Controversies surrounding the validity of the toxic proteinopathy theory of Alzheimer’s disease have led the scientific community to seek alternative theories in the pathogenesis of neurodegenerative disorders (ND). Recent studies have provided evidence of a microbiome in the central nervous system. Some have hypothesized that brain-inhabiting organisms induce chronic neuroinflammation, leading to the development of a spectrum of NDs. Bacteria such as Chlamydia pneumoniae, Helicobacter pylori, and Cutibacterium acnes have been found to inhabit the brains of ND patients. Furthermore, several fungi, including Candida and Malassezia species, have been identified in the central nervous system of these patients. However, there remains several limitations to the brain microbiome hypothesis. Varying results across the literature, concerns regarding sample contamination, and the presence of exogenous deoxyribonucleic acids have led to doubts about the hypothesis. These results provide valuable insight into the pathogenesis of NDs. Herein, we provide a review of the evidence for and against the brain microbiome theory and describe the difficulties facing the hypothesis. Additionally, we define possible mechanisms of bacterial invasion of the brain and organism-related neurodegeneration in NDs and the potential therapeutic premises of this theory.

Purpose: Triple-negative breast cancer (TNBC) is a subset of breast cancer which is known to carry a poor prognosis because of lack of targets for hormonal therapy. Research efforts have focused in recent years on discovering biomarkers of management in TNBCs. KI-67 Labelling Index (LI) is a nuclear protein which has proven to play diagnostic and prognostic roles in many cancers. Materials and methods: We analysed the expression of KI-67 LI by immunohistochemistry in TNBC cases from the University hospital. This expression was cross-checked against clinical-pathological criteria of TNBC patients and against Vimentin expression in TNBC patients with significant KI-67 expression. Results: KI-67 LI was significantly expressed in the majority of TNBC cases. This expression was significantly correlated with lymph node metastases, tumour invasion, high tumour nuclear grade, clinical stage, adverse survival outcome, and failure to achieve pathological complete response. TNBCs’ KI-67 LI expression was also correlated with Vimentin expression, the mesenchymal chief marker of the EMT phenomenon. Conclusion: Collectively, our study presents a strong argument for the use of KI-67 LI as a biomarker of aggressive, metastatic TNBC disease with poor outcome. This study, along with mounting evidence in the scientific literature, presents a case for the use of this nuclear protein in diagnosis, prognosis, and follow-up of patients with this difficult diagnosis.

Claudins are the main sealing proteins of the intercellular tight junctions and play an important role in cancer cell progression and dissemination. This study examined and compared the expression of claudin-1 by immunohistochemistry in 60 squamous cell carcinomas of different tissue types and normal 33 controls, arranged in 2 tissue microarray slides. A score was generated to classify claudin-1 expression into negative, low, medium, and high. Most squamous cell carcinomas (91.67%) showed positive membranous staining. Medium to high claudin-1 expression was prevalent in carcinomas from the head–neck, skin, and genitourinary regions and was less frequent in other locations. An inverse correlation was noted between claudin-1 expression and tumor grade in tumors of the genitourinary and breast–gynecologic regions. Of the normal organs, significant claudin-1 expression was present mainly in the skin whereas other epithelial tissues had only minimal to low expression levels. Claudin-1 expression in squamous cell carcinoma varies in organ-specific manner reflecting influence of local factors and different mechanisms of claudin-1 expression. Knowledge of this fact is important in planning biologic therapy targeting claudin-1.

Background:Claudins are the main sealing proteins of the intercellular tight junctions and play an important role in cancer cell progression and dissemination. The authors have previously shown that overexpression of claudin-1 is associated with angiolymphatic and perineural invasion, consistent with aggressive tumor behavior and with advanced stage disease in oral squamous cell carcinomas (OSCCs). Our goal in this study was to examine claudin-1 expression in a tissue microarray of OSCCs taken from multiple sites within the oral cavity.Materials and Methods:This study examined and compared the expression of claudin-1 by immunohistochemistry in 60 tissue samples (49 OSCCs and 10 cases of non-neoplastic tissue, single core per case) were analyzed for claudin-1 expression by immunohistochemistry. The tumors included SCCs from the tongue (n=28), the cheek (n=9), gingival (n=4), lip (n=3), and oral cavity (n=5). Nonmalignant normal oral mucosa from the tongue (unmatched cases, n=2). Cancer adjacent tissue samples were taken from the tongue (n=6), gingival (n=2), and palate (n=1).Results:This study demonstrates the expression of claudin-1 protein across a sample of OSCCs originating from multiple locations in the oral cavity. The highest expression of claudin-1 was observed in well-differentiated OSCCs, whereas poorly differentiated OSCCs exhibited mostly negative staining for claudin-1. In addition, we hereby report differential pattern of expression among tumors of different sites within the oral cavity, and between benign and cancerous samples. Our understanding of the exact function and role of claudin-1 in tumorigenesis is expanding exponentially.

Background Needlestick injuries (NSIs) and sharps injuries (SIs) remain significant hazards in most healthcare facilities that expose healthcare workers (HCWs) to blood-borne pathogens (e.g., HIV, hepatitis B, and hepatitis C). This study aims to review the incidence of NSIs and SIs in King Fahad Medical City (KFMC) and correlate this incidence with several parameters related to the event, including age, sex, length of work experience, type of injury, type of instrument causing the injury, type of activity during which the injury happened, nature of the job of the HCWs, and location within the hospital where the injury happened. Methodology This cross-sectional study involves all self-reported documents related to needlestick and sharp injuries among HCWs at King Fahad Medical City (KFMC) in Riyadh, Kingdom of Saudi Arabia, from January 2017 to December 2020. The data of 389 reports of needlestick and sharp injuries detailing incidence and site, shift, type, and instrument related to the incidents were reported to the infection control department for coding and analysis using the Statistical Package for the Social Sciences (SPSS) version 22 (IBM SPSS Statistics, Armonk, NY, USA). Results Our data showed that NSIs/SIs could be caused by a wide range of objects used by healthcare workers, including needles, suture needles, scalpels, and sharp devices. Remarkably, the most common cause of NSIs was handling the sharp object (38.8%), followed by disposing of the sharp object (19.3%). Furthermore, nurses were found to be the highest at-risk category of HCWs experiencing NSIs (49.9%), while medical waste handlers (1.5%) and dentists (1.3%) were least likely to incur injuries. Conclusion This study sheds some light on the incidence rates of NCIs and SIs at KFMC and correlates these rates with several demographical, occupational, and experiential parameters related to these events.

Premalignant lesions of the gastrointestinal tract are a group of disorders which act as the harbinger of malignant tumors. They are the ground-zero of neoplastic transformation, and their identification and management offer patients the best opportunity of blocking the progress of cancer. However, diagnoses of some of these conditions are hard to make, and their clinical importance is difficult to assess. Recent reports indicated that several claudin proteins have altered expressions in many cancers, including esophageal, gastric, colon, liver, and pancreatic cancers. The early identification of the aberrant expression of these proteins could lead to the early diagnosis and management of gastrointestinal tumors. Specifically, claudins -1, -2, -3, -4, and -18 are frequently overexpressed in gastrointestinal preneoplastic lesions. These altered expressions have shown clinical value in several tumors, providing diagnostic and prognostic information. In this article, we review the literature on the aberrant expression of claudins in preneoplastic lesions of the gastrointestinal tract. Additionally, we summarize their diagnostic and prognostic implications.