The comparative anatomy of the pig middle ear cavity: a model for middle ear inflammation in the human?

This study was undertaken to develop a functional model of otitis media with effusion (OME) in the pig (Sus scrofa), with the purpose of investigating the origin of lymphocytes populating the middle ear during the course of an inflammatory process. The relevance of the model to the human condition of OME is to a large extent dependent on the anatomical and physiological similarities between the middle ear cavity and the pharyngeal lymphoid tissue of the pig and man. Anatomical specimens were collected from 7 young Large White pigs to determine the gross anatomy of the middle ear cavity and the histological characteristics of the middle ear mucosa. It was found that the anatomy of the 3 parts of the middle ear cavity in man and in the pig is broadly similar, although some minor differences were observed. The porcine eustachian tube was seen to be cartilaginous throughout its length in contrast to the part osseous, part cartilaginous structure found in man; the porcine ossicles were slightly different in shape to those of man and the air cell system was situated inferior to the tympanic cavity in the pig as opposed to posteriorly in man. This paper describes the structure and morphology of the pig middle ear cavity and compares and contrasts it with that of man. The minor differences observed are of anatomical importance but do not diminish the usefulness of the pig middle ear cleft as a potential model for human middle ear disorders.

Structure of the crypt epithelium in human palatine tonsils

Material from human palatine tonsils from a group of 18 tonsillectomised patients aged 22 months to 8 years was studied by LM, TEM and SEM. Special attention was focused on the structure of the epithelium lining the tonsillar crypts. This is of a dynamic nature in the living organism. In contrast to the stratified squamous epithelium covering the oropharyngeal surface of the tonsil it was often reticulated and invaded by non-epithelial cells. However, it was not uniform throughout. When studied by LM and TEM, adjacent patches of epithelium varied in degree of reticularity. The reticulated epithelium was either covered by a thin layer of squamous cells, or this was disrupted in places where non-epithelial cells passed through. Hence the intact surface, as seen on the SEM, is not a reliable indication of the nature of the underlying structure of the epithelium. Small blood vessels were frequently observed in association with the reticulated epithelium. They formed numerous finger-like projections surrounded by a sleeve of subepithelial connective tissue, and also a fine capillary network within the epithelial thickness. It is proposed that such an organisation of the crypt epithelium offers favourable means for the capturing and processing of antigens by the palatine tonsils.

Vimentin, cytokeratin 8 and cytokeratin 18 are not specific markers for M-cells in human palatine tonsils

Standard immunohistochemical methods were used to detect the presence of vimentin, cytokeratin 8, cytokeratin 18, macrophages and Langerhans cells in the human tonsillar epithelium in formalin-fixed and frozen tissue specimens. Vimentin detection was restricted to infiltrating cells of the lymphoid series, dendritic and vascular endothelial cells. All epithelial cells were negative. Cytokeratin 8 and 18 were readily detected in a large proportion of epithelial cells lining the crypt, but these cells bore no resemblance to the intestinal M-cells. Langerhans cells and macrophages were seen in both the oropharyngeal and crypt epithelium and were more common in the latter. This study confirms the presence of antigen-presenting cells, macrophages and Langerhans cells in the tonsillar epithelium and shows that intermediate filament proteins, vimentin, cytokeratin 8 and 18 are unreliable markers for human tonsillar M-cells, if indeed such cells exist in human tonsils.

The distribution and abnormal morphology of plasma cells in rheumatoid synovium

This study assessed the distribution and structural features of plasma cells in rheumatoid synovial tissue. Plasma cells were found to be the predominant infiltrating mononuclear cells (mean 40%) in relation to lymphocytes and monocytes, and there was a direct relationship between their number in the infiltrates and the total number of mononuclear leucocytes (P = 0.007). Plasma cells were also seen in intimate contact with macrophages intermixed with synovial lining cells, and closely associated with small blood vessels. They often surrounded these blood vessels and sometimes were seen lying within the vessel walls themselves. Ultrastructural analysis revealed that many synovial plasma cells were considerably larger than plasma cells of a normal size and possessed a marked distension of the cisternae of rough endoplasmic reticulum. Furthermore, plasma cells in close proximity to blood vessels often appeared to be undergoing migration. These observations imply that in rheumatoid synovium, plasma cells are metabolically very active and occupy a pivotal position for the secretion of antibodies into both the vascular and the extravascular compartments.

