Large B-cell lymphomas: fine-needle aspiration plays an important role in initial diagnosis of cases which are falsely negative by flow cytometry

Large B-cell lymphomas (LBCLs) have significant false-negative results when immunophenotyped by flow cytometry (FC). To clarify the role fine-needle aspiration (FNA) in reducing this false-negative rate, 28 cases ultimately diagnosed as LBCL that had FNA as part of the workup and a negative FC were identified. We examined their clinical and cytologic features, in comparison with cases of LBCL with FNAs that were positive by FC. In 24/28 FC-negative cases (86%) a cytologic diagnosis of suspicious or positive for malignancy was rendered. We conclude that cytologic analysis is more sensitive than FC in the diagnosis of malignancy in FNA of LBCL, particularly in aspirates with low cellularity and/or low viability. Examination of cytospin preparations of the actual material analyzed by FC may provide an indication that an FC result is falsely negative. It is important to recognize the potential of false-negativity by FC of LBCLs when interpreting FNAs with features suggesting lymphoma.     

Comparative genomic hybridization in ganglioneuroblastomas.

The ganglioneuroblastoma are rare lesions with widespread neuronal differentiation that have been classified as intermediate stages between neuroblastoma and ganglioneuroma. To identify overall chromosome aberrations in ganglioneuroblastoma, we performed comparative genomic hybridization. All of the five tumor samples were found to exhibit multiple gains involving different chromosomal regions. Chromosomal gains displayed by chromosomes and chromosome loci were 2p25 approximately pter (60%), 5p15.1 approximately p15.3 (60%), 7 (60%), 13q22 approximately q31 (60%), and 22 (60%), which were detected as minimal common regions in all five tumor samples. Chromosome 22 gain, which had not been reported in neuronal tumors before, and novel site 13q22 approximately q31 may be considered to play an important role in progression and differentiation of ganglioneuroblastoma.     

Differential infiltration by CD45RO and CD45RA subsets of T cells associated with human heart allograft rejection.

Subsets of T cells express different isoforms of the leukocyte common antigen CD45; those expressing the glycoprotein 220 isoform (CD45RA) have been characterized as naive in their response to antigens, and those expressing the glycoprotein 180 isoform (CD45RO) as memory T cells. The association between the rejection status of human cardiac allograft recipients and the relative infiltration of the CD45 subsets of both CD8+ and CD4+ T cells was examined using two-color immunohistological labeling techniques on 33 heart transplant biopsies, categorized by routine histological and clinical criteria as mild (requiring no treatment) or moderate (requiring antirejection therapy) rejection. Double-labeling was performed using pairs of monoclonal antibodies to define the following populations: CD4+ CD45RA+, CD4+ CD45RO+, CD8+ CD45RA+, and CD8+-CD45RO+. The number of cells per high-power field (HPF) for each of these cell subsets was counted in every biopsy. In cases with mild rejection, infiltration was predominant for CD4+ CD45RA+ cells (median = 5.0 cells/HPF) relative to CD4+ CD45RO+ (3.12 cells/HPF), CD8+ CD45RA+ (2.14 cells/HPF), and especially CD8+ CD45RO+ (1.22 cells/HPF) populations. In cases with moderate rejection, all four subpopulations increased but were essentially equivalent in intensity, such that in comparison to cases with mild rejection, the smallest increase was seen for CD4+ CD45RA+ cells (6.67 cells/HPF, P < 0.09) and the greatest for CD8+ CD45RO+ cells (7.00 cells/HPF, P < 0.002). A majority of CD8 cells expressed CD45RA in 14 of 16 (88%) cases of mild rejection compared to only 2 of 17 cases of moderate rejection. Moreover, the ratio of CD45RO+ to CD45RA+ cells in each biopsy was higher in moderate versus mild rejection for both CD4 (median ratios = 1.13 versus 0.68, respectively; P < 0.008) and CD8 (1.43 versus 0.58, respectively; P < 0.005) subsets. A majority of T cells expressed CD45RO in cases of moderate rejection (11 of 14 or 79%), compared to only 1 of 13 (8%) cases of mild rejection. These findings indicate that during generally self-limited mild acute cardiac allograft rejection there is a predominance of naive CD45RA+ T cells, especially of the CD4 phenotype, whereas during moderate rejection there is a significant shift toward activated CD45RO+ T cells, especially in the CD8 population.     

