Immunohistochemical investigation of nerve distribution in mature parotid and submandibular glands of rats with a liquid diet

Background: Although feeding with a liquid diet does not affect the growth of rat submandibular glands, it inhibits the growth of rat parotid glands during growth periods. In these growth-inhibited parotid glands, the growth of parasympathetic nerves is also suppressed. Meanwhile, the mature parotid glands of animals maintained on a liquid diet become morphologically and functionally atrophic, however, there is no effect of a liquid diet on mature submandibular glands. The objective of the present study was to clarify whether the nerve distribution in the mature salivary glands of rats was affected by a liquid diet. Materials and methods: Seven-week-old male Wistar rats were used in this study. Half of the rats were kept on a pellet diet, and half were kept on a liquid diet, for 3, 7, 14, or 21 days. All rats were euthanised by isoflurane at each endpoint. Then, the parotid and submandibular glands were removed, frozen in liquid nitrogen, cryosectioned, and stained with antibodies against protein gene product 9.5 (PGP 9.5; general nerve marker), tyrosine hydroxylase (TH; sympathetic nerve marker), or neuronal nitric oxide synthase (nNOS; parasympathetic nerve marker). Results: In parotid and submandibular glands of the pellet diet group, PGP 9.5- and TH-like immunoreactivity were seen around acini and ducts, and nNOS-like immunoreactivity was lower than PGP 9.5- and TH-like immunoreactivity. In the parotid glands of the liquid diet group, similar immunoreactivities were seen throughout the experimental period. The distribution of antibody labelling in the submandibular glands of the liquid diet group was similar to that of the pellet diet group and remained unchanged during the experimental period. Conclusions: The present study demonstrated no regressive effects of a liquid diet on the distribution of sympathetic or parasympathetic nerves in mature parotid glands and submandibular glands. This differed from inhibitory effects on the growth of parotid glands seen during growth periods

Physical inactivity is associated with decreased growth differentiation factor 11 in chronic obstructive pulmonary disease

Rie Tanaka,1 Hisatoshi Sugiura,1 Mitsuhiro Yamada,1 Tomohiro Ichikawa,1 Akira Koarai,1 Naoya Fujino,1 Satoru Yanagisawa,1 Katsuhiro Onodera,1 Tadahisa Numakura,1 Kei Sato,1 Yorihiko Kyogoku,1 Hirohito Sano,1 Shun Yamanaka,1 Tatsuma Okazaki,1 Tsutomu Tamada,1 Motohiko Miura,2 Tsuneyuki Takahashi,3 Masakazu Ichinose1 1Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan; 2Department of Respiratory Medicine, Tohoku Rosai Hospital, Aoba-ku, Sendai, Japan; 3Department of Internal Medicine, Tohoku Medical and Pharmaceutical University Wakabayashi Hospital, Wakabayashi-ku, Sendai, Japan Background: Growth differentiation factor 11 (GDF11) is reported to possess anti-aging and rejuvenating effects, including muscle regeneration and to be highly expressed in skeletal muscle. Recently, we demonstrated that the levels of plasma GDF11 were decreased in COPD. However, the effect of decreased circulating GDF11 in the pathophysiology of COPD remains unknown. The aim of this study is to investigate the association between the plasma GDF11 levels and various clinical parameters in patients with COPD. Patients and methods: Eighteen ex-smokers as control subjects and 70 COPD patients participated in the current study. We measured the levels of plasma GDF11 using immunoblotting, lung function, physical activity using a triaxial accelerometer, quadriceps strength, exercise capacity, and systemic inflammatory markers. We investigated the association between the levels of plasma GDF11 and these clinical parameters. Results: The levels of plasma GDF11 in the COPD patients had significant positive correlations with the data of lung function. Furthermore, the levels of plasma GDF11 were significantly correlated with the physical activity, quadriceps strength, and exercise capacity. Moreover, the levels of plasma GDF11 were significantly correlated with the data of inflammatory markers. Although various factors were related to GDF11, the multiple regression analysis showed that physical activity was significantly associated with the levels of plasma GDF11. Conclusion: Physical inactivity was significantly related to the decreased GDF11 levels in COPD, which might be useful for understanding the pathogenesis of COPD. Clarifying the relationships between the physical inactivity and GDF11 may reveal a potentially attractive therapeutic approach in COPD via increasing the plasma levels of GDF11. Keywords: physical activity, muscle strength, rejuvenating factor, COP

A New Device Facilitating Intracorporeal Purse-string Suture during Endoscopic Surgery

