Analytical evaluation of primer engineered multiplex polymerase chain reaction-restriction fragment length polymorphism for detection of factor V Leiden and prothrombin G20210A

Factor V Leiden and prothrombin G20210A are clinically relevant genetic risk factors for venous thrombosis. Analysis for both mutations is increasingly being performed on patients exhibiting hypercoagulability. The goal of the current study was to evaluate the performance of primer-engineered multiplex polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for the simultaneous detection of factor V Leiden and prothrombin G20210A. Primer-engineered multiplex PCR-RFLP methods for the detection of factor V Leiden and prothrombin G20210A from the medical literature were reviewed. A modified method was optimized in which both mutations generate HindIII RFLPs and the prothrombin amplicon contains an invariant HindIII recognition site to assess the completeness of endonuclease digestion. Digested amplification products were analyzed by agarose gel electrophoresis in a single gel lane and visualized by ethidium bromide. Primer-engineered multiplex PCR-RFLP was used to analyze 205 human genomic DNA samples whose factor V Leiden genotypes had been previously determined by MnlI PCR-RFLP. Complete concordance for factor V Leiden genotypes was observed between the two methods in the 205-sample cohort comprising 139 wild-type, 62 heterozygous mutant, and four homozygous mutant individuals. For prothrombin G20210A, primer-engineered multiplex PCR-RFLP identified 196 wild-type and nine heterozygous mutant individuals in the 205-sample cohort. To independently verify prothrombin genotypes, the nine heterozygous mutants and an additional 11 wild-type patient samples (representing 10% of patient samples) were subjected to DNA sequencing. Complete concordance was observed between DNA sequencing and primer-engineered multiplex PCR-RFLP results. In further validation, 123 of the DNA samples consisting of four heterozygous mutant and 119 wild type individuals were genotyped with the Invader Assay for Factor II (prothrombin G20210A). Results showed 100% concordance between the Invader Assay and primer-engineered multiplex PCR-RFLP. A primer-engineered multiplex PCR-RFLP based on single restriction endonuclease digestion has been evaluated and shown to simultaneously and accurately detect factor V Leiden and prothrombin G20210A mutations. The method is robust and readily adaptable to the clinical molecular diagnostic laboratory.

Estrus and estrogen changes in mated and unmated free-living European ground squirrels

The course of behavioral and vaginal estrus and patterns of circulating estrogens were followed in free-living European ground squirrels (Spermophilus citellus) after their emergence from hibernation. Normally mating females were compared to a second group in an area where males had been removed from the population before female emergence. Both groups showed vaginal estrus, but the patterns differed. Mating shortened vaginal estrus to a 3-day period compared to 8 days in unmated females. The extent (cell number) of cell cornification during estrus and the cellular components (percentage distribution) of metestrus did not differ between the two groups. Females in the area without males had significantly higher estrogen levels during estrus and metestrus compared to those in the control area. European ground squirrels were found to be monestrous, as none of the unmated females reentered estrus after metor diestrus was detected. The prolongation of vaginal estrus in unmated females can be viewed as either a physiological inevitability or an adaptation to low mate availability. The extension is still relatively short compared to other sciurid species and perhaps a product of constraints producing a strict time frame for reproduction.

Successful treatment of massive arterial air embolism during open heart surgery

We report a case of a 5-year-old girl who suffered a massive arterial air embolism during surgical closure of an atrial septal defect. The risk of permanent neurologic deficits or even fatal outcome is significant (mortality rate, 31%). We successfully treated a proven arterial air embolism with intraoperative (retrograde cerebral perfusion) combined with postoperative procedures (deep barbiturate anesthesia and hyperbaric oxygenation). At discharge the girl had fully recovered from the initial neurologic defects.

