MICROSCOPIC FEATURES OF THE SPLEEN UNDER THE INFLUENCE OF LAPROXIDES.

Rapid technology growth and its implementation in all spheres of the people's lives dictates the necessity for thorough study of the influence of different chemicals on human's health. This study was undertaken to elucidate the structural changes that occur in the matured rats' spleen experimentally induced by selected xenobiotic, so, purpose of our work was detection of microscopic peculiarities of the spleen under the influence of laproxides. In subacute experiment were uncovered organometric alterations of the matured male rat's spleen after the administration of 1/10 LD50 of polyether-tryglycidyl ether of polyoxypropylene triol (TEPPT). The study was performed on 72 outbreed WAG male matured rats with the weight 200±10g. Histological slides were studied with performing morphometric and statistical methods. We revealed changes of morphologiс data in comparison to control data which shows reactivity of the spleen in response to the induced xenobiotic. The received and analyzed data demonstrate the morphological changes of the spleen, specifically changes of the linear dimensions and weight of the spleen due to the influence of the TEPPT. The spleen is very sensitive to the effects of xenobiotics, in particular, TEPPT that is even reflected in its grossly (weight and linear dimensions) and histological features (reliable changes of the of the white pulp area of the spleen from 17.87±1.04% to 27.37±1.71%, diameter of lymphatic follicles from 426.59±11.18 µm to 382.31±11.73 µm, width of the mantle zone from 45.73±1.08 µm to 37.18±2.29 µm, width of the marginal zone from 81.32±1.79 µm to 74.63±2.08 µm, width of the periarterial zone from 88.73±2.69 µm to 97.24±2.61 µm).

Rapid lymph accumulation of polystyrene nanoparticles following pulmonary administration.

PURPOSE: Pulmonary administration of polymeric nanoparticle drug delivery systems is of great interest for both systemic and local therapies. However, little is understood about the relationship of particle size and pulmonary absorption. We investigated uptake and biodistribution of polystyrene nanoparticles (PN) of 50 nm, 100 nm, 250 nm, and 900 nm diameters in mice following administration to lungs via pharyngeal aspiration. METHODS: The amount of PN in tissues was analyzed by gel permeation chromatography (GPC). RESULTS: At 1 h, larger diameter PN (250 nm and 900 nm) had the highest total uptake at around 15% of administered dose, whereas the smaller diameter PN (50 nm and 100 nm) had uptake of only 5-6%. However, at 3 h, the 50 nm PN had the highest total uptake at 24.4%. For each size tested, the highest nanoparticle deposition was observed in the lymph nodes (LN) as compared to other tissues accounting for a total of about 35-50% of absorbed nanoparticles. CONCLUSION: PN size impacts the rate and extent of uptake from lungs and, further, the extent of LN deposition. The extent of uptake and lymph distribution of the model, non-degradable PN lends potential to pulmonary administered, biodegradable polymeric nanoparticles for delivery of therapeutics to regional lymph nodes.

Morphological analysis of aqueous humor drainage using QD nanoparticles and indocyanine green.

This study represents the first morphological description of the lymphatic drainage of the ciliary body in vivo by comparative hyperspectral fluorescence imaging techniques of Quantum Qdot655 (QD) nanoparticles and indocyanine green (ICG). A volume of 1.25 µl of QD was injected into the left anterior camera of all rats. Similarly,1.25 µl of ICG diluted at a ratio of one-fourth with physiological saline solution was injected into the right anterior camera of all rats. The thickness of the skin in the mandibular area, connective tissue, and the depth of the mandibular lymph node (MLN) made image retrieval difficult. For QD, 302 nm UV excitation and 605 nm fluorescence peak emission were applied. The detection of QD and ICG used in this study in the MLNs is definitive evidence that aqueous humor (AH) follows a uveolymphatic pathway. Scanning electron microscope and the energy dispersive X-ray analyzer spectrum were used to examine both the Schlemm's canal and the MLN. For the first time, the QD was detected in the cortex of MLN. The QCM analysis of both QD-AH and ICG-AH was used to determine whether there was any interaction between them. This comparative study shows the importance of experimental animal modeling in pharmacological studies regarding eye research and drugs. In a female rat, the signal was taken from the parotid lymph node with QD injections.

Fluorescence imaging of lymphatic outflow of cerebrospinal fluid in mice.

