Reverse Ordered Sequential Mechanism for Lactoperoxidase with Inhibition by Hydrogen Peroxide

Lactoperoxidase (LPO, FeIII in its resting state in the absence of substrates)—an enzyme secreted from human mammary, salivary, and other mucosal glands—catalyzes the oxidation of thiocyanate (SCN−) by hydrogen peroxide (H2O2) to produce hypothiocyanite (OSCN−), which functions as an antimicrobial agent. The accepted catalytic mechanism, called the halogen cycle, comprises a two-electron oxidation of LPO by H2O2 to produce oxoiron(IV) radicals, followed by O-atom transfer to SCN−. However, the mechanism does not explain biphasic kinetics and inhibition by H2O2 at low concentration of reducing substrate, conditions that may be biologically relevant. We propose an ordered sequential mechanism in which the order of substrate binding is reversed, first SCN− and then H2O2. The sequence of substrate binding that is described by the halogen cycle mechanism is actually inhibitory.

Heterotopic Gastric Mucosa in Gastric Propria Muscularis Treated by Endoscopic Submucosal Dissection: A Case Report and Literature Review.

Background: Heterotopic gastric mucosa（HGM）is a congenital anatomical variation. It can occur in various tissues and organs of the gastrointestinal tract. Part of the HGM appeared as a solitary, sessile submucosal lesions covered with normal mucosa, and because it was relatively rare, thereby resulting in some HGM to be easily missed or misdiagnosed. We report on a case of heterotopic gastric mucosa in gastric propria muscularis.Case presentation: A 32-year-old man with abdominal distension for one month. Upper gastrointestinal endoscopy revealed hemispherical lesion covered with smooth mucosa located in gastric antrum. Endoscopic ultrasound (EUS) revealed that it might be derived from the submucosa, with no echogenic nodules, and a partition is visible inside. Endoscopic submucosal dissection (ESD) was performed and histological examination revealed scattered heterotopic mucosal glands (HGG) located in the propria muscularis. Regular follow-up, the patient's abdominal distension was significantly relieved.Conclusion: HGM of the type of submucosal tumor-like lesion is rare. EUS is a well-established method for submucosal lesion. On EUS, these lesions showed cystic anechoic central core in the submucosa with no solid component,which is similar to gastric cyst. Therefore, this requires us to be alert to the possibility of HGM in order to further evaluate and treat, and if necessary, it can be removed by ESD.

A case of Helicobacter pylori-negative early gastric adenocarcinoma with gastrointestinal phenotype

A 40-year-old man with slightly depressed (0-IIc) type gastric cancer of the pyloric anterior gastric area underwent pre-operative screening for tetralogy of Fallot and endoscopic submucosal dissection (ESD) and was tested for Helicobacter pylori antigens and antibodies. Both tests were negative. He did not have a history of eradication. Pathological diagnosis of ESD showed a well-differentiated adenocarcinoma. The tumor was CD10-positive, MUC5AC-negative, and MUC6-confocal positive; it showed differentiation with gastrointestinal phenotype. Moreover, the tumor cells were lysozyme-positive, resembling Paneth cells. Mucosal glands exhibited intestinal metaplasia on the anal side of the tumor lesion. On the oral side of the tumor, metaplasia was non-existent, with normal pyloric glands present in the mucosal layer. The patient was not infected with H. pylori; however, intestinal metaplasia existed around the early gastric cancer. This suggested that the intestinal metaplasia occurred due to bile reflux, and the gastric neoplasia arose with the metaplasia without an H. pylori infection. This case may potentially help explain gastric cancer development in the absence of H. pylori infection.

Anatomical, Histological and Histochemical Features of the Guinea Pig (Cavia porcellus) Caecum

In this study, the caecum of five guinea pigs was anatomically, histologically, and histochemically analyzed. From an anatomical point of view, it has been proved that the caecum in guinea pigs occupies the caudal segment of the abdominal cavity and consists of three parts: the ampullary portion, the body of the caecum, and the apex of the caecum, without a caecal appendix. In our histological analysis, we observed that the caecum has a simple structure, and the cecal mucosal glands are rare and contain, in addition to enterocytes, a small number of goblet cells, which are better represented in the deep part of the glands. Histochemically it has been observed that goblet cells are PAS and Alcian blue positive, which shows that they secrete both neutral and acidic mucins. The intensity of these two histochemical reactions is similar to that of goblet cells from other intestinal segments, proving that they are typical goblet cells. The large volume of the caecum suggests that this is an important section for the digestion process, although the relatively simple structure of the caecal mucosa suggests that the digestion here is not preponderant, but only complements the intestinal one.

X-Linked Hypohidrotic Ectodermal Dysplasia in Crossbred Beef Cattle Due to a Large Deletion in EDA

X-linked hypohidrotic ectodermal dysplasia-1 (ECTD1) in people results in a spectrum of abnormalities, most importantly hypotrichosis, anodontia/oligodontia, and absent or defective ectodermally derived glands. Five Red Angus-Simmental calves born over a 6-year period demonstrated severe hypotrichosis and were diagnosed as affected with ECTD1-like syndrome. Two died of severe pneumonia within a week of birth. The skin of three affected calves revealed a predominance of histologically unremarkable small-caliber hair follicles. Larger follicles (>50 µm) containing medullated hairs (including guard and tactile hairs) were largely restricted to the muzzle, chin, tail, eyelids, tragus and distal portions of the limbs and tail. The mean histological density of hair follicles in flank skin of two affected calves was slightly greater than that in two unaffected calves. One affected calf was examined postmortem at 10 days of age to better characterize systemic lesions. Nasolabial, intranasal and tracheobronchial mucosal glands were absent, whereas olfactory glands were unaffected. Mandibular incisor teeth were absent. Premolar teeth were unerupted and widely spaced. Other than oligodontia, histological changes in teeth were modest, featuring multifocal disorganization of ameloblasts, new bone formation in dental alveoli, and small aggregates of osteodentin and cementum at the margins of the enamel organ. A 52,780 base pair deletion spanning six out of eight coding exons of EDA and all of AWAT2 was identified. Partial deletion of the EDA gene is the presumed basis for the reported X-chromosomal recessive inherited genodermatosis.

