Preparation of Polymer-Clay Nanocomposites by Melt Mixing in a Twin Screw Extruder: Using On-Line SAOS Rheometry to Assess the Level of Dispersion

A prototype on-line rotational rheometer was fixed between a twin screw extruder and a multi-rod die of an industrial pelletization line used for the manufacture of polymer-clay nanocomposites. After diverting the required amount of melt to the device, measurements were performed in small amplitude oscillatory shear and used to estimate the level of dispersion of the organoclay in the polypropylene matrix, by means of correlations that are commonly utilized. The aim is to determine whether changes in clay type, clay content, feed rate and screw speed cause detectable alterations in the rheological response and thus in the level of dispersion, with a view to practical process monitoring and control. The analysis of the data is supported by XRD and electron (scanning and transmission) microscopy observations.

Invasive cervical cancer and human immunodeficiency virus (HIV) infection in KwaZulu-Natal, South Africa

The human immunodeficiency virus (HIV) can be expected to influence the course of disease and response to treatment of invasive carcinoma of the cervix. The extent and nature of this influence, however remains largely unknown. We therefore undertook a retrospective analysis of patients with carcinoma of the cervix at a tertiary referral centre in an African setting where HIV prevalence is high. There were 271 patients seen during a period of 1 year. Of these, 45 of the 206 tested were HIV infected (21.8%). The corresponding HIV prevalence for antenatal attendees was 38.7% in the region. The HIV-infected patients had lower mean haemoglobin levels and body mass indices than the HIV-non-infected women and were on average 13 years younger (p < 0.001), but otherwise did not differ with respect to demographics or disease parameters. They were, however, less likely to complete planned treatment. CD4 counts were below 200 in only 6 (21%) of 29 women tested. HIV-infected women in the African setting present with carcinoma of the cervix at a younger age, but the same disease stage as HIV-non-infected women, and without evidence of advanced immunocompromise. Circumstantial evidence is put forward by the study to suggest a more rapid decline in health and earlier demise for HIV-infected women with carcinoma of the cervix.

Identification of four new translocations involving FGFR1 in myeloid disorders

The 8p11 myeloproliferative syndrome (EMS) is associated with three translocations, t(8;13)(p11;q12), t(8;9)(p11;q33), and t(6;8)(q27;p11), that fuse unrelated genes (ZNF198, CEP110, and FOP, respectively) to the entire tyrosine kinase domain of FGFR1. In all cases thus far examined (n = 10), the t(8;13) results in an identical mRNA fusion between ZNF198 exon 17 and FGFR1 exon 9. To determine if consistent fusions are also seen in the variant translocations, we performed RT-PCR on four cases and sequenced the products. For two patients with a t(8;9), we found that CEP110 exon 15 was fused to FGFR1 exon 9. For two patients with a t(6;8), we found that FOP exon 5 (n = 1) or exon 7 (n = 1) was fused to FGFR1 exon 9. To determine if FGFR1 might be involved in other myeloid disorders with translocations of 8p, we developed a two-color FISH assay using two differentially labeled PAC clones that flank FGFR1. Disruption of this gene was indicated in a patient with a t(8;17)(p11;q25) and Ph-negative chronic myeloid leukemia in association with systemic malignant mast cell disease, a patient with acute myeloid leukemia with a t(8;11)(p11;p15), and two cases with T-cell lymphoma, myeloproliferative disorder, and marrow eosinophilia with a t(8;12)(p11;q15) and ins(12;8)(p11;p11p21), respectively. For the patient with the t(8;11), the chromosome 11 breakpoint was determined to be in the vicinity of NUP98. We conclude that 1) all mRNA fusions in EMS result in splicing to FGFR1 exon 9 but breakpoints in FOP are variable, 2) two-color FISH can identify patients with EMS, and 3) the t(8;17)(p11;q25), t(8;11)(p11;p15), t(8;12)(p11;q15), and ins(12;8)(p11;p11p21) are novel karyotypic changes that most likely involve FGFR1.

Structural abnormalities of chromosome 7q in chronic lymphoproliferative disorders

Structural abnormalities of 7q are common in myeloid malignancies but rarely reported in chronic lymphoproliferative disorders. 7q abnormalities were found in 29 of 796 patients (3.6%) with chronic lymphoid malignancies. The most common association was found in splenic lymphoma with villous lymphocytes (SLVL) in which 8 of 31 cases (26%) has one or more abnormalities of 7q. The most common abnormalities were deletions involving 7q32 and deletions or translocation of 7q22. There was no correlation between the type of lymphoid disorder or clinical course and specific structural abnormalities. We postulate that genes important in the pathogenesis of SLVL may reside on 7q22 and/or 7q32.

