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Biomedical subjects

F Fend

Publications and source records attributed to F Fend.

At least 55 records · Page 3Linked to original sources
PubMed1995

Seminomas positive for Epstein-Barr virus by the polymerase chain reaction: viral RNA transcripts (Epstein-Barr-encoded small RNAs) are present in intratumoral lymphocytes but absent from the neoplastic cells.

A possible role of Epstein-Barr virus (EBV) in the pathogenesis of testicular germ cell neoplasms has been suggested repeatedly, but direct evidence for an association of testicular cancer with EBV is lacking. We examined 26 cases of classical seminoma, two spermatocytic seminomas, and 12 cases of nonseminomatous or combined germ cell tumors for the presence and cellular location of EBV with a combined approach using the polymerase chain reaction and nonradioactive in situ hybridization for EBV-encoded small RNAs (EBER1/2). After exclusion of cases without amplifiable DNA, 4/21 (19%) seminomas, but none of the other tumors, were positive for EBV by polymerase chain reaction. In situ hybridization for EBER1/2 showed rare positive lymphocytes, probably latently infected B-cells, in two of these four EBV-positive cases. No EBER-positive tumor cells were found in any of the analyzed tumors. The occurrence of EBV-positive lymphoid cells was not correlated to the frequency of intratumoral lymphocytes, including B-cells, which were present in seminomas in significant numbers. Our study demonstrates the absence of EBV from the neoplastic cells of testicular germ cell tumors and makes a direct role of EBV in the development of these malignancies improbable. Whether the presence of EBER-positive lymphocytes in some seminomas simply reflects the normal occurrence of latently infected cells in lymphoid tissue of seropositive individuals or is influenced by local factors remains to be determined.

Antibodies, Monoclonal↗
PubMed1994

Subcutaneous abscess due to gallstones lost during laparoscopic cholecystectomy.

No complications caused by gallstones lost during laparoscopic cholecystectomy have yet been described in the literature. In one animal study in rats, it has been shown that pigment calculi, but not cholesterol stones, lead to severe local inflammation of the abdominal cavity. We present a case of a chronic subcutaneous and subfascial abscess in the lower abdomen, which included multiple pigment calculi, six months after laparoscopic cholecystectomy. During the procedure, multiple small pigment calculi had been lost into the free abdominal cavity.

Abdomen↗
PubMed1994

Detection of monoclonal B-cell populations in decalcified, plastic-embedded bone marrow biopsies with the polymerase chain reaction.

Polymerase chain reaction (PCR) has been employed successfully for the detection of clonal immunoglobulin gene rearrangements in paraffin-embedded clinical samples. The authors examined whether this technique can also be applied to fixed, decalcified, and plastic-embedded bone marrow biopsies. DNA extracted from 66 glycolmethacrylate-embedded trephine biopsy samples was amplified for the detection of rearranged VDJ regions of the immunoglobulin heavy chain genes using both a single-step and a semi-nested PCR technique. After exclusion of samples with inadequate DNA, clonality was confirmed in 16 (67%) of 24 cases with B cell malignancy, whereas all 11 non-B cell neoplasms, and 6 of 9 cases with normal bone marrow showed evidence of a polyclonal B cell population. Patterns indicating oligo- or monoclonality were observed in three plastic-embedded samples of normal bone marrow, although control PCR of frozen bone marrow samples obtained in parallel showed no evidence of clonality. Repeated PCR of these cases revealed inconsistent bands, probably due to the amplification of rare templates from polyclonal B cells. Decalcified, plastic-embedded bone marrow biopsies are suitable for PCR-based determination of B-cell clonality. To exclude the possibility of false-positive results, monitoring of template DNA quality and independent control amplifications are mandatory.

B-Lymphocytes↗
PubMed1994

HDL and plasma phospholipids in coronary artery disease.