Characterization of lineage-specific chimaerism in patients with acute leukaemia and myelodysplastic syndrome after allogeneic stem cell transplantation before and after relapse

Recently, we have shown that patients with acute leukaemias and myelodysplastic syndromes (MDS), who showed increasing mixed chimaerism (MC) upon serial PCR analysis after transplant, have a significantly increased risk of relapse. To determine whether the increasing MC in these patients is caused by the reappearance of normal recipient haematopoiesis or by the reoccurrence of malignant cells, we purified different leucocyte subpopulations and analysed these subfractions with regard to their donor-recipient ratio by a PCR-based method for the analysis of minisatellite DNA regions. In 14 patients [eight acute lymphoblastic leukaemia (ALL), three acute myelogenous leukaemia (AML) and three MDS] subfractions were analysed when increasing MC was first noted upon serial analysis of the peripheral blood. In seven of these 14 patients (four ALL, two AML and one MDS), subfractions were characterized at the time of frank haematological relapse. In all 14 patients investigated with increasing MC, recipient cells were detected in different mononuclear cell subpopulations. In patients characterized during frank relapse, two distinct distribution patterns were found. Patients who relapsed before day +300 (one ALL, two AML and one MDS) showed recipient-derived (normal) cells in addition to blast populations in different mononuclear subsets as well as granulocytes. In patients with acute leukaemias who relapsed after day +300 (two ALL and one AML), only leukaemic cells were found that were of recipient origin, whereas all other haematopoietic cell lines were donor derived. These data show that persistent MC in the early post-transplant period is caused predominantly by normal recipient haematopoietic cells. This finding further supports the hypothesis that a state of mixed haematopoietic chimaerism may reduce the clinical graft-versus-leukaemia (GVL) effect of alloreactive donor-derived effector cells in patients with acute leukaemias and MDS, and thus facilitate the proliferation of residual malignant cells that may have survived the preparative regimen.

Locally advanced breast carcinoma: evaluation of mammography in the prediction of residual disease after induction chemotherapy

BACKGROUND

We aimed to assess the mammographic features of locally advanced breast carcinoma treated with neoadjuvant chemotherapy and to evaluate morphological criteria that determine the value of mammography in therapy monitoring.

MATERIALS AND METHODS

We reviewed the pre- and post-therapeutic mammograms of 44 patients with stage III-breast carcinoma with regard to tumor characteristics and malignant calcifications and compared to histopathological results.

RESULTS

Delineation of the tumor proved to be the most significant criterion. In 34 tumors more than 50% of the lesion was defined; these showed a high correlation between the mammographically determined tumor diameter and that determined on histopathological examination (r = 0.77). Less than 50% of the mass was definable in 14 tumors; here the correlation between mammographically and histopathologically determined tumor diameter was low (r = -0.19).

CONCLUSIONS

The diagnostic value of mammography in the evaluation of tumor response to induction chemotherapy depends primarily on the extent to which the tumor can be delineated from the adjacent breast tissue. For tumors whose margins can be defined by more than 50% on the baseline mammogram, the diagnostic reliability of mammography is high. Ill-defined masses should preferably be assessed with other imaging procedures such as ultrasonography or magnetic resonance imaging.

Expression of rat kidney anion exchanger 1 in type A intercalated cells in metabolic acidosis and alkalosis

By enzyme-linked in situ hybridization (ISH), direct evidence is provided that acid-secreting intercalated cells (type A IC) of both the cortical and medullary collecting ducts of the rat kidney selectively express the mRNA of the kidney splice variant of anion exchanger 1 (kAE1) and no detectable levels of the erythrocyte AE1 (eAE1) mRNA. Using single-cell quantification by microphotometry of ISH enzyme reaction, medullary type A IC were found to contain twofold higher kAE1 mRNA levels compared with cortical type A IC. These differences correspond to the higher intensity of immunostaining in medullary versus cortical type A IC. Chronic changes of acid-base status induced by addition of NH(4)Cl (acidosis) or NaHCO3 (alkalosis) to the drinking water resulted in up to 35% changes of kAE1 mRNA levels in both cortical and medullary type A IC. These experiments provide direct evidence at the cellular level of kAE1 expression in type A IC and show moderate capacity of type A IC to respond to changes of acid-base status by modulation of kAE1 mRNA levels.

