Autologous tissue patch rich in stem cells created in the subcutaneous tissue

AIM: To investigate whether we could create natural autologous tissue patches in the subcutaneous space for organ repair.METHODS: We implanted the following three types of inert foreign bodies in the subcutaneous tissue of rats to produce autologous tissue patches of different geometries: (1) a large-sized polyvinyl tube (L = 25 mm, internal diameter = 7 mm) sealed at both ends by heat application for obtaining a large flat piece of tissue patch for organ repair; (2) a fine polyvinyl tubing (L = 25 mm, internal diameter = 3 mm) for creating cylindrically shaped grafts for vascular or nerve repair; and (3) a slurry of polydextran particle gel for inducing a bladder-like tissue. Implantation of inert materials was carried out by making a small incision on one or either side of the thoracic-lumbar region of rats. Subcutaneous pockets were created by blunt dissection around the incision into which the inert bodies were inserted (1 or 2 per rat). The incisions were closed with silk sutures, and the animals were allowed to recover. In case of the polydextran gel slurry 5 mL of the slurry was injected in the subcutaneous space using an 18 gauge needle. After implanting the foreign bodies a newly regenerated encapsulating tissue developed around the foreign bodies. The tissues were harvested after 4-42 d of implantation and studied by gross examination, histology, and histochemistry for organization, vascularity, and presence of mesenchymal stem cells (MSCs) (CD271+CD34+ cells).RESULTS: Implanting a large cylindrically shaped polyvinyl tube resulted in a large flat sheet of tissue that could be tailored to a specific size and shape for use as a tissue patch for repairing large organs. Implanting a smaller sized polyvinyl tube yielded a cylindrical tissue that could be useful for repairing nerves and blood vessels. This type of patch could be obtained in different lengths by varying the length of the implanted tube. Implanting a suspension of inert polydextran suspension gave rise to a bladder-like tissue that could be potentially used for repairing heart valves. Histologically, the three different types of tissue patches generated were organized similarly, consisting of three layers, increasing in thickness until day 14. The inner layer in contact with the inert material was avascular; a middle layer that was highly vascular and filled with matrix, and an outer layer consisting of loose connective tissue. MSCs identified as CD271+CD34+ cells were present in the medial layer and around major blood vessels at day 4 but absent at later time points. The early-harvested tissues, endowed with MSCs, could be used for tissue repair, while the later-harvested tissues, being less vascular but thicker and tougher, could be used as filler tissue for cosmetic purposes.CONCLUSION: An autologous, vascularized tissue patch of desired shape and size can be created in the subcutaneous space by implanting different types of inert bodies.     

Ontogenetical changes in adipose tissue of the cat: Convertible adipose tissue

The ultrastructural characteristics of the inguinal, interscapular, and perirenal adipose tissue in kittens and cats were studied. There were no qualitative differences among adipocytes in the three anatomical areas. The only recorded difference was in the amount of lipids stored in the adipocytes in younger stages. Immediately after birth lipids occupied 25% of the volume in the inguinal area, 15% in interscapular fat tissue, and 10% in perirenal fat tissue. At this stage the adipose tissue morphologically resembled brown adipose tissue (BAT) of rodents. Two weeks after birth, lipids accumulated and adipocytes in the inguinal area became unilocular and appeared similar to white adipose tissue (WAT). A similar transition occurred approx 25 days after birth in interscapular fat and approx 6 weeks after birth in the perirenal area. No morphological signs of any cell degradation or destruction, nor any increased activity of preadipocytes, were seen during this conversion from BAT-like to WAT-like adipose tissue. The conversion of the adipose tissue was correlated with a decrease in vascularization and innervation, a loss of intercellular connections, and a changed mitochondrial population. Mitochondria in multilocular adipocytes resembled those in typical BAT which contain uncoupling protein (“UC-mitochondria”). After conversion to unilocular adipocytes the amount of mitochondria was halved, their cristae even more reduced, and their appearance was of a WAT-type (UCP-lacking mitochondria, which are coupled under physiological conditions; “C-mitochondria”). Since this category of adipose tissue differs from both typical brown and white adipose tissue, the name “convertible adipose tissue” (CAT) is proposed. Apparently adipose tissue from comparatively large mammals is of this convertible type.     

