Human macrophage gamma interferon decreases gene expression but not replication of Mycobacterium tuberculosis: analysis of the host-pathogen reciprocal influence on transcription in a comparison of strains H37Rv and CMT97

Mycobacterium tuberculosis is an intracellular pathogen that readily survives and replicates in human macrophages (MPhi). Host cells have developed different mycobactericidal mechanisms, including the production of inflammatory cytokines. The aim of this study was to compare the MPhi response, in terms of cytokine gene expression, to infection with the M. tuberculosis laboratory strain H37Rv and the clinical M. tuberculosis isolate CMT97. Both strains induce the production of interleukin-12 (IL-12) and IL-16 at comparable levels. However, the clinical isolate induces a significantly higher and more prolonged MPhi activation, as shown by reverse transcription-PCR analysis of IL-1beta, IL-6, IL-10, transforming growth factor beta, tumor necrosis factor alpha, and gamma interferon (IFN-gamma) transcripts. Interestingly, when IFN-gamma transcription is high, the number of M. tuberculosis genes expressed decreases and vice versa, whereas no mycobactericidal effect was observed in terms of bacterial growth. Expression of 11 genes was also studied in the two M. tuberculosis strains by infecting resting or activated MPhi and compared to bacterial intracellular survival. In both cases, a peculiar inverse correlation between expression of these genes and multiplication was observed. The number and type of genes expressed by the two strains differed significantly.

Tumor markers in breast cancer monitoring should be scheduled according to initial stage and follow-up time: a prospective study on 859 patients

PURPOSE

The purpose of this study was to identify and standardize optimal decision criteria for maximizing the effectiveness of tumor markers in clinical use during the follow-up of patients operated on for breast cancer.

MATERIALS AND METHODS

The study was prospectively performed on 859 patients enrolled in 10 institutions. A total of 13,337 determinations of CEA and 14,330 determinations of CA15.3 were available. The median number of samples per patient was 16 for CEA and 17 for CA15.3. The median follow-up was 7 years. Receiver-operating characteristic analysis was used to evaluate the ability of CEA and CA15.3 to discriminate relapses from patients who had no evidence of disease. The diagnostic performances of the two markers were evaluated using decision criteria based on both dichotomic cut-off points and dynamic variations among serial samples.

RESULTS

We selected decision levels corresponding to preset levels of 90% and 99% specificity. Patients with CEA and/or CA15.3 levels above the cut-off values were considered positive only if a 1.5-fold increase occurred among the last sample and the mean of the first three samples. According to the different cut-offs used, specificity ranged from 94% to 99% and sensitivity from 48% to 63%. We calculated predictive values using the prevalence expected with reference to the stage of primary tumor and the length of follow-up. Positive predictive values ranged from 1.6% to 93.7%, and negative predictive values from 88.9% to 100%, according to the clinical scenarios and the decision criteria used. The choice of the decision criteria significantly affected positive predictive values within each patient subset. Differences related to time from surgery were still remarkable for every decision criteria (i.e., positive predictive values ranged from 36.6% to 2.8% in node-negative patients according to the year of observation, although the same cut-off point was used).

DISCUSSION

The results of the present prospective study show that different decision criteria may provide different diagnostic performances for the same tumor marker and in the same patient. Therefore, we suggest that different decision criteria be settled and used according to the clinical goals.

Tuberculosis and lung cancer. An interesting case study

This report describes the case of a patient with lung cancer who completely recovered when he was suffering from tuberculosis. Since bacillus Calmette-Guerin (BCG) has beneficial effects in certain types of cancer, it was hypothesized that infection with Mycobacterium tuberculosis induced an effective response against the tumour. M. tuberculosis-infected blood T-lymphocytes of the patient were cultured with two lung tumour cell lines. T-lymphocytes in vitro remained attached to tumour cells that appeared reduced in number. Moreover, M. tuberculosis isolated from the patient was a strong inducer, in infected macrophages, of the expression of the inducible form of the nitric oxide synthase, that may regulate cytotoxic activity of human macrophages.

Novel splicing and missense mutations in autosomal dominant polycystic kidney disease 1 (PKD1) gene: expression of mutated genes

Autosomal dominant polycystic kidney disease (ADPKD) is a common disorder mostly characterized by cyst formation in kidney tubules. The majority of ADPKD cases is caused by mutations in the PKD1 gene, but no prevalent mutation has been reported. By heteroduplex analysis of the 3' single-copy region of the gene, we have searched for mutations in subjects from 40 ADPKD families of Northern Italy. Seven novel polymorphisms and three novel disease-associated mutations (R3718Q, L3851P and IVS45+56del25) were identified. Both missense mutations are located in the major extracellular loop of polycystin-1. The 25 bp deletion inside intron 45 did not affect 5' and 3' consensus splicing sites, but caused a 56 nucleotide out of frame-deletion due to activation of a cryptic 3' splice site in exon 46. The mutated RNA should produce a truncated polycystin 1 at the G binding peptide in the intracellular C-terminal end of the protein. RT-PCR analysis showed that the disease-associated mutations were present in transcribed sequences. In particular, RNA analysis of BHK cells transfected with PKD1 genomic DNA, including the deleted intron, showed that no normal transcript is produced by the deleted gene. This intronic mutation, found in a large pedigree, seems to be associated with a prevalence of cerebrovascular disease.

Biofilms invade nephrology: effects in hemodialysis

Bacteria attach to surfaces and aggregate in a biopolymer matrix to form biofilm. Studies on biofilm have shown its presence in many prosthetic devices used in nephrology as well as in fluid pathways of hemodialysis plants and monitors. Once present, this community of bacteria increases resistance to biocide due to slime production and, as a result, chemical products for dialysis monitor disinfection and descaling procedures do not result in an effective treatment. Ultrapure dialysate is a goal in modern hemodialysis, and ultrafiltration is used to obtain sterile and apyrogen fluids. Microbial colonisation of ultrafilters may occur if, due to inadequate disinfection protocols, membrane is exposed to persistent bacterial contamination, and biofilm is allowed to form and to grow. As more and more data link final dialysate microbial contamination to clinical effects of bioincompatibility from chronic inflammation in dialysis patients, attention has to be focused on possibilities of biofilm avoidance.

