Ontogeny of the testicular excurrent duct system of male Japanese quail (Coturnix japonica): A histological,ultrastructural, and histometric study

The testicular excurrent duct system undergoes several physiological and morphological changes during the reproductive stage or breeding season in mammals, birds, and reptiles. Studies on normal age-related histomorphological changes in the excurrent duct system of Japanese quails (Coturnix japonica) remain unreported, despite the extensive use of this bird as an avian model in research studies. The current study investigated the histological, ultrastructural, and histometric changes in the testicular excurrent duct system of the Japanese quail during three reproductive stages, namely prepubertal, pubertal, and adult. Simple squamous to low cuboidal cells formed the epithelia of the rete testis in prepubertal and pubertal birds, while in adult birds the lining was low cuboidal to cuboidal. In pubertal and adult birds, the nonciliated Type I epithelial cells of the proximal efferent duct displayed a subapical endocytotic apparatus comprising coated pits, coated apical tubules, and endosomes. There was a significant increase (p ≤ .001) in epithelial heights of all ducts of the excurrent duct system in the mature, sexually active, adult birds when compared to the other age groups. The luminal and tubular diameters, and the cross-sectional areas of efferent ducts and the epididymal duct unit increased significantly (p ≤ .001) with age. It is concluded that the morphology and morphometry of the excurrent ducts of the testis of the Japanese quail change as birds mature.     

Region‐specific localization of NOS isoforms and NADPH‐diaphorase activity in the intratesticular and excurrent duct systems of adult domestic cats (Felis catus)

Nitric oxide (NO) is produced by nitric oxide synthases (NOSs) and plays an important role in all levels of reproduction from the brain to the reproductive organs. Recently, it has been discovered that all germ cells and Leydig cells in the cat testis exhibit stage‐dependent nuclear and cytoplasmic endothelial (eNOS) and inducible (iNOS)‐NOS immunoreactivity and cytoplasmic nicotinamide adenine dinucleotide phosphate‐diaphorase (NADPH‐d) reactivity. As a continuation of this finding, in this study, cellular localization of NADPH‐d and immunolocalization and expression of all three NOS isoforms were investigated in the intratesticular (tubuli recti and rete testis), and excurrent ducts (efferent ductules, epididymal duct and vas deferens) of adult cats using histochemistry, immunohistochemistry and western blotting. NADPH‐d activity was found in the midpiece of the spermatozoa tail and epithelial cells of all of ducts, except for nonciliated cells of the efferent ductules. Even though the immunoblotting results revealed similar levels of nNOS, eNOS and iNOS in the caput, corpus and cauda segments of epididymis and the vas deferens, immunostainings showed cell‐specific localization in the efferent ductules and region‐ and cell‐specific localization in the epididymal duct. All of three NOS isoforms were immunolocalized to the nuclear membrane and cytoplasm of the epithelial cells in all ducts, but were found in the tail and the cytoplasmic droplets of spermatozoa. These data suggest that NO/NOS activity might be of importance not only for the functions of the intratesticular and excurrent ducts but also for sperm maturation. Microsc. Res. Tech. 79:192–208, 2016. © 2016 Wiley Periodicals, Inc.     

Relationship between structure and function in distal tubule and collecting duct

The relationship between structure and function in the distal tubule and collecting duct has been studied with morphologic and physiologic techniques, including morphometric analysis, to identify functionally distinct cell populations. The distal tubule, including the thick ascending limb (TAL) and the distal convoluted tubule (DCT), is involved in active reabsorption of sodium chloride. It is characterized by extensive invaginations of the basolateral plasma membrane, numerous mitochondria, and high Na-K-ATPase activity, features characteristic for an epithelium involved in active transport. Between the distal tubule and the collecting duct is a transition region, the connecting segment or the connecting tubule (CNT), which exhibits species differences with respect to both structure and function. The collecting duct includes the cortical (CCD), the outer medullary (OMCD), and the inner medullary (IMCD) collecting ducts. Principal cells are present throughout the collecting duct, whereas intercalated cells are located mainly in the CCD and OMCD. Morphometric analysis combined with micropuncture and microperfusion studies has provided evidence that the CNT and principal cells are responsible for potassium secretion in the connecting segment and the CCD. The OMCD is a main site of hydrogen ion secretion, and morphometric studies have provided evidence that the intercalated cells in this segment secrete hydrogen ion at least in the rat. Two configurations of intercalated cells exist in the CCD—a type A and a type B. The A cells are similar in ultrastructure to the intercalated cells in the OMCD and are believed to be involved in hydrogen ion secretion. The function of the B cells remains to be established. The inner two-thirds of the IMCD corresponds to the papillary collecting duct, which has a high permeability to urea. The relationship between structure and function in the IMCD has not been studied in detail. This review emphasizes the role of morphometric analysis in establishing the relationship between structure and function in the distal nephron.     

