Splenic Blood Vessels Research Articles

Transcriptome analysis of host anti-Aeromonas hydrophila infection revealed the pathogenicity of A. hydrophila to American eels (Anguilla rostrata)

Aeromonas hydrophila is a commonly pathogenic bacterium in cultivated eels, but its pathogenicity to American eel (Anguilla rostrata) and the molecular mechanism of host anti-A. hydrophila infection remains uncertain. In this study, LD50 of A. hydrophila to American eels was determined and bacterial load in the liver and kidney of eels was assessed post 2.56 doses of LD50 of A. hydrophila infection. The results showed that the LD50 of A. hydrophila to American eels was determined to be 3.9 × 105 cfu/g body weight (7.8 × 106 cfu/fish), and the bacterial load peaked at 36 h post the infection (hpi) in the liver. Then, the histopathology was highlighted by congestion in splenic blood vessels, atrophied glomeruli, and necrotic hepatocytes. Additionally, the results of qRT-PCR revealed that 18 host immune-related genes showed significantly up or downregulated post-infection compare to that of pre-infection. Finally, results of the RNA-seq revealed 10 hub DEGs and 7 encoded proteins play essential role to the anti-A. hydrophila infection in American eels. Pathogenicity of A. hydrophila to American eels and RNA-seq of host anti-A. hydrophila infection were firstly reported in this study, shedding new light on our understanding of the A. hydrophila pathogenesis and the host immune response to the A. hydrophila infection strategies in gene transcript.

Distal pancreatectomy with partial preservation of the spleen: a new surgical technique.

Presently, spleen-preserving distal pancreatectomy is predominantly utilized for benign or low-grade malignant tumors of the pancreatic body and tail. The splenic blood vessel-preserving Kimura technique and non-splenic blood vessel-preserving Warshaw technique represent the two primary procedures. In prior reports, total splenectomy was most frequently performed when splenic blood vessels could not be preserved, and severe splenic congestion and ischemia were identified following the dissection of splenic blood vessels. This paper introduces a new method of spleen-preserving distal pancreatectomy, entailing a distal pancreatectomy with partial spleen preservation, illustrated through the presentation of two surgical cases. During physical examination, two patients were identified to have benign or low-grade malignant masses in the pancreatic tail. Preoperative examination indicated that the lesion was closely associated with the splenic blood vessels or splenic hilum. During surgery, neither the Kimura technique nor the Warshaw technique could be executed. After resecting the pancreatic body and tail, and a portion of the spleen, the superior pole of the spleen was successfully preserved by maintaining the short gastric blood vessels therein. This technical report demonstrates the viability of this novel spleen-preserving distal pancreatectomy, a distal pancreatectomy with partial spleen preservation, for benign and low-grade malignant pancreatic body and tail lesions. The innovative technique achieves partial spleen preservation by effectively preserving the short gastric blood vessels in the superior pole of the spleen.

Pathogenicity of Edwardsiella anguillarum to American eels (Anguilla rostrata) and RNA-seq analysis of host immune response to the E. anguillarum infection

Edwardsiella anguillarum is a commonly pathogenic bacterium in cultivated eels, but its pathogenicity to American eel (Anguilla rostrata) and the molecular mechanism of host anti-E. anguillarum infection remains uncertain. In this study, LD50 of E. anguillarum to American eels was determined and bacterial load in the liver and kidney of eels was assessed post the LD50 of E. anguillarum infection. The results showed that LD50 of E. anguillarum to American eels was determined to be 2.5 × 105 cfu/g body weight, and the bacterial load peaked at 36 and 72 h post the infection (hpi) in the kidney and liver, respectively. Then, the histopathology was highlighted by congestion in splenic blood vessels, atrophied glomeruli, and necrotic hepatocytes, as well as ultrastructural pathology in the kidney were charactered by acute nephritis, showing necrosis of the renal tubular epithelial cells, glomerular capillaries dilate, mitochondria swelling and ribosomes separate from the endoplasmic reticulum. Furthermore, the results of qRT-PCR revealed that 12 host immune-related genes showed significantly up or downregulated post-infection compare to that of pre-infection. Finally, results of the RNA-seq revealed 6 hub DEGs play essential role to the anti-E. anguillarum infection in American eels. Pathogenicity of E. anguillarum to American eels and hub genes related host anti- E. anguillarum infection were firstly reported in this study, shedding new light on our understanding of the E. anguillarum pathogenesis and the host immune response to the E. anguillarum infection strategies in gene transcript.