Human immunodeficiency virus type 1 infection modulates the interleukin (IL)-1beta and IL-6 responses of human macrophages to CD40 ligand stimulation

Better understanding of the mechanisms of proinflammatory cytokine production during human immunodeficiency virus (HIV) type 1 infection is of pivotal importance. The effect of HIV-1 infection on recombinant CD40 ligand (CD40L)-induced interleukin (IL)-1beta and IL-6 production by human macrophages was analyzed. ELISA and cytofluorometric analysis demonstrated that CD40L stimulation of HIV-1-infected macrophages resulted in substantial production of IL-1beta and IL-6. In contrast, no cytokine response was observed in uninfected cells. No modulation of the receptor for CD40 was found to account for the enhanced response to CD40L. The CD40L effect was not due to lipopolysaccharide contamination and was completely abrogated by preincubation with a monoclonal anti-CD40L antibody. mRNA studies indicated that the priming effect of HIV-1 on the macrophage response to CD40L was regulated at the transcriptional level. Finally, the effect of HIV-1 on the cytokine response could not be abolished by the HIV-1 protease inhibitor U75875 at concentrations that completely suppressed HIV-1 replication.

Dialysate flow distribution in hollow fiber hemodialyzers with different dialysate pathway configurations

The efficiency of a hemodialyzer is largely dependent on its ability to facilitate diffusion, since this is the main mechanism by which small solutes are removed. The diffusion process can be impaired if there is a mismatch between blood and dialysate flow distribution in the dialyzer. The objective of the paper was to study the impact of different dialysate compartment designs on dialysate flow distribution and urea clearances. Eighteen hollow fiber 1.3 m2 hemodialyzers were studied, 6 each of 3 designs: Type A--standard fiber bundle (PAN 65DX Asahi Medical, Tokyo, Japan); Type B--spacing filaments external to the fibers (PAN 65SF Asahi Medical, Tokyo, Japan); Type C--fibers waved to give Moiré structure (FB130 Nissho-Nipro, Osaka, Japan).

IN VITRO STUDIES

3 dialyzers of each type were studied following dye injection into the dialysate compartment. Dynamic sequential imaging of longitudinal sections of the dialyzer were undertaken, using a new generation helical CT scanner (X-Press/HS1 Toshiba Corporation, Tokyo, Japan). In vivo studies: 3 dialyzers of each type were studied, in randomized sequence, in 3 different patients under standardized dialysis conditions. Blood- and dialysate-side urea clearances were measured at 30 and 150 minutes of treatment. Macroscopic and densitometrical analysis revealed that flow distribution was most homogeneous in the dialyzer with Moiré structure (Type C) and least homogeneous in the standard dialyzer (Type A). Space yarns (Type B) gave an intermediate dialysate flow distribution. Significantly increased urea clearances (p<0.001) were seen with Types B and C, compared to the standard dialyzer. Type C (Moiré) had the highest clearances although these were not significantly greater than Type B (space yarns). In conclusion, more homogeneous dialysate flow distribution and improved small solute clearances can be achieved by use of spacing yarns or waved (Moiré structure) patterns of fiber packing in the dialyzer. These effects are achieved probably as a result of reduced dialysate channeling resulting in a lower degree of mismatch between blood and dialysate flows. The new radiological technique using the helical CT scanner allows detailed flow distribution analysis and has the potential for testing future modifications to dialyzer design.

Mycobacterium tuberculosis H37Rv comparative gene-expression analysis in synthetic medium and human macrophage

Mycobacteria are intracellular pathogens that survive and grow in host macrophages. Following phagocytosis, sustained intracellular bacterial growth depends on its ability to avoid destruction by macrophage-mediated host defences such as lysosomal enzymes, reactive oxygen and the reactive nitrogen intermediates. This suggests that the interaction between host cell and microbe is delicately balanced, and can be tipped in favour of either organism. The identification of Mycobacterium tuberculosis H37Rv (MTB) genes expressed within host cells would contribute greatly to the development of new strategies to fight tuberculosis. In the present study, we compared MTB gene expression in the course of intra- (human macrophages) and extracellular growth (Sauton's medium) to ascertain whether differences might occur between gene-expression patterns in the two habitats of replication. Using reverse-transcriptase polymerase chain reaction (RT-PCR) on a group of 14 MTB-Complex-specific genes, we found that MT10Sa (a small stable RNA), 35 kDa (unknown), ahpC (alkyl hydroperoxide reductase, AhpC), sigF (alternative RNA Polymerase sigma factor), and katG (catalase-peroxidase, HPI) genes are expressed in both the environments, while Ag85B, Ag85C (members of the Antigen 85 Complex), rpoV (RNA Polymerase sigma factor) and ESAT6 (early secretory antigen, 6 kDa) are expressed only in the in vitro culture; on the other hand, Ag85A (Antigen 85 Complex), rpoB (RNA Polymerase beta sub-unit), pab (Protein antigen b), invA and invB genes (encoding proteins that show homologies with p60 of Listeria monocytogenes) are expressed only inside the macrophage. Positive RT-PCR products on cDNAs for these genomic regions were not obtained from approximately 1000-fold more bacteria grown in Laboratory Broth. Identification of M. tuberculosis genes expressed in response to phagocytosis by human macrophages increases our basic understanding of the host-pathogen interaction, and helps to identify bacterial factors necessary for in vivo survival and growth.

Low concentrations of glucose degradation products in peritoneal dialysis fluids and their impact on biocompatibility parameters: prospective cross-over study with a three-compartment bag

The side effects of glucose degradation products (GDPs) in conventional peritoneal dialysis (PD) fluids are well described. Using the three-compartment bag concept--that is, in situ preparation of concentrated glucose solution into a standard ionic solution--a GDP-free solution can be processed. To investigate the possible impact of this product on biological and clinical parameters, we carried out a prospective cross-over study with 31 patients, comparing the short-term effects of conventional PD and GDP-free PD solutions. Classical peritoneal parameters and ultrafiltration rate did not change during the study. After three months and after six months with the three-compartment bag, cancer antigen 125 (CA125) concentration in overnight fluid increased significantly (p < 0.001) from 24.4 IU/mL to 44.4 IU/mL and 41.1 IU/mL respectively. CA125 decreased significantly (p < 0.01) to 21.7 IU/mL after three months with the conventional solution. No change in hyaluronan concentration was observed. A slight increase of procollagen III N-terminal peptide in overnight effluent with the GDP-free solution was followed by a significant reduction after three months with standard solution. In summary, our data show that the GDP-free PD fluid improves mesothelial cell mass and turnover even after a short-term period of three months. A better quality of PD solution is obtained by using the three-compartment bag.

Evaluation with breast scintigraphy of breast lesions of indeterminate significance after conventional triple diagnostic approach

The role of breast scintigraphy in the evaluation of 30 women with an uncertain diagnosis following triple assessment was investigated. Scintigraphy was positive in 7 of 13 cancers and 3 of 17 benign lesions and dubious in 1 of 13 cancers and 2 of 17 benign lesions. Sensitivity ranged from 61.5% to 53.8% depending whether dubious lesions were designated as positive or negative. This study shows that breast scintigraphy is not sufficiently sensitive or specific to use in the evaluation of lesions of uncertain diagnosis following triple assessment.

