A prospective multicentre study evaluating the outcomes of the abdominal wall dehiscence repair using posterior component separation with transversus abdominis muscle release reinforced by a retro-muscular mesh: filling a step.

BACKGROUND: This study aimed to evaluate the results of posterior component separation (CS) and transversus abdominis muscle release (TAR) with retro-muscular mesh reinforcement in patients with primary abdominal wall dehiscence (AWD). The secondary aims were to detect the incidence of postoperative surgical site occurrence and risk factors of incisional hernia (IH) development following AWD repair with posterior CS with TAR reinforced by retromuscular mesh. METHODS: Between June 2014 and April 2018, 202 patients with grade IA primary AWD (Björck's first classification) following midline laparotomies were treated using posterior CS with TAR release reinforced by a retro-muscular mesh in a prospective multicenter cohort study. RESULTS: The mean age was 42 ± 10 years, with female predominance (59.9%). The mean time from index surgery (midline laparotomy) to primary AWD was 7 ± 3 days. The mean vertical length of primary AWD was 16 ± 2 cm. The median time from primary AWD occurrence to posterior CS + TAR surgery was 3 ± 1 days. The mean operative time of posterior CS + TAR was 95 ± 12 min. No recurrent AWD occurred. Surgical site infections (SSI), seroma, hematoma, IH, and infected mesh occurred in 7.9%, 12.4%, 2%, 8.9%, and 3%, respectively. Mortality was reported in 2.5%. Old age, male gender, smoking, albumin level < 3.5 gm%, time from AWD to posterior CS + TAR surgery, SSI, ileus, and infected mesh were significantly higher in IH. IH rate was 0.5% and 8.9% at two and three years, respectively. In multivariate logistic regression analyses, the predictors of IH were time from AWD till posterior CS + TAR surgical intervention, ileus, SSI, and infected mesh. CONCLUSION: Posterior CS with TAR reinforced by retro-muscular mesh insertion resulted in no AWD recurrence, low IH rates, and low mortality of 2.5%. Trial registration Clinical trial: NCT05278117.

Hepatobiliary manifestations following two-stages elective laparoscopic restorative proctocolectomy for patients with ulcerative colitis: A prospective observational study.

BACKGROUND: Hepatobiliary manifestations occur in ulcerative colitis (UC) patients. The effect of laparoscopic restorative proctocolectomy (LRP) with ileal pouch anal anastomosis (IPAA) on hepatobiliary manifestations is debated. AIM: To evaluate hepatobiliary changes after two-stages elective laparoscopic restorative proctocolectomy for patients with UC. METHODS: Between June 2013 and June 2018, 167 patients with hepatobiliary symptoms underwent two-stage elective LRP for UC in a prospective observational study. Patients with UC and having at least one hepatobiliary manifestation who underwent LRP with IPAA were included in the study. The patients were followed up for four years to assess the outcomes of hepatobiliary manifestations. RESULTS: The patients' mean age was 36 ± 8 years, and males predominated (67.1%). The most common hepatobiliary diagnostic method was liver biopsy (85.6%), followed by Magnetic resonance cholangiopancreatography (63.5%), Antineutrophil cytoplasmic antibodies (62.5%), abdominal ultrasonography (35.9%), and Endoscopic retrograde cholangiopancreatography (6%). The most common hepatobiliary symptom was Primary sclerosing cholangitis (PSC) (62.3%), followed by fatty liver (16.8%) and gallbladder stone (10.2%). 66.4% of patients showed a stable course after surgery. Progressive or regressive courses occurred in 16.8% of each. Mortality was 6%, and recurrence or progression of symptoms required surgery for 15%. Most PSC patients (87.5%) had a stable course, and only 12.5% became worse. Two-thirds (64.3%) of fatty liver patients showed a regressive course, while one-third (35.7%) showed a stable course. Survival rates were 98.8%, 97%, 95.8%, and 94% at 12 mo, 24 mo, 36 mo, and at the end of the follow-up. CONCLUSION: In patients with UC who had LRP, there is a positive impact on hepatobiliary disease. It caused an improvement in PSC and fatty liver disease. The most prevalent unchanged course was PSC, while the most common improvement was fatty liver disease.