The use of selective splenic vascular control in laparoscopic splenic vessels and spleen preservation distal pancreatectomy.

In the process of laparoscopic splenic vessels and spleen preservation distal pancreatectomy (LsvSPDP), because the splenic blood vessels have many small branches, how to safely separate the splenic blood vessels from the pancreas has always been the focus and difficulty of this operation. Many cases were switched to laparotomy, or the Warshaw method due to the inability to control bleeding during the separation of the splenic blood vessels. Therefore, we tried to use the selective splenic vascular control method when separating the splenic blood vessels to observe its effect on the conditions of the surgical patients during and after the operation. We retrospectively collected 35 cases of LsvSPDP conducted in our center from September 2015 to December 2020, including 5 males and 30 females. Considering the influence of the surgical learning curve, the cases were divided into three groups. Finally, through statistics of its intraoperative and postoperative conditions, the effectiveness of selective splenic vascular control method can be judged. Patients in Group 2 and 3 showed significantly less blood loss (172.5 and 134.44 mL, respectively) compared to patients in Group 1 (541.43 mL; P=0.01). However, the amount of blood loss was not significantly different between Group 2 and 3. The amount of bleeding was significantly reduced by splenic blood vessel control technology. And it can improve the success rate of spleen preservation, preserve the success rate of splenic blood vessels, and reduce intraoperative bleeding.

PB1864 MORE THAN 2 YEARS DELAY IN DIAGNOSIS OF PNH DUE TO GASTROINTESTINAL MASK OF BONE MARROW INSUFFICIENCY

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is an ultrarare bone marrow insufficiency of childhood consisted of the triad of diagnostic symptoms: hemolytic anemia, thrombosis, and peripheral blood cytopenias. Acute abdominal pain is one of the most important prodrome of PNH mostly due to venous thrombosis of intra-abdominal veins, including hepatic, portal, mesenteric, and splenic blood vessels. Aims: To show how a complicated course of diseases due to “abdominal mask” resulted in more than 2 years delay in diagnosis might be fatal to a PNH patients. Methods: We report a boy of 15th, suffered from PNH, who presented long before the diagnosis with seasonal (spring and autumn only) paroxysmal acute and severe (8-9 VAS score) abdominal pain with cramps and tenderness and no other hematological presentation of disease. There were a couple attacks observed during the season with complete resolution of abdominal symptoms in between. He had been diagnosed as acute appendicitis, peptic ulcer disease, pancreatitis or cholecystitis especially when hyperbilirubinemia emerge, Crohn and atypical celiac disease for more than 2 years. Since a peripheral pancytopenia followed by severe anemia required erythrocyte transfusions during the last 2 attacks occurred, hematologist had been asked for consultation. Due to severe anemia with reticulocytosis, hyperbilirubinemia, highly elevated LDH, meaningful splenomegaly and almost nondetectable concentration of serum haptoglobin and a dark urine with confirmed hemoglobinuria, with a weak bone marrow aplasia, the diagnosis of PNH was feasible. The cytometric results, which revealed no expression of GPI proteins in 93.8% of type III PMNs, confirmed the diagnosis (percentage of RBC lacking GPI was not persuasive, as he has been previously transfused). Up to this point of his disease, except of transient, he had no fixed postembolic lessons in liver and kidney, and a negligible bowel signs revealed for the several time in CT/MR-angiography. He had no other embolic events in other organs as well. Results: As the results of HSCT are questionable in PNH, especially in children, we decided to start eculizumab. The complete clinical remission assessed as complete symptoms resolution had been achieved with the 2nd dose, and complete biochemical remission, based on LDH normalization, was confirmed with the 3rd dose of a MoAb therapy. The presence and percentage of PNH clones tested twice since diagnosis in both PNMs and RBCs did not change till now. We have not observed any complications during a year and half of treatment up to date of publication. Summary/Conclusion: The insidious and hidden course of thrombosis of intra-abdominal veins even accompanied by hemolysis may mask the real reason and significantly prolong the diagnosis of ultrarare disease such as a PNH, especially in children. Eculizumab is a treatment of choice of childhood PNH.