Adherence to and damage of endothelial cells by Cryptococcus neoformans in vitro: role of the capsule.

Escape from the intravascular compartment is likely a critical step in the development of hematogenously disseminated cryptococcal infections, such as meningitis. The capsule of Cryptococcus neoformans is considered to be a virulence factor because of its antiphagocytic properties. To further investigate the role of the capsule in escape from the intravascular compartment, we used isogenic strain pairs, an acapsular mutant, and an encapsulated clinical isolate to determine the effects of the capsule of C. neoformans on adherence to, phagocytosis by, and damage of endothelial cells in vitro. Acapsular C. neoformans adhered significantly more to endothelial cells and caused greater endothelial cell injury than did encapsulated organisms. Coating of an acapsular strain with cryptococcal glucuronoxylomannan decreased both adherence to and damage of endothelial cells by 61.7% +/- 9.1% and 76.6% +/- 10.2%, respectively. Transmission electron microscopy demonstrated internalization of acapsular, but not encapsulated, organisms by endothelial cells. Internalization of an acapsular strain occurred through endothelial cell phagocytosis and was inhibited by cytochalasin D. Phagocytosis required a heat-labile serum factor, probably complement. These results suggest that acapsular or poorly encapsulated C. neoformans may be the form(s) that escapes from the vasculature during initiation of hematogenously disseminated disease.     

Interleukin-1beta increases urine flow rate and inhibits protein expression of Na(+)/K(+)-ATPase in the rat jejunum and kidney.

The effect of interleukin-1beta (IL-1beta) on urine flow rates and Na(+)/K(+)-ATPase activity and expression was studied in rat intestinal and renal epithelia. The cytokine produced a significant diuretic effect and increased urine flow rate by around 10-fold compared with the control. This effect was considered to be secondary to the well-documented natriuretic effect of the cytokine described in the literature. On the other hand, we have shown previously that IL-1beta inhibits glucose absorption from the jejunum. As sodium excretion and glucose absorption are both dependent on Na(+)/K(+)-ATPase activity, the effect of the cytokine on the renal and intestinal pump was investigated. IL-1beta inhibited, in a dose-dependent manner, the activity of Na(+)/K(+)-ATPase in villus and crypt jejunal cells and in medullary and cortical kidney cells. Western blot analysis revealed a decrease in the protein expression of the enzyme, which was confirmed by the radiolabeled ouabain binding assay. The results suggest that the diuretic and natriuretic effect of IL-1beta and its inhibitory effect on glucose absorption are all due to downregulation of the Na(+)/K(+) pump in the kidney and jejunum.     

Observer variation in the histopathological classification of thymoma: correlation with prognosis.

AIMS--To assess the ability of three histopathologists, experienced in thoracic surgical reporting, consistently to classify thymomas as cortical, medullary, or mixed pattern tumours. METHODS--Three histopathologists classified 74 thymomas (none frank carcinomas) as of either cortical, medullary, or mixed pattern, on two separate occasions. Kappa statistics were used to assess inter- and intra-observer agreement. Tumour type was compared with surgical stage as a predictor of biological behaviour. RESULTS--Inter- and intra-observer agreement were only moderate (kappa 0.48 and 0.52, respectively). For only 26 of 74 tumours could a categorisation be consistently agreed on. Follow up information was obtained for 73 cases, with a mean follow up period of five years. The prognoses for those 26 of 74 cases appeared to be at variance from previously reported studies, and showed internal inconsistency, with the mixed pattern category showing a worse survival than the cortical category. For the group as a whole, however, stage at presentation was related to survival, with an overall five year survival of 78% (100% for stage I, 84% for stage II, 27% for stage III and 0% for stage IV). CONCLUSIONS--The classification of thymomas into cortical, medullary, or mixed pattern tumours is difficult to apply. Surgical stage remains a better guide to prognosis.     