A comparison between different management surgical approaches in the treatment of splenic flexure colon cancer

Background: There are many surgical approaches which described extent of resection of the colon for adequate surgicalmanagement of splenic flexure cancer, but up till now there is no established surgical procedure, this is because the presence of double lymphatic drainage of themesenteric vessels. Segmental resection of the colon for the management of splenic flexure cancer was a recently accepted surgical procedure. Objective: In the present study, we aimed to compare three surgical management techniques to clarify the best management approach of Egyptian patients with splenic flexure cancer regarding operative, clinical, and oncological outcomes: segmental resection, and extended left or right hemicolectomy,. Materials and Methods In the present study, we included 90 patients with splenic flexure cancer. Cases were divided into 3 groups. Each group included 30 patients in order to compare three surgical techniques: segmental resection, extended left hemicolectomy, and extended right hemicolectomy. Results: We have found no statistically significant differences between the three included groups regarding operative findings, postoperative complications, local recurrence, distant recurrence, disease progression, recurrence-free survival rate, progression-free survival rate, and overall survival rate. The operative time was longer, and the number of lymph nodes was higher in the extended right hemicolectomy group (p<0.001). Conclusion: We have shown that segmental resection of the splenic flexure is surgically and clinically suitable for the adequate management of operable cases of carcinoma of the splenic flexure. (AU)

Prognostic and clinicopathological significance of TMEFF2, SMOC-2, and SOX17 expression in endometrial carcinoma.

Background there is a need for novel biomarkers and targeting therapies for predicting Endometrial carcinoma (EC) progression and recurrence. TMEFF2 is a gene that was found to play a role in EMT. SMOC-2 is expressed in embryogenesis and it was identified as a recent stem cell-related gene that has a role in cancer progression. SRY-box 17 (SOX17) is a member of the SRY-related HMG-box (SOX) family of transcription factors. Dysregulation or downregulation of SOX17 expression was found in many cancer tissues. AIM: In the present study, we aimed to assess the tissue protein expressions of TMEFF2, SMOC-2, and SOX17 in EC using immunohistochemistry to evaluate their clinicopathological values and prognostic roles in EC patients. PATIENTS AND METHODS: This is prospective cohort study included 120 patients with EC. Sections from 120 paraffin blocks were retrieved and stained with TMEFF2, SMOC-2, and SOX17 using immunohistochemistry, the expression of markers in all tissue samples was assessed, analyzed and correlation of pathological parameters with the levels of expression was done. All patients were followed up till death or till the last known alive data for about 50 months (range from 25 to 60). RESULTS: TMEFF2, SMOC-2 expression was correlated with the presence of lymph node metastases (p = 0.023), distant metastasis (p = 0.039) recurrence of the tumor after successful therapy, overall survival, and disease-free survival (p < 0.001). SOX17 positive expression was positively correlated with low grade (p = 0.019), absence of lymph node metastasis (p = 0.001), absence of distant metastasis (p = 0.013), low stage (p = 0.03), and its negative expression was positively correlated with recurrence of the tumor after successful therapy, overall survival and disease-free survival (p = 0.001). In conclusion, we demonstrated that both TMEFF2 and SMOC-2 were highly expressed in EC and were associated with a shortened survival rate, dismal outcome, and poor prognosis in EC patients. While SOX17 expression was related to a favorable outcome and its down-regulation was associated with dismal EC patient's survival.

Prognostic and clinicopathological implications of expression of Beclin-1 and hypoxia-inducible factor 1α in serous ovarian carcinoma: an immunohistochemical study.