Molecular definition of a narrow interval at 7q22.1 associated with myelodysplasia

Chromosome 7 translocations, deletions, or monosomy are associated with myelodysplasia (MDS) and acute myeloid leukemia both in children and adults. These chromosomal anomalies represent one of the most common cytogenetic abnormalities associated with these diseases and usually herald a poor prognosis. In this study two cosmid DNA probes that mapped to 7q22.1 and were known to be separated by approximately 500 kb were identified to flank the proximal inversion breakpoint in a patient carrying a constitutional inversion (7q22.1-34) associated with MDS. A yeast artificial chromosome (YAC) clone that encompassed the two cosmids was identified and shown to span the breakpoint. Fluorescence in situ hybridization was then used to analyze six additional patients with myelodysplasia and chromosomal rearrangements of the 7q22 region (three patients had translocations and three carried deletions). The breakpoint in one of the patients was found to be contained within the same YAC clone that spanned the inversion breakpoint. Moreover, this same interval was determined to be absent in all three patients with chromosomal deletions. These results suggest that this segment of DNA on chromosome 7q22.1 may contain specific gene(s) that have a significant role in myeloid malignancies.

Trisomy 12 and structural abnormalities of 13q14 occurring in the same clone in chronic lymphocytic leukaemia

Trisomy 12 and deletions or translocations of 13q14 are the commonest cytogenetic abnormalities in chronic lymphocytic leukaemia but rarely co-exist in the same patient. We describe eight patients from a series of > 400 patients with CLL in whom trisomy 12 and t or del 13 occur in the same clone. Using FISH we have identified clones with trisomy 12 alone, t or del 13q14 alone and both abnormalities, in each of the patients studied. This implies that neither trisomy 12 nor t or del 13q14 is the initiating event in leukaemogenesis, but does not exclude the possibility of a submicroscopic abnormality of 13q14 occurring as an early event.

Karyotypic evolution in a granulocytic sarcoma developing in a myeloproliferative disorder with a novel (3;4) translocation

A 59-year-old man presented with a granulocytic sarcoma arising in the manubrium, and splenomegaly. The blood count showed 1.2 x 10(9)/l eosinophils and a marrow aspirate was hypercellular with eosinophilia. Cytogenetic analysis of the marrow revealed a novel t(3;4) (p13;q12) and analysis of cells aspirated from the granulocytic sarcoma showed the same abnormality and an additional trisomy 8. Intensive chemotherapy and local radiotherapy led to resolution of the chest mass but persistence of the chromosome translocation in the marrow.

Chromosome abnormalities in hairy cell leukaemia variant

We describe chromosome abnormalities in 6 patients with hairy cell leukaemia (HCL) variant, a rare B-cell disorder with clinical and laboratory features intermediate between HCL and B-prolymphocytic leukaemia (B-PLL). All but one had marked splenomegaly and a raised white blood cell count (median 40 x 10(9)/l) with over 80% nucleolated hairy cells. These cells had a B-cell immunophenotype distinct from that of typical HCL. All patients but one are alive with stable disease with a median follow-up of 60 months. Numerical chromosome changes included loss of chromosomes 2, 3, 4, 6, 10, 19, 21, and X. three cases had translocations involving the immunoglobulin gene regions: t(14;17)(q32;q11), t(14;22)(q32;q11), and t(2;8)(p11.12;q24). Immunocytochemistry demonstrated the presence of the MYC protein in cells from the case with t(2;8) but not in two others. Other structural abnormalities included t(3;10)(q27;q22) and t(3;12)(q27;q13) in the same patient, der(17)t(7;10;17)(p11;q27;q22), t(1;3)(q25;p21), t(8;21)(p12;q11), t(17;21)(p11;p11), del(6)(q15), del(7)(q34), and del(14)(q24).

BCL2 translocations in leukemias of mature B cells

Although translocations of the BCL2 gene are frequent in B-cell non-Hodgkin's lymphomas (B-NHL) the incidence, nature, and prognostic significance of similar translocations in the phenotypically related chronic leukemias of mature B cells are unknown. Therefore, we examined 170 cases of B-cell chronic lymphocytic leukemia (B-CLL), 7 cases of B-cell prolymphocytic leukemia (B-PLL), 25 cases of hairy cell leukemia (HCL) and 22 cases of splenic lymphoma with villous lymphocytes (SLVL) with defined cytogenetic abnormalities by DNA blot using both 5' and 3' BCL2 probes to search for rearrangement of the BCL2 locus. Translocation t(14;18) (q32.3;q21.3) was detected cytogenetically in 3 cases of B-CLL. All had breakpoints in the 3' region of BCL2, mapping between the major breakpoint region (MBR) and the minor cluster region (mcr), the breakpoint clusters commonly detected in B-NHL. In 2 of the 3 cases, the breakpoint within BCL2 was mapped to a 1.0-kb EcoRI-HindIII fragment indicating a clustering of breakpoints. Two cases of B-CLL had cytogenetically detectable t(2;18)(p11;q21.3) or t(18;22)(q21.3;q11). Both had rearranged the 5' region of the BCL2 gene to the corresponding lg light-chain gene. Molecular cloning of the t(18;22)(q21.3;q11) showed that the translocation disrupted the BCL2 promoter region and the first untranslated BCL2 exon. Nevertheless, high levels of BCL2 protein were seen in this case. Only 2 other cases in whom cytogenetic analysis was not successful showed rearrangement of the 5' region of BCL2, an overall incidence of 2.3%. No cases of B-PLL, HCL, or SLVL showed either 5' or 3' BCL2 rearrangement. These data confirm the cytogenetic observations that translocations involving the BCL2 locus in all forms of leukemia of mature B cells are rare, and limited to a minor subset of B-CLL. BCL2 translocations in B-CLL involve hot spots of recombination of both the 5' and 3' regions of the BCL2 gene, which are distinct from those commonly seen in B-NHL, suggesting distinct pathogenic mechanisms.