新型空调静压送风道主风道流速衰减规律研究

分析了新型静压均匀送风道送风机理，研究了主风道内流速衰减规律，得出了主风道内流速不呈线性衰减变化规律，为进一步摸清送风道的送风机理，优化送风道的结构，提高送风道的送风均匀性提供了实验依据。     

LDA耦合系统透镜导管的理论与实验研究

用光线追迹的方法,理论推导了透镜导管各参数优化的一般公式,给出了优化参数;在此基础上,模拟了导管内光线的传输,统计了透镜导管出射光束的强度分布,讨论了各参数对耦合效果的影响。依据理论优化的结果,设计加工了透镜导管并进行了耦合实验,测量了输出光束的强度分布,给出了光斑图像。实验测得耦合效率高于91%,输出光束强度分布平滑均匀,光斑质量良好,与理论模拟吻合并优于以往的研究结果。     

Confocal microscopy with double immunofluorescence staining reveals the functional transient receptor potential vanilloid subtype 1 expressed in myoepithelial cells of human submandibular glands

Myoepithelial cells (MECs) mainly surround acini and intercalated ducts in the human salivary glands. The contraction of MECs provides the expulsive force to promote salivation. We previously found functional transient receptor potential vanilloid subtype 1 (TRPV1) was expressed in rabbit and human submandibular glands and increased saliva secretion. However, it was unknown whether TRPV1 was expressed in MECs of submandibular glands. In this study, we observed the immunoflourescence of TRPV1 was not only located in serous acini and ducts but also surround the basal layer of the acinus and intercalated ducts of human submandibular glands. Double immunofluorescence staining revealed colocalization of TRPV1 with calponin, vimentin, and α-smooth muscle actin, which indicated the myoepithelial expression of TRPV1. Treating submandibular gland tissues with capsaicin, an agonist of TRPV1, substantially increased the phosphorylation of the 20-kDa regulatory light-chain subunit of myosin (MLC(20) ), a crucial molecule for contraction of smooth muscle cells, in MECs. Pretreatment with capsazepine, a specific TRPV1 inhibitor, blocked capsaicin-induced MLC(20) phosphorylation. These results suggest that TRPV1 is expressed in MECs of the human submandibular gland and mediates myoepithelial contraction via a mechanism involving MLC(20) phosphorylation.     

Ultimobranchial and parathyroid glands of the pigeon Columba livia in response to 1,25OH2D3 administration

Columba livia were given daily intraperitoneal injections of 100 pmol of 1,25(OH)(2)D(3)/100 g body wt. for 15 days. Ultimobranchial and parathyroid glands were fixed on 1st, 3rd, 5th, 10th and 15th day of the experiment. Following 1,25(OH)(2)D(3) treatment, the plasma calcium levels of pigeon remain unchanged on day 1. The levels increase significantly after day 3 which progresses up to day 10. The plasma calcium level becomes normal at day 15. The plasma inorganic phosphate levels of Columba livia injected with 1,25(OH)(2)D(3) remain unaffected up to day 3. The levels exhibit a progressive increase from day 5 to day 10. The levels become normophosphatemic at day 15. Up to day 3 following 1,25(OH)(2)D(3) treatment, there is no change in the ultimobranchial gland of Columba livia. The gland exhibits an increased activity after 5 days 1,25(OH)(2)D(3) treatment which is evident by the increased nuclear volume and weak staining response of the cytoplasm of ultimobranchial cells. After day 10, the nuclear volume depicts a further increase and a few completely exhausted cells are discerned. Following 15-day 1,25(OH)(2)D(3) treatment the nuclear volume records an increase and degenerating cells have been observed at certain places. The parathyroid glands of 1,25(OH)(2)D(3)-treated Columba livia remain unaffected up to day 5. After day 10 and day 15, there is a progressive decrease in the nuclear volume of parathyroidal cells and reduced chromaticity of nuclei has been noticed. Moreover, after 15 days few degenerating cells are observed.     