Serous ovarian carcinoma (SOC) is an ovarian cancer with a high fatality rate. Therefore, a lot of researchers have tried to identify novel prognostic biomarkers which might improve the patient prognosis. The aims of the study were to detect the tissue protein expression of Beclin-1 in addition to HIF-1α in SOC patients, to evaluate the relationship between their expression, the clinicopathological parameters, patients' prognosis, and the relation to chemotherapy resistance in SOC. We evaluated the expression of Beclin-1 in addition to HIF-1α in 60 patients with SOC using immunohistochemistry, followed all patients for about 36 months, analyzed associations between both markers' expression, clinicopathological data, and patients' prognosis. Beclin-1 expression was related to low grade (p = 0.002), early SOC stage, absence of peritoneal spread (p = 0.006), and absence of lymph nodes, and distant metastases (p = 0.004 and < 0.001 respectively), while HIF-1α expression was associated with higher grade and stage (p = 0.007), and presence of nodal and distant metastases (p < 0.001 and = 0.012 respectively). High Beclin-1 expression and low HIF-1α expression were positively associated with good response to chemotherapy (p = 0.047 and p = 0.022 respectively), a lower recurrence rate after successful therapy (p = 0.006 and < 0.001 respectively), and increased three-year recurrence-free and overall survival rates (p < 0.001). In SOC patients; Beclin-1 is a good prognostic marker, while HIF-1α is a poor prognostic marker.

Evaluating the value of Amphiregulin, Phosphatase and Tensin Homologue (PTEN) and P21 Expression for Anti-EGFR Treatment in Metastatic Colorectal Carcinoma.

BACKGROUND: Despite the significant progress in target therapy for the treatment of metastatic colorectal carcinoma (mCRC), the overall survival isn't satisfactory. METHODS: We assessed the expression of Amphiregulin, PTEN, and P21 in sections from 23 paraffin blocks prepared from 23 patients with left-sided mCRC using immunohistochemistry (IHC). The relationship between their level of expressions, clinicopathological parameters, response to anti-EGFR, and prognosis were analyzed. RESULTS: High Amphiregulin, PTEN and low P21 expression levels were associated with low tumor grade (p= 0.038 and 0.025 respectively), better response to anti-EGFR treatment (p <0.001), and favorable outcome {progression-free survival (PFS) and overall survival (OS)} (p <0.05). There was a direct relation between Amphiregulin and PTEN expressions (phi coefficient=+0.840), while there was an inverse relation between P21expression and both Amphiregulin (phi coefficient= -0.840) and PTEN expressions (phi coefficient = -1.000), which was statistically significant (P <0.001). CONCLUSION: High Amphiregulin and PTEN expression levels and low P21 expression levels were associated with better response to anti-EGFR therapy and improved survival outcome. They might be considered predictive markers of response to anti-EGFR therapy in mCRC.

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Relation between mutations in the 5' UTR of ANKRD26 gene and inherited thrombocytopenia with predisposition to myeloid malignancies. An Egyptian study.

Inherited thrombocytopenias are a heterogeneous group of diseases characterized by a reduced number of platelets and a bleeding tendency that ranges from very mild to life threatening especially in surgery. Mutations in the 5' untranslated region (UTR) of Ankirin repeat domain 26 (ANKRD26) are responsible for autosomal-dominant form of thrombocytopenia, that is known as ANKRD26-related thrombocytopenia (ANKRD26 RT), characterized by a moderate thrombocytopenia with mild propensity to bleeding and predisposition to hematological malignancies including AML and MDS. We included 90 unrelated patients with inherited thrombocytopenia. In addition, we investigated 45 patients with ITP. Peripheral blood and bone marrow samples were collected and examined and molecular detection of mutations in the 5︡ UTR of ANKRD26 gene was performed for all the patients. Also, screening of the mutation and development of myeloid malignancies in the extended series of the affected subjects was done. ANKRD26 mutations were identified in 10% of the patients with inherited thrombocytopenia. The most common types were c.128 G > A and c.127A>T, while no mutations were found in the ITP group. In those affected, the median number of platelets was 69 x109/L (43-106) with normal MPV in most of the patients (9.4-11.6). There was a statistically significant increase in the unexpected high frequency of myeloid malignancies in the extended series of the mutated subjects compared with the ITP group-extended series (P < .001). So, we can conclude that ANKRD26 RT is associated with increased risk for developing myeloid malignancies and ANKRD26 mutations can represent a valuable tool for making therapeutic decisions.