Endocrine differentiation of extra-pulmonary small cell carcinoma demonstrated by immunohistochemistry using antibodies to PGP 9.5, neuron-specific enolase and the C-flanking peptide of human pro-bombesin

Several recent studies have confirmed the endocrine nature of small cell carcinoma of the lung. In extra-pulmonary sites, small cell 'undifferentiated' carcinomas have classical morphological features similar to their pulmonary counterpart. We therefore investigated, using immunocytochemistry, the possibility that the non-pulmonary neoplasms may also be endocrine in nature. Sections of 29 small cell carcinomas from oesophagus, stomach, larynx, colon and urinary bladder were immunostained using antisera to protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), cytokeratin, leucocyte common antigen and peptides including bombesin, the C-flanking peptide of human probombesin, adrenocorticotrophic hormone, neurotensin, calcitonin and pancreatic polypeptide. All the tumours showed immunoreactivity for at least one of the two general endocrine markers PGP 9.5 and NSE. Twenty-three of the 29 cases were immunoreactive for PGP 9.5, 27 for NSE. All were positive for cytokeratin and negative for leucocyte common antigen. Of the regulatory peptides, immunoreactivity was obtained with antisera to bombesin (one case), the C-flanking peptide of human pro-bombesin (14 cases), adrenocorticotrophic hormone (one case) and calcitonin (three cases). No PGP 9.5-, NSE- or peptide-like immunoreactivity was detected in 25 control tumours from similar sites, including lymphomas and poorly differentiated tumours. These results suggest that non-pulmonary small cell carcinoma has an endocrine character.     

PCR-amplified 16S and 23S rDNA restriction analysis for the identification of Acinetobacter strains at the DNA group level

The genus Acinetobacter is phenotypically rather homogeneous, but genotypicaliy heterogeneous. In this study, a simple method based on restriction analysis of a PCR-amplrfied large fragment (4.5 kb) of most of the ribosomal operon (16S and 23S ribosomal genes and the spacer in-between) was investigated. Sixty-seven collection strains belonging to the 20 DNA groups proposed until 1993 were studied. Using the enzyme Sau3AI, 25 DNA profiles were obtained. Strains belonging to DNA groups 1, 3, 6, TU13 and TU15 showed two profiles each, and DNA groups 4, 5 and 7 showed profiles with variants showing less intensive additional bands. The remaining 12 groups showed 12 different profiles. The profiles obtained were DNA-group-specific except for one profile which was shared between the unnamed DNA group 3 and a rarely encountered genotypicaliy related DNA group. These two DNA groups could be separated by using the enzyme Hinf1. Twenty-five additional clinical isolates previously characterized by standard DNA-DNA hybridization were selected in a double-blind fashion for identification at the DNA group level to check the reliability of the assay. All strains were correctly identified at the DNA group level. PCR-amplified 16S and 23S rDNA restriction analysis is both an accurate and rapid method for the identification of Acinetobacter at the DNA group level.     

Comparison of immunoblot analysis of emergent multidrug-resistant Salmonella typhimurium definitive phage type 104 with a non-multidrug-resistant definitive phage type 104 strain.

BACKGROUND AND PURPOSE: The emergent multidrug-resistant (MDR) Salmonella typhimurium definitive phage type 104 (DT104) is a public and veterinary health problem not only due to its wide host range and potential for enhanced virulence, but also the difficulty associated with its control. There is thus a need to investigate possible antigens of MDR DT104. METHODS: Using standard protocols, whole cell lysates, outer membrane extracts and cell-free ultracentrifuge supernatants of selected isolates of MDR DT104 were prepared, electrophoretically separated and tested for their antigen-antibody reactivity in comparison with a non-MDR DT104 strain. RESULTS: Protein antigens of both strain types were recognized by antibodies in chick serum in a similar manner for all methods of antigen preparation used. CONCLUSIONS: This study did not find differences between the antibody recognition of MDR DT104 and that of the non-MDR DT104 strain tested. This observation should strengthen the quest for the possible use of vaccines to control this emergent strain in poultry.