Cerebrospinal fluid (CSF) is known to be reabsorbed by the lymphatic vessels and drain into the lymph nodes (LNs) through peripheral lymphatic vessels. In the peripheral lymphatics, the contractile pumping action of lymphangions mediates lymph drainage; yet it is unknown whether lymphatic vessels draining cranial and spinal CSF show similar function. Herein, we used non-invasive near-infrared fluorescence imaging (NIRFI) to image (i) indocyanine green (ICG) distribution along the neuraxis and (ii) routes of ICG-laden CSF outflow into the lymphatics following intrathecal lumbar administration. We demonstrate lymphatic contractile function in peripheral lymphatics draining from the nasal lymphatics to the mandibular LNs. In addition, we observed afferent sciatic lymphatic vessels, which also show contractile activity and transport spinal CSF into the sciatic LNs. This drainage pattern was also visualized by NIRFI following intrathecal thoracic injection. In situ intravital imaging following intrathecal lumbar injection of blue dye shows similar distributions to that seen in vivo with ICG. NIRFI could be used as a tool to probe CSF pathology including neurological disorders by imaging CSF outflow dynamics to lymphatics.

Biodegradable Photonic Melanoidin for Theranostic Applications.

Light-absorbing nanoparticles for localized heat generation in tissues have various biomedical applications in diagnostic imaging, surgery, and therapies. Although numerous plasmonic and carbon-based nanoparticles with strong optical absorption have been developed, their clearance, potential cytotoxicity, and long-term safety issues remain unresolved. Here, we show that "generally regarded as safe (GRAS)" melanoidins prepared from glucose and amino acid offer a high light-to-heat conversion efficiency, biocompatibility, biodegradability, nonmutagenicity, and efficient renal clearance, as well as a low cost for synthesis. We exhibit a wide range of biomedical photonic applications of melanoidins, including in vivo photoacoustic mapping of sentinel lymph nodes, photoacoustic tracking of gastrointestinal tracts, photothermal cancer therapy, and photothermal lipolysis. The biodegradation rate and renal clearance of melanoidins are controllable by design. Our results confirm the feasibility of biodegradable melanoidins for various photonic applications to theranostic nanomedicines.

Morphological observations on the fate of liposomes in the regional lymph nodes after footpad injection into rats.

Multilamellar liposomes composed of equimolar egg phosphatidylcholine and cholesterol and containing carboxyfluorescein or colloidal gold were injected subcutaneously into the footpad of the hind-leg of rats. The draining popliteal lymph nodes of animals killed at time intervals after injection were then dissected and sections examined by fluorescence microscopy (carboxyfluorescein), light microscopy using an immunogold silver kit to enhance gold particles or by transmission electron microscopy. Morphological observations confirmed that subcutaneously injected liposomes accumulate in large numbers in the draining lymph node. The majority of liposomes arrived at the subcapsular sinuses, probably via afferent lymphatic vessels, as such, i.e., in a non-cell bound form. Subsequently, liposomes were dispersed throughout the lymph node either by permeation as free vesicles along the sinuses or by cells involved in vesicle uptake. The majority of such cells were free macrophages, littoral cells and reticular cells (fixed macrophages). Once within cells, liposomes were seen digested by the lysosomal apparatus with varying loss of their lamellar structure, leaving free gold particles within the lysosomes.

Lymphatic uptake and biodistribution of liposomes after subcutaneous injection . IV. Fate of liposomes in regional lymph nodes.

The ability of clodronate-containing liposomes to deplete lymph nodes of macrophages was used as a tool to investigate the fate of liposomes in regional lymph nodes after subcutaneous (s.c.) administration. Reduced lymph node localization of liposomes in macrophage-depleted lymph nodes confirmed that phagocytosis by macrophages plays an important role in lymph node retention of liposomes. Depletion of macrophages had less effect on lymph node localization of small liposomes than on the lymph node localization of large liposomes. Inclusion of distearoylphosphatidylethanolamine (DSPE)-poly(ethyleneglycol) (PEG-PE) into the liposomes, which is known to oppose macrophage uptake, did not affect lymph node localization in macrophage-depleted or control lymph nodes. We conclude that PEG-liposomes retained by lymph nodes are also taken up by lymph node macrophages. Morphological observations visualizing the uptake of PEG-liposomes by lymph node macrophages support this conclusion.