Prognostic Significances of NEDD-9 and FOXL-1 Expression in Intestinal Type Gastric Carcinoma: an Immunohistochemical Study.

BACKGROUND: Gastric cancer (GC) is mostly diagnosed at advanced stage, so prognosis is poor. Therefore, it is necessary to understand the molecular mechanism of GC development to design new targeted treatment to improve the prognosis of gastric cancer patients. AIM OF THE WORK: To assess the prognostic value of NEDD-9 and FOXL-1 expression in intestinal type gastric cancer patients, as well as their relationship to clinicopathologic features of the disease and patients outcome. PATIENTS AND METHODS: This is a retrospective study; we included 50 sections from formalin-fixed, paraffin-embedded tissue samples which included intestinal type GC and adjacent non-neoplastic gastric mucosa in the same block that were subjected to immunohistochemistry with anti-NEDD-9 and anti-FOXL-1 antibody. Patients were retrospectively followed up for about 5 years for assessment of tumor progression and survival in relation to marker expression. RESULTS: High NEDD-9 and low FOXL-1 expression were found in intestinal type GC more than adjacent non-neoplastic mucosa (p < 0.001). NEDD-9 high expression and FOXL-1 low expression were associated with presence of helicobacter pylori gastritis (p = 0.010, 0.049), high grade (p = 0.007, 0.004), high stage (p < 0.001), presence of distant metastases (p = 0.029, 0.021), poor DFS (p = 0.003), and OS rates (< 0.001). CONCLUSION: NEDD-9 overexpression and FOXL-1 deficiency in intestinal type GC can help in prediction of tumor prognosis and it can guide the selection of patients for future therapies in gastric carcinoma.

Utilization of a recombinant defensin from Maize (Zea mays L.) as a potential antimicrobial peptide.

The search for effective and bioactive antimicrobial molecules to  encounter the medical need for new antibiotics is an encouraging area of research. Plant defensins are small cationic, cysteine-rich peptides with a stabilized tertiary structure by disulfide-bridges and characterized by a wide range of biological functions. The heterologous expression of Egyptian maize defensin (MzDef) in Escherichia coli and subsequent purification by glutathione affinity chromatography yielded 2 mg/L of recombinant defensin peptide. The glutathione-S-transferase (GST)-tagged MzDef of approximately 30 kDa in size (26 KDa GST + ~ 4 KDa MzDef peptide) was immunodetected with anti-GST antibodies. The GST-tag was successfully cleaved from the MzDef peptide by thrombin, and the removal was validated by the Tris-Tricine gel electrophoresis. The MzDef induced strong growth inhibition of Rhizoctonia solani, Fusarium verticillioides, and Aspergillus niger by 94.23%, 93.34%, and 86.25%, respectively, whereas relatively weak growth inhibitory activity of 35.42% against Fusarium solani was recorded. Moreover, strong antibacterial activities were demonstrated against E. coli and Bacillus cereus and the moderate activities against Salmonella enterica and Staphylococcus aureus at all tested concentrations (0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 µM). Furthermore, the in vitro MTT assay exhibited promising anticancer activity against all tested cell lines (hepatocellular carcinoma, mammary gland breast cancer, and colorectal carcinoma colon cancer) with IC50 values ranging from 14.85 to 29.85 µg/mL. These results suggest that the recombinant peptide MzDef may serve as a potential alternative antimicrobial and anticancer agent to be used in medicinal application.

Changing the innate consensus about mesh fixation in trans-abdominal preperitoneal laparoscopic inguinal hernioplasty in adults: Short and long term outcome. Randomized controlled clinical trial.