Binucleated and multinucleated forms of plasma cells in synovia from patients with rheumatoid arthritis

A morphological examination of synovial tissue from 25 patients with rheumatoid arthritis revealed that binucleated or multinucleated plasma cells were present in all samples and absent in synovia obtained from 16 control patients. Plasma cells containing two, three of four nuclei constitute a mean 3% of the total plasma cell population. They were always found amongst plasma cell infiltrates and in close association with small blood vessels. Ultrastructural analysis found no evidence of cellular membranes separating the individual nuclei in binucleated or multinucleated plasma cells, suggesting that the cells did not arise from fusion. Some of these plasma cells had a diameter approaching 100 microns, and many were in intimate contact with macrophages. The demonstration of a few cells with mitotic figures within the infiltrates suggests that the maintenance of plasma cell numbers in rheumatoid synovium may depend, in part, upon their local proliferation.

Differential atrial stunning after electrical cardioversion: an echo tissue Doppler case study

Left atrial stunning after cardioversion is a well-known phenomenon. It has been associated with higher risk of postcardioversion thromboemboli and increased risk of recurrence of atrial fibrillation. We present a case of differential atrial stunning after electrical cardioversion for atrial fibrillation. Diagnosis was made by pulsed wave Doppler of mitral, tricuspid, and pulmonary vein inflow and mitral and tricuspid annuli. Differential mechanical atrial stunning may be a common phenomenon after cardioversion and may suggest difference in right and left atrial transport function. Its prevalence needs to be determined by a large study. Doppler tissue imaging might be routinely used in patients after cardioversion for atrial fibrillation to detect atrial stunning.

Association of polymorphisms in myeloperoxidase and catalase genes with precancerous changes in the gastric mucosa of patients at inner-city hospitals in New York

Gastric carcinogenesis is a multistep process progressing from chronic gastritis, through glandular atrophy (GA), intestinal metaplasia (IM) and dysplasia. We have previously demonstrated that minority patients at New York City hospitals are infected with a relatively virulent strain of H. pylori (Hp) and that Hp infection is associated with an increased incidence of precancerous changes in the gastric mucosa. Nevertheless, precancerous changes are not observed in every Hp-infected individual, suggesting that environmental and genetic factors may also play a role in the formation and appearance of precancerous lesions. In the present study, the association between polymorphisms in the promoter regions of human myeloperoxidase (MPO -463G--> A) and catalase (CAT -262C-->T) genes and the appearance of precancerous changes in the gastric mucosa of our patient population were examined. Patients enrolled in this study were undergoing endoscopy for gastrointestinal complaints. Samples were collected from 126 patients at Kings County Hospital in Brooklyn and St. John's Episcopal Hospital in Queens. One antral biopsy was taken for genotyping, while additional biopsies were taken from the antrum and fundic region for histological analysis and were scored with respect to acute and chronic inflammation, GA, IM and Hp infestation according to the Sydney classification. MPO and CAT genotypes were determined by PCR and RFLP. CAT genotypes did not influence the incidence or severity of precancerous lesions in the fundic or antral regions of the stomach, whereas the MPO -463A allele was associated with an increase in intensity of gastric atrophy in the fundic mucosa. In Hp-infected individuals, the MPO -463G/G genotype was associated with an increase in the incidence of IM in the antrum, whereas the A allele was associated with an increase in IM in the fundic region. These paradoxical findings suggest that different MPO genotypes are associated with the appearance of IM in distinct anatomical regions of the stomach. However, since the majority of gastric cancer (GC) cases in our patient population occurred in the antrum, the MPO -463G/G genotype, which is associated with increased MPO expression and antral IM, may be considered a risk factor for GC.

Molecularly Imprinted Polymers in Diagnostics: Accessing Analytes in Biofluids

Bio-applied molecularly imprinted polymers (MIPs) are biomimetic materials with tailor-made synthetic recognition sites, mimicking biological counterparts known for their sensitive and selective analyte detection. MIPs, specifically designed for biomarker analysis...

The ontogeny of adhesion molecules expressed on the vascular endothelium of the developing human skin