Ultrasonography guidance for total splenectomy in donkeys

There are varieties of surgical approaches reported for equine splenectomy and all of them were dealing with the most reachable situation of splenic hilus and easy handling of the spleen. The aim of this work was to establish the normal ultrasound parameters of spleen in donkeys (normal echogenicity, hilus situation, topographic location and correlation with neighboring organs) as a guide to select the best approach for total splenectomy in donkeys. Splenic ultrasound was carried out on six normal donkeys before experimental total splenectomy in the standing position. The splenic topographic location was recorded among 4 rows including 30 squares. These animals were divided into two groups according to the surgical approach of total splenectomy. Total splenectomy after left 16th and 17th ribs partial resection in standing position was carried out in group1 and group 2, respectively. Ultrasonographically, the spleen had homogenously echogenic pattern and appeared hyperechoic to the liver. Only one third of the spleen was located in front of the 16th rib where the hilus and splenic blood vessels were nearly under the 16th rib. The splenic artery and splenic vein were ultrasonographically visualized between the left 16th and 17th ribs 10–15 cm from dorsal midline. This area was the site of the important ligation during total splenectomy. In conclusion, ultrasonography guidance for total splenectomy in donkeys assisted the surgical findings and proved that technique following partial resection of the 17th rib at the standing position is the most convenient surgical approach for total splenectomy in donkeys.

Evaluation of electrofishing adopted by Egyptian fish farmers

Upon the demand of a private fish farmer, this study was applied to assess the influence of electro-fishing adopted by some Egyptian fish farmers on the fish welfare and quality. Therefore, a total of 60 Nile tilapia (Oreochromis niloticus) were sampled; from which 30 were stunned by electrofishing and the remainders by conventional fishing. Biochemical analysis (oxidative stress and energy status), meat quality based on total bacterial count (TBC) and pathological alterations were assessed. Biochemical analysis in both liver and muscle tissue showed that electro-stunned fish exhibited low oxidative stress and high energy status. Meat of electro-stunned fish showed an acceptable limit of TBC (Max. limit 107) while the histopathological examination revealed various tissue reactions. These were in the form of congestion in branchial, hepatoportal, brain and splenic blood vessels with edema in brain and pericardium. In addition, there was mild inflammatory reaction together with the presence of eosinophilic granular cells and perivascular melanophores aggregation in both branchial and muscular tissue.As a consequence of this work, we recommend the use of electrofishing method in Egypt after modifying the current tool by reducing applied voltage. Further studies and more optimization are needed to cover both fish farmers and animal welfare issues, and take in consideration the human safety precautions.

β2-microglobulin is required for the full expression of xenobiotic-induced systemic autoimmunity

Mercury exposure in both humans and mice is associated with features of systemic autoimmunity. Murine HgCl2-induced autoimmunity (mHgIA) requires MHC Class II, CD4+ T-cells, co-stimulatory molecules, and interferon-γ (IFN-γ), similar to spontaneous models of systemic lupus erythematosus (SLE). β2-microglobulin (B2m) is required for functional MHC Class I molecules and the neonatal Fc receptor (FcRn). Deficiency of B2m in lupus-prone strains is consistently associated with reduced IgG levels, but with variable effects on other manifestations. Herein, we examined the role of B2m in mHgIA and show that in the absence of B2m, mercury-exposed mice failed to exhibit hypergammaglobulinemia, had reduced anti-nucleolar autoantibodies (ANoA), and had a lower incidence of immune complex deposits in splenic blood vessels, whereas IgG anti-chromatin autoantibodies and renal immune deposits were largely unaffected. Subclass analysis of the IgG anti-chromatin, however, revealed a significant reduction in the IgG1 subtype. Examination of IFNγ, IL-4, and IL-2 in exposed skin, draining lymph nodes, and spleen following mercury exposure showed reduced IL-4 in the spleen and skin in B2m-deficient mice, consistent with the lower IgG1 anti-chromatin levels, and reduced IFNγ expression in the skin. These findings demonstrate how a single genetic alteration can partially but significantly modify the clinical manifestations of systemic autoimmunity induced by exposure to xenobiotics.

