Molecular epidemiologic investigation of tuberculosis in an area of increasing incidence in inner-city Dublin.

In 2002 the tuberculosis (TB) incidence in Dublin was 13.1 cases per 100,000 persons. In inner city Dublin, the TB incidence was > 20 per 100,000 persons. TB notification rates have remained elevated. The objective of the study is to characterize the population affected in this inner city area and to investigate transmission patterns and potential risk factors for TB disease. This hospital-based molecular epidemiologic study included all culture positive cases of TB between January 1, 1998 and December 31, 2002 from the Mater Misericordiae University Hospital. 142 cases were analyzed. 84 (59%) had clustered Mycobacterium tuberculosis (Mtb) isolates, 58 (41%) had unique isolates by molecular typing. There were 13 clusters; the largest two clusters had 26 cases each, one linked to pubs, the other linked through family contact. In multivariate logistic regression analysis, birth in Ireland, pulmonary TB, and younger age were significantly associated with recent transmission. Dublin is a developed city with persistent areas of high rates of TB in the native population. Despite a functioning public health system and lack of predisposing risk factors such as HIV, immigration, and extreme poverty, TB can persist in pockets of the younger, native population.

BCL-6 and other genomic alterations in non-Hodgkin's lymphoma (NHL).

This study reports on the frequency and disease association pattern of a number of gene rearrangements in a large panel of lymphoid tumours (n = 94). We detected the t(11;14) translocation, involving rearrangement of the BCL-1 locus, in 60% of mantle cell lymphomas. The BCL-2 gene, located at band 18q21, was rearranged in 42% of follicle centre lymphomas (FCL) and in 15% of diffuse large B-cell (DLBC) lymphomas. In this study, 80% of the c-MYC rearrangements were detected in aggressive diffuse lymphoma subsets but, interestingly, 9% of FCL showed involvement of t(8q24) translocation. In our study, rearrangements of the BCL-6 gene at band 3q27 were found in 31% of DLBC lymphomas. Interestingly, 50% of the BCL-6 rearrangement positive lymphoma cases had coexisting gene rearrangements involving all of the aforementioned gene loci. The molecular dissection of these genes will improve our understanding of the genesis of the diverse clinicopathological subtypes.

Amplification of the MDM2 gene in human breast cancer and its association with MDM2 and p53 protein status.

The present study reports on the frequency of MDM2 gene amplification and MDM2 protein expression in a series of 100 breast carcinomas and its association with accumulation of the p53 protein. Of the 100 cases, frozen samples for 82 cases were available for Southern blotting. Three of the 82 (4%) demonstrated MDM2 gene amplification of up to 6-fold. Immunohistochemical analysis of the formalin-fixed, paraffin-embedded tumours demonstrated that 7/97 (7%) had nuclear expression for MDM2 in 10-50% of the tumour cells (type 2 staining) and were denoted MDM2+. Two of the MDM2-amplified samples were MDM2+ with one of the two tumours also displaying type 2 p53 nuclear staining. Finally at the protein level, MDM2+ tumours were significantly associated with tumours having low levels of p53 staining (0-10% cells positive) (P = 0.03). We conclude that MDM2 gene amplification occurs at a lower frequency in breast cancer than in non-epithelial tumours. Alterations in MDM2 and p53 may represent alternative pathways in tumorigenesis, but they are not mutually exclusive in all cases.

Bcl-2 rearrangement in Hodgkin's disease and reactive lymph nodes.

The chromosomal translocation t(14;18)(q32;q21), which involves the bcl-2 oncogene, occurs in most follicular lymphomas. Recent evidence suggests that this translocation occurs in Hodgkin's disease, linking its cellular origin and oncogenesis to follicular non-Hodgkin's lymphomas. Using polymerase chain reaction, the authors examined both Hodgkin's disease (n = 60) and reactive lymph nodes (n = 34) for the presence of bcl-2/JH breakpoint fragments, which are indicative of the t(14;18) chromosomal translocation in the major breakpoint region of the bcl-2 gene. The translocation was detected in approximately 10% of both Hodgkin's disease and nonmalignant reactive lymph node cases. These results suggest the possibility that the translocation may occur in the reactive component of Hodgkin's disease and not in the putative malignant cells, the Reed-Sternberg cells. Furthermore, the detection of the translocation in reactive lymph nodes suggests that it may not be the primary factor in the oncogenesis of follicular lymphoma.

Localized, late-onset, high-grade lymphoma following bone marrow transplantation: response to combination chemotherapy.

Non-Hodgkin's lymphoma is the commonest secondary cancer following bone marrow transplantation (BMT). We report the case of a 42-year-old man who developed a laryngeal high-grade B-cell lymphoma 5 years following a matched T depleted BMT for CML. Polymerase chain reaction (PCR) analysis using the microsatellite marker Cyp 19 demonstrated the donor origin of involved tissue. Epstein-Barr virus (EBV) genomic sequences were identified by PCR. Although EBV related B-cell lymphoproliferative disorders (BLPD) post BMT are difficult to treat, there was a complete remission in this patient following three courses of chemotherapy (CHOP) administered with G-CSF. This case of late-onset BLPD appears clinically distinct from the well-defined, aggressive, early post-transplant BLPD.