One of the important functions of adhesion molecules is to regulate the trafficking of lymphocytes and other leucocytes between the different organs and tissues of the body. These molecules are expressed on both the endothelial cells and the leucocytes, enabling them to adhere to one another and ultimately lead to extravasation of the leucocytes from the circulation into the surrounding tissue. P and E-selectin promote 'rolling' of leucocytes along the blood vessel walls, whereas ICAM-1 and VCAM-1 mediate subsequent firm adhesion, thus committing the leucocytes to extravasation. We have investigated the expression of the above endothelial adhesion molecules in relation to the developing dermal vasculature of fetal skin using histology and immunocytochemistry. This study showed that already at 11 wk of gestation some dermal vessels expressed P-selectin and ICAM-1. However, by 18 wk these molecules were identified on a significant number of vessels, including small capillaries supplying the forming dermal pegs. In contrast, E-selectin and VCAM-1 molecules were rarely seen in all specimens examined. Our results show that even at 11 wk of gestation, the fetal skin has a mechanism in place for circulating leucocytes to extravasate and provide primitive immunosurveillance. Furthermore, the similarities between the distribution of P-selectin and ICAM-1 in the 18 wk fetal skin and in the normal adult skin were striking. These findings may shed light on our understanding of how the fetus detects and reacts to infections and may, in the future, lead to advances in the management of some intrauterine infections.

ACUTE TOXICITY OF COUMACINES: AN IN VIVO STUDY

The design and synthesis of new drugs are increasingly challenging in chemistry settings. The synthesis is itself lured by the properties of the product after synthesis, including solubility, hygroscopicity, intensive adverse effects, and biological inefficacy; hence, the creation of a new drug should be considered in light of the avoidance of these downside features, if any. The present study is designed to investigate the acute toxicity of newly discovered heterocyclic frameworks derived from the coumarin backbone, namely coumacine I and coumacine II. To do so, a mouse model of 25 mice was subclassified into 5 groups (5 mice control, 5 mice coumacine I 1000 mg/kg, 5 mice coumacine II 1000 mg/kg, 5 mice coumacine I 2000 mg/kg, and 5 mice coumacine II 2000 mg/kg), a single dose was given, and mice were sacrificed after 4 hours post-dose. The blood sample and tissue were collected for biochemical and histopathological studies. Serums were analyzed for the measurement of renal function and liver enzyme activity using classical biochemical methods. A high dose of either compound caused deleterious changes, as evidenced by a significant (p<0.05) increase in creatinine, urea, GOT, and GPT, as well as disrupting tissue quasi-equilibrium at the cellular level in both kidney and liver. To sum up, coumacine I and coumacine II are relatively safe unless otherwise used in high doses, knowing that either dose in the present study is remarkably higher than the therapeutic dose of coumarins currently in use in clinical settings.

Redefining drug therapy: innovative approaches using catalytic compartments

INTRODUCTION

Rapid excretion of drug derivatives often results in short drug half-lives, necessitating frequent administrations. Catalytic compartments, also known as nano- and microreactors, offer a solution by providing confined environments for in situ production of therapeutic agents. Inspired by natural compartments, polymer-based catalytic compartments have been developed to improve reaction efficiency and enable site-specific therapeutic applications.

AREAS COVERED

Polymer-based compartments provide stability, permeability control, and responsiveness to stimuli, making them ideal for generating localized compounds/signals. These sophisticated systems, engineered to carry active compounds and enable selective molecular release, represent a significant advancement in pharmaceutical research. They mimic cellular functions, creating controlled catalytic environments for bio-relevant processes. This review explores the latest advancements in synthetic catalytic compartments, focusing on design approaches, building blocks, active molecules, and key bio-applications.

EXPERT OPINION

Catalytic compartments hold transformative potential in precision medicine by improving therapeutic outcomes through precise, on-site production of therapeutic agents. While promising, challenges like scalable manufacturing, biodegradability, and regulatory hurdles must be addressed to realize their full potential. Addressing these will be crucial for their successful application in healthcare.

Immunohistochemical and ultrastructural analysis of an extracellular matrix bound antigen preferentially associated with mucosal postcapillary venules

Human lymphoma derived monoclonal antibody (anti "mucosal vessel associated antigen' [MVAA]) binds to high endothelial venules (HEV) in gut-associated lymphoid tissue, but shows only weak reactivity with HEV in peripheral lymphoid tissues. We have used immunohistochemistry and immunoelectron microscopy to define the precise ultrastructural distribution of the molecule, and to determine whether there is any association between this molecule and cellular traffic. We have observed that MVAA is a component of basement membrane which is only expressed by a subset of blood vessels. Although it is restricted to vessels which support lymphocyte traffic within lymphoid tissue, we did not observe any association between the distribution of MVAA and extravasating lymphocytes. MVAA is expressed in the fetal intestine in association with a subset of larger vessels. It is therefore not necessarily induced as a consequence of antigenic challenge. It is likely that MVAA has a structural role related to its restricted microanatomical distribution; possibly the maintenance of integrity of vessel walls which are continuously disrupted by the extravasation of lymphocytes.