Use of a retinoblastoma gene probe to investigate clonality in Richter's syndrome

A 69-year-old woman presented with Rai stage 0 chronic lymphocytic leukemia. Ten years later she developed a diffuse centroblastic lymphoma involving the stomach. The surface membrane phenotype of the CLL cells was MD lambda while that of the large cell lymphoma (LCL) cells was MD kappa. The two populations had different heavy and kappa light chain rearrangements. Cytogenetic analysis of the CLL cells showed a deletion involving chromosome 13, band q14, but was unsuccessful in the LCL cells. However, use of a probe (p68 RS2.0) which recognizes a variable number tandem repeat sequence in the retinoblastoma gene, localized to chromosome 13q14, showed two alleles in the LCL cells but only one in the CLL cells. These data suggest that in this case of Richter's syndrome the CLL cells and the LCL cells are clonally distinct.

Cytogenetic studies in splenic lymphoma with villous lymphocytes

We report the cytogenetic findings on 31 cases of splenic lymphoma with villous lymphocytes (SLVL). TPA stimulated cells from peripheral blood (28 cases), spleen (two cases) and lymph node (one case) with SLVL have been analysed. A clonal chromosome abnormality was found in 27/31 patients (87%); this was identified as a simple abnormality in 12 cases and a complex one in 15. Four recurring abnormalities were seen: t(11;14)(q13;q32) in five patients, deletions or translocations involving 7q in seven patients, iso 17q in four patients and translocations involving 2p11 in four patients. The high frequency of clonal chromosome abnormalities in SLVL contrasts with the usually benign clinical course of this disease. Abnormalities found frequently in patients with chronic lymphocytic leukaemia (CLL) such as trisomy 12 and deletions or translocations involving 13q14 were each seen in only one patient. No case had the t(14;18) characteristic of follicular lymphoma. Our findings demonstrate the high frequency of clonal and often complex chromosome abnormalities in SLVL. Although a unique chromosome rearrangement has not been identified, a pattern of four recurrent abnormalities has emerged. Our results suggest that SLVL is distinct on cytogenetic grounds from B-CLL and follicular lymphoma but shows similarity with mantle cell lymphoma, lymphoplasmacytic lymphoma and B-PLL.

Molecular and cytogenetic analysis of a familial microdeletion of Xq

Cytogenetic analysis of a male infant referred for poor neurological development and failure to thrive showed a microdeletion of the X chromosome, his karyotype being 46,Y,del(X)(pter----q21.1:: q21.2----qter). His mother and grandmother were also found to carry the deletion. DNA probes were used to define the deletion molecularly and it was shown to span intervals 2 to 6 of Cremers et al, a portion of Xq that contains the TCD gene and genes whose absence is associated with deafness and mental retardation. RFLP analysis together with X inactivation studies using the probe M27 beta verified the carrier status of the female relatives and showed non-random X inactivation in the heterozygous females.

Rearrangements involving four chromosomes in a child with congenital abnormalities

This report describes a complex structural rearrangement between chromosomes X and 1 and a 7;13 translocation (together involving six break points) in a child with multiple congenital defects. Both parents showed a normal chromosome complement, suggesting that the changes may have originated either in a gametic nucleus or at a very early stage of zygotic development.

Two cases of trisomy 21 and one XXY case with atypical clinical features

Three patients with mental retardation and multiple congenital abnormalities are described. Although their clinical appearance was not suggestive of Down's syndrome, chromosome studies showed a non-disjunctional trisomy 21 in two of the patients. The third case had an unsuspected XXY karyotype.

Trisomy 9 associated with an enlarged 9qh segment in a liveborn

This report describes the third case of a complete trisomy 9 in a liveborn infant. A tentative explanation for the origin of a "very large" h-segment which was not present in either parent of the proposita is put forward.