Effects of trypsin digestion on flagellar structures and their relationship to motility.

Flagellar axonemes isolated from sea urchin sperm were digested with trypsin for various time periods. The course of digestion was monitored turbidimetrically and was found to take two different courses depending on the presence or absence of ATP in the digestion mixture. It was found that ATP induced active disintegration of the axonemes after slight digestion. Samples of the digested axonemes were examined with the electron microscope to determine the effects of trypsin digestion on the substructures of the axonemes. The rate at which trypsin sensitized the axonemes to ATP paralleled the rate at which it damaged the radial spokes and the nexin links, while the dynein arms were removed much more slowly. The results suggest that inactive dynein arms form cross bridges between the adjacent doublet tubules in digested axonemes, and that when activated by the addition of ATP, they induce an active shearing force between adjacent doublets. The radial spokes and the nexin links are not directly involved in the production of mechanical force, but they may participate in regulating the sliding between tubules to produce a propagated bending wave.

Frequency of the Bcl-2/IgH rearrangement in normal individuals: implications for the monitoring of disease in patients with follicular lymphoma.

PURPOSE: To determine the incidence and frequency of the Bcl-2/IgH rearrangement in the peripheral blood of normal individuals to define the potential complication this may pose for the molecular monitoring of disease in patients with follicular lymphoma (FL). MATERIALS AND METHODS: The incidence and frequency of the major breakpoint cluster region rearrangement in DNA extracted from peripheral blood or lymphoblastoid cell lines from 481 normal individuals was determined using a TaqMan real-time polymerase chain reaction assay (PE Applied Biosystems, Foster City, CA). RESULTS: Twenty three percent of samples were positive for the Bcl-2/IgH rearrangement, with approximately 3% of these at levels of more than 1 in 10(4) cells. CONCLUSION: The presence of circulating Bcl-2/IgH+ cells, other than those derived from the malignant clone, could confound the detection and quantitation of minimal residual disease in patients with FL, particularly at low levels of tumor burden.

High-dose therapy with autologous bone marrow support as consolidation of remission in follicular lymphoma: long-term clinical and molecular follow-up.

PURPOSE: To evaluate the long-term results of high-dose therapy (HDT) in follicular lymphoma, with specific emphasis on the prognostic significance of polymerase chain reaction (PCR)-detectable Bcl-2/IgH rearrangements. PATIENTS AND METHODS: Between June 1985 and October 1995, 99 patients with follicular lymphoma received HDT as consolidation of second or subsequent remission. Bone marrow was treated in vitro with anti-B-cell antibodies and complement. RESULTS: Sixty-five patients remained alive, 49 treatment-failure free, with a median follow-up of 5.5 years (range, 1.5 to 12.5 years). Four "early" and 10 "late" deaths occurred from treatment-related causes; seven of the latter were due to secondary myelodysplasia (s-MDS) or secondary acute myeloblastic leukemia. Overall, 12 (12%) of the 99 patients developed s-MDS or acute myeloblastic leukemia. Kaplan-Meier estimates of freedom from recurrence (FFR) and survival rates at 5 years were 63% (95% confidence interval [CI], 52% to 72%) and 69% (95% CI, 58% to 78%), respectively. For all 99 patients, in multivariate analysis, absence of the Bcl-2/IgH rearrangement at the time of diagnosis (hazards ratio [HR], 0.39; P =.04) and three or fewer treatment episodes before HDT (HR, 0.03; P =.001) were significant prognostic factors for improved survival. For patients bearing Bcl-2/IgH rearrangements, in univariate and multivariate analyses, absence of a PCR-detectable Bcl-2/IgH rearrangement during follow-up was associated with a significantly lower risk of recurrence (adjusted HR, 0.13; P <.001) and death (HR, 0.25; P =.02), whereas the PCR status of the reinfused bone marrow did not correlate with outcome. CONCLUSION: Prolonged FFR can be achieved in patients with follicular lymphoma after HDT, but as yet there is no survival advantage compared with conventional treatment. These results confirm that elimination of cells bearing the Bcl-2/IgH rearrangement is highly desirable and should be attempted. The incidence of s-MDS is of increasing concern in this setting.

Adenosine triphosphate-induced sliding of tubules in trypsin-treated flagella of sea-urchin sperm.

Axonemes isolated from the sperm of the sea urchin, Tripneustes gratilla, were briefly digested with trypsin. The digested axonemes retained their typical structure of a cylinder of nine doublet-tubules surrounding a pair of single tubules. The digestion modified the axonemes so that the subsequent addition of 0.1 mM ATP caused them to disintegrate actively into individual tubules and groups. The nucleotide specificity and divalent-cation requirements of this disintegration reaction paralleled those of flagellar motility, suggesting that the underlying mechanisms were closely related. Observations by dark-field microscopy showed that the disintegration resulted from active sliding between groups of the outer doublet-tubules, together with a tendency for the partially disintegrated axoneme to coil into a helix. Our evidence supports the hypothesis that the propagated bending waves of live-sperm tails are the result of ATP-induced shearing forces between outer tubules which, when resisted by the native structure, lead to localized sliding and generate an active bending moment.