Structural abnormalities of the X chromosome in non-Hodgkin's lymphoma

It has recently been reported that additional X chromosomes occur in over 30% of B-cell non-Hodgkin's lymphomas (NHL), and that monosomy of the X chromosome occurs in 38% of female patients with T-cell leukaemia or lymphoma. These observations have suggested a possible role for the X chromosome in the evolution of NHL. We have now examined 280 cases of NHL, and have identified 19 examples of structurally altered X chromosomes in the malignant cells from 17 of these cases. These abnormalities were mainly characterized by either a translocation involving Xp22, or a translocation/deletion involving Xq28. The relevance of these observations is discussed with respect to other published reports, and together they suggest that lymphoma-associated oncogenes may exist on the X chromosome at bands p22 or q28.     

Molecular genetic evidence for the conversion hypothesis of the origin of malignant mixed müllerian tumours

The origin of malignant mixed Müllerian tumours (MMMTs) has long been debated, due to the indefinite relationship between epithelial and mesenchymal malignant cells. In order to obtain insight into the clonal relationship between the two components of these tumours, molecular genetic changes were investigated at the level of loss of heterozygosity (LOH) in both cells types. LOH was studied in a series of six cases with 74 polymorphic microsatellite markers mapping to 19 different chromosomes. The epithelial and the mesenchymal neoplastic cells were separately microdissected from formalin-fixed, paraffin-embedded tissue, prior to DNA isolation. LOH was observed for 35 different markers mapping to chromosomes 3, 6, 8, 11, 15, 16, 17, 18, 21, and X. The most frequently involved chromosomes were 17p, 17q, 11q, 15q, and 21q. LOH was observed in five out of six cases and identical alleles were lost in the epithelial and in the mesenchymal cells. No genetic differences were observed between the two cell types for any of the informative markers. Immunohistochemistry (IHC) and TP53 mutation analysis revealed involvement of TP53 in all cases. Mutations were identified in five MMMTs. In four tumours, of which three had a missense mutation, strong nuclear staining for p53 was observed. In the remaining two cases, the mutation resulted in a stop codon, with no nuclear staining for p53 by IHC. The results support a monoclonal origin of MMMTs, with the absence of genetic changes uniquely associated with either of the phenotypes. The latter finding is compatible with current opinion that these neoplasms should be considered as metaplastic carcinomas and supports the conversion hypothesis.     

Effects of increasing doses of alpha-tocopherol in providing protection of low-density lipoprotein from oxidation

Taking for granted the sensitivity of the Quantitative Buffy Coat (QBC) system, as documented in a murine experimental model, we assayed to detect Trypanosoma cruzi in the peripheral blood of 100 patients with Chagas disease in its chronic phase. By means of the method, no positivity occurred, evently as a consequence of small parasitemias, undetectable by this technique as assessed by the cases in consideration.     

Complications of surgery for epiretinal membranes

PURPOSE: Surgery has been successful in removing epiretinal membranes (ERM) from the macula, allowing some improvement in vision in 80-90% of patients; however, complications are relatively frequent. We conducted a retrospective study to evaluate the rate of peri- and postoperative complications and their influence on functional outcome of eyes having been operated on for ERM. MATERIAL AND METHODS: Preoperative findings, intraoperative and postoperative complications as final results of 70 consecutive cases of idiopathic or secondary ERM operated on by the same retina surgeon were analyzed. RESULTS: In all cases the ERMs were successfully removed from the fovea. The mean visual acuity (VA) increased from 0.34 +/- 0.2 to 0.54 +/- 0.31 (P < 0.05) postoperatively. Idiopathic and secondary ERM both showed significant improvement after surgery. Complications included intraoperative hemorrhage and retinal tears and postoperative progressive nuclear sclerosis, retinal tears causing detachments, macular edema and retinal pigmentary epitheliopathy. Final VA was not significantly different from the mean after complications, apart from when retinal detachments involved the macular area. CONCLUSIONS: Performing surgery for ERM is worthwhile in eyes with major decreased VA and in eyes with metamorphopsia but only moderately reduced vision. Postoperative complications are frequent but can usually be managed successfully. Of them, only retinal detachment has a negative effect on the final functional outcome.     