High-resolution scanning electron microscopy of frozen-hydrated and freeze-substituted kidney tissue

Inner surfaces and fracture faces of rabbit kidney tissue were investigated with high-resolution scanning electron microscopy using two different cryopreparation techniques: (i) for the observation of fracture faces, cryofixed tissue was fractured and coated in a cryopreparation chamber dedicated to SEM, vacuum transferred onto a cold stage and observed in the frozen-hydrated state; (ii) for the observation of inner surfaces of the nephron, water was removed after freezing and fracturing by freeze substitution and critical-point drying of the tissue. By both methods, macromolecular structures such as intramembranous particles on fracture faces and particles on inner surfaces were imaged. The latter method was used to investigate in more detail surface structures of cells in the cortical collecting duct. These studies revealed a heterogeneity of intercalated cells not described thus far.     

Prenatal development and histochemical characteristics of gastrointestinal mucins in sheep fetuses

The object of this study was to describe the prenatal development and histochemical properties of mucins in the sheep gastrointestinal tract. To determine changes in the mucin profile, the sections were stained with specific histochemical stains for carbohydrates. While neutral and mixed mucins were observed in the superficial epithelial cells of the abomasal pyloric region, acidic mucins were detected in the secretory ducts and corpus of the glands. Acidic mucins consisted predominantly of sialomucins. In the duodenal villi, the number of goblet cells containing neutral mucins increased toward the end of gestation, whereas Brunner's glands contained acidic mucins until the 95th day of gestation and both acidic and neutral mucins thereafter. The jejunal goblet cells contained either acidic, neutral, or mixed mucins. Goblet cells containing acidic mucins, which were mainly localized to the ileal crypts and villi, mostly contained sulfated mucins. While villi were observed in the proximal colon until the 115th day of gestation, later the typical crypt structure emerged. During the period in which the villi were found in the proximal colon, the goblet cells containing sulphomucins were predominant, whereas the goblet cells containing sialomucins were predominant after the typical crypt structure was formed. In conclusion, gastrointestinal mucins may be involved in the formation of meconium during the prenatal period, and acidic mucins may contribute to the strength of the intestinal barrier against pathogens and digestive enzymes, as the barrier is not fully functional after birth.     

Histochemical analysis of lymphatic endothelial cells in lymphostasis

The ultrastructure of endothelial cells of intestinal lymphatics and the thoracic duct (TD) and the relation to lymphostasis were examined in rats and monkeys. Localization of 5'-nucleotidase (5'-Nase) and endothelial nitric oxide synthase (eNOS) was studied. In normal lymphatic endothelial cells, 5'-Nase reaction product was evenly deposited on the cell surface in vivo and on cultured TD endothelial cells (TDECs), whereas eNOS was evenly distributed throughout the nucleus and cytoplasm. TDECs had a long filamentous process extending towards the subendothelial extracellular matrix but became flat and regular within 30-40 minutes after gastric perfusion with olive oil. According to their electron-density, two types of cells were found in the TD endothelial layer. The cells with low electron-density exhibited stronger 5'-Nase activity. Valves were bicuspid formations and the valvular endothelial surface of the convex side showed weaker 5'-Nase activity than the concave side. During TD blockage-induced lymphostasis in rats, the 5'-Nase product was almost not discernible in the TDECs within 2 weeks. Larger vesicles were found in the endothelial cytoplasm of the ligated TD. Their number decreased after 6-12 weeks. The small intestinal lymphatics in the mucosa and submucosa were dilated, with numerous open intercellular junctions. The endothelial lining appeared to have reduced activities for 5'-Nase and eNOS in 9 of 11 experimental animals. The results indicated that the inability of the open intercellular junctions, normally working as one-way endothelial flap valves, may be a key morphological feature after TD blockage. Reduced eNOS and 5'-Nase may functionally influence contractile activity and transport capability of the lymphatic vessels in the lymphostasis.     

Ultrastructural characterization of apoptotic granulosa cells in caprine ovary

The unique phenomenon of cell proliferation and apoptosis is encountered in the ovarian follicles undergoing early stages of atresia. The aim of this study was to verify the morphological variations in these two physiologically distinct processes operating in antral follicles of caprine ovaries using histological and ultrastructural techniques. Histologically the degenerating granulosa cells were characterized by condensed cytoplasm, and nucleus fragmentation in hazy cytosol. The pyknotic nuclei of degenerating cells stained darkly with haematoxylin and giemsa while the cytoplasm was eosinophilic. Under electron microscopy, apoptosis was marked by asymmetrical shrinkage, vacuolization of cytoplasm, swollen and vacuolated mitochondria, increased irregularity and/or fragmentation of nucleus, chromatin condensation and finally, production of membrane enclosed nuclear fragments containing intracellular material, the apoptotic bodies. The parallel use of these two methods on caprine ovaries has enabled us to analyse the decline in the frequency of granulosa cells during follicular atresia due to apoptosis.     