Prostate cancer tumor grade differentiation with dynamic contrast-enhanced MR imaging in the rat: comparison of macromolecular and small-molecular contrast media--preliminary experience

PURPOSE

To differentiate prostate cancers of different histopathologic grades with dynamic gadolinium-enhanced magnetic resonance (MR) imaging. Results with a conventional small-molecular contrast medium (CM) were compared to those with a prototypic macromolecular CM.

MATERIALS AND METHODS

High- and low-grade tumors, sublines of the Dunning R3327 rat prostate cancer line, were subcutaneously implanted into the flanks of 12 male Copenhagen rats. Dynamic contrast material-enhanced MR imaging was performed with small-molecular CM and macromolecular CM at an interval of 1 day. Microvascular permeability, as estimated with the endothelial transfer coefficient, and fractional plasma volume were calculated for each tumor and each CM by means of a two-compartmental, bidirectional kinetic model.

RESULTS

Mean endothelial transfer coefficient values for both macromolecular CM and small-molecular CM were significantly different between the two tumor sublines (P = .0004 and P = .01, respectively). For the high- and low-grade tumors, no overlap of values was seen with macromolecular CM, but a broad overlap was seen with small-molecular CM despite a significant difference in mean values.

CONCLUSION

Dynamic contrast-enhanced MR imaging permits differentiation of histopathologic prostatic tumor types. Quantitative microvascular permeability characteristics estimated from macromolecular CM-enhanced data were significantly superior to those derived from small-molecular CM-enhanced data.

Matrix metalloproteinase upregulation in chronic inflammatory demyelinating polyneuropathy and nonsystemic vasculitic neuropathy

OBJECTIVE

To determine the expression pattern and cellular source of matrix metalloproteinases (MMPs) in chronic inflammatory demyelinating polyneuropathy (CIDP) and nonsystemic vasculitic neuropathy (NSVN).

BACKGROUND

MMPs are endopeptidases involved in tissue destruction and infiltration by immune cells in multiple sclerosis and Guillain-Barré syndrome. Enzyme inhibitors of MMPs attenuate clinical symptoms in corresponding animal models of these diseases. MMP inhibition may therefore be a novel approach for the treatment of CIDP and NSVN. However, the spectrum of MMPs expressed in chronic inflammatory neuropathies has not been established.

METHODS

The expression of MMP-2, MMP-3, MMP-7, and MMP-9 in T cells, macrophages, and stromal cells in CIDP, NSVN, and noninflammatory neuropathies (NIN) was quantitated by immunohistochemistry. Results were correlated with clinical and electrophysiologic findings.

RESULTS

The production of MMP-2 and MMP-9 is increased in nerve tissue in CIDP and NSVN compared with NIN. T cells are the predominant source of MMP-2 and MMP-9 in CIDP and NSVN, whereas macrophages contribute only to a minor extent. Stromal cells of the perineurium/epineurium are an additional source of MMP-2 in NSVN, but not in CIDP. Expression of MMP-3 and MMP-7 was not detectable in CIDP or NSVN. Expression of MMP-2 and MMP-9 did not correlate with clinical disease activity and electrophysiologic measurements.

CONCLUSIONS

The upregulation of MMP-2 and MMP-9 is a specific feature of CIDP and NSVN, and selective inhibitors of these enzymes could be used to prevent inflammatory tissue damage. The similar increase of MMP-2 and MMP-9 in both demyelinating (CIDP) and nondemyelinating (NSVN) neuropathies raises doubts about whether MMPs play a primary role in demyelination.

Evolution of CT findings in patients with cystic fibrosis

OBJECTIVE

The aim of our study was to assess the evolution of pulmonary CT findings in cystic fibrosis patients.

MATERIALS AND METHODS

Serial CT examinations were performed in four different follow-up periods on 107 patients with cystic fibrosis. Lung images of the initial and follow-up CT were reviewed and scored for specific morphologic findings. CT findings were correlated with the results of the pulmonary function tests and clinical (Shwachman-Kulczycki) scores.