In vitro and in vivo evaluation of a new polysulfone membrane for hemodialysis. Reference methodology and clinical results. (Part. 2: in vivo study)

Different high flux membranes have been recently developed. The present study is aimed at describing the technical features and the clinical performances of a new high flux polysulfone membrane (T-sulfone, Toray, Japan). The study has been carried out on two different dialyzers (surface area = 1.3 and 1.8 m2). The filters have been tested in vivo during hemodialysis and hemodiafiltration. The in vivo study was carried out on 12 ESRD patients on regular hemodialysis treatment. The protocol was reviewed and approved by the local ethical committee. The in vivo clearances (K) at 300 ml/min of blood flow are reported in the following Table: [Table in text]. Beta-2-m reduction ratio exceeded 50% in all sessions. Beta-2-m mass balance executed by collection of spent dialysate and elution from the used filters evidenced that removal is obtained mostly by filtration while absorption is negligible. Excellent tolerance and hemocompatibility was observed in all the studied sessions.

In vitro and in vivo evaluation of a new polysulfone membrane for hemodialysis. Reference methodology and clinical results. (Part 1: in vitro study)

Different high flux membranes have been recently developed. The present study is aimed at describing the technical features and the clinical performances of a new high flux polysulfone membrane (T-sulfone, Toray, Japan). The study has been carried out on two different dialyzers (surface area = 1.3 and 1.8 m2). The filters have been tested in vitro under definite experimental conditions. The hydraulic flow resistance, the pressure drop in the blood compartment and the hydraulic permeability have been determined in a wide range of in vitro experimental conditions. The in vitro sieving coefficients for various solutes have also been determined utilizing human blood. Hydraulic permeability was found in the range of 28.4 ml/h/mm Hg/m2 and sieving coefficients were between 0.96 and 1.0 for all low molecular weight solutes. The sieving coefficient for inulin was 0.95. The pressure drop in the filter at 300 ml/min of blood flow was 95 mm Hg for the 1.3 m2 and 57 mm Hg for the 1.8 m2. The filters are then designed to operate in the presence of high blood flows without excessive resistance in the blood compartment. The blood compartment analyzed by means of a special radiological sequence obtained with a helical scanner after dye injection confirmed the homogeneous distribution of the blood flow in several cross sections of the bundle. Adequate distribution of dialysate was confirmed with a similar method applied to the dialysate compartment. The new imaging techniques utilized were greatly helpful to determine adequacy of filter design and flows distribution.

Expression of CCR5 is increased in human monocyte-derived macrophages and alveolar macrophages in the course of in vivo and in vitro Mycobacterium tuberculosis infection

Human immunodeficiency virus (HIV) replicates more efficiently in Mycobacterium tuberculosis (MTB)-infected macrophages than in uninfected controls. We investigated whether this may be partly explained by changes in expression of CCR5 in the course of mycobacterial infection, as this molecule has been shown to be a coreceptor for HIV entry. Since the lung is the preferential organ of HIV replication in the course of tuberculosis, we preliminarily analyzed beta-chemokine receptor expression in alveolar macrophages from patients with active tuberculosis, using flow cytometry based on an MIP-1alpha ligand-biotin/avidin-FITC detection system. Increased MIP-1alpha receptor (MIP-1alphaR) expression in alveolar macrophages from infected patients was observed whereas no detectable expression could be revealed in uninfected controls. Since MIP-la can also bind CCR1 and CCR4, the presence of CCR5 mRNA was investigated in bronchoalveolar lavage (BAL) cells and detected in alveolar macrophages from tuberculosis patients only. The study was then extended to in vitro MTB-infected macrophages. Monocyte-derived macrophages (MDMs) were left to differentiate for 7 days before MTB H37Rv infection, and CCR5 expression was monitored, by using a specific monoclonal antibody, on days 1, 6, and 11 after infection. Increased CCR5 expression in MTB-infected macrophages was observed, with a peak on day 6 (64% in MTB-infected versus 33% in control cultures) and a decrease by day 11 (25% in MTB infected versus 13% in control cultures). These results show that CCR5 expression is enhanced in the course of in vitro MTB infection and during active pulmonary tuberculosis.

Cellulose triacetate: another membrane for continuous renal replacement therapy

The evolution of technology and biomaterials has permitted a parallel development of renal replacement therapies in the acute, critically ill patient. From the original continuous artero-venous hemofiltration method new techniques such as continuous veno-venous hemofiltration, hemodiafiltration and high-flux dialysis have been developed and are clinically used. Similar progress has been made with artificial membranes. We investigated the possibility of using a modified cellulosic membrane for continuous therapies, assessing the hydraulic characteristics and clearance performances of high-flux cellulose triacetate hemodiafilter (0.7 m2) in vitro and in vivo. The flowdynamic characteristics of the filter suggest its optimal use in veno-venous pump-drive techniques. Efficiency was excellent, with urea daily clearances as high as 50 liters or more. The high permeability and porosity of the membrane also increased the clearances of larger solutes such as creatinine and inulin. No side effects occurred during treatment and we conclude that cellulose triacetate may be considered a good alternative to synthetic membranes in continuous renal replacement therapies.

Mutations in autosomal dominant polycystic kidney disease 2 gene: Reduced expression of PKD2 protein in lymphoblastoid cells

The polycystic kidney disease 2 (PKD2) gene, encoding a 968-amino acid integral membrane protein with six predicted membrane-spanning domains and intracellular NH2 and COOH termini, is mutated in approximately 15% of the cases of autosomal dominant polycystic kidney disease (ADPKD), a common genetic disease frequently resulting in renal failure. For a better understanding of the cause of this disorder, we searched for mutations in the PKD2 gene in two PKD2-linked families characterized by different clinical phenotypes. A common polymorphism, a nonsense mutation, and a frameshift mutation were found. Both mutations are predicted to produce truncated proteins of 314 and 386 amino acids, arrested at the first extracellular loop of the protein. Restriction enzyme analysis of polymerase chain reaction (PCR) and reverse transcriptase (RT)-PCR products, respectively, showed that mutations cosegregated with the disease and mutated alleles were expressed at the messenger RNA level in lymphoblastoid cell lines. However, in these cells, Western blot analysis showed only PKD2 normal protein, and it was expressed at a lower level than that found in cells without the PKD2 mutation. These findings suggest that in lymphoblastoid cells, the truncated protein product of the mutant allele may not be stable.