Lipid fractions of native plasma and of high-density lipoprotein (HDL) were analyzed, and the clotting times of native platelet-rich and -poor plasma were recorded in patients with coronary artery disease and age-matched control subjects not taking any medication known to alter plasma lipid levels, coagulation, or platelet aggregation. Patients with coronary artery disease had lower HDL cholesterol and particularly HDL phospholipids but elevated HDL triglycerides, plasma triglycerides and diglycerides, and fibrinogen. Plasma lysolecithin was diminished. Accelerated coagulation was observed in native plasma and may be related to these changes in plasma lipids. The HDL content in cholesterol may be less relevant than that in phospholipids, which, because of their amphiphilic properties, may be essential for the removal and transport of hydrophobic cholesterol. The lower lysolecithin levels also suggest diminished esterification of cholesterol and reduced degradation of phospholipids, which may add to the poor lysability of platelet-rich and thus phospholipid-rich thrombi. Coagulation inhibition may be related to HDL phospholipids: in control subjects they correlated directly with clotting times of platelet-rich and -poor plasma and inversely with fibrinogen. In contrast, the enhanced thrombus formation in coronary artery disease may be related to altered HDL and plasma phospholipids, in particular to increased phosphatidylethanolamine. These adverse changes, particularly diminished HDL phospholipids, may result in increased deposition and reduced degradation and transport of lipids from arteriosclerotic lesions and thrombi and may therefore be significant in the development of coronary artery disease.

Blood Coagulation Tests↗
PubMed1994

Early diagnosis of gastric lymphoma: gene rearrangement analysis of endoscopic biopsy samples.

The diagnosis of gastric lymphoma in endoscopic biopsy specimens remains difficult despite the emergence of accepted criteria for the histologic diagnosis of lymphomas originating from mucosa-associated lymphoid tissue (MALT). The sensitivity and validity of immunoglobulin (Ig) gene rearrangement analysis of mucosal biopsies for the diagnosis of malignant B-cell lymphoma were investigated in comparison with conventional histology and immunohistology. Biopsy specimens from 34 different endoscopies of 20 patients with a previous history, or tentative diagnosis of gastric lymphoma, and 12 control samples were analyzed for the presence of clonal Ig gene rearrangements. A clonal B-cell population was detected by Southern blot analysis in all patients with a definitive histologic diagnosis of lymphoma. In addition, in two patients the detection of clonal rearrangements in biopsy specimens preceded by several months the histologic diagnosis of lymphoma, and clonality was confirmed in three further patients where histology remained inconclusive. In some cases of low-grade MALT-lymphoma, discrete spreading of malignant cells within chronically inflamed mucosa was suggested by the presence of identical clonal rearrangements in all simultaneously obtained biopsies, with or without histologically detectable involvement by lymphoma. Our results show that immunoglobulin gene rearrangement studies of endoscopic biopsy samples are an additional powerful tool for the diagnosis of gastric lymphoma, especially for detecting early recurrence, and improve the preoperative assessment of the extent of mucosal involvement.

Biopsy↗
PubMed1993

Monocytoid B-cell lymphoma: its relationship to and possible cellular origin from marginal zone cells.

Monocytoid B-cell lymphoma, the neoplastic counterpart of the monocytoid B cells, is a now well-recognized variant of low-grade, malignant B-cell lymphomas. However, monocytoid B-cell lymphomas state of differentiation, its cellular origin, and its relationship to other B-cell compartments are still obscure. We investigated an unusual case of monocytoid B-cell lymphoma with generalized disease at presentation, including infiltration of the abdominal lymph nodes, spleen, liver, and bone marrow, as well as involvement of the peripheral blood. The tumor showed the typical sinusoidal and perifollicular growth pattern in the lymph nodes. In the spleen the main infiltrate was confined to the marginal zone. These features and the characteristic immunoreactivity of the tumor cells (KiM1P+, KiB3-) in our case suggest that monocytoid B cells and their neoplastic counterparts are closely related to and probably derived from marginal zone cells.

