The tissue renin-angiotensin system in human pancreas

Evidence exists for the presence of a discrete tissue renin-angiotensin system (RAS) in mouse and rat pancreas that is thought largely to be associated with the vasculature. To investigate this in the human pancreas, and to establish whether the cellular sites of RAS components include the islets of Langerhans, we used immunocytochemistry to localise the expression of angiotensin II (AT1) receptors and (pro)renin, and non-isotopic in situ hybridisation to localise transcription of the (pro)renin gene. Identification of cell types in the islets of Langerhans was achieved using antibodies to glucagon and insulin. The results show the presence of the AT1 receptor and (pro)renin both in the beta cells of the islets of Langerhans, and in endothelial cells of the pancreatic vasculature. Transcription of (pro)renin mRNA, however, was confined to connective tissue surrounding the blood vessels and in reticular fibres within the islets. These findings are similar to those obtained in other tissues, and suggest that renin may be released from its sites of synthesis and taken up by possible cellular sites of action. The results presented here suggest that a tissue RAS may be present in human pancreas and that it may directly affect beta cell function as well as pancreatic blood flow.

Localisation of renin-angiotensin system (RAS) components in breast

Angiotensin II has mitogenic and angiogenic effects and its receptors are widespread, particularly in epithelial tissue. Tissue renin angiotensin systems (tRASs) may be a local source of angiotensin II that has specific paracrine functions. To investigate the presence of a tRAS in normal human breast and tumours. Immunocytochemistry, and quantitative RT–PCR was used to establish: (i) the presence and localisation of RAS components, (ii) the possibility of their involvement in cancer. (1) mRNA coding for angiotensinogen, prorenin, angiotensin converting enzyme (ACE), and both AT1 and AT2 receptors was demonstrated in normal and diseased breast tissues. (2) (pro)renin was identified in epithelial cells in both normal and diseased tissue, but in invasive carcinoma, its distribution was mostly confined to fibroblasts or could not be detected at all. (3) Angiotensin converting enzyme was shown in epithelial cells in both normal and malignant tissue. The results are consistent with the hypothesis that a tRAS is present in the breast, and is disrupted in invasive cancer.

Transcription of the prorenin gene in normal and diseased breast

The angiotensin II type 1 (AT1) receptor is present in a wide variety of human and animal tissues, and is particularly abundant in epithelial cells. Because of this, and because it is known that tissue renin angiotensin systems (RASs) exist that have specific local functions, we investigated the expression and localisation of components of the RAS in normal and diseased breast tissue. Using a monoclonal antibody to the AT1 receptor, immunocytochemistry confirmed that the AT1 receptor was characteristically distributed in ductal epithelial cells in both normal and malignant tissue, and in most, although not all, cells in invasive tumours. Transcription of prorenin mRNA was studied by in situ hybridisation, using a DIG-ddUTP tail-labelled probe specific for the human prorenin gene. In normal tissue, and in cases of ductal carcinoma in situ, prorenin mRNA was distributed in myoepithelial cells and in a band of connective tissue cells completely surrounding the AT1-containing ductal epithelial cells. This prorenin transcribing tissue was disrupted and attenuated in invasive tumours, and in some of these, prorenin mRNA transcription could not be detected at all. Functions ascribed to the tissue RASs include regulation of mitosis and tissue modelling, as well as fluid and electrolyte transport. The results presented here strongly suggest the possibility that a tissue RAS may also be present in the breast, closely coupled to the provision of angiotensin II to the AT1 receptors in ductal epithelial cells. This mechanism is disrupted in cancer.

Efficacy of 16S rRNA variable regions high-resolution melt analysis for bacterial pathogens identification in periprosthetic joint infections

BACKGROUND

Accurate and rapid identification of microorganisms causing periprosthetic joint infections (PJIs) are necessary for choosing an appropriate antibiotic therapy. Therefore, molecular techniques are suggested for diagnosis in suspected PJIs. The Broad-range PCR and High-Resolution Melt Analysis (HRMA) were evaluated for the identification of causative organisms of PJIs in this study.

RESULTS

For 47 of 63 specimens, both the culture and broad-range PCR were positive. The culture was found to be able of organism's detection in 74.6% (47/63) of patients. Of 47 positive cultures, 11 (23.4%) were polymicrobial and 36 (76.59%) were monomicrobial cultures, in which 34 (91.89%) cases were detected by HRM assay. The sensitivity, specificity of HRMA vs monomicrobial culture were 91.89, 93.75%, respectively. The sensitivity, specificity of total HRMA (mono + poly) vs culture were 82.92, 93.75%.

CONCLUSIONS

HRM assay coupled with broad-range PCR are effective screening, rapid, and relatively cost-effective methods for discrimination of PJIs especially in aiding culture method. Using computer programs such as the Matlab-2018b program for HRM data analysis is also valuable and helpful in diagnosis.

Bilateral Synovial Knee Chondromatosis in a Patient with Rheumatoid Arthritis: Case-report and Literature Review

We presented a female patient with RA complaining of progressive pain, swelling, and crepitation of the knee joints that was diagnosed with bilateral synovial chondromatosis (SC) of both knees. Radiographies revealed characteristic findings of SC including multiple calcified multifaceted loose bodies within both knees. Removal of cartilaginous segments as well as total synovectomy was performed arthroscopically on the left side and via open surgery on the right side. Short-term postoperative follow-up of our patient revealed improved knee function and resolution of all symptoms.

A More Positive Culture by Resin-containing Media Usage after Suspicious Arthroscopic Infections in Patients Receiving Antimicrobial Therapy

BACKGROUND

Although infections following arthroscopic surgery of cruciate ligament and meniscus are uncommon, they have potentially serious consequences for the graft and articular cartilage. This study aimed to investigate the efficacy of correct sampling and appropriate media, especially resin-containing media, for the detection of infections in patients receiving antibiotics under suspicion of joint infection after arthroscopic anterior cruciate ligament (ACL) and meniscal surgery. In such cases, proper sampling and the use of suitable culture media that cause the neutralization of antibiotics are very effective in isolating microorganisms from the patient samples and positive cultures.

METHODS

In total, 10 patients who had received antibiotics with suspected knee infection after arthroscopic ACL and meniscal surgery were identified after referral to surgeons during a period of 10 months and investigated in this study. The sample collection, culture on various media (i.e., resin-containing culture media), microbiological tests, and antibiotic susceptibility tests were performed in this study. The amplification of the mecA gene using PCR assay was accomplished for methicillin-resistant staphylococcus strains.

RESULTS

This study was conducted on 10 patients who underwent arthroscopic procedures and had received antibiotics. Overall, joint fluid and tissue culture were positive in 60% of the patients. The resin-containing media revealed a trend toward increased detection of bacteria. Coagulase-negative staphylococcus strains were the most frequently isolated bacteria in arthroscopic ACL surgery infections. Out of five methicillin-resistant staphylococcus strains, four strains were found that were resistant to cefoxitin and positive-mecA designated as methicillin-resistant strains. Except for one case, the rest of the staphylococcal strains were resistant to methicillin but susceptible to vancomycin.

CONCLUSION

Despite uncommon and low percentage of infections after arthroscopic ACL and meniscal surgery, the results of our study showed that correct sampling, appropriate cultures, especially aerobic and anaerobic resin-containing media, and microbiological testing remained useful and valuable for diagnosing bacterial infections.