[Tumor markers in the diagnosis of pancreatic cancer]

The difficulty in an early diagnosis of pancreatic cancer is in the absence of early symptoms due to lower limit of detection of the actual imaging techniques. Clinical symptoms like weight loss, abdominal pain and jaundice indicate an advanced cancer stage. Today 50% of pancreatic tumors are diagnosed in advanced metastatic stage and only 20-30% show resectable cancer. Ultrasound and determination of a mucine like antigen as CA 19-9, CA 50 and CA 195 seem to allow an earlier diagnosis with a higher rate of resective surgery and a prolonged survival for these patients. The mucines are high molecular weight glycoproteins consistent of a backbone protein to which oligosaccarides are attached. The linkage of carbohydrate to the peptide is termed O-glycosidic and involves the hydroxylic groups of serine or threonine with N-acetylglucosamine. Only the backbone proteins are genetically determined (genes MUC). The gangliosides are the same or derivative of Lewis antigen. CA 19-9, CA 50 and CA 195 are assays directed to different epitopes probably present on the same mucinous antigen. These epitopes are not present in different mucines as CA 15-3, CA 125 and TAG 72. Recently other two mucines are emploied CA 242 and CAM 17.1 but they are not better than CA 19-9. The use of a "triplet" of tumor markers as CA 19-9, CA 125 and CEA is the best diagnostic tool for cancer of pancreas in an "integrated" use with ultrasonographic evaluation of the lesion. CA 19-9 permits differential diagnosis from neuroendocrine tumor or pancreatitis, the values of CA 125 and CEA are useful in the evaluation of the stage, resectability and prognosis of pancreatic cancer. The recent use of CA19-9 for the evaluation of radiochemotherapy in preoperative management of the patient is a mode of a well known application of tumor markers in a kinetic evaluation of the tumor for the radicality of therapy, follow-up, recurrence and the effectiveness of the palliative therapy.

Which level of cytokine production is critical in haemodialysis?

Monocyte activation with cytokine production is a well known event in the course of dialysis treatment but its relation to symptoms of haemodialysis or long-term pathological changes in chronic dialysis patients is still under discussion. Cytokine production depends on the balance between inducers and inhibitors while effects rely on the peculiar uraemic environment and cell metabolism. 'Foot-prints' for monocyte activation have been found, but no marker for clinical symptoms has been demonstrated clearly. In this scenario it is almost impossible to link a specific symptom to a definite stimulus such as dialysate microbial contamination or membrane complement generation. The topics discussed in this paper include cytokines synthesis modulation factors, levels in haemodialysis patients, and results of finding markers of clinical relevance. Special attention is paid to microbial contamination of dialysis fluid with analysis of cytokine inducing substances in commercial sterile solutions. Data on cytokine synthesis and activity in the aged are also discussed, with special regard to the haemodialysis setting.

Vascular access for haemodialysis: from surgical procedure to an integrated therapeutic approach

During the past 10 years the type of vascular access for haemodialysis procedures have changed markedly in our centre: more elbow AV fistulae and more central venous catheters are now used. Nevertheless, early referral to nephrologists and availability of central venous catheters and peritoneal dialysis allow elderly people to be admitted for dialysis treatment. Since vascular access for haemodialysis plays a key role in patient well-being, it is mandatory to apply quality assurance criteria to vascular access for haemodialysis surgery. Based on the results of a national survey, in Italy this policy is still in its early stages: monitoring of vascular access differs amongst centres, interventional radiology is used in a differing way, planning of vascular access for haemodialysis in pre-dialysis patients often remains an unsolved problem. According to our initial experience, we propose the use and validation of a quality-index [(minimum success rate) in elective vascular access for haemodialysis surgery], allowing accreditation of a department and a single surgeon for access management. Prevalence of central venous catheters at first dialysis of chronic renal failure patients is also proposed to evaluate the efficiency in access planning. Better knowledge of vascular access management by different teams could eventually lead to definition of guidelines for this 'Cinderella of dialysis'.

Retention of limulus amoebocyte lysate reactive bacterial products by polysulfone dialyzers is affected by the type of disinfectant

To reduce the level of contamination by bacterial products, ultrafiltration systems have been introduced and validated for their capacity to block the passage of bacterial components reactive to the limulus amoebocyte lysate (LAL) test. In this study, the absorptive capacity of polysulfone membranes undergoing disinfection cycles with free chlorine and peracetic acid were evaluated at various concentrations and contact times. The results of this study implicate a relevant physicochemical derangement of the polysulfone membranes treated with sodium hypochlorite but not with peracetic acid, diluted peracetic acid (Dialox) or Amuchina. The implications for the practical use of ultrafilters are discussed.

Maternal serum screening for trisomy 18 in the first trimester of pregnancy

The aim of this study was to evaluate the feasibility of first-trimester biochemical screening for trisomy 18, by using pregnancy-associated plasma protein A (PAPP-A) and free beta human chorionic gonadotropin (hCG) in combination with maternal age. Maternal serum levels of PAPP-A and free beta-hCG were assayed retrospectively in stored sera from 323 singleton pregnancies at 8-13 weeks' gestation. These samples included 23 trisomy 18 pregnancies and 300 unaffected controls, diagnosed either at chorionic villus sampling or at mid-trimester amniocentesis. The median MOM in affected pregnancies was 0.25 for PAPP-A and 0.34 for free beta-hCG. Statistically significant reductions were found in the mean levels of both PAPP-A (t test: P < 0.000001) and free beta-hCG (p < 0.000001) in trisomy 18 affected pregnancies when compared with the unaffected samples. Screening for trisomy 18 using a combination of maternal age, PAPP-A and free beta-hCG would achieve a detection rate of 76.6 per cent for a false-positive rate of 0.5 per cent. These results suggest that first-trimester biochemical screening for trisomy 18 might be possible. Further investigations in a general population are needed before introducing such screening into clinical practice.

Water quality for on-line haemodiafiltration

The term 'ultrapure water' is a common way to define water used for on-line treatments: it refers to the absence of chemical, organic and microbiological contamination. To be more accurate in definition, every known and potential contaminant has to be fixed at its limit value. AAMI recommendations and various Pharmacopoeias have set limits for dialysate based on traditional dialysis treatments, but on-line treatments should also be regulated by guidelines for infusion solutions. Modern water treatment technology allows us to obtain a proper chemical quality both for dialysate and infusion solutions in on-line dialysis. Technology alone, however, cannot guarantee adequate microbiological quality if water treatment is not linked to the appropriate maintenance, monitoring, cleaning and sanitizing procedures. On-line dialysis treatments, as well as high-flux dialysis, use the monitor as an on-site pharmaceutical factory where sterilization by filtration forces nephrologists to look for procedures to keep sterile water sterile.

