Lymph nodes, one of peripheral lymphoid organs, are the sites, where the lymphocytes receive their initial instructions for producing effector functioning resulting in humoral or cell-mediated immunity. Each lymph node consists of an outer cortex in which there are aggregates of cells constituting the follicles, B-cell areas. Some follicles have central areas called germinal centers, which stain lightly. Germinal centers are B lymphoblast cell areas arising eccentrically in primary lymphoid follicles in response to T-cell dependent antigenic stimulation and are the generally accepted sites of generation of memory B cells and undergoing isotype switching and somatic mutation. We observed the morphologic, cellular, protein and molecular events arising in mouse popliteal lymph nodes in response to T-cell dependent antigenic stimulation. In this study mice were immunized into footpads with TNP-chicken ovalbumin. The germinal center formation in primary follicles of popliteal lymph nodes was first observed 6 days after immunization and germinal centers persisted until 24 days of immunization. Lymph node cells were stained with PE-labeled anti-B220 antibody and/or FITC labeled PNA and analyzed by using FACScan. B cells (B220(+) cell) in lymph node increased after 3 days and peaked between 6 and 18 days after immunization. The proportion of germinal center B cells (B220, PNA(high) cells) among lymph node B cells was low (2%) before immunization but increased at day 6 (9%) and reached the peak (30%) at day 18. The expression of IgG1 productive mRNAs and germline transcripts were observed by using RT-PCR. The expression of IgG1 productive mRNA was detected at day 10 and continued until 24 days after immunization. The expression of IgG1 germline transcripts was observed 10 days after immunization and rapidly declined over the next one week. IgG1 anti-TNP antibody, main isotype of anti-TNP antibodies, was first detected at day 14 and reached the peak level 24 days after immunization. Taken these data together, we can conclude that the first immunological event observed from mouse popliteal lymph node in response to T-cell dependent antigenic stimulation is the increase in the number of B cells, and this event is followed by appearance of germinal center B cells and at the same time by the formation of germinal center in primary lymphoid follicles. Once the germinal center is formed, the process of isotype switching to IgG1 occurs in lymph node and antigen-specific IgG1 antibody is produced.
Animals ; Antibodies ; B-Lymphocytes ; Fluorescein-5-isothiocyanate ; Germinal Center ; Immunity, Cellular ; Immunization ; Immunoglobulin Class Switching ; Immunoglobulin G ; Immunoglobulins* ; Lymph Nodes* ; Lymphocytes ; Memory ; Mice ; Ovalbumin ; RNA, Messenger ; T-Lymphocytes

No abstract available.
Humans ; Spondylolisthesis*

Primary cardiac tumors in infancy and childhood are rare, with fibromas being the second most common tumor after rhabdomyomas. Although cardiac fibromas are characteristically benign intramural tumors, they may exhibit exhibit expansile growth resulting in obstruction, valvular dysfunction, as well as other problems so early diagnosis and successful surgical excision are important. We report a case of cardiac fibroma in a 2 month-old male infant. He presented with generalized cyanosis from birth. Echocardiography showed oval round large mass filing the right atrium and ventricle which infiltrated into the lateral wall of the ventricle. Partial excision of the tumor was done after another echocardiogram showed a pericardial effusion and restriction of blood flow to the right ventricle due to the tumor. The resected tumor was ovoid, gray-tan, slightly firm and measuring 5x3x2.5 cm. Histologically, the tumor was composed of spindle-shaped fibroblasts and hyalinized fibrous tissue interdigitating with the surrounding myocardium.
Infant ; Child ; Male ; Female ; Humans

No abstract available.
Carcinoma, Squamous Cell* ; Cervix Uteri* ; Female ; Biomarkers, Tumor*

No abstract available.
Osteoblasts*

Experimental melanin-induced uveitis[EMIU]was induced in Lewis rats to investigate the mechanisms of the tissue destruction and spontaneous turning off of the endogenous uveitis. The eyes were enucleated serially, and immunohistochemistry, TUNEL stains, and flow cytometry were performed. The major infiltrating inflammatory cells were CD4 T cells in the uveal tissue of EMIU. Apoptosis of these cells has occurred and progressed throughout the inflammatory period in EMIU eyes. Most TUNEL positive cells revealed CD4 positive. These results suggest that apoptotic cell death occurred primarily in the infiltrating inflammatory cells not in the tissue cells of the eye and the apoptosis of CD4 T cells may play a key role in the spontaneous turning off mechanism of intraocular inflammation in EMIU.
Animals ; Apoptosis* ; Cell Death ; Coloring Agents ; Flow Cytometry ; Immunohistochemistry ; In Situ Nick-End Labeling ; Inflammation ; Rats ; T-Lymphocytes ; Uveitis*

No abstract available.
Animals ; Nerve Regeneration* ; Rats* ; Sciatic Nerve*

To evaluate the radiographic characteristics of osteochondritis dissecans (OCD) and useful parameter for predicting mechanical stability, we retrospectively analysed 26 plain radiographic examinations and seven MR imagings in 28 cases of OCD in 24 patients. Typical radiologic findings were osteochondral defect with sclerotic rim of variable thickeness and osteochondral fragment. Sites of osteochondral defect were medial (35.9%) or lateral (32%) femoral chondyle and medial (7.1%) or lateral (25%) side of talar dome. Sclerotic rim was seen in 24 cases (85%) and osteochondral fragments including nine loose bodies were seen in 21 cases (75%). The size of osteochondral defect with unstable fragment (average 2.05cm) and loose body (2.04cm) in the knee joint were similar to, but statistically larger than that with stable fragment (1.35cm). All osteochondral defects were well visualized on MR images. Abnormalities of articular cartilage and effusion in the interface between the parent bone and fragment were seem in five cases of which there were confirmed three unstable cases arthroscopically. We conclude that size of defect may be a good parameter for predicting mechanical stability and MRI may be useful in the diagnosis of OCD and determining the methods of treatment.
Cartilage, Articular ; Diagnosis ; Humans ; Knee Joint ; Magnetic Resonance Imaging ; Osteochondritis Dissecans* ; Osteochondritis* ; Parents ; Retrospective Studies

No abstract available.
Teratoma*

No abstract available.
Hematoma* ; Orbit*