Ultrastructural localization of intracellular immunoglobulins in Epon-embedded human lymph nodes. An immunoelectron microscopic investigation using the immunogold staining (IGS) and the avidin-biotin-peroxidase complex (ABC) methods.

The ultrastructural localization of intracellular immunoglobulins on ultrathin sections of glutaraldehyde-fixed, postosmicated, and Epon-embedded human lymph nodes has been achieved using such highly sensitive immunocytochemical techniques as immunogold staining and avidin-biotin-peroxidase complex. These immunoelectron microscopic techniques allow the identification of intracellular immunoglobulins without affecting the ultrastructural morphology of the tissue, since they do not require any pretreatment of the sections with proteolytic enzymes or deresinating agents. Therefore, immunoglobulins can be precisely localized in the cell organelles; structures whose morphology is well preserved. The availability of a reliable postembedding staining procedure for the ultrastructural localization of immunoglobulins is of definite value for investigations on human lymphoid tissue, both normal and pathological.

Smooth muscle distribution in the capsule and trabeculae of the caprine superficial cervical lymph node.

This study centers around the dichotomy found in the literature concerning the presence of smooth muscle cells in the trabeculae and capsule of lymph nodes. Various superficial lymph nodes (mammary, mandibular, popliteal, subiliac, and superficial cervical) of the goat were collected and examined by light and electron microscopy. Smooth muscle cells were demonstrated in the capsule and trabeculae of lymph nodes independent of the blood and lymph vessels.

Analysis of the three-dimensional lymphatic architecture of the periodontal tissue using a new 3D reconstruction method.

Few studies of lymphatic vessels have been reported because diacrisis of this vascular system is rare. A complete examination of diacrisis of venula is not yet possible even using recent enzyme-histochemical or immunohistochemical techniques. In this study, we examined a lymphatic vessel by serial sectioning from the afferent lymphatic of the lymph node to the periphery by three-dimensional observation using a three-dimensional reconstitution method. This method was conventional and accurate, and the time required for processing was markedly reduced by using a computer. Reconstitution of the vasculature became possible utilizing the entire section instead of a portion of a parenchymatous organ. We examined the lymphatic vessel architecture of various oral regions, including gingiva, tongue, and the floor of the mouth, using this method. In the future, using this method, we plan to investigate the alteration of lymphatic vessel architecture in a pathological region, and correlate these changes with the dynamics of lymphatic vessel absorption.

Mast cell types and cell-to-cell interactions in lymph nodes of the opossum Didelphis albiventris.

Previous light-microscopic studies have shown a unique population of mast cells in lymphatic sinuses of lymph nodes located in the head, neck, axillary fossa and inguinal region of the opossum. In the present work, scanning and transmission electron-microscopic studies in the opossum mandibular and superficial axillary lymph nodes have strengthened the differences between connective-tissue mast cells (CTMC) and the lymphatic-sinus mast cells (LSMC). Further, close appositions of mast cells to other cells were described. At the nodal capsule, CTMC contacted fibroblast and granulocytes. In the lymphatic sinuses a few CTMC contacted LSMC, macrophages and reticular cells. The LSMC contacted macrophages, reticular cells and other LSMC. A few LSMC could be located in the medullary cord in close contact with plasma cells or other lymphoid cells, keeping the same ultrastructural features of those found in the lymphatic sinuses. An important new finding was provided by light-microscopic studies in nine abdominal lymph nodes. Most of them (para-aortic, common iliac, cardial, cecocolic and those of the body and tail of the pancreas) displayed numerous LSMC with the same distribution and histological features described herein. However, the mesenteric, pyloric and head-of-pancreas lymph nodes were virtually devoid of LSMC. Instead, their mast cells occurred mainly at the medullary cords and were very similar to the CTMC. Ultrastructural studies at the mesenteric lymph nodes confirmed the CTMC character of the mast cells located at both medullary cords and sinuses, and disclosed interactions with macrophages and lymphoid cells.

Comparative investigations of regional lymph nodes and pseudocapsules after implantation of joint endoprostheses.