Erythropoietin upregulates the expression of its own receptor in TF-1 cell line

In the erythroleukemia cell line TF-1, recombinant human erythropoietin (rHEpo), but not c-kit ligand, enhanced the number of cells expressing the erythropoietin receptor (EpoR), as measured by flow-cytometric analysis of binding of the biotin-labeled Epo. Moreover, 125I-Epo binding and Scatchard analyses, indicated that TF-1 cells, maintained in standard conditions with IL-3, and those stimulated with c-kit ligand, bear a single class of EpoR. On the other hand, cells cultured in the presence of rHEpo had a higher number of receptors than IL-3 or c-kit ligand-stimulated cells, and had two binding sites with different affinities for the ligand. EpoR mRNA expression was higher in cells exposed to rHEpo than in IL-3 or c-kit-stimulated cells. This difference may have been dependent on either a higher level of transcription or an increased stability of mRNA. The observed changes of EpoR in rHEpo-stimulated TF-1 cell line could cooperate, together with the alteration of the gene (3' end deletion), in the occurrence of the erythroleukemic process. Changes induced in EpoR by rHEpo were not accompanied by an increase in the expression of glycophorin A or globin chain mRNAs. This may suggest that rHEpo is unable to induce erythroid differentiation in TF-1 cells. The results also indicate that this cell line could be a model for the investigation of the role of transcription factor(s) in the expression of EpoR, and for the study of the mechanism(s) underlying the changes in the number and affinity of the cell receptors.

Mycobacterium tuberculosis enhances iNOS mRNA expression and HIV replication in human astrocytoma cells

The aim of this study was to investigate whether Mycobacterium tuberculosis (MTB) infection affects human immunodeficiency virus (HIV) replication in T67 human astrocytoma cells and whether HIV and MTB infections induce iNOS mRNA expression in T67 cells. T67 cells were susceptible to both HIVLai and MTB infections, and MTB was able to increase HIV infection in T67 cells, as demonstrated by a marked increase in p24 release. Furthermore, both HIV and MTB infections strongly induced inducible nitric oxide synthase (iNOS) mRNA expression, as verified by RT-PCR. These findings suggest that HIV and MTB-induced iNOS expression of astroglial cells may be involved in the neuronal damage associated with HIV infection, particularly in the presence of opportunistic infections such as tuberculosis.

No direct evidence of increased lipid peroxidation in hemodialysis patients

Lipid peroxidation, as measured by the thiobarbituric acid test, has been reported to have increased in hemodialysis (HD) patients, even though the test has low specificity in vivo. Conjugated diene fatty acid (CDFA) hydroperoxides are formed during lipid peroxidation, but not all conjugated dienes (CD) detected in humans originate from lipid peroxidation: octadeca-9,11-dienoic acid, a nonhydroperoxide CD derivative of linoleic acid (CDLA), has a dietary origin. We evaluated CDFA hydroperoxides, CDLA and linoleic acid, using high-performance liquid chromatography, in lipids extracted from plasma, adipose tissue and RBC membranes obtained from 25 patients treated with HD, 16 patients treated with hemodiafiltration (HDF) and 29 controls. No differences in the levels of CDFA hydroperoxides and linoleic acid were seen in any of the groups. Concentrations of CDLA were found to be significantly high in the adipose tissue and low in the RBC membranes of HD patients. HDF-treated patients showed the same results as HD patients. No direct evidence of increased lipid peroxidation was found in HD patients. This does not exclude the possibility that lipid peroxidation is increased and escapes direct detection due to the body's homeostatic control eliminating the increased production of hydroperoxides. Both HD- and HDF-treated patients showed a significant change in CDLA concentrations, either in the adipose tissue, or in the RBC membranes. These dietary CD may be mistaken for markers of lipid peroxidation by conventional methodologies.

How alternative are immunoassay systems employing non-radioisotopic labels? A comparative appraisal of their main analytical characteristics

The immunoassay is one of the most sensitive and reliable analytical techniques available in the clinical laboratory. The original label for immunoassays was radioisotopes, and these methods, radioimmunoassay (RIA) and immunoradiometric assay (IRMA) are still the reference methods, because of invulnerability of the radioactive emission with respect to environmental interference. Labels other than radioisotopes have been tested for use in immunoassay to improve the sensitivity and reliability and to avoid some of the disadvantages of radioisotopic techniques. New labels have continued to be developed (Horseradish peroxidase-HPR-, pyrophosphatase, luciferases, pyrodopirazines, europium cryptates, porphirins, phosphors) and new label detection methods have been set up (e.g. chemiluminescence assay, thermometric assay, NADP+ and FADP- based coupled assay). New immunoassay strategies such as simultaneous multianalyte automated test have been developed and the reliability of the assays has in some cases caused division among researchers about the choice between the radioisotopic immunoassay or the non-radioisotopic immunoassay, as considerable effort and investment had been devoted to the search for more sensitive and practicable tests than the classic RIA-IRMA methods. The evolution of immunoassays (Monoclonal Antibodies, non-radioactive tracers, automation) has produced systems which allow a large number of laboratories to determine a great number of analytes with very good practicability. The availability of fully automated systems has generated the opinion that analytical performance of immunoassays can be considered similar to that of many traditional parameters of clinical chemistry. This conclusion seems however too optimistic, in fact data collected from interlaboratory studies demonstrate that problems concerning the analytical reliability of the measurements still remain not completely solved. In the authors' opinion, this opposition between immunological assay based on isotopic or non-isotopic labels is misleading, because each assay (whether it uses isotopic, enzymatic, fluorimetric or luminescent labels) has its own analytical characteristics and performance. For this reason the term "alternative", used to indicate all non-isotopic assays as a unique class of tests, should be abandoned. From a theoretical point of view the choice should not be between isotopic and non isotopic techniques. For each analyte to be tested, it is advisable to use the immunological assay that suits the requirements of the laboratory, irrespective of type of label. From a practical point of view, the choice should be based on the analytical performance and on the characteristics of each assay, on its cost and the type of instrumentation available in the laboratory, and on the experience and the knowledge of the laboratory personnel.

Leaching and corrosion of polyvinyl chloride (PVC) tubes in a dialysis water distribution system

PVC tubes, from the dialysis water distribution system of a 14 and a 7 year old plant, were analysed by scanner electron microscopy (SEM) and X-ray microanalysis (EDAX). Results showed that the leaching of material occurs depending on time of use. The phenomenon does not modify the chemical composition of the material. Results suggest that PVC alterations, induced by time, could support bacterial proliferation thus reducing the quality of dialysate.

Serum eosinophil cationic protein (ECP) in bullous pemphigoid

BACKGROUND

The importance of eosinophils in the pathogenesis of the major forms of pemphigoid (bullous pemphigoid, cicatricial pemphigoid, herpes gestationis) remains to be confirmed.

METHODS

To evaluate the role of eosinophilic infiltrates in these diseases and to detect the presence and activity of eosinophils, we compared the serum levels of eosinophil cationic protein (ECP), an eosinophil-derived protein, in 11 healthy subjects and in 10 patients with pemphigoid diseases (8 with bullous pemphigoid, one with cicatricial pemphigoid, and one with herpes gestationis). The serum of two patients with epidermolysis bullosa acquisita (EBA) and one with linear IgA bullous dermatosis (LABD) were utilized as a further control.