成品雷管导通工位泄爆烟管的安全探讨

本文通过对泄爆烟管进行实验分析,提出在原成品导通工位增设泄爆烟管的思路,在杜绝电雷管发生爆炸时能及时将爆轰波排泄出去,减少伤亡的问题上取得了良好的效果。     

Toxicity of trifluralin herbicide in a representative of the edaphic fauna: Histopathology of the midgut of Rhinocricus padbergi (Diplopoda)

The aim of this study was to use the diplopod Rhinocricus padbergi as test organism to verify the possible toxic effects of the herbicide trifluralin in a representative of the edaphic fauna. Histological and histochemical techniques were applied in the midgut of the animals after exposure to different concentrations of trifluralin for 7 and 90 days (acute and subchronic exposure, respectively). The individuals from the control group did not present alterations to any of the exposures. In the acute exposure, the group exposed to a quarter and half of the field dose presented an accumulation of cytoplasmic granules in the hepatic cells; the field dose group presented an increase in the rate of epithelial renewal and the group exposed to double the field concentration presented an increase in the release of secretory vesicles. The subchronic response was obtained with the field dose and double field dose because the animals from a quarter and half groups did not survive until the end of the experiment. In both groups, the animals presented disruption of the epithelium and higher occurrence of hemocytes among the hepatic cells. The group exposed to double the field dose presented sites of cytoplasmic vacuolization, dilatation of the intercellular space, increase in the epithelial renewal, and release of secretory vesicles. The results alert for a careful use of this herbicide, since it promoted alterations in the midgut cells of the test organism used. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

General morphology and ultrastructure of the female reproductive apparatus of Trichomalopsis shirakii crawford (Hymenoptera,Pteromalidae)

The morphology and ultrastructure of the female reproductive system were examined for a larval–pupal parasitoid Trichomalopsis shirakii Crawford of Oulema oryzae Kuwayama using light and electron microscopes. The reproductive system includes two ovaries, two pairs of accessory glands, an unbranched venom gland, a large venom reservoir and a Dufour gland. Each ovariole contains follicles and oocytes at different stages of maturation. A fibrous layer covers the surface of mature egg. The accessory glands are made up of a layer of secretory cells surrounded by muscle fibers. In these secretory cells, numerous mitochondria, electron‐dense secretory granules and vesicles filled with dense granular particles are present. These granular particles appear as virus‐like particles (VLPs). The venom gland consists of a single layer of secretory cells which are organelle rich with abundant rough endoplasmic reticulum, mitochondria and vesicular organelles, a layer of duct cells and an inner intima. The reservoir consists of a muscular sheath, epidermal cells with few organelles and an intima layer. The Dufour gland has a relatively large lumen surrounded by a single layer of columnar epithelial cells which are characterized by clusters of smooth endoplasmic reticulum and lipid droplets. Aside from the venom, the fibrous layer coating the egg and the granular particles which may be VLPs have been discovered in our study. They may serve as one of the parasitoid‐associated factors in their host–parasitoid relationship and play a role in host immune suppression. Microsc. Res. Tech. 79:625–636, 2016. © 2016 Wiley Periodicals, Inc.     

加固计算机中双风道散热应用研究

以某高功耗军用加固计算机热设计为实例,介绍了热设计过程中,加固计算机主板芯片到风道这一传导路径热阻计算的具体方法,对比了军用加固计算机采用单、双风道各自的传导热阻.并用Ice-Pak热分析软件对采用单、双风道的加固计算机主板温度分布进行了仿真计算,通过实践证明了双风道散热形式在高功耗加固计算机中的可实施性和优越性.     

高速列车风道传声特性及其优化设计

空调系统噪声是高速列车静置噪声的主要噪声源之一,改善风道传声特性是其减振降噪的关键所在。针对某高速列车阻抗复合消声风道结构,采用FE-SEA混合法,建立了风道传声特性分析模型,计算了100～3 150 Hz频率区段的风道传声特性,同时,基于声学有限元法计算了风道结构的声学模态,并据此分析了风道传声损失峰值和谷值的成因。为提高风道传声损失,分别从声学阻性和抗性优化两方面着手,对风道进行优化,包括选材、吸声包数量和位置等优化设计。计算结果表明：吸声选材优化可显著提高其传声损失,最大可达11.3 dB;吸声包数量和位置优化可提高其传声损失4.8 dB;阻抗复合优化方案最高可提高风道传声损失15.6 dB。相关结论可为高速列车空调系统减振降噪提供参考。     