INTRODUCTION: Inguinal hernioplasty is the standard treatment for inguinal hernia in adults. Mesh fixation was used to keep mesh in place for which various mesh fixation techniques have been used in laparoscopic inguinal hernia repair in adults, but their effectiveness has remained inconclusive. AIM OF THE WORK: to evaluate non fixation method of mesh laparoscopic inguinal hernioplasty as safe and effective as regard short and long term outcomes. PATIENTS AND METHODS: Over the period from July 2013 to July 2018, 798 patients with oblique inguinal hernias undergoing Trans abdominal preperitoneal technique (TAPP) were randomized into 3 groups: Group A; mesh non fixation 266 patients. Group B; tacker mesh fixation 266 patients Group C: Cyanoacrylic tissue glues (Histoacryl) mesh fixation 266 patients. Clinical effects were assessed by the following variables: intraoperative data, postoperative outcome as regard recurrence rate, postoperative pain [on visual analogue score (VAS)], analgesic consumption, operation time, hospital stay, and patient costs. Follow up was 18 months. RESULTS: There was no statistical difference between groups (A) and Group (C) regarding operative time, postoperative complications, and length of hospital stay and risk of chronic groin pain, postoperative pain score. In Group (B): the postoperative pain and complications were higher. There were 5 cases of hernia recurrence in all groups, but no significant differences among the three groups. CONCLUSION: Tacker Mesh fixation increased the risk of chronic groin pain. Pain score was higher with tacker mesh fixation. Laparoscopic TAPP inguinal hernia repair without tacker mesh fixation was safe and feasible with no significant increase in recurrence rates. Furthermore, mesh fixation with tacker procedure increased the risk of postoperative complications and patient costs. All ethical approval was given by our Faculty of Medicine medical ethical committee.

Impact Effect of Methyl Tertiary-Butyl Ether "Twelve Months Vapor Inhalation Study in Rats".

We investigated the early risk of developing cancer by inhalation of low doses (60 µL/day) of methyl tertiary butyl ether (MTBE) vapors using protein SDS-PAGE and LC-MS/MS analysis of rat sera. Furthermore, histological alterations were assessed in the trachea and lungs of 60 adult male Wistar rats. SDS-PAGE of blood sera showed three protein bands corresponding to 29, 28, and 21 kDa. Mass spectroscopy was used to identify these three bands. The upper and middle protein bands showed homology to carbonic anhydrase 2 (CA II), whereas the lower protein band showed homology with peroxiredoxin 2. We found that exposure to MTBE resulted in histopathological alterations in the trachea and the lungs. The histological anomalies of trachea and lung showed that the lumen of trachea, bronchi, and air alveoli packed with free and necrotic epithelial cells (epithelialization). The tracheal lamina propria of lung demonstrated aggregation of lymphoid cells, lymphoid hyperplasia, hemorrhage, adenomas, fibroid degeneration, steatosis, foam cells, severe inflammatory cells with monocytic infiltration, edema, hemorrhage. Occluded, congested, and hypertrophied lung arteries in addition, degenerated thyroid follicles, were observed. The hyaline cartilage displayed degeneration, deformation, and abnormal protrusion. In conclusion, our results suggest that inhalation of very low concentrations of the gasoline additive MTBE could induce an increase in protein levels and resulted in histopathological alterations of the trachea and the lungs.

Construction, Expression and Evaluation of Recombinant VP2 Protein for serotype-independent Detection of FMDV Seropositive Animals in Egypt.