Cell Transformation, Neoplastic↗
PubMed1993

Goodpasture's syndrome. Unusual presentation after exposure to hard metal dust.

An unusual case of Goodpasture's syndrome in a 26-year-old man with occupational exposure to hard metal dust is described. The patient developed a life-threatening interstitial lung disease that was followed by a rapidly progressive glomerulonephritis two months later. To our knowledge, association of Goodpasture's syndrome and hard metal exposure has not been reported previously.

Adult↗
PubMed1993

Immunoglobulin gene rearrangement in plasma cell dyscrasias: detection of small clonal cell populations in peripheral blood and bone marrow.

The bone marrow (BM) and peripheral blood (PB) samples of 71 patients with plasma cell dyscrasias were analysed by the Southern blot technique for the presence of clonal immunoglobulin (Ig) gene rearrangements. 53% of BM samples examined were archival material such as air dried BM slides or frozen trephine biopsies. The results were related to bone marrow plasmacytosis as determined by cytology and flow cytometry, and other clinical parameters. Clonal Ig gene rearrangements were found in BM samples of 45 (83%) of 54 MM patients and in 3 of 6 patients with monoclonal gammopathy of unknown significance (MGUS). Clonal cell populations in the PB were detected in 11 (30%) of 37 examined MM patients, but in none of the patients with MGUS or solitary plasmacytoma of bone. PB involvement was associated with progressive disease. Circulating monoclonal cells were significantly associated with higher M-protein levels (p < 0.05). Thus, circulating clonal precursor cells are encountered more frequently in active MM.

Adult↗
PubMed1993

B-cells in thymic epithelial tumours. An immunohistochemical analysis of intra- and extraepithelial B-cell compartments.

A total of 26 thymomas and thymic carcinomas were studied by immunohistochemistry to determine the presence and distribution of intratumoural B-cells. Double staining experiments revealed two distinct B-cell populations in the thymic epithelial tumours. One was found within the perivascular space (PVS), which is separated from the neoplastic epithelium by a basement membrane. In all tumours the PVS contained lymphocytes with the immunophenotype of peripheral B-cells. Large numbers of B-cells with germinal centre formation were found almost exclusively in myasthenia gravis (MG)-associated tumours, mainly in cortical thymomas and well differentiated thymic carcinomas. A second population of B-cells was located in the neoplastic epithelial meshwork, mostly in areas of organoid medullary differentiation characterized by epidermoid cells or Hassall's corpuscules. This population frequently comprised large, CD23+ cells with dendritic features resembling the special type of intramedullary B-cells of the normal human thymus. In contrast, B-cells were uncommon in areas of mixed thymoma showing spindle celled medullary differentiation, and were almost completely absent from tumour areas composed of cortical type epithelium. Hence a medullary microenvironment with epidermoid cells corresponding to Hassall's corpuscules seems to be necessary for specific intrathymic B-cell homing.

Adult↗
PubMed1993

High-affinity substance P binding sites of neurokinin-1 receptor type autoradiographically associated with vascular sinuses and high endothelial venules of human lymphoid tissues.