RESULTS

Morphologic changes were minor within the first 18 months of follow-up compared with the period after 18 months. The increase of the overall score was significantly higher in groups with follow-up periods longer than 18 months compared with groups with follow-up periods shorter than 18 months. Various components of morphologic changes contributed to the sequential changes seen on the CT scans. All morphologic changes and the CT scores correlated significantly (p < .0001) with pulmonary function tests and clinical score. CONCLUSION. Serial CT scans allow assessment of the evolution of pulmonary abnormalities in patients with cystic fibrosis. CT seems to have advantages over pulmonary function tests and clinical scoring in the depiction of pulmonary changes over time.

Adult celiac disease: US signs

PURPOSE

To examine whether distinct ultrasonographic (US) signs exist in patients with adult celiac disease.

MATERIALS AND METHODS

In a partly retrospective study, abdominal sonograms were obtained in 11 patients with adult celiac disease. Fifty matched control subjects also were examined. After the patients had fasted overnight, they were examined with 2-4-MHz abdominal and high-frequency 5-10-MHz linear-array US transducers.

RESULTS

The authors found several US pathologic signs in patients with untreated disease, including abnormal fluid-filled small intestine in all 11 patients, flaccid and moderately dilated small-bowel loops (2.5-3.5 cm) in eight, slight diffuse thickening of the small-bowel wall (3-5 mm) in seven, increased peristalsis of the small intestine in eight, enlarged mesenteric lymph nodes (anteroposterior diameter 5-10 mm) in nine, dilated caliber of the superior mesenteric artery or portal vein in seven, free fluid in the abdominal cavity in five, and increased echogenicity of the liver in six. None of these signs was present in the control group.

CONCLUSION

There are several US signs associated with adult celiac disease. None of the signs identified is specific, but a combination of signs is characteristic and indicates suspicion of this disease in a high percentage of cases. US could help to avoid diagnostic delay, especially in patients who have atypical clinical presentations.

Assessment of SNRPN expression as a molecular tool in the diagnosis of Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is associated with lesions of the paternal chromosome 15q11- 13. Recently, loss of expression of a paternally expressed gene in this region, SNRPN, has been proposed as a molecular hallmark of PWS. The goal of this study was to determine the diagnostic accuracy of SNRPN expression in a well-characterized cohort of PWS patients.

METHODS

SNRPN expression was analyzed by reverse transcription coupled to polymerase chain reaction (RT-PCR). RNA was isolated from peripheral blood leukocytes and subjected to multiplex RT-PCR in which expression of SNRPN and a constituitively expressed internal control gene were analyzed. The amplified products were electrophoresed in agarose gels and visualized by ethidium bromide staining.

RESULTS

Multiplex RT-PCR was applied to RNAs isolated from 30 normal control subjects and 30 well- characterized PWS patients. All control patients expressed the SNRPN and internal control genes. In contrast, all 30 PWS patients demonstrated loss of SNRPN expression, with integrity of RNA being demonstrated by the presence of internal control gene expression.

CONCLUSIONS

Loss of SNRPN expression appears to be a consistent finding in PWS. Expression analysis of SNRPN offers a novel approach for the diagnostic evaluation of PWS that is robust and can be performed in a single day.

Randomized in vitro and in vivo evaluation of different biopsy needles and devices for breast biopsy

In an experimental study (in vitro and in vivo) we evaluated the efficacy of various biopsy needles/devices for breast biopsy. In vitro, biopsies of five human cadaveric breast specimens were performed using 33 different needles/devices ranging from 14 to 20-gauge. Of these 33 needles/devices, 22 optimally performing needles were selected for the in vivo study. In the clinical part of the study, 44 breast lesions were randomly biopsied with each of the 22 needles/devices under stereotactic guidance. Tissue specimens were analysed quantitatively and qualitatively. Several automatic long-throw guns (Acecut, Asap, Biopty, Magnum) obtained greater tissue areas and had a better histopathologic score than the conventional type of a side-notch needle like Trucut, an aspiration needle like Surecut, or an end-cut needle like Autovac. The automatic long-throw guns performed better than the short-throw Monopty gun. Regardless of needle size (14-20-gauge), breast biopsies should be routinely performed with automated long-throw side-notch guns (Acecut, Asap, Biopty, Magnum).