Aspectos histológicos de fragmentos esplênicos autotransplantados em ratos

Estudou-se a viabilidade do autotransplante de tecido esplênico, um terço do baço, associado à esplenectomia parcial, e verificou-se a cinética evolutiva de sua regeneração, sob o aspecto macroscópico e histológico. Foram utilizados 28 ratos Wistar, adultos, machos, com média de peso de 300g, distribuídos em quatro grupos experimentais. Cada animal foi submetido à esplenectomia parcial, e um fragmento de baço foi transplantado para o omento maior, por períodos de 30, 60, 90 e 120 dias. Após cada período pré-estipulado, os tecidos esplênicos autotransplantados foram coletados e analisados histologicamente. Os resultados mostraram regeneração da cápsula esplênica, dos vasos sanguíneos e das polpas branca e vermelha. Aos 90 dias, a arquitetura microscópica apresentava-se semelhante à do baço normal.

Hemophagocytic Histiocytic Sarcoma in a Japanese Black Cow

At necropsy, an 11-year-old Japanese Black cow with anemia, leukocytopenia, and progressive hind limb ataxia had marked diffuse splenomegaly and multiple masses in the thoracic vertebrae. Histologically, neoplastic erythrophagocytic histiocytes were in the splenic red pulp, vertebral masses, and blood vessels of the liver and lungs. The spinal cord was compressed by the vertebral masses. Clinicopathological, macroscopic, and histologic findings were consistent with hemophagocytic histiocytic sarcoma. Vertebral involvement with spinal cord compression and resultant hind limb ataxia is an unusual presentation for this tumor, which has been described mainly in dogs and cats.

Splenic Injury as a Complication of Colonoscopy – a Case Series

Purpose: To recognize splenic injury as under-recognized and under-reported complication of colonoscopy. To also recognize 5 associated factors that may play a role in splenic injury during colonoscopy. Methods: We examined the medical records from nine patients who underwent colonoscopy and developed a complication of splenic rupture. Results: The patients' ages ranged from 44 to 77, 7 were women and 2 were men. The time to completion of the procedure (s) ranged from 8 minutes to 36 minutes. All patients experienced pain at the completion of the procedure and one patient fainted in recovery but all were discharged home except one despite complaining of pain that became more severe requiring transfer to the emergency department. Abdominal X-rays did not show free air and did not indicate a colon perforation. On the other hand, a CT abdomen was virtually diagnostic showing the pooling of blood in the abdominal cavity and splenic damage in all cases. Five of nine patients had a history of taking aspirin regularly. All patients except for one were long term cigarette smokers. Sedation was provided by an anesthesiologist in five patients with propofol being the predominant sedative. All patients were seen by surgeons: Seven patients required splenectomies while two patients were treated conservatively with blood transfusions. Conclusion: In conclusion, though screening colonoscopy is a generally safe and well tolerated procedure, good bowel prep is important and endoscopists must be vigilant to avoid complications. Passage of the colonoscope around the splenic and hepatic flexure needs to be performed carefully with minimal force in order to prevent shearing forces that may tear the splenocolic ligaments and splenic blood vessels and result in splenic rupture. Conscious sedation where the patient remains awake might be safer than propofol because the patient can respond to abdominal pain and warn the endoscopist prior to injury. In these cases, excessive force used to pass the colonoscope seemed responsible for the ruptured spleen. A history of cigarette smoking, a history of aspirin use, inadequate colon clean-out, and the use of stronger sedatives such as propofol may increase the risk of splenic injury. Furthermore, we found contrast enhanced CT of the abdomen to be the test of choice in patients complaining of abdominal pain post colonoscopy and should be performed immediately when the abdominal x-ray is negative.