Cell adhesion in the process of asexual reproduction of tunicates

Cell adhesion during budding of tunicates is reviewed from the viewpoints of histology, cytology, biochemistry, and molecular biology. Two kinds of multipotent cells play important roles in bud formation and development: epithelial cells, such as the atrial epithelium of botryllids and polystyelids, and mesenchymal cells, referred to as haemoblasts. Haemoblasts are able to aggregate to form a solid mass of cells, which soon becomes a hollow vesicle. The vesicular epithelium has junctional complexes that contain adherens junctions, and, sometimes, tight junctions; both occur apicolaterally on the plasma membrane. The hollow vesicle develops into the heart, the pyloric gland and duct, the gonad, including germ cells, and even the multipotent epithelium of buds. Cell culture studies suggest that multipotent epithelial cells may be interchangeable with haemoblasts. Several kinds of calcium-dependent, galactose-binding tunicate lectins (TC-14s) have been isolated and sequenced, and have been found to facilitate both in vivo and in vitro cell aggregation and migration. Tunicate homologs of cadherin and integrin genes have recently been isolated from Botryllus and Polyandrocarpa, respectively. Their unique molecular characteristics are discussed in the context of roles that they play in cell adhesion in the process of tunicate budding.     

高功耗抗恶劣环境计算机散热研究

以某高功耗军用加固计算机热设计为实例,介绍了热设计过程中,加固计算机主板芯片到风道这一传导路径热阻计算的具体方法,对比了军用加固计算机采用单、双风道各自的传导热阻.并用IcePak热分析软件对采用单、双风道的加固计算机主板温度分布进行了仿真计算,通过实践证明了双风道散热形式在高功耗加固计算机中的可实施性和优越性.     

Ultrastructure of in situ perfusion-fixed avian liver, with special reference to structure of the sinusoids

Broiler chicken and laying hen livers were fixed using a simple technique of in situ puncture perfusion of cacodylate-buffered fixative, which allowed characterisation of the fine structure of hepatic parenchyma, hepatocytes, bile ductules, and, in particular, the sinusoidal cells including endothelial, Kupffer, and Ito cells. Sinusoidal endothelial cells with their bulging perinuclear cytoplasm, evident in both transmission and scanning electron micrographs, were easily distinguishable from Kupffer cells, which possessed numerous pseudopodia. Bile ductular epithelium and hepatocytes of the laying hens contained large amounts of lipid. The ultrastructural characteristics of intercalated cells (putative extra-sinusoidal macrophages of chicken liver) are described and their possible role as precursors of Kupffer cells is discussed.     

Structural changes and cell properties of human ovarian surface epithelium in ovarian pathophysiology

The surface epithelial cells of the ovary, which are modified peritoneal cells, form a single, focally pseudostratified layer. The Müllerian ducts differentiate after invagination of the coelomic mesothelium over the gonadal ridges during the 6th week of embryonic life. On the basis of the embryologically putative Müllerian potential of this epithelium, endometriosis can be explained by coelomic metaplasia from the peritoneum, including ovarian surface epithelium. Some pelvic endometriosis specimens have shown that epithelial cells on the ovary or pelvis are serially changed to endometriotic gland cells. Immunohistochemistry as well as scanning electron microscopy also reinforce the light-microscopical findings. A three-dimensional culture system demonstrated that human ovarian surface epithelial cells exhibited a glandular-stromal structure when they were cocultured with endometrial stromal cells in an estrogen-rich environment. Ovarian carcinomas in the epithelial-stromal category are thought to arise from the surface epithelium and its inclusions. The ovarian surface epithelium is physiologically involved in follicular rupture, oocyte release, and the subsequent repair of follicle wall during reproductive age. Simultaneously, ovulation may cause a loss of integrity of the surface epithelium, followed by accumulation of multiple mutations. The cortical invagination, surface stromal proliferation, and Müllerian differentiation of these cells are likely not to be an early step in the cancer development. However, the inclusion cysts are closely related with carcinogenesis because they are significantly more common in ovaries contralateral to those containing epithelial cancers than in control ovaries. As an in vitro study, ovarian carcinoma cell lines were established from simian virus 40 large T antigen-transformed human surface epithelial cells of the ovary. Further investigations of these cell lines may lead to insights into the preneoplastic and early stages of carcinomas. To clarify the pathogenesis of endometriosis and epithelial ovarian cancer, specifically designed studies of ovarian surface epithelium are required.