Standard laparoscopic colorectal surgery requires additional incision or enlargement of the trocar incision for the retrieval of the surgical specimen. A natural orifice specimen extraction （NOSE） procedure, in which the specimen is retrieved through the anus or vagina without any additional skin incision, requires purse-string suture （PSS） of the rostral intestinal segment in order to fix the anvil head of the stapler and perform extracorporeal mechanical anastomosis. Colorectal surgery has a limited NOSE in cases where the end of the rostral segment could be pulled through the anus. Broader application of NOSE depends on intracorporeal PSS. We developed a new forceps for intracorporeal PSS during NOSE and evaluated its efficacy. The PSS instrument was refined to pass through a 12-mm trocar in an intracorporeal PSS and achieve anastomosis using double stapling. In trials utilizing an endoscopic practice box, regular spacing of stitches during PSS were consistent （n＝10）, and tight intracorporeal anastomosis of the porcine colon was successfully performed （n＝2）. We then confirmed efficacy through an operation on a pig. Our novel PSS device will help us perform NOSE not only in laparoscopic colorectal surgery but also in any operation requiring intracorporeal PSS, which should contribute to further advances in endoscopic digestive surgery

Hertwig's epithelial root sheath cells do not transform into cementoblasts in rat molar cementogenesis

It is generally accepted that cementoblasts originate in the process of differentiation of mesenchymal cells of the dental follicle. Recently, a different hypothesis for the origin of cementoblasts has been proposed. Hertwig's epithelial root sheath cells undergo the epithelial-mesenchymal transformation to differentiate into cementoblasts. To elucidate whether the epithelial-mesenchymal transformation occurs in the epithelial sheath, developing rat molars were examined by keratin-vimentin and Runx2 (runt-related transcription factor 2)-keratin double immunostaining. In both acellular and cellular cementogenesis, epithelial sheath and epithelial cells derived from the epithelial sheath expressed keratin, but did not express vimentin or Runx2. Dental follicle cells and cementoblasts, however, expressed vimentin and Runx2, but did not express keratin. No cells showed coexisting keratin-vimentin or Runx2-keratin staining. These findings suggest that there is no intermediate phenotype transforming epithelial to mesenchymal cells, and that epithelial sheath cells do not generate mineralized tissue. This study concludes that the epithelial-mesenchymal transformation does not occur in Hertwig's epithelial root sheath in rat acellular or cellular cementogenesis and that the dental follicle is the origin of cementoblasts, as has been proposed in the original hypothesis

Morphological variety of capillary ends invading the epiphyseal plate in rat femora using scanning electron microscopy with osmium maceration

Objectives: The function of capillary ends at the epiphyseal plate has been actively investigated. However, their morphology is still poorly understood. This study was designed to examine the capillary ends invading the epiphyseal plate three-dimensionally by scanning electron microscopy and discuss the relationship between their morphology and function. Methods: Distal halves of the femora of eight-week-old male Wistar rats were used. The specimens were divided into two groups for transmission and scanning electron microscopy. For transmission electron microscopy, sagittal ultrathin sections were routinely prepared after the demineralization of the specimens, and the chondro-osseous junction was examined at the epiphyseal plate. For scanning electron microscopy, the specimens were sagittally freeze-cracked, osmium-macerated, and routinely processed. Results: Endothelial cells of capillary ends had fine fenestrations, and hence they were distinguishable from perivascular cells (also known as septoclasts). Based on the outline and the presence or absence of pores, the capillary ends were divided into four types: closed dome, closed spire, porous dome, and porous spire. The two dome types generally occupied more than half of a lacuna, whereas the two spire types generally occupied only a small part of a lacuna. The porous types engulfed cellular remnants, indicative of degraded chondrocytes, via their pores. Some of the spire types penetrated the transverse septum. Conclusions: The morphological variety of capillary ends reflected their functional variety. Observations suggest that the capillary ends change their morphology dynamically in response to various functions, including the removal of degraded chondrocytes and perforation of transverse septa. (c) 2022 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved

Responses of salivary glands to intake of soft diet

Background: Modernization has made individuals prefer processed and cooked foods (soft food), but this eating habit may have negative effects on the oral cavity. However, laboratory animals fed with soft diet are commonly used in an attempt to clarify this issue, and various oral tissues, including the salivary glands have been examined. In this review, we summarize the findings of previous studies concerning the responses of salivary glands to daily intake of soft diet. Highlight: The weight of the parotid glands decreased in rodents fed with soft diet (liquid or powder). In atrophic parotid glands, acinar cell shrinkage is histologically observed and the DNA content is reduced, showing that the atrophy is caused by a decrease in the size and number of acinar cells. Immunohistochemical examinations showed that the decrease in the acinar cell number was induced by suppression of acinar cell proliferation and acceleration of apoptosis. The atrophic parotid glands recovered following a change from soft to pellet diet. Other salivary glands, such as the submandibular, sublingual, and palatine glands, responded only slightly to the soft diet feeding. Conclusion: Accumulated research data showed that a soft diet negatively affects the parotid glands much more than other salivary glands and that atrophic parotid glands are able to recover by switching to a hard diet. Therefore, it should be emphasized that good eating habits are important for not only digestion but also the health of oral tissues, including the salivary glands