Cover Picture: The cover image features a frozen section from an embryonic day 16 mouse spleen stained by immunofluorescence to demonstrate the presence and location of lymphoid tissue inducer (LTi) cells. Withers et al. (pp. 3240–3245) show that these cells form the focus of lymphocyte accumulation in the developing mouse spleen. Red staining for CD45 marks haemopoietic cells, green shows

AbstractCD4+CD3– lymphoid tissue inducer (LTi) cells are crucial for the development and organisation of lymph nodes and gut associated lymphoid tissues. In this report, we characterise their appearance in the developing spleen and highlight their importance in relation to the development of splenic T cell zones. LTi cells were detected in embryonic spleen from embryonic day 13, although their progenitors were present at embryonic day 12. These cells clustered initially around splenic blood vessels in a lymphotoxin (LT)‐independent manner, but up‐regulation of VCAM‐1 expression on stromal cells associated with the blood vessels was LT dependent. After birth, T cell colonisation of these clusters to form nascent white pulp areas was also LT dependent. Transfer experiments reconstituting RAG–/– mice with either WT or LTα–/– splenocytes demonstrated that lymphocyte expression of LT was not essential for the organisation of a discrete CD3+ T cell zone with localised podoplanin and CCL21 expression. Our studies indicate that a combination of LT signals from LTi cells and LT‐independent signals from lymphocytes is sufficient for expression of podoplanin and CCL21 on splenic T cell zone stroma and subsequent T cell organisation.

The role of lymphoid tissue inducer cells in splenic white pulp development

CD4(+)CD3(-) lymphoid tissue inducer (LTi) cells are crucial for the development and organisation of lymph nodes and gut associated lymphoid tissues. In this report, we characterise their appearance in the developing spleen and highlight their importance in relation to the development of splenic T cell zones. LTi cells were detected in embryonic spleen from embryonic day 13, although their progenitors were present at embryonic day 12. These cells clustered initially around splenic blood vessels in a lymphotoxin (LT)-independent manner, but up-regulation of VCAM-1 expression on stromal cells associated with the blood vessels was LT dependent. After birth, T cell colonisation of these clusters to form nascent white pulp areas was also LT dependent. Transfer experiments reconstituting RAG(-/-) mice with either WT or LTalpha(-/-) splenocytes demonstrated that lymphocyte expression of LT was not essential for the organisation of a discrete CD3(+) T cell zone with localised podoplanin and CCL21 expression. Our studies indicate that a combination of LT signals from LTi cells and LT-independent signals from lymphocytes is sufficient for expression of podoplanin and CCL21 on splenic T cell zone stroma and subsequent T cell organisation.

Electron microscopic cytochemical studies of anionic sites in the rat spleen.

The distribution patterns of the intensity of negative charge on the free surfaces (glycocalyx of the plasma membrane) of endothelial cells (ECs) in blood vessels and reticular cells (RCs) in the splenic cord of the rat spleen were studied by an electron microscopic cytochemical method using polyethyleneimine (PEI) as a cationic probe. Spleens from adult male rats were perfusion-fixed with 0.5% glutaraldehyde -4% paraformaldehyde containing 0.05% cetylpyridinium chloride and then perfused with 0.5% PEI at pH 7.4. On the free surfaces (glycocalyx of the plasma membrane) of the ECs examined, distinct PEI-positive reactions were observed in blood vessels, such as trabecular arteries, central arteries, arterial capillaries, pulp veins and trabecular veins. These PEI-positive electron-dense substances in the trabecular arteries, central arteries, and trabecular veins took the shape of a band of 170-250 nm in thickness. On the other hand, the corresponding ultrastructure of the ECs lining the splenic sinuses and the RCs in the splenic cord showed exceedingly weak PEI reactions. The PEI-reactive deposits were significantly thinner than those in the above blood vessels. As the thickness of the electron-dense substances can be related to the density of the negative charge, these results suggest that there is a high intensity of negative charge on the free surfaces (glycocalyx of the plasma membrane) of ECs in blood vessels where blood cells and plasma pass into the red pulp or are discharged from the red pulp. In contrast, the splenic sinuses and RCs, which are the main components of the red pulp, contain weakly negative-charged sites. This may contribute to the microcirculation of the splenic blood vessels and elucidate the possible physiological functions of the spleen, such as blood storage.

Senescent jejunal mast cells and eosinophils in the mouse preferentially translocate to the spleen and draining lymph node, respectively, during the recovery phase of helminth infection.