Morphological alterations of pseudocapsules and regional lymph nodes were studied by light and electron microscopy and by Laser Microprobe Mass Analysis (LAMMA). The tissue specimens originated from 32 autopsies of patients with hip joint endoprostheses (time in situ: 3 weeks - 15 years, average: 6 years) and two cases with knee joint endoprostheses. Characteristic changes of the lymph nodes as well as of the pseudocapsules consisted in an infiltration by monocytic histiocytes with various intracytoplasmatic wear particles. The foreign material consisted mainly of the components of bone cement: polymethylmethacrylate (PMMA) and zirconium oxide, to a lesser degree of polyethylene from the articulating surfaces. In two cases with special types of prostheses ceramic or metallic wear particles could be detected too. Most of the wear particles were found in the ipsilateral parailiac lymph nodes and in the paraaortic lymph nodes bilaterally. In the cases with mostly stable prostheses small amounts of wear particles were found in the lymph nodes as soon as 1.5 years after insertion and their number increased in all groups of lymph nodes after longer duration of the implant. The phagocytosing histiocytes showed degenerative changes. At present it is not clear, if the cell damage is caused by the amount of phagocytosed wear particles alone or if specific toxic effects of certain substances are of importance.

An investigation of the use of chromium, platinum and gold coating for scanning electron microscopy of casts of lymphoid tissues.

Resin casts replicate the internal structure of organs and provide a three-dimensional representation of the arrangement of vessels and intercellular spaces. Casting media are insulators and must be coated with a conductor to prevent sample charging and to allow the adequate production of secondary electrons from the specimen to generate sufficient signal to form a clear image. Visualization of surface structures depends largely on the metal coating. The use of gold or platinum, deposited on Mercox casts of lymphoid tissues using plasma-magnetron sputtering, and of chromium coating of casts by Penning ion-beam coating, was investigated. Casts were examined using a field emission scanning electron microscope at 3-3.5 kV. Thick coatings of gold were necessary to reduce cast charging but they obscured fine structural information. Charging effects were less pronounced when casts were coated with platinum, but charge lines were present at slow scan rates. The dimensions of cast impressions for both platinum and chromium coatings were similar to those described in fixed tissues. Negligible charging and maximal cast thermal stability and structural information was obtained from casts which were tumbled during chromium coating.

Early infection of interdigitating dendritic cells in the pig lymph node with African swine fever viruses of high and low virulence: immunohistochemical and ultrastructural studies.

The role of interdigitating dendritic cells (IDCs) in the early pathogenesis of African swine fever (ASF) was investigated using mandibular lymphoid tissue from normal pigs and pigs inoculated oronasally with highly virulent Lisbon 60 (L-60) and moderately virulent Dominican Republic 1979 (DR-2) ASF virus (ASFV) isolates. Paraffin-embedded tissue sections were immunostained for ASFV antigen and S-100 protein, a marker of IDCs, using an avidin-biotin alkaline phosphatase procedure. Swine IDCs were identified morphologically by light microscopy, electron microscopy, and S-100 immunostaining. Infection with ASFV caused a marked reduction in S-100 staining by 3 days postinfection (DPI) that persisted through 14 DPI. Early ASFV infection of IDCs was demonstrated at 3 DPI by double immunohistochemical staining of cryosections and by transmission electron microscopy. These results support the hypothesis that the failure of a humoral immune response to virulent ASFV may be due to a primary infection of IDCs and the inability of IDCs to initiate an immune response. Infection of IDCs has also been demonstrated with human immunodeficiency virus (HIV-1), and these infections have some aspects in common.

Scanning electron microscopic view of auditory tonsil in turkey.

The auditory tonsil of the turkey was studied by scanning electron microscopy. It is a sizable mass of lymphatic tissue dorsal to the infundibular opening in the auditory tube. The infundibular opening is in the roof of the turkey's mouth, caudal to the nasal cleft, and is the external orifice of the auditory tube that connects with the air spaces of the pneumonic bones in the head. Folds of the auditory tonsil that project toward or into the infundibular opening contained numerous lymphatic nodules in their lamina propria. The epithelial surface of the folds was covered with ciliated and nonciliated columnar cells, goblet cells with microvilli, and ductal openings of mucous glands located in the area. The lymphoid nodules were either oval or round and consisted of a thick reticular network that contained lymphocytes, fibroblasts, and erythrocytes. From some of the lymphatic nodules, there were sinusoids that contained lymphocytes and extended to the epithelial surface, whereas from others there was a lymphocytic infiltration of the surrounding lamina propria.