Greater superficial petrosal nerve and its surgical importance: a review

The greater superficial petrosal nerve (GSPN) is an important but often underappreciated branch of the facial nerve. The GSPN is a mixed nerve which contains both sensory and parasympathetic fibers. It serves as the motor root of the pterygopalatine (sphenopalatine) ganglion. GSPN has a long course which passes across the middle skull base between the petrous bone and dura mater and running through the foramen lacerum. It then incorporates to the deep petrosal nerve and crosses along the pterygoid canal to the pterygopalatine ganglion. The postganglionic nerve fibers innervates the lacrimal glands, nasal mucosa and palatal mucosal glands via branches of the zygomatic nerve/zygomaticotemporal branch, sphenopalatine, greater palatine, lesser palatine nerves and pharyngeal nerve. Surgical anatomy of the GSPN nerve is often unfamiliar to many clinicians. As this nerve is usually unrecognized without use of high resolution microscope or endoscope, its anatomical knowledge is essential for surgeons basically otologists and other head and neck surgeon to minimize the risk of injury during surgical intervention. This review article surely increases the precise knowledge of the GSPN including its embryology, surgical anatomy, blood supply, relations with other structures and imaging.

Treatment of Atrophic Rhinitis with Manuka Honey–a non-randomized control trial, and a new theory of etiopathogenesis for the disease.

Exact etiology of Atrophic rhinitis (AtR) is yet unknown. Polygenic and polybacterial causes have been implicated in the onset and progression of this disease. AtR doesn’t respond to any particular modality of treatment that targets specific etiology, this describes its multifactorial nature. In this study, we report on a non-randomized control trial on the use of a nasal spray of 10% Manuka honey in patients with AtR attending the out-patient unit of the Department of Otorhinolaryngology and Head Neck Surgery. In this study, we show significant observations: 1. Decreased fetid smell, 2. Thickening of the mucosa, 3. Decreased inflammation with healed mucosal ulcers, 4. Increased concentration of the mucosal glands, 5. Alteration in Nasal microbiome, and 6. Increased expression of SCFA receptors. These changes occurred in response to honey therapy, and are consequent to the resetting of the Nasal microbiome.

Mucin secretion in cystic fibrosis – a systematic review

Background Mucus protects the epithelium against invaders and toxic materials. Sticky and thick mucus is characteristic of CF. Objective The aim of this systematic review is to characterize the specific mucins secreted in the lung and intestinal tract of CF patients. Methods A systematic literature search was conducted up to 31.12.2019. The following terms were used: "cystic fibrosis" AND "mucin". Case control studies comparing mucin expression in CF patients to healthy controls were included. Results We found 741 eligible studies, 694 studies rejected because they were performed in animals and not in full text, and 32 studies were excluded being editorials, duplications, review articles, meta-analysis, or not in English. Fifteen studies were eligible for our study, including 150 CF patients compared to 82 healthy controls all fulfilled the inclusion criteria. The main mucin types expressed in the sinus sub-mucosal glands, sputum, trachea-bronchial surface epithelium and lung sub -mucosal glands were MUC5AC and MUC5B. Increase in the number of sinusoidal sub-mucosal glands and expression of MUC5B was found in CF patients, but no such difference from healthy controls was found for the number of goblet cells in the surface epithelium nor in the expression of MUC5AC. The opposite was found in the trachea-bronchial surface epithelium and in the lungs. Conclusions Increased expression of MUC5AC in the surface epithelium and of MUC5B in the sub-epithelial glands may be the result of higher secretion rate of mucin into the lumen of the respiratory tract, causing mucus plaque, infection and inflammation.

Histological studies on the oesophageal tonsils of broiler ducks

Histomorphological study was conducted on the oesophageal tonsils in six broiler Vigova Super-M ducks of six to eight weeks age. The location of the tonsil was at the junction between oesophagus and proventriculus. In histological sections six to eight isolated tonsillar units were seen in the lamina propria near the base of the oesophageal folds. Each tonsillar unit consisted of a crypt lined by lymphoepithelium and surrounded by dense lymphoid tissue. The tonsillar units were seen encapsulated by connective tissue and composed of many large lymphoid nodules separated by internodular areas. The secretory portion of the mucosal glands of the oesophagus were firmly associated with the lymphoid tissue and the cylindrical epithelium was transformed to lymphoepithelium. The oesophageal tonsils offered immunological protection at the entrance of stomach. Keywords: Oesophageal tonsils, Histomorphology, Ducks

To pathology of the mucosa of the uterine body.

The author received material for research during curettage or extirpation of the uterus in a wide variety of painful processes. All cases, if possible, are followed clinically. In this article, the author focuses on 2 points: the ratio of adenoma to carcinoma, and the ratio of endometritis and neoplasms of the mucosal glands to simultaneous changes in the muscular layer of the uterus.