Because mice infected with Trichinella spiralis experience a pronounced, but transient, mastocytosis and eosinophilia in their intestine, this disease model was used to follow the fate of senescent T cell-dependent mast cells (MCs) and eosinophils. Very few MCs or eosinophils undergoing apoptosis were found in the jejunum during the resolution phase of the infection, even though apoptotic MCs were common in the large intestine. Although the mesenteric draining lymph nodes contained large numbers of apoptotic eosinophils, MCs were rarely found at this location. During the recovery phase, large numbers of MCs were present in the spleen, and many of these cells possessed segmented nuclei. These splenic MCs were not proliferating. Although MCs from the jejunum and spleen of noninfected mice failed to express mouse MC protease (mMCP) 9, essentially all of the MCs in the jejunal submucosa and spleen of T. spiralis-infected mice expressed this serine protease during the recovery phase. The MCs in the jejunum expressed mMCP-9 before any mMCP-9-containing cells could be detected in the spleen. The fact that mMCP-9-containing MCs were detected in splenic blood vessels as these cells began to disappear from the jejunum supports the view that many jejunal MCs translocate to the spleen during the recovery phase of the infection. During this translocation process, some senescent jejunal MCs undergo nuclear segmentation. These studies reveal for the first time different exit and disposal pathways for T cell-dependent eosinophils and MCs after their expansion in the jejunum during a helminth infection.

Seasonal changes in intra‐ and interorgan occurrence of rodlet cells in freshwater bream

Significant seasonal differences in intra‐ and interorgan prevalence, abundance and distribution of rodlet cells (RC) were observed in freshwater bream caught in May and August 1997 from a PCB‐polluted lake, Lake Kernaala, Finland. In May, the majority of RCs in liver were seen in blood vessel endothelium, while in August most cells were located in the epithelium of the intrahepatic biliary ducts. In kidney, a significant increase in RCs in the columnar epithelium of the collecting ducts was observed from May to August. RCs in spleen were extremely rare in May, but were seen frequently in the endothelium of the splenic blood vessels in August. In gill and intestine, RCs were found in every tissue sample studied, with no statistical differences in their abundance or distribution between seasons. No RCs were seen in gonads. Total numbers of RCs increased dramatically from May to August in kidney and in spleen. The frequency of RCs corresponded strongly with the current phase of parasitic infections in liver, kidney, and spleen. It is concluded that RCs play a role in host defence mechanisms in fish, displaying induced expression at the times of peak parasitic prevalences.

Seasonal changes in intra- and interorgan occurrence of rodlet cells in freshwater bream

Significant seasonal differences in intra- and interorgan prevalence, abundance and distribution of rodlet cells (RC) were observed in freshwater bream caught in May and August 1997 from a PCB-polluted lake, Lake Kernaala, Finland. In May, the majority of RCs in liver were seen in blood vessel endothelium, while in August most cells were located in the epithelium of the intrahepatic biliary ducts. In kidney, a significant increase in RCs in the columnar epithelium of the collecting ducts was observed from May to August. RCs in spleen were extremely rare in May, but were seen frequently in the endothelium of the splenic blood vessels in August. In gill and intestine, RCs were found in every tissue sample studied, with no statistical differences in their abundance or distribution between seasons. No RCs were seen in gonads. Total numbers of RCs increased dramatically from May to August in kidney and in spleen. The frequency of RCs corresponded strongly with the current phase of parasitic infections in liver, kidney, and spleen. It is concluded that RCs play a role in host defence mechanisms in fish, displaying induced expression at the times of peak parasitic prevalences.

Identification of a new mouse beta-chemokine, thymus-derived chemotactic agent 4, with activity on T lymphocytes and mesangial cells.