Foot-and-mouth disease virus (FMDV) is one of the most devastating viral pathogens of cloven-hoofed animals. The detection of antibodies (Ab) against FMDV structural proteins (SP) using virus neutralization test (VNT) and liquid-phase blocking ELISA (LPBE) is the standard procedure in use for monitoring seroconversion in animals post vaccination, the prevalence of infection-surveillance, proving clinical cases and seronegative status of FMDV-free/naïve-animals prior transportation. However, due to variations within SP of FMDV serotypes, each serotype-specific Ab should be detected separately which is laborious and time-consuming. Accordingly, it is crucial to develop a sensitive, rapid, and accurate test capable of detecting FMDV-specific Ab, regardless its serotype. This study describes the heterologous expression of VP2 protein in E. coli, and its evaluation as a capture antigen in a simple indirect ELISA for serotype-independent detection of anti-FMDV Ab. Sequence analysis revealed that the VP2-coding sequence is considerably conserved among FMDV serotypes. The recombinant VP2 (rVP2), a 22 kDa polypeptide, was purified to near homogeneity by affinity chromatography under native conditions. Immunoreactivity of the rVP2 was confirmed by using a panel of positive sera including sera from animals vaccinated with the local trivalent vaccine and guinea pig FMDV antiserum, which is routinely used as tracing/detecting Ab in LPBE testing. The results obtained from the VP2-based ELISA were comparable to those determined by VNT and LPBE standard diagnostic assays. Specificity and sensitivity of rVP2 in capturing anti-FMDV Ab were 98.3% and 100%, respectively. The developed VP2-ELISA is proved reliable and time-efficient assay for detection of FMDV seropositive animals, regardless the FMDV serotype that can be implemented in a combination with VNT and/or LPBE for rapid diagnosis of an ongoing FMDV infection.

SPOP, ZEB-1 and E-cadherin expression in clear cell renal cell carcinoma (cc-RCC): Clinicopathological and prognostic significance.

BACKGROUND: Clear cell renal cell carcinoma (cc-RCC), is a serious cancer regarding; its fatality, liability for metastases and chemoresistance, so identification of recent therapeutic targets to improve the patients prognosis is needed. SPOP is a BTB/POZ domain containing speckle-type POZ protein, has been identified as an E3 ubiquitin ligase component. ZEB1 is an essential epithelial mesenchymal transition (EMT) activator; E-cadherin is a cell adhesion protein that had been detected in normal epithelial cells membrane. AIM: Was to assess the tissue protein markers SPOP, ZEB1 & E-cadherin expressions in benign areas of neoplastic kidney specimens and in cc-RCC patients, then correlating their expression levels with patients clinicopathological and prognostic data. METHODS: We evaluated SPOP, ZEB-1 & E-cadherin expression using immunohistochemistry in samples from 50 cc-RCC and 20 benign areas of neoplastic kidney specimens, then we followed our patients for 5 years and finally we have analyzed correlations between the levels of markers expressions with patients clinicopathological and prognostic criteria in cc-RCC. RESULTS: Positive expression of SPOP & ZEB1 in addition to negative E- cadherin expression was detected in cc-RCC more than benign areas of neoplastic kidney specimens (p = 0.004 and p < 0.001 respectively). In cc-RCC Positive expression of SPOP, ZEB1 and negative E- cadherin expression was associated with higher grade (p = 0.006, 0.007 & <0.001 respectively), advanced AJCC stage (p = 0.013, 0.023 & <0.001 respectively), presence of L.N metastases (p = 0.002 = 0.010 and <0.001 respectively), distant metastases (p = 0.001, 0.003 & 0.035 respectively), poor PFS and OS rates (p < 0.001 and p = 0.013 respectively). CONCLUSION: Positive expression of SPOP& ZEB1 in addition to negative E- cadherin are associated with poor prognosis in cc-RCC patients.

Porcine skin gelatin-silver nanocomposites: synthesis, characterisation, cell cytotoxicity, and antibacterial properties.

Silver nanoparticles (AgNPs) were synthesised with hydrothermal autoclaving technique by using AgNO3 salt (silver precursor) at different concentrations (0.01, 0.1, 0.55, 1.1, 5.5, and 11 mM) and porcine skin (1% (w/v) ) gelatin polymeric matrix (reducing and stabiliser agent). The reaction was performed in an autoclave at 103 kPa and 121°C and the hydrothermal autoclaving exposure time and AgNO3 molar concentration were varied at a constant porcine skin gelatin concentration. The as-prepared AgNPs were characterised by UV-visible spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The antibacterial properties of AgNPs were tested against gram-positive and gram-negative bacteria. Furthermore, 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide and 2,2-diphenyl-1-picrylhydrazyl assays were used to test whether the synthesised AgNPs can be potentially applied in cancer therapy or used as an antioxidant. This approach is a promising simple route for synthesising AgNPs with a smaller average particle 10 nm diameter. Furthermore, AgNPs exhibited a good cytotoxicity activity, reducing the viability of the liver cancer cell line HepG2 with a moderate IC50; they also showed a low-to-fair antioxidant activity. In addition, AgNPs had a remarkable preferential antibacterial activity against gram-positive bacteria than gram-negative bacteria. Therefore, these fabricated AgNPs can be used as an antibacterial agent in curative and preventive health care.

Percutaneous trans-abdominal external looped needle with two holes in the trocar sheath for port-site closures in difficult obese cases.

INTRODUCTION: Port closure is essential after successful laparoscopic surgery to prevent incisional hernia. However, good fascial closure still represents a problem, especially in obese patients and when the port wound is oblique. We report a novel technique for port-site closures in such cases. METHODS: This study involved 67 obese patients who underwent laparoscopic surgery. We used a novel technique for port-site closure that employed a looped needle passed through two holes in the port sheath. RESULTS: The method was used in 67 patients (45 laparoscopic cholecystectomies, 22 laparoscopic hernia repairs), with a mean BMI of 35.7 kg/m2 . No intraoperative incidents or port-site hernias were reported during follow-up (mean, 22 months). CONCLUSION: Our procedure is safe, easy, and effective for fascial port site closures, especially in cases of difficult obese patients and oblique port wounds.

Genes encoding proteins with peritrophin A-type chitin-binding domains in Tribolium castaneum are grouped into three distinct families based on phylogeny, expression and function.

This study is focused on the characterization and expression of genes in the red flour beetle, Tribolium castaneum, encoding proteins that possess one or more six-cysteine-containing chitin-binding domains related to the peritrophin A domain (ChtBD2). An exhaustive bioinformatics search of the genome of T. castaneum queried with ChtBD2 sequences yielded 13 previously characterized chitin metabolic enzymes and 29 additional proteins with signal peptides as well as one to 14 ChtBD2s. Using phylogenetic analyses, these additional 29 proteins were classified into three large families. The first family includes 11 proteins closely related to the peritrophins, each containing one to 14 ChtBD2s. These are midgut-specific and are expressed only during feeding stages. We propose the name "Peritrophic Matrix Proteins" (PMP) for this family. The second family contains eight proteins encoded by seven genes (one gene codes for 2 splice variants), which are closely related to gasp/obstructor-like proteins that contain 3 ChtBD2s each. The third family has ten proteins that are of diverse sizes and sequences with only one ChtBD2 each. The genes of the second and third families are expressed in non-midgut tissues throughout all stages of development. We propose the names "Cuticular Proteins Analogous to Peritophins 3" (CPAP3) for the second family that has three ChtBD2s and "Cuticular Proteins Analogous to Peritophins 1 (CPAP1) for the third family that has 1 ChtBD2. Even though proteins of both CPAP1 and CPAP3 families have the "peritrophin A" domain, they are expressed only in cuticle-forming tissues. We determined the exon-intron organization of the genes, encoding these 29 proteins as well as the domain organization of the encoded proteins with ChtBD2s. All 29 proteins have predicted cleavable signal peptides and ChtBD2s, suggesting that they interact with chitin in extracellular locations. Comparison of ChtBD2s-containing proteins in different insect species belonging to different orders suggests that ChtBD2s are ancient protein domains whose affinity for chitin in extracellular matrices has been exploited many times for a range of biological functions. The differences in the expression profiles of PMPs and CPAPs indicate that even though they share the peritrophin A motif for chitin binding, these three families of proteins have quite distinct biological functions.