Matrix metalloproteinase-9 (gelatinase B) is selectively elevated in CSF during relapses and stable phases of multiple sclerosis

Matrix metalloproteinases (MMPs) are a family of endopeptidases capable of enzymatic digestion of subendothelial basement membrane and other components of the extracellular matrix. Expression of MMP-2, -3, -7 and -9 is increased around multiple sclerosis plaques and in brain tissue in experimental allergic encephalomyelitis. To measure quantitatively the expression of these MMPs and their endogenous inhibitors (TIMP-1 and -2), we analysed samples from 52 patients with relapsing-remitting and primary progressive multiple sclerosis by ELISA (enzyme-linked immunosorbent assay) and substrate-gel electrophoresis (zymography). MMP-9 was increased over controls in 100% of relapsing-remitting multiple sclerosis cases, with similar levels detected in relapses and clinically stable phases of disease. In primary progressive multiple sclerosis, MMP-9 was increased in 57% of CSF samples, but concentrations were below those encountered in the relapsing-remitting form. The selective upregulation of MMP-9 suggests that T-cells and macrophages invading the brain parenchyma and the CSF space are the predominant source of MMP-9 in multiple sclerosis. TIMPs and other MMPs (MMP-2 and -3) were not upregulated or not detectable (MMP-7) in CSF of patients with relapsing-remitting and primary progressive multiple sclerosis. The sustained increase of MMP-9 in clinically stable multiple sclerosis supports the concept that multiple sclerosis is associated with ongoing proteolysis that may result in progressive tissue damage. The selective inhibition of MMP-9 could be a useful approach for the prevention of disease progression in multiple sclerosis.

[Computer-assisted quantitative evaluation method of color Doppler images in tumor diagnosis]

METHODS

This article reviews methods for objective color Doppler quantification. The principles, limitations and reliability of an objective computer-assisted method of quantitative color Doppler image analysis are described and its role in the assessment of tumor vascularization with regard to differential diagnosis, prognosis and monitoring of therapy effects is evaluated.

DISCUSSION

Color Doppler images are quantitatively characterized by the percentage of color pixels in a selected region of interest and the flow velocities corresponding to the encoding colors.

Chloride channels ClC-2 and ICln mRNA expression differs in renal epithelial ontogeny

Development-dependent mRNA expression of the chloride channels ClC-2 and ICln was studied by quantitative reverse transcriptase-polymerase chain reaction in rat ureteric bud and cortical collecting duct primary monolayer cultures. Abundance of ClC-2 mRNA increased in ureteric bud cells between embryonic day 15 (E15) and E17, peaked at postnatal day 3 (P3), and was down-regulated at P7 when morphogenesis is complete, suggesting a specific embryonic function. Expression of ICln mRNA, in contrast, up-regulated continuously with development.

Detection of multiple vascular endothelial growth factor splice isoforms in single glomerular podocytes

Glomerular podocytes are major determinants of filtration permselectivity in the glomerulus. Although the molecular mechanisms determining the characteristics of the glomerular filtration unit are incompletely understood, vascular endothelial growth factor (VEGF) has been implicated. To analyze this process in situ, we established a method that allows exploration of in vivo mRNA expression of podocytes using single-cell reverse transcriptase-polymerase chain reaction (RT-PCR). Microdissected mouse glomeruli were held in a patch-clamp apparatus, and single podocytes were harvested by aspiration. After lysis, the cells were reverse transcribed, and PCR was performed (45 cycles). The podocyte nature of the material was confirmed by detection of podocyte-specific mRNA (glomerular epithelial protein 1 and Wilms' tumor protein 1). Using specific oligonucleotide primers, VEGF was detected in mRNA obtained from renal cortex, single microdissected glomeruli, cultured murine podocytes, and single podocytes in situ. All cells examined expressed three VEGF isoforms (121, 165, and 189). These differ in their capacity for binding to extracellular matrix and could have different potencies regulating glomerular endothelial permeability. Our approach should allow a semiquantitative, isoform-specific evaluation of VEGF mRNA expression in podocytes during nephrogenesis and in glomerular disease.