A scanning electron microscope study of the human cervical lymph node.

Arterial casts of human cervical lymph nodes were studied using scanning electron microscopy. Human cervical lymph nodes appear to be much more complex and dense than their animal counterparts. Human lymph nodes have a separate medulla arising from the hilar artery complex and cortical structure derived from capillaries. Also present is a previously unknown rosette formation of blood vessels. The possible implications of these findings for inflammatory and neoplastic diseases are discussed.

Lymphocytosis in rats treated with polyacids.

Inoculation of rats i.v. with dextran sulfate or polymethacrylic acid causes lymphocytosis. Electron microscopy of sections of cervical lymph nodes in control rats showed active passage of small lymphocytes through the high endothelial cells (HEC) of the post-capillary venules. In treated rats there was no indication of such passage: the HEC were free of small lymphocytes; and in about 25% of the venules apparently stationary lymphocytes, lacking microvilli, were found appressed to the luminal walls of the HEC.

Blood vessel architecture in lymph nodes of the dog viewed by scanning electron microscopy.

Scanning electron microscopy was used to investigate the submicroscopic organization of the blood vessels of dog lymph nodes (LN). The LN vessels were casted by systemic perfusion of the animals vasculature with two resins of distinct viscosity. This resulted in the retrieval of two types of LN vascular replicas that depicted either the arterial blood system alone (methacrylate casting) or both the arterial and venous blood systems (Mercox casting). We found that the dog LN showed a significantly higher density of arterial vessels in the cortex than in the medulla. In the cortical domain, a subcapsular layer stood out because of its rich content in arterial capillaries. The use of the high-resolution resin (mercox) resulted in excellent structural detail of the luminal surface of the LN vessels that allowed a clear distinction between arterioles and venules based on the geometrical pattern of the imprints left in the replicas by the nuclei of endothelial cells. At the cortex-medulla frontier, most arterioles showed narrowings of their lumen that suggested the existence of sphincters at this level. Our findings document that the microanatomical arrangement of blood vessels in the LN of the dog is different from that of LN from other mammals studied so far, in particular from rodents where vascular-poor microdomains have been reported in the LN cortex. The arteriolar sphincters that we detected at the innermost zone of the cortex may represent the structural counterpart of the physiological modulation of the blood supply of the cortex exerted by arterial branches coming from the hilus.

Development of follicular lymphoma of the cervical lymph nodes in a postoperative patient with tongue cancer.

Patients with head and neck squamous cell carcinoma are at an increased risk of developing second malignancies. Most commonly, these second primary malignancies are squamous cell carcinoma of the head and neck region, but also noted are esophageal cancer or lung cancer. Hematologic malignancies are uncommon second malignancies. Diagnosis can be challenging, particularly when a patient suffers metastases of squamous cell carcinoma to the cervical lymph nodes in addition to synchronous or metachronous malignant lymphoma that originates in the cervical lymph nodes. This article describes a case of primary follicular lymphoma in the cervical region that was discovered during a postoperative follow-up after partial glossectomy and neck dissection for tongue cancer.

The long-term stability and biocompatibility of fluorescent nanodiamond as an in vivo contrast agent.

Nanocarbon is a promising type of biomaterial for diagnostic and therapeutic applications. Fluorescent nanodiamond (FND) containing nitrogen-vacancy centers as built-in fluorophores is a new addition to the nanocarbon family. Here, we study the long-term stability and biocompatibility of 100-nm FNDs in rats through intraperitoneal injection over 5 months and develop the potential application of this biomaterial for sentinel lymph node mapping in a mouse model. From both in vivo and ex vivo fluorescence imaging as well as transmission electron microscopy, we found that the intradermally administered FND particles can be drained from the injection sites by macrophages and selectively accumulated in the axillary lymph nodes of the treated mice. Our measurements of water consumption, fodder consumption, body weight, and organ index showed no significant difference between control and FND-treated groups of the rats. Histopathological analysis of various tissues and organs indicated that FNDs are non-toxic even when a large quantity, up to 75 mg/kg body weight, of the particles was administered intraperitoneally to the living animals. With the properties of wide-ranging biocompatibility and perfect chemical and photophysical stability, FND is well suited for use as a contrast agent for long-term in vivo imaging.