Thymus-derived chemotactic agent 4 (TCA4), a new member of the beta-chemokine family, was cloned from a mouse thymic cDNA library. High levels of TCA4 mRNA are expressed in thymus; lower levels of message are found in spleen, heart, and kidney. Anti-TCA4 antibodies were used to localize sites of TCA4 expression within lymphoid tissues. In the thymus, UEA-1+ medullary epithelial cells, some endothelial cells, and additional undefined stromal elements were stained with anti-TCA4. TCA4 was also expressed as a meshlike network in splenic white pulp and in the medullary region of the lymph nodes. In addition, some lymph node and splenic blood vessels stained with anti-TCA4 antibodies. Rel B NFkappaB-deficient mice lack a transcription factor required for the generation of dendritic cells and the development of an organized thymic medulla. Rel B-deficient animals express very low levels of TCA4 in the thymus and little or no TCA4 in the periphery. At subnanomolar concentrations, TCA4 is a chemoattractant of mature T cells; the potential role of this novel chemokine in facilitating normal lymphocyte traffic is discussed. TCA4 is also a chemoattractant of cultured mesangial cells. Neutralizing anti-TCA4 mAb was used to demonstrate the specificity of TCA4-mediated cell migration. Finally, competitive binding studies with a SV40-transformed mouse mesangial cell line demonstrated that other murine beta-chemokines (monocyte chemotactic protein-1, macrophage inflammatory protein-1alpha, macrophage inflammatory protein-1beta, and thymus-derived chemotactic agent 3) do not compete for TCA4 binding.

Acute hematopoietic toxicity of aniline in rats

In the present study, acute hematopoietic toxicity of aniline as a function of time was investigated in rats. The animals were given a single oral dose of aniline hydrochloride (2 mmol/kg) and euthanized at zero (control), 0.25, 0.5, 1, 3, 6, 12, 24 and 48 h following the treatment. The blood methemoglobin level increased dramatically and attained a peak level of 37% (31 fold greater than the controls) at 0.5 h. Thereafter, the increases were less pronounced and the level declined with time. Spleen weight to body weight ratio remained unchanged up to 24 h, but increased ∼25% at 48 h. Lipid peroxidation (MDA content) in the spleen increased by 39% at 24 h and remained steady even at 48 h. MDA-protein adducts, as quantitated by a competitive ELISA, showed 94, 126 and 265% increases in the spleen homogenates at 12, 24 and 48 h, respectively, following the treatment. However, no changes were observed in the splenic protein oxidation. Morphological examination showed congestion of splenic blood vessels and marked expansion of red pulp at 24 and 48 h. These studies suggest that aniline related changes in the blood are reflected very early as evident from increases in the methemoglobin content, whereas changes in the spleen appear later and are characterized by splenic weight changes, increased lipid peroxidation, MDA-protein adduct formation and morphological changes after a single high dose exposure. The increased lipid peroxidation in the spleen also suggests that free radical-mediated reactions could be the potential mechanism of splenic toxicity of aniline and lipid peroxidation precedes protein oxidation.

Monoclonal antibodies against mouse splenic stromal cells.

A panel of rat monoclonal antibodies directed against mouse splenic stromal cells were isolated. These monoclonal antibodies were immunohistochemically divided into four groups which reacted with non-lymphoid cells of the murine spleen; (I) in the white pulp, (II) at the marginal zone, (III) in the red pulp, and (IV) on the endothelium of splenic blood vessels. These monoclonal antibodies were studied immunohistochemically in lymphoid organs by means of light and electron microscopy. Monoclonal antibodies SS-4 (group I) reacted with fibroblastic reticulum cells that were distributed only in the white pulp of the spleen and in the follicular areas of lymph nodes. The SS-4 staining cell, in clustered splenic stromal cells, formed colonies which included a small number of Thy-1 positive lymphocytes. Therefore, we concluded that SS-4 staining stromal cells comprise the lymphoid compartment. In contrast, monoclonal antibodies SS-1, SS-3 and SS-5 (group II) reacted with dendritic shaped cells in the marginal zone of the spleen. Examination of splenic extramedullary hematopoiesis in mice rescued by bone marrow transplantation after lethal irradiation revealed that SS-3 and SS-5 reacted with dendritic shaped stromal cells in clonal nodules of engrafted marrow in the red pulp. SS-3 and SS-5 staining cells could not be observed in physiologic hematopoiesis of non-transplanted mice. It was suggested that SS-3 and SS-5 staining stromal cells are involved in primitive hematopoiesis. Monoclonal antibodies SS-2, SS-6 and SS-7 (group III) mainly reacted with dendritic cells and macrophages in the red pulp. Monoclonal antibodies SS-B and SS-9 (group IV) reacted with endothelial cells of blood vessels and sinuses. These findings of heterogeneity in mouse splenic stromal cells are further evidence that specific micro-environments are composed by specialized stromal cells.