Comparable prognostic factors and survival in elderly patients with aggressive non-Hodgkin's lymphoma treated with standard-dose adriamycin-based regimens.

We retrospectively analysed the prognostic factors at diagnosis, clinical response, and survival of 192 patients with newly diagnosed aggressive NHL treated in a single institution between 1985 and 1991. Overall, 37.5% (72/192) of patients were 65 years or older (average age 71 years, range 65-85 years), and 62.5% (120/192) were under 65 years of age (average age 45, range 16-64 years). All patients were completely staged and had intermediate- or high-grade NHL. 127 patients were treated on similar regimens with the same chemotherapy dose intensity irrespective of age. Standard-dose m-BACOD (methotrexate, bleomycin, Adriamycin, cyclophosphamide, vincristine, prednisone) or CHOP were used to treat 60/72 (83%) elderly patients and 67/120 (56%) patients less than 65 years. The remaining younger patients were treated with more intensive regimens. There were no significant differences between the groups with regard to stage, histological grade, cell type, elevated LDH, number of extranodal sites, presence of B symptoms, or bulky disease. More elderly patients had a significantly (p < 0.02) poorer performance status (PS), with 42% (25/60) having a PS of 2 or more, compared to 22% (15/67) in those less than 65 years of age. Elderly patients had an inferior complete response rate, 65% versus 76%. However, overall response rates of 95% and 92% were similar. The disease-free survival at 3 years for complete responders in elderly patients was 74% compared to 82% in those under 65. The comparable 3-year overall survival was 59% and 62%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The detection of specific gene rearrangements in non-Hodgkin's lymphoma using the polymerase chain reaction.

Characteristic gene rearrangements are present in most non-Hodgkin's lymphomas (NHL). These are usually detected by Southern blotting techniques. In this study, the ability of the polymerase chain reaction (PCR) to detect the t(14;18) chromosomal translocation and immunoglobulin heavy chain (IgH) gene rearrangement was evaluated. DNA from 14 follicular and 42 diffuse B-cell lymphomas was examined using oligonucleotide primers specific for opposing sides of the IgH gene rearrangement on chromosome 14 (towards conserved VH and JH sequences) and opposing sides of the t(14;18) chromosomal translocation (towards the major breakpoint region of the bcl-2 gene on chromosome 18 and conserved JH sequence on chromosome 14). The t(14;18) translocation was detected in 57% of follicular lymphomas and 21% of diffuse B-cell lymphomas. Clonal IgH gene rearrangements using PCR were detected in 50% follicular and 52% of the diffuse lymphomas. Either or both of these rearrangements were detected in 93% follicular and in 59% of diffuse lymphomas. PCR is a rapid and easy technique that can detect the abnormal rearrangement of the bcl-2 gene and clonal IgH rearrangement, indicating the presence of lymphoma. This may be of benefit in monitoring response to therapy and in predicting prognosis in this disease.

The binding of endogenous and exogenous substance-P in human plasma.

High levels of substance-P are present in the plasma of patients with carcinoid tumours and some thyrotoxic conditions. The majority of the substance-P in the blood plasma was shown, by immunoassay, to be associated with high molecular-weight material in a complex that could be dissociated by repeated gel-filtration. Smaller amounts of an intermediate molecular-weight (about 65,000 Da) complex were also detected. Chemical crosslinking with glutaraldehyde was used to show that the radioactively-labelled derivative [125I]Tyr-8-substance-P was able to bind to the high-Mr fraction of human plasma and also to human serum albumin. Binding to serum albumin was also demonstrated by equilibrium gel-filtration. Substance-P added to human plasma from a thyrotoxic subject, which contained high endogenous levels of the tachykinin (980 pg/mL), was rapidly degraded during incubation at 37 degrees, whereas the endogenous substance-P was considerably more stable. These results suggest that the binding of substance-P to blood plasma components may play an important role in protecting it against degradation. Furthermore, immunoassay techniques involving prior extraction, which fail to detect the bound substance-P, will give inaccurate measurements of the levels of this peptide in plasma.

Substance P in the blood plasma in hypophysial portal vessels.

The aim of the present study was to check if Substance P (SP) is released from the hypothalamus into the hypophysial portal vessels and by this route exerts its direct influence on the adenohypophysis. For this purpose SP radioimmunoactivity was assayed in the blood plasma collected from hypophysial portal vessels and from the cephalic end of the external jugular vein. The SP levels in blood plasma collected from hypophysial portal vessels and from the jugular vein do not differ significantly. Neither does application of a noxious factor, such as bilateral femoral bone fracture, change significantly the SP level in the blood plasma from portal vessels and from the jugular vein. Hypoxia seems to increase the SP level in portal blood plasma and may be followed by its decrease. It is concluded that hypothalamic SP is not released into the hypophysial portal vessels under normal conditions and its direct influence on the adenohypophysis is not mediated this way.