Subplasmalemmal Ca-stores in Paramecium tetraurelia. Identification and characterisation of a sarco(endo)plasmic reticulum-like Ca(2+)-ATPase by phosphoenzyme intermediate formation and its inhibition by caffeine

Considering increasing interest in calcium stores in protozoa, including parasitic forms, and specifically in subplasmalemmal stores in higher eukaryotes, we have isolated subplasmalemmal calcium stores (alveolar sacs) from the ciliated protozoan, Paramecium tetraurelia. Using antibodies against established sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCAs) we detected in Western blots of subcellular fractions a band of approximately 106 kDa size selectively in alveolar sacs--but not, for example, in plasma membranes--and concomitant restriction of immunofluorecence labelling to the cell cortex of permeabilised cells. These results are the same as with ABs against a peptide derived from a cloned SERCA-like gene from Paramecium [Hauser K., Pavlovic N., Kissmehl R., Plattner H. Molecular characterization of a sarco(endo)plasmic reticulum Ca(2+)-ATPase gene from Paramecium tetraurelia and localisation of its gene product to subplasmalemmal calcium stores. Biochem J 1998; 334: 31-38]. When such isolated alveolar sacs were now tested for phosphoenzyme intermediate (EP) formation, a phosphoprotein of the same apparent molecular mass (approximately 106 kDa) as in blots could be identified in gel autoradiograms. This EP corresponds to that formed in the reaction cycle of different SERCA-types, with dependency on Ca2+ and Mg2+, sensitivity to La3+ or insensitivity towards calmodulin, calmodulin antagonists and vanadate. However, EP formation in alveolar sacs is not inhibited by established SERCA inhibitors (e.g. thapsigargi[ci]n tested up to 100 microM). Surprisingly, caffeine, which is frequently used to mobilise Ca2+ from intracellular stores, strongly inhibits EP formation. In parallel experiments, we did not find any similar effect with sarcoplasmic reticulum isolated from skeletal muscle. We conclude that the approximately 106 kDa protein of alveolar sacs in Paramecium may represent a SERCA-like Ca(2+)-ATPase with some unorthodox features, which might be relevant also for some other protozoan systems. In this case, the established Ca(2+)-mobilizing effect of caffeine may be amplified by inhibiting store refilling.

Human myelin basic protein specific T cell lines display differential cytotoxicity against astrocytes, but are consistently cytotoxic against monocytes

In experimental allergic encephalomyelitis (EAE) myelin basic protein (MBP) specific T cells differ in their encephalitogenic potential. To investigate the functional diversity of human MBP specific T cell lines, we analysed their cytotoxic activity against human astrocytes and monocytes. Five out of 14 MBP specific T cell lines killed astrocytes in the presence of MBP. Nevertheless, all lines lysed blood derived monocytes. T cell lines that lysed astrocytes efficiently in the presence of MBP, recognized peptide aa 80-99/86-105 in context with HLA-DRB5 * 0101, peptide aa 50-69/61-83 in context with HLA-DRB1 * 1501 and peptides aa 139-153, and aa 148-162 in context with HLA-DRB1 * 0101. There was no correlation of MBP-mediated lysis of astrocytes with TCR-Vbeta usage, HLA-restriction and the production of tumor-necrosis-factor-alpha (TNF-alpha), lymphotoxin (LT) and interferon-gamma (IFN-gamma). Different lysis of astrocytes, however, revealed a functional heterogeneity of MBP specific T cells, which was not observed by using monocytes as targets.

Effects of a microbubble contrast agent on breast tumors: computer-assisted quantitative assessment with color Doppler US--early experience

PURPOSE

To evaluate objectively the effects of a microbubble contrast agent on the color Doppler ