Hemoglobin adducts of benzo[a]pyrene diolepoxide in newspaper vendors: association with traffic exhaust

Benzo[a]pyrene diol epoxide adducts with hemoglobin (Hb) weremeasured to detect human exposure to environmental benzo[a]pyrenefrom traffic exhaust. Benzo[a]pyrene tetrahydrotetrols (BPTs)released from Hb after acid hydrolysis were quantitated by gaschromatography-mass spectrometry after immunoaffinity chromatography.Fifty three newspaper vendors were enrolled. The median adductconcentration was 0.3 fmol BPTs/mg Hb in high density traffic-exposedvendors and     

Immunoglobulin heavy chain Diversity genes rearrangement pattern indicates that MALT-type gastric lymphoma B cells have undergone an antigen selection process

Gastric MALT lymphoma usually develops from chronic gastritis, the vast majority of which (>90%) is associated with Helicobacter pylori infection. We sequenced the third complementarity determining region (CDR3) of immunoglobulin heavy chain genes in 19 gastric MALT lymphoma clones to determine the pattern of variable (V), diversity (D) and joining (J) gene utilization during immunoglobulin gene rearrangement.
DNA was extracted from paraffin-embedded sections and the rearranged CDR3 regions were amplified using a semi-nested polymerase chain reaction (with primers complementary to the conserved framework-three segment of the variable region [FR3A] and J regions). The DNA used for cloning and sequencing was obtained after purification of monoclonal bands excised from polyacrylamide gels. The N-D-N region specific to each clone was compared with known germline D sequences.
Similarly to that observed in normal and leukaemic B cells, our series of gastric MALT lymphomas showed apparent preferential utilization of genes from the DXP family. In two cases no similarity between the CDR3 nucleotide sequences of the neoplastic clones and the known germline D sequences could be found. In 10/19 analysed alleles the lymphoma B-cell clones appeared to contain two D gene segments (D-D recombination), a rare occurrence in normal individuals but one which has been described as a significant event in the determination of idiotype expression and antigen-binding affinity. Remarkably, despite the use of different D and J segments, the resultant amino acid sequences matched in two patients, suggesting the presence of a common selecting antigen.
The observed pattern of D gene rearrangement suggests that MALT lymphoma B-cell clones have undergone antigen selection, which seems to indicate that the antigen stimulation plays a pivotal role in the development of the lymphoma.     

Changes in Neutrophil Oxidative Potential in Patients Undergoing Cardiopulmonary Bypass with Polypropylene Hollow Fiber Oxygenators

Neutrophil oxidative metabolism, C3d and beta 2 microglobulin levels, were assessed in nine consecutive patients undergoing cardiopulmonary bypass surgery with polypropylene hollow fiber oxygenators for open cardiac operations. Generation of oxygen free radicals by neutrophils was measured as luminol-enhanced chemiluminescence after stimulation with opsonized Zymosan and phorbol myristate acetate. A significant increase in light emission was detected by using both of the chemiluminescence stimulators. Moreover, a remarkable and significant increase in C3d levels was found already at 10 min. Conversely minimal changes in levels of beta 2 microglobulin were detected during cardiopulmonary bypass surgery. These data suggest that the impact of the patient blood with the foreign surface of cardiopulmonary bypass results in activation of phagocyte cells with increased potential in oxygen consumption. These effects could be partially complement-mediated.     

Post-biopsy arteriovenous fistulas of the native kidneys diagnosed by Doppler US

Two patients with arteriovenous fistulas of the native kidney occurring after needle biopsy were evaluated using duplex and color Doppler ultrasonography. The first patient had a fistula with associated pseudoaneurysm: color Doppler showed the lesion as a small rounded area with whirling flow; spectral analysis allowed recognition of both the afferent artery with low impedance flow and the draining vein with pulsatile, arterialized flow. The second patient had a normal color Doppler study; however, spectral analysis demonstrated signals with low vascular impedance from an intra-parenchymal artery at the lower pole, and a jet of turbulent flow. Following disappearance of clinical findings, such Doppler abnormalities were no longer detectable. When a iatrogenic arteriovenous fistula is considered on clinical grounds, both color and Doppler spectral analysis of waveforms from intra-parenchymal vessels should be performed. Possibly, further advances in color Doppler technology will permit the use of this examination as the first imaging procedure in these clinical situations.Correspondence to: L. E. Derchi     

BILIARY HYPERPRESSURE IN RAT EXTRAHEPATIC CHOLESTASIS ALTERS HORSERADISH PEROXIDASE BILIARY EXCRETION

1. The authors investigated the effect of two extrahepatic cholestasis models (one by bile duct ligation and the other by choledocho-jugular fistula) on the hepatic clearance of horseradish peroxidase in male Sprague-Dawley rats divided into four groups. 2. In groups A (n = 5 rats) and B (n = 5), bile duct ligation was performed, while a choledocho-jugular fistula was created in groups C (n = 5) and D (n= 7). A 10 mg intravenous bolus of horseradish peroxidase was injected after 24 h (groups A and C), 48 h (groups B and D) or 1 h (Group E; five sham-operated rats). Serum and bile samples were then serially collected for 2 h. 3. In all groups, serum horseradish peroxidase levels increased soon after injection and then rapidly decreased, the curves being similar. Biliary excretion increased for 30 min and then slowly decreased. The highest horseradish peroxidase biliary concentrations and outputs were found in Group B followed by Group A; both groups had significantly higher levels than Group E. No difference was found between horseradish peroxidase biliary excretion of groups C and D and that of sham-operated rats. 4. When each group was considered separately, sampling times correlated with the corresponding ratios of bile/ plasma HRP. Significant differences were found between the relative slopes of groups A, B and E, but not between those of groups C, D and E. 5. In conclusion, bile duct obstruction greatly affects the plasma-bile transfer of fluid phase markers, such as horseradish peroxidase, while single retention, caused by choledocho-jugular fistula, has no influence. The increased biliary hyperpressure related to the duration of cholestasis may account for the degree of horseradish peroxidase transfer which, in turn, probably depends on an enhanced paracellular passage.     

Self-expanding mesh stent for endoscopic palliation of rectal obstructing tumors: a preliminary report

Summary The endoscopic insertion of self-expanding mesh stents in four patients affected by obstructing rectal malignant tumors is reported. The preliminary experience shows that, in the short term, normal defecation was achieved, with no complications. Longer follow-up is necessary to evaluate the duration and the quality of the palliative effect.     

A decomposition approach to suboptimal control of discrete-time systems

A suboptimal controller for a class of discrete-time systems is presented. The controller is derived by first solving ‘off-line’ a simplified optimal control problem obtained by neglecting part of the system state and by considering a larger time step, then by solving ‘on-line’ at each time step an optimization problem based on the results of the previously solved ‘off-line’ problem. A simple numerical example is presented to illustrate the control scheme.