) and in intermediately differentiated lymphocytic lymphomas (IDL) (0.59). Histologic compartmentalization of the CRL subtypes was observed in frozen sections of normal lymphoid tissue. CR1+ cells were present in lymphoid follicles interfollicular areas, and in splenic red pulp. CR2+ cells were confined to lymphoid follicles. These findings strongly suggest that complement receptor phenotypes may be useful markers of B-cell differentiation.     

Evaluation of fluoride release from experimental TiF4 and NaF varnishes in vitro

Fluoride varnishes play an important role in the prevention of dental caries, promoting the inhibition of demineralization and the increase of remineralization.

Objective

This study aimed to analyze the amount of fluoride released into water and artificial saliva from experimental TiF₄ and NaF varnishes, with different concentrations, for 12 h.

Material and Methods

Fluoride varnishes were applied on acrylic blocks and then immersed in 10 ml of deionized water and artificial saliva in polystyrene bottles. The acrylic blocks were divided in seven groups (n=10): 1.55% TiF₄ varnish (0.95% F, pH 1.0); 3.10% TiF₄ varnish (1.90% F, pH 1.0); 3.10% and 4% TiF₄ varnish (2.45% F, pH 1.0); 2.10% NaF varnish (0.95% F, pH 5.0); 4.20% NaF varnish (1.90% F, pH 5.0); 5.42% NaF varnish (2.45% F, pH 5.0) and control (no treatment, n=5). The fluoride release was analyzed after 1/2, 1, 3, 6, 9 and 12 h of exposure. The analysis was performed using an ion-specific electrode coupled to a potentiometer. Two-way ANOVA and Bonferroni''s test were applied for the statistical analysis (p<0.05).

Results

TiF₄ varnishes released larger amounts of fluoride than NaF varnishes during the first 1/2 h, regardless of their concentration; 4% TiF₄ varnish released more fluoride than NaF varnishes for the first 6 h. The peak of fluoride release occurred at 3 h. There was a better dose-response relationship among the varnishes exposed to water than to artificial saliva.

Conclusions

The 3.10% and 4% TiF₄ -based varnishes have greater ability to release fluoride into water and artificial saliva compared to NaF varnish; however, more studies must be conducted to elucidate the mechanism of action of TiF₄ varnish on tooth surface.     

Erosive cola-based drinks affect the bonding to enamel surface: an in vitro study

Objective

This study aimed to assess the impact of in vitro erosion provoked by different cola-based drinks (Coke types), associated or not with toothbrushing, to bonding to enamel.

Material and Methods

Fifty-six bovine enamel specimens were prepared and randomly assigned into seven groups (N=8): C- Control (neither eroded nor abraded), ERO-RC: 3x/1-minute immersion in Regular Coke (RC), ERO-LC: 3x/1-minute immersion in Light Coke (LC), ERO-ZC: 3x/1-minute immersion in Zero Coke (ZC) and three other eroded groups, subsequently abraded for 1-minute toothbrushing (EROAB-RC, EROAB-LC and EROAB-ZC, respectively). After challenges, they were stored overnight in artificial saliva for a total of 24 hours and restored with Adper Single Bond 2/Filtek Z350. Buildup coronal surfaces were cut in 1 mm² -specimens and subjected to a microtensile test. Data were statistically analyzed by two-way ANOVA/Bonferroni tests (α=0.05). Failure modes were assessed by optical microscopy (X40). The interface of the restorations were observed using Confocal Laser Scanning Microscopy (CLSM).

Results

All tested cola-based drinks significantly reduced the bond strength, which was also observed in the analyses of interfaces. Toothbrushing did not have any impact on the bond strength. CLSM showed that except for Zero Coke, all eroded specimens resulted in irregular hybrid layer formation.

Conclusions

All cola-based drinks reduced the bond strength. Different patterns of hybrid layers were obtained revealing their impact, except for ZC.     

Romosozumab Enhances Vertebral Bone Structure in Women With Low Bone Density

Romosozumab monoclonal antibody treatment works by binding sclerostin and causing rapid stimulation of bone formation while decreasing bone resorption. The location and local magnitude of vertebral bone accrual by romosozumab and how it compares to teriparatide remains to be investigated. Here we analyzed the data from a study collecting lumbar computed tomography (CT) spine scans at enrollment and 12 months post-treatment with romosozumab (210 mg sc monthly, n = 17), open-label daily teriparatide (20 μg sc, n = 19), or placebo (sc monthly, n = 20). For each of the 56 women, cortical thickness (Ct.Th), endocortical thickness (Ec.Th), cortical bone mineral density (Ct.bone mineral density (BMD)), cancellous BMD (Cn.BMD), and cortical mass surface density (CMSD) were measured across the first lumbar vertebral surface. In addition, color maps of the changes in the lumbar vertebrae structure were statistically analyzed and then visualized on the bone surface. At 12 months, romosozumab improved all parameters significantly over placebo and resulted in a mean vertebral Ct.Th increase of 10.3% versus 4.3% for teriparatide, an Ec.Th increase of 137.6% versus 47.5% for teriparatide, a Ct.BMD increase of 2.1% versus a −0.1% decrease for teriparatide, and a CMSD increase of 12.4% versus 3.8% for teriparatide. For all these measurements, the differences between romosozumab and teriparatide were statistically significant (p < 0.05). There was no significant difference between the romosozumab-associated Cn.BMD gains of 22.2% versus 18.1% for teriparatide, but both were significantly greater compared with the change in the placebo group (−4.6%, p < 0.05). Cortical maps showed the topographical locations of the increase in bone in fracture-prone areas of the vertebral shell, walls, and endplates. This study confirms widespread vertebral bone accrual with romosozumab or teriparatide treatment and provides new insights into how the rapid prevention of vertebral fractures is achieved in women with osteoporosis using these anabolic agents. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).