Effect of glucamylase on tissue glycogen and tissue glucamylase in the rat

1. A fungal glucamylase (alpha-1,4-glucan glucohydrolase, EC 3.2.1.3) from Aspergillus niger depresses liver glycogen stores after intraperitoneal injection into the rat. The injected enzyme rapidly disappears (within about 8hr.) from the serum; less than 1% is excreted in the urine, but it is rapidly taken up in the liver, spleen, kidney, cardiac and skeletal muscle. Elevated glucamylase concentrations could be demonstrated in liver and spleen tissues for 1-4 days after injection, but in kidney, cardiac and skeletal muscle elevated glucamylase concentrations could be shown only for periods of less than 24hr. after injection of the enzyme.     

神经组织缝隙连接

近年来神经组织中缝隙连接的分布和功能研究取得了一些显著进展。分子生物学方法的应用促进了ＧＪ结构,亚型及生物物理特性的揭示,染料偶联实验和Ｃａ＾２＋成像技术为ＧＪ的功能研究提供了直观有效的手段。ＧＪ的调控涉及ＧＪ的表达,导通性的改变等环节。ＧＪ胞间通讯的基本形式是交换第二信使和电偶联。     

Nasal lymphoid tissue in the rat

Summary The structure and organization of paired lymphoid tissue in the nasal mucosa, situated in the transitional zone on both sides of the septal opening to the pharyngeal duct, of conventionally-housed rats was examined by light microscopy and scanning and transmission electron microscopy. Each lymphoid structure consisted of follicles containing T- and B-cell areas, and was covered with specialized epithelium. This epithelium consisted of cuboidal ciliated cells with oval nuclei parallel to the basal lamina. Goblet cells were sparse. Occasionally, islands of microvilli-bearing cells (so called membraneous or M cells) covered the lymphoid structures. M Cells were also found as single cells among the ciliated cells. The morphological characteristics and the particular localization justify the conclusion that the nasal lymphoid tissue described belongs to the mucosa-associated lymphoid tissue. It is therefore suggested that this nasal structure be designated nasal lymphoid tissue.     

Heterotopic brain tissue in the scalp

A hairy mass was excised from the occipital area of a 6-month-old girl. Pathology examination revealed microscopic characteristics of meningeal tissue and gliosis consistent with brain. The possible developmental possibilities are discussed.     

Maintenance of rat adipose tissue in tissue culture

• 1.1. Various systems for the maintenance of rat adipose tissue in tissue culture have been compared.
• 2.2. Optimal conditions for tissue culture were medium 199 supplemented with insulin (10 μg/ml). streptomycin (10μ/ml). penicillin (6 μg/ml) and buffered with 25 mM Hepes. pH 7.3. with a gas phase of air and a temperature of 33 C; adipose tissue was either placed on grids at the air-liquid interface or was allowed to float on the liquid, depending on the age of the rat from which it came.
• 3.3. The rates of glucose metabolism to CO₂, fatty acids and glyceride glycerol. and also palmitate esterification in adipose tissue slices changed (but not in synchrony) over 3 days in tissue culture.
• 4.4. It is concluded that the system should be of value for studying effects of hormones and other substances on adipose tissue metabolism over a period of several days.

     

Bacteria in the plant tissue culture environment

Bacteria and plants are joined in various symbiotic relationships that have developed over millennia and have influenced the evolution of both groups. Bacteria inhabit the surfaces of most plants and are also present inside many plant organs. These bacteria may have positive, neutral or negative impacts on their plant hosts. Probiotic effects may improve plant nutrition or increase resistance to biotic and abiotic stresses. Conversely pathogenic bacteria may kill or reduce the vigor of plant hosts. In addition some bacteria inhabit plants and profit from excess metabolites or shelter while not injuring the plant. Micropropagation of plants is based on the stimulation of organogenesis or embryogenesis from explants that are superficially decontaminated and placed into a sterile environment. If successful, this process removes bacteria from surfaces, but those inhabiting inner tissues and organs are usually not affected by these steriliants. In vitro conditions are designed for optimal plant growth and development, however these conditions are also often ideal for bacterial multiplication. The presence of bacteria in the in vitro environment was almost universally considered negative for plant culture, but more recently this view has been questioned. Certain bacteria appear to have a beneficial effect on the explants in culture; increasing multiplication and rooting, increasing explant quality, and organo- and embryogenesis of recalcitrant genotypes. The most important role of beneficial bacteria for micropropagated plants is likely to be during acclimatization, when growth is resumed under natural conditions. This review includes the role of bacterial interactions in plants, especially those grown in vitro.