[Megakaryocytic myelosis--clinical aspects, morphology and platelet function]

Helicobacter pylori adheres selectively to Fusobacterium spp

Helicobacter pylori strains ATCC 43504 and ATCC 43629 were tested for their ability to coaggregate with 79 strains of bacteria representing 16 genera. All except two of the strains were of human origin, and most of the strains were isolated from the oral cavity. The helicobacters failed to coaggregate with all strains except the fusobacteria. Several coaggregations were partially or completely inhibited by lactose. Strong coaggregation was seen with each of four subspecies of Fusobacterium nucleatum and with Fusobacterium periodonticum ATCC 33693, all of human dental plaque origin. In contrast, the helicobacters failed to coaggregate with non-plaque isolates, Fusobacterium mortiferum ATCC 25557 and Fusobacterium ulcerans ATCC 49185. Heat treatment of the fusobacteria inactivated their ability to coaggregate, whereas heating of the Helicobacter partners had no effect, suggesting the presence of an adhesin on the fusobacteria and a corresponding receptor on the helicobacters. The potential ability of H. pylori to colonize the oral cavity by adhering selectively to the ubiquitous fusobacteria gives credence to the possibility that dental plaque may serve as a reservoir for this pathogen outside of the stomach.

Should a platelet limit of 600 x 10(9)/l be used as a diagnostic criterion in essential thrombocythaemia? An analysis of the natural course including early stages

In order to evaluate the natural history of essential thrombocythaemia (ET), clinical data and prognostic factors of 143 patients with ET were retrospectively analysed (mean observation time 6.1 +/- 4.6 years). In 42 patients the early phase of the disease with initial platelet counts between 250 and 600 x 10(9)/l was assessed. In most early cases, ET was suggested by clinical symptoms (79%) and increased megakaryopoiesis (95%) with abnormal megakaryocytes in bone marrow histology (n = 34) and cytology (n = 5). Other myeloproliferative disorders and reactive thrombocytosis were excluded according to the diagnostic criteria of the Polycythemia Vera Study Group. During follow-up of the 38 early cases not treated cytoreductively at diagnosis, the platelet counts increased to >600 x 10(9)/l in 28 patients (74%) and remained between 450 and 600 x 10(9)/l in 10 patients (26%). In primarily asymptomatic patients (n = 46) with initial platelet counts above (n = 37) and below 600 x 10(9)/l (n = 9) the rates of increase of symptomatic patients were similar at about 7% per year. No influence of the initial platelet count on survival was seen in multivariate analysis of prognostic factors which included all 143 cases. Survival was mainly influenced by the rate of ET-related complications during follow-up (P = 0.002). Analysing the influence of cytoreductive therapy on symptom-free survival, platelet reduction benefited patients under 60 years (19 cytoreductively treated v 65 untreated patients, P = 0.075). The results demonstrate the possible clinical relevance of the early stages of ET and suggest that the features of pathologic megakaryopoiesis in the bone marrow are a more reliable diagnostic criterion than a definite platelet limit. Therefore, further therapeutic studies should include all stages of the disease and all age groups.