Interleukin-6 and small intestinal luminal immunoglobulins

Our aim was to determine the relationships between interleukin-6 and immunoglobulin levels within small intestinal luminal secretions. Twenty adult subjects with small intestinal bacterial overgrowth (N = 13), irritable bowel syndrome (N = 4), and nonulcer dyspepsia (N = 3) underwent endoscopic aspiration of secretions from the small intestinal mucosal surface for assessment of IL-6, IgA1, IgA2, IgM, IgG1, IgG2, IgG3, and IgG4 concentrations. Serum immunoglobulin concentrations and small intestinal histology were also determined. IgA2 and IgG3 were the predominant IgA and IgG subclasses in luminal secretions in 19/20 (95%) and 20/20 (100%) subjects, respectively. IgA1 and IgG1 predominated in serum in all subjects. No subject had villous atrophy. Luminal IL-6 concentrations correlated significantly with luminal IgA2, IgM, and IgG3 concentrations but not with IgA1 or any other IgG subclass levels. Conversely, luminal IL-6 or immunoglobulin concentrations did not correlate significantly with levels of any immunoglobulin isotype in serum. These observations suggest that important relationships exist between local IL-6 and IgA2, IgM, and IgG3 responses in human small intestinal luminal secretions. Local investigation is mandatory when assessing intestinal immune activity.     

Inhibition of repetitive thrombus formation in the stenosed canine coronary artery by enoxaparin, but not by unfractionated heparin

Experiments were designed to compare the antithrombotic efficacy of enoxaparin and unfractionated heparin (UH) in a model of platelet-dependent cyclic flow reductions (CFRs) in the stenosed canine circumflex coronary artery. Low-molecular-weight heparins (LMWHs) are safe and effective in the prevention and treatment of venous thromboembolism. The present experiments were designed to evaluate the potential use of LMWHs in arterial thrombotic indications by comparing the antithrombotic effect of an LMWH with that of UH in an animal model of unstable angina. After establishment of consistent CFRs by experimentally induced vascular stenosis and damage, vehicle (saline), enoxaparin, or UH was administered intravenously as a loading dose plus a continuous infusion for 1 hour. The inhibition of CFRs was taken as an indicator of antithrombotic efficacy. Enoxaparin inhibited repetitive platelet thrombus formation in a dose-dependent manner, with significant inhibition of CFRs achieved at 0.5 mg/kg + 5 microg/kg per minute. This dose of enoxaparin resulted in anti-Xa levels of 0.9 to 1.0 IU/mL, anti-IIa levels of 0.2 to 0.3 IU/mL, activated partial thromboplastin time (APTT) of 1.3-fold over baseline, and a 1.4-fold increase (NS) in template bleeding time. Near-complete abolishment of CFRs was achieved with enoxaparin at 1.0 mg/kg + 10 microg/kg per minute. This dose of enoxaparin produced anti-Xa levels of 2 to 2.2 IU/mL, anti-IIa levels of 0.5 to 0.6 IU/mL, an increase in APTT of 1.4- to 1.5-fold over baseline, and a 1.9-fold increase (P<0.05) in template bleeding time. In contrast, UH had no significant effect on CFRs at a dose (100 U/kg + 10 U/kg per minute) that resulted in anti-Xa levels of 1.2 to 1.6 IU/mL, anti-IIa levels of 1.8 to 2.4 IU/mL, an increase in APTT greater than 10-fold over baseline, and a 2.5-fold increase (P<0.05) in template bleeding time. Compared with the vehicle group, circulating platelet count and hematocrit were not changed significantly by any dose of enoxaparin or UH tested. Enoxaparin, unlike UH, prevented repetitive platelet-dependent thrombus formation in the dog, thereby supporting the potential use of enoxaparin as a replacement for heparin in the treatment of arterial thrombotic disorders such as unstable angina.     

Cell-contact-stimulated formation of filamentous appendages by Salmonella typhimurium does not depend on the type III secretion system encoded by Salmonella pathogenicity island 1

The formation of filamentous appendages on Salmonella typhimurium has been implicated in the triggering of bacterial entry into host cells (C. C. Ginocchio, S. B. Olmsted, C. L. Wells, and J. E. Galán, Cell 76:717-724, 1994). We have examined the roles of cell contact and Salmonella pathogenicity island 1 (SPI1) in appendage formation by comparing the surface morphologies of a panel of S. typhimurium strains adherent to tissue culture inserts, to cultured epithelial cell lines, and to murine intestine. Scanning electron microscopy revealed short filamentous appendages 30 to 50 nm in diameter and up to 300 nm in length on many wild-type S. typhimurium bacteria adhering to both cultured epithelial cells and to murine Peyer's patch follicle-associated epithelia. Wild-type S. typhimurium adhering to cell-free culture inserts lacked these filamentous appendages but sometimes exhibited very short appendages which might represent a rudimentary form of the cell contact-stimulated filamentous appendages. Invasion-deficient S. typhimurium strains carrying mutations in components of SPI1 (invA, invG, sspC, and prgH) exhibited filamentous appendages similar to those on wild-type S. typhimurium when adhering to epithelial cells, demonstrating that formation of these appendages is not itself sufficient to trigger bacterial invasion. When adhering to cell-free culture inserts, an S. typhimurium invG mutant differed from its parent strain in that it lacked even the shorter surface appendages, suggesting that SPI1 may be involved in appendage formation in the absence of epithelia. Our data on S. typhimurium strains in the presence of cells provide compelling evidence that SPI1 is not an absolute requirement for the formation of the described filamentous appendages. However, appendage formation is controlled by PhoP/PhoQ since a PhoP-constitutive mutant very rarely possessed such appendages when adhering to any of the cell types examined.     

Development and validation of transient isotachophoretic capillary zone electrophoresis for determination of peptides

Although capillary zone electrophoresis (CZE) is known for its high resolution power and low mass detection limits, the concentration detection limits are rather poor when ultraviolet absorbance detection is used. To overcome this limitation, several on-column transient isotachophoresis (tITP) protocols have been developed and validated for the determination of both cationic and anionic model peptides, separately. Using this preconcentration method, up to 72% of the capillary can be filled with sample solution, without any loss in resolution. Thus, without any modification of the hardware set-up, the sensitivity is increased about two orders of magnitude. For the model cationic peptides (gonadorelin, angiotensin II) good linearity and reproducibility is observed in the 20 to 100 ng/mL concentration range. For the anionic peptides (N-t-Boc-Pentagastrin and two related peptides), a tITP method was developed using a dynamically coated capillary. The coating was prepared by adding Fluorad FC-135 to the leading electrolyte buffer. In this way a positively charged bilayer was formed on the inside of the capillary, producing an electroosmotic flow towards the outlet using reversed polarity conditions. In this way, acceptable analysis times were achieved. Using the developed tITP method, up to 72% of the capillary can be filled with sample solution as well. The anionic peptides are separated even better than when using CZE conditions. Linearity and reproducibility in the 20-100 ng/mL range proved to be excellent.     

The relationship of local and distant failure from endometrial cancer: defining a clinical paradigm

Water-soluble amyloid beta-peptides (sA beta), ending at residue 42, precede amyloid plaques in Down's syndrome (DS). Here we report that sA beta consists of the full-length A beta(1-42) and peptides truncated and modified by cyclization of the N-terminal glutamates, A beta[3(pE)-42] and A beta[11(pE)-42]. The A beta[3(pE)-42] peptide is the most abundant form of sA beta in Alzheimer's disease (AD) brains. In DS, sA beta[3(pE)-42] concentration increases with age and the peptide becomes a dominant species in the presence of plaques. Both pyroglutamate-modified peptides and the full-length A beta form a stable aggregate that is water soluble. The findings point to a crucial role of the aggregated and modified sA beta in the plaque formation and pathogenesis of AD.