BACKGROUND: Factors that affect leukocyte-endothelial cell interaction in high endothelial postcapillary venules and vascular sinuses of lymphatic tissues indirectly regulate immune function. Studies in sheep demonstrated that acute infusion of substance P (SP) into cannulated popliteal lymph node afferent lymphathics produced a marked and prolonged increase in the output of lymphocytes into nodal efferent lymph. The proposed mechanism is an influence of SP on lymph vascular systems. Such functional importance of the immunoregulatory properties of SP in man is unknown. EXPERIMENTAL DESIGN: The expression and distribution of SP receptors in human lymphoid tissue was investigated using slide-mounted fresh-frozen sections of lymph node, hyperplastic tonsillitis, and spleen for ligand binding and autoradiographic studies. RESULTS: Specific binding of radiolabeled SP to lymph node and tonsils reached a plateau within approximately 40 minutes, being half-maximal at 20 minutes. The specific binding was between 65 and 75% of total binding. In contrast, iodinated neurokinin A under identical incubation conditions, did not significantly associate with the tissues. Neither the SP nor the neurokinin A tracer specifically associated with spleen. Binding specificity of radiolabeled SP was analyzed in binding competition experiments. Synthetic SP, SP (3-11), a selective neurokinin-1 agonist and a neurokinin-1 antagonist competed with the specific binding of SP to lymph node and tonsil sections. The half-maximal inhibition of binding was obtained at a concentration of about 0.5 nmol/liter of SP. The fragment SP (1-4) and selective neurokinin-2 ligands did not compete with the specific binding of SP. Scatchard and nonlinear algorithm analyses revealed two binding sites for SP. For lymph node and tonsil, one site showed a high affinity of about 0.4 nmol/liter and 0.7 nmol/liter and a low capacity for SP, respectively. The second site exhibited a lower affinity of 100 nmol/liter and 50 nmol/liter and a higher capacity for SP in lymph node and tonsil, respectively. Autoradiographic localization of the binding sites shows a very high concentration of silver grains when compared with controls. The reaction occurred mainly over vascular sinuses and high endothelial venules with heterogenous density. Silver grain accumulation was also noticed over the marginal sinuses of the B cell follicles. CONCLUSIONS: The biochemical results indicate the presence of neurokinin-1 receptors in human lymph node and tonsil. We suggest that the neurokinin-1 receptors localized to vascular tissues of lymph node and tonsil mediate the affects of SP on lymphocyte traffic, and we propose that SP plays a regulatory role in lymphocyte homing in man.

Autoradiography↗
PubMed1992

[B-cells in thymic epithelial tumors: phenotype, distribution and relation to the intramedullary B-cell population of the normal thymus].

Immunohistochemical analysis of 26 thymomas and thymic carcinomas revealed the occurrence of two different intratumoral B-cell populations. High numbers of B-lymphocytes with formation of lymphoid follicles were found in the extra-epithelial perivascular spaces of cortical thymomas and well differentiated thymic carcinomas associated with myasthenia gravis. On the other hand, B-cells within the epithelial meshwork frequently occurred in organoid medullary islands of predominantly cortical and cortical thymomas. In their distribution and phenotype, these cells correspond to the intramedullary B-cell population of the normal thymus, reflecting a specific intratumoral B-cell homing dependent on medullary epithelial differentiation.

Antigens, CD↗
PubMed1991

Phenotype and topography of human thymic B cells. An immunohistologic study.

Using single and double labeling immunohistochemical techniques and a large panel of monoclonal antibodies against B-cell differentiation antigens, including those newly defined at the Fourth International Leucocyte Typing Workshop, we have examined the immunophenotype and tissue distribution of human thymic B-cells. The existence of a distinct B-cell population as a constant constituent of the thymic microenvironment has been noted only recently. We found a significant population of B-lymphocytes in the thymic medulla expressing the B-cell restricted antigens CD19, CD20, CD22, CD37, CD72, CD76 and IgM and IgD. As with other extrafollicular B-lymphocytes, they differ significantly from both follicle mantle and germinal center cells in morphology and immunophenotype, which points to alternative modes of B-cell differentiation. Thymic B-cells themselves show considerable heterogeneity and a subpopulation with dendritic features and the expression of CD23 has been referred to as "asteroid" cells. Their close association with T-cells and medullary epithelial cells points to a functional role for B-cells in the thymus. A second population of B-lymphocytes together with frequent lymph follicles is found within the extrathymic perviascular space. Though separated from the medulla by a layer of epithelial cells, a clear distinction between the B-cells of these two compartments is not always possible. The intramedullary B-cell compartment shows a parallel numeric increase with the occurrence of germinal centers in the perivascular space, mostly due to an accumulation of B-cells in the medulla adjacent to these lymph follicles. Thus a close relationship between the intra- and extramedullary B-cell population of the thymus seems likely.

Adolescent↗