RESULTS

There was a significant difference between the mean of serum ECP levels in patients with pemphigoid diseases (25.1 +/- 12.3 micrograms/L, M = SD) and control subjects (2.30 +/- 2.41, micrograms/L +/- SD 2.41) (T = 4.272 P < 0.0001). The two patients with EBA (10.8 and 17.7 micrograms/L) showed contrasting results; the patient with LABD had normal ECP serum levels. The serum levels of ECP were not significantly correlated with the blood eosinophil count (R = 0.103; P = 0.777) in any of the cases.

CONCLUSIONS

In pemphigoid disease, the serum levels of ECP seem to be correlated with the activated secreting and tissue-damaging eosinophils found in the dermis, supporting the concept of an active participation of eosinophils in generating cutaneous lesions.

Tumor markers in breast cancer follow-up: a potentially useful parameter still awaiting definitive assessment. Forza Operativa Nazionale sul Carcinoma Mammario (FONCaM)

BACKGROUND

Although tumor markers are frequently used in the follow-up of patients with breast cancer, two points are still being debated: 1) their cost/effectiveness has been neither demonstrated nor disproved; 2) the reliability of the currently used dichotomous division into a positive/negative cut-off should be definitely validated. Dynamic criteria of interpretation based on serial serum samples would probably be more effective for early detection of relapse.

PATIENTS AND METHODS

The aim of the present study was to compare the dichotomous cut-off based decision criteria to a dynamic serial sample based assessment of tumor markers. Since 1989, 794 patients have been followed in 11 institutions. CEA and CA15.3 were measured once a month for three months before every clinical examination. The present paper concerns the evaluation variability in 405 patients without evidence of disease in the first three institutions joining the study.

RESULTS

In patients without evidence of disease, the coefficient of variation of all samples for every patient showed a median value of 19 for CEA and 21 for CA15.3. Variability was negatively associated with the antigen level and was most likely due to the analytical component. This was also confirmed by the significant difference in variability among the three institutions evaluated. The median value of the critical difference was 53% for CEA and 57% for CA15.3.

CONCLUSIONS

1) Individually tailored dynamic decision criteria are applicable in about 50% of the cases. 2) The problem of improving the precision of tumor marker assays in the low dose range must be urgently addressed to the manufacturers of tumor markers by the scientific community in order to apply individually tailored decision criteria for patients in whom the serum level of biological markers is low.

Amniotic fluid levels of CA 19.9 and CA 15.3 in normal and Down's syndrome pregnancies

CA 125, CA 19.9 and CA 15.3 are antigenic determinants on glycoproteins commonly used as serum markers in gynecologic oncology. CA 125 was also investigated in the amniotic compartment of Down's syndrome pregnancies. The objective of this study was to evaluate the concentration of CA 19.9 and CA 15.3 in the amniotic fluid of normal and Down pregnancies. The concentration of these antigens was measured in stored amniotic fluid samples from 15-19 weeks pregnancies with and without Down's syndrome fetuses and expressed in multiples of the median for normal pregnancies of the same gestational age. The study group included 20 samples selected from single Down's syndrome pregnancies. Each of these samples were matched with three control samples from unaffected pregnancies, matched for maternal age, gestational age and duration of storage of the sample. The median MoM values of CA 19.9 and CA 15.3 in Down's syndrome pregnancies were respectively 1.11 MoM and 1.16 MoM, not significantly different from those of unaffected pregnancies (CA 19.9: 1.02 MoM; CA 15.3: 0.99 MoM). In the present study we have not found significantly different levels of CA 19.9 and CA 15.3 in the amniotic fluid of fetuses affected by Down's syndrome and in the controls.

On line filtration of dialysate: structural and functional features of an asymmetric polysulfone hollow fiber ultrafilter (Diaclean)

The endotoxin transfer across dialysis membranes has been investigated using specific in vitro circuits. Backdiffusion and backfiltration have been analyzed and most dialysis membranes have shown to be permeable to LAL positive substances. Synthetic membranes however display the better capacity of retention of these products despite their higher porosity and permeability. For such reason synthetic polysulfone ultrafilters are used as pyrogen filters to obtain ultrapure dialysate. We have investigated the characteristics of a polysulfone ultrafilter named Diaclean and manufactured by Amicon Ireland. The capacity of endotoxin retention has been investigated both in filtration and backfiltration modes on new and used ultrafilters. The capacity of endotoxin adsorption was investigated as well. Used ultrafilters appeared to maintain the retention capacity and the adsorption capacity up to 4 months of use. Only slight differences were noted from the baseline values (p = n.s.). The best adsorption capacity is always displayed by the outer layer of the membrane suggesting its best utilization in back filtration mode with tangential flow. No morphological changes were observed in the used membrane analyzed by scanning electron microscopy.

Selective expansion of cytotoxic T lymphocytes with a CD4+CD56+ surface phenotype and a T helper type 1 profile of cytokine secretion in the liver of patients chronically infected with Hepatitis B virus

Highly purified CD4+ T cells isolated from liver biopsies of patients with hepatitis B virus-induced CAH had a strong cytotoxic activity and were comprised of a substantial number of cells (25%-40%) expressing CD56 surface marker. These cells were absent in CD4+ T cells from the peripheral blood of CAH patients or normal controls and these suspensions did not have cytotoxic activity. CD4+CD56+ T cells were further characterized by studies at the clonal level. A total of 71 hepatitis B envelope antigen-specific CD4+ T cell clones was investigated (23 from liver biopsies, 48 from peripheral blood of patients or normal vaccinated individuals). A total of 16 out of 23 (69.5%) of the clones from liver biopsies, but only 4.1% (2 out of 48) of those from PBLs, expressed CD56. A clone was defined as CD56+ when 40% or more of the cells expressed the marker. Production of TNF-alpha, IL-4, IL-5, IL-2, and IFN-gamma was investigated in 15 CD4+CD56+ and in 18 CD4+CD56- T cell clones, which shared the same HLA restriction element (DR2w15) and the same fine specificity (peptide 193-207 of the S region). All of the clones from the two groups released TNF-alpha and IL-2. However, all of the CD4+CD56+ T cell clones produced IFN-gamma but not IL-4 and IL-5 (Th1-like cell clones). Fourteen of the CD4+CD56- clones released IFN-gamma, IL-4, and IL-5 (Th0-like cell clones); three produced IL-4 and IL-5 but not IFN-gamma (Th2-like cell clones); and only one had a Th1 cytokine secretion profile. Cell fractionating studies within single CD4+CD56+ T cell clones showed that cells expressing high density CD56 had a stronger cytotoxic activity and produced higher levels of IFN-gamma than cells with low density CD56, thus further supporting a correlation between CD56 expression and cell functions. The results indicate that: 1) in CAH patients, cytotoxic CD4+ T cells with a Th1 cytokine secretion profile are compartmentalized in the liver, 2) these cells may be identified by the expression of CD56, 3) the expansion of these cells may be facilitated by antigenic stimulation within the inflammatory environment of the liver, and 4) CD4+CD56+ cells may play a pathogenetic role in hepatitis B virus infection.

Selective expansion of cytotoxic T lymphocytes with a CD4+CD56+ surface phenotype and a T helper type 1 profile of cytokine secretion in the liver of patients chronically infected with Hepatitis B virus

Highly purified CD4+ T cells isolated from liver biopsies of patients with hepatitis B virus-induced CAH had a strong cytotoxic activity and were comprised of a substantial number of cells (25%-40%) expressing CD56 surface marker. These cells were absent in CD4+ T cells from the peripheral blood of CAH patients or normal controls and these suspensions did not have cytotoxic activity. CD4+CD56+ T cells were further characterized by studies at the clonal level. A total of 71 hepatitis B envelope antigen-specific CD4+ T cell clones was investigated (23 from liver biopsies, 48 from peripheral blood of patients or normal vaccinated individuals). A total of 16 out of 23 (69.5%) of the clones from liver biopsies, but only 4.1% (2 out of 48) of those from PBLs, expressed CD56. A clone was defined as CD56+ when 40% or more of the cells expressed the marker. Production of TNF-alpha, IL-4, IL-5, IL-2, and IFN-gamma was investigated in 15 CD4+CD56+ and in 18 CD4+CD56- T cell clones, which shared the same HLA restriction element (DR2w15) and the same fine specificity (peptide 193-207 of the S region). All of the clones from the two groups released TNF-alpha and IL-2. However, all of the CD4+CD56+ T cell clones produced IFN-gamma but not IL-4 and IL-5 (Th1-like cell clones). Fourteen of the CD4+CD56- clones released IFN-gamma, IL-4, and IL-5 (Th0-like cell clones); three produced IL-4 and IL-5 but not IFN-gamma (Th2-like cell clones); and only one had a Th1 cytokine secretion profile. Cell fractionating studies within single CD4+CD56+ T cell clones showed that cells expressing high density CD56 had a stronger cytotoxic activity and produced higher levels of IFN-gamma than cells with low density CD56, thus further supporting a correlation between CD56 expression and cell functions. The results indicate that: 1) in CAH patients, cytotoxic CD4+ T cells with a Th1 cytokine secretion profile are compartmentalized in the liver, 2) these cells may be identified by the expression of CD56, 3) the expansion of these cells may be facilitated by antigenic stimulation within the inflammatory environment of the liver, and 4) CD4+CD56+ cells may play a pathogenetic role in hepatitis B virus infection.

Ultrafiltration and endotoxin removal from dialysis fluids

Biocompatibility in hemodialysis is now regarded as a multifactorial problem and dialysate represents a main risk. Pyrogenic fractions mostly coming from gram-negative bacteria easily pass through dialysis membrane, either by backdiffusion or by backfiltration, and induce blood cell activation. To demonstrate the long-term efficiency of a 2 m2 polyamide ultrafilter in producing a pyrogen free solution, we used an experimental circuit ultrafiltering for 240 hours (500 ml/min) a bicarbonate dialysate contaminated (5 to 48 EU/ml) by a Pseudomonas aeruginosa filtrate. The efficiency was monitored by LAL-test and IL-1 PBMC so to detect not only lipid A containing endotoxins but also other cytokines inducing bacterial fractions. At the post-ultrafilter sampling port the LAL-test was < 0.005 to 0.034 EU/ml; IL-1 PBMC was below the detection limit (20 pg/ml) being 27 to 63 pg/ml at the pre-ultrafilter level. Polyamide ultrafiltration represents an efficient system to obtain an endotoxin-free dialysate and a single filter works up to 240 hours.

Effects of low-dose captopril on renal hemodynamics and function in patients with cirrhosis of the liver

BACKGROUND

In cirrhotic patients with ascites, captopril has deleterious effects on renal function, which have been referred to as captopril-induced arterial hypotension. The effects of this drug on renal function in cirrhosis were evaluated using low-dose captopril, thereby avoiding any change in arterial pressure.

METHODS

In a randomized, double-blind, placebo controlled, cross-over trial, the effects of 12.5 mg captopril on renal plasma flow, glomerular filtration rate (measured by radioisotopic techniques), and sodium excretion in healthy controls and cirrhotic patients with and without ascites were determined.

RESULTS

In healthy subjects, captopril only induced a significant, 18% increase in renal plasma flow. In contrast, glomerular filtration rate significantly decreased in patients with (from 108 +/- 7 to 78 +/- 9 mL/min) and without ascites (from 102 +/- 4 to 88 +/- 3 mL/min), whereas renal plasma flow did not change. Urinary sodium excretion also significantly decreased in ascitic patients (from 43.8 +/- 4.4 to 30.6 +/- 3.8 mumol/min).

CONCLUSIONS

These data suggest that angiotensin II contributes to maintain renal hemodynamics in cirrhosis with and without ascites.

Variability of tumor markers in the follow-up of patients radically resected for breast cancer

The biological and analytical components of variability of tumor markers should be distinguished from the variations due to tumor progression. The aim of the present study was to evaluate tumor marker variability in the follow-up of patients resected for breast cancer. So far, we have carried out 2,085 CEA and 2,550 CA 15-3 determinations in 435 patients. The total variability of both CEA and CA 15-3 was widely scattered among different subjects (CEA coefficient of variation 0-105%; CA 15-3 coefficient of variation 0-89.2%). The biological variability of CA 15-3, which was calculated in a limited number of cases, was scattered between 0 and 23% and was higher than the intra-assay variability. From these findings we conclude that when evaluating serial marker assays the intra-individual variability should be assayed initially to obtain a reference value of individual variability in relapse-free conditions.

Conjugated diene fatty acids in patients with chronic renal failure: evidence of increased lipid peroxidation?

Conjugated diene fatty acids (CDFA) were evaluated by second derivative spectrophotometry in the plasma and adipose tissue of 42 chronic renal failure (CFR) patients in conservative treatment, 40 patients treated by hemodialysis (HD) with cuprophane, cellulose acetate or hemophan, 29 treated by hemodiafiltration (HDF) with polysulfone, polyacrylonitrile or polyamide, and 28 healthy controls. Plasma CDFA were also evaluated at the beginning, at 30 min and at the end of the dialytic session. CDFA were unchanged in CRF patients with creatinine clearance (Ccr) > 10 ml/min respect to the controls, CRF patients with Ccr < 10 ml/min showed a higher level of CDFA both in plasma and adipose tissue (p < 0.02). HD patients showed values similar to those of the control group. The lowest level of CDFA was found in HDF patients (p < 0.01 for plasma, p < 0.05 for adipose tissue versus both control and any other group). A significant relationship between plasma and adipose tissue CDFA was found in all groups. In the group of CRF patients with Ccr < 10 ml/min, females exhibited a higher level of CDFA both in plasma and adipose tissue. No significant change was found during dialytic session, independently from the membrane used. CDFA are not only primary products of lipid peroxidation, but also have a dietary origin, primarily from dairy products. Taking into account the reduced dietary intake, the increase in end-stage CRF may be due to an enhanced oxidative stress and/or to abnormalities in CDFA metabolism. Uremic patients, particularly in the predialytic stage, should be considered at risk for increased oxidative stress. HDF treatment better corrects the abnormality compared to conventional HD.

Red cell membrane during erythropoietin therapy in hemodialysis and in hemodiafiltration

This study assessed the effect of recombinant human erythropoietin (r-HuEPO) on red cell membrane behaviour in patients undergoing hemodialysis (HD) and hemodiafiltration (HDF). We studied erythrocyte osmotic fragility (EOF), mechanical fragility (EMF) and deformability (ED) before and after r-HuEPO therapy in patients on conventional dialysis treatment with a cuprophan membrane and in subjects undergoing HDF with a polyacrylonitrile membrane. Non-uremic, non-anemic subjects were enrolled as controls. Red cell membrane defects were more evident in HD than in HDF; r-HuEPO seemed to improve deformability in both groups compared to controls (p less than 0.005) possibly through the great production of red cells during this therapy.

Serum NSE, CEA, CT, CA 15-3 levels in human lung cancer

The significance of neuron specific enolase (NSE) was investigated in comparison with other tumor markers (CEA, CT, CA 15-3) used in the diagnosis and treatment monitoring of lung cancer. As previously described, the calcitonin assay proved to have very low sensitivity for small cell lung cancer (SCLC). The serum NSE assay was, however, shown to be a useful diagnostic aid for discrimination between histologically different lung cancers, and therefore this assay may be a valuable tool for treatment monitoring in SCLC patients. CA 15-3, also an unspecific marker, showed similar sensitivity to the NSE assay in SCLC patients, the sensitivity being higher than CEA in non small cell lung cancer (NSCLC).

Acute Fisher's syndrome during the course of chronic uremia: is the hemodialysis implicated in onset and relapses?

An uremic patient, in chronic dialytic treatment, developed a Miller-Fisher's syndrome acutely after a dialysis. Clinical diagnosis was supported by findings of persistent conduction block in upper and lower extremities and by raised proteins in CSF. Contrast-enhanced CT and MRI scans excluded lesions in the brain stem. The course of this illness was characterized by waxing and waning in cranial nerve deficits, in relation with the hemodialytic treatments. We suggest that, when the patient recovered, reversible changes occurred in the nerves, either due to reversibly impaired sodium permeability or to an ischemic process related to the ultrafiltration dialysis.

Improved biocompatibility by modified cellulosic membranes: the case of hemophan

The rising problem of biocompatibility is encouraging the development of new dialysis membranes, but the high cost of synthetic ones precludes their wide use. The authors compared the biocompatibility of cuprophan (CU), cellulose acetate (CA), and hemophan (HE), evaluating both in vitro and in vivo polymorphonuclear leukocyte (PMN) oxidative metabolism activation by resting chemiluminescence and complement activation by C3a; in vivo PMN counts during dialysis were also performed. The lowest increase in in vitro PMN resting chemiluminescence using HE was + 71.3% with CA, +49.3% with CU, and + 21.4% with HE (p less than 0.001 versus CA and CU); furthermore, HE did not significantly stimulate PMN resting chemiluminescence during in vivo hemodialysis: + 56.6% with CA, + 38.8% with CU, and + 3.7% with HE (p less than 0.01 versus CU and p less than 0.001 versus CA). C3a concentration increased with all membranes both in vitro and in vivo, but HE (in both experimental conditions) showed the lowest increase at any time (p less than 0.001 versus CA and CU). After 15 min of dialysis, PMN count dropped to 20.3% of basal values with CU, to 49.8% with CA, and to 76.5% with HE (p less than 0.001 versus CU and CA). Among cellulosic membranes, HE is the most biocompatible and appears to be an important step in preventing blood-membrane interactions and related complications.

Evaluation of maternal serum alpha-fetoprotein and ultrasound examination to screen fetal chromosomal abnormalities

Maternal serum alpha-fetoprotein (MSAFP), anatomic anomalies and precocious defects of foetal growth were shown as possible "indicators" of foetal chromosomal pathology, in particular Down's syndrome, and thus suggested for prenatal screening of risk patients for this chromosomal abnormalities. The Authors carried out a retrospective study on 1472 patients who underwent amniocentesis for prenatal diagnosis. Between the 15th and the 20th week, a dosage of MSAFP was effected, in order to evaluate if the serum concentration of this substance could predict Down's syndrome. A contemporary study by echographic monitoring was effected on 500 patients from the 1st trimester of pregnancy, in order to detect possible foetal growth retardation precociously and to determine the karyotype in these cases. Results are very interesting and suggest both the dosage of MSAFP and the ecographic monitoring for prenatal screening of trisomy 21, especially in maternal age classes younger than 40 years, where the cost/benefit ratio of screening for maternal age is less favourable.

Polymorphonuclear oxygen free radical production and complement activation induced by dialysis membranes as assayed in an experimental model

Activation of polymorphonuclear leukocytes with subsequent production of reactive oxygen metabolites has been reported to occur during hemodialysis related to a membrane bioincompatibility. We used an experimental dialysis model to evaluate, by chemiluminescence, the production of reactive oxygen metabolites and, by C3a, complement activation induced by cuprophan, cellulose acetate, hemophan, polysulfone, polyacrylonitrile, polymethylmethacrylate or polyvinyl chloride blood lines alone. No differences were obtained in the system, at time 30 min compared to initial values, as far as zymosan-activated chemiluminescence is concerned; resting chemiluminescence increased markedly with cellulose acetate (+71%), cuprophan (+49%), polymethylmethacrylate (+22%), hemophan (+21%) but had no variation with polysulfone, polyacrylonitrile and blood line. The time course of C3a levels up to 120 min showed a marked rise with cuprophan and cellulose acetate, a moderate increase with hemophan, polysulfone and blood line, and a decrease with polymethylmethacrylate and polyacrylonitrile. The results obtained documented a different behavior of the production of reactive oxygen metabolites compared to complement activation and support the hypothesis that the production of reactive oxygen metabolites by polymorphonuclear leukocytes is stimulated not only by complement activation but also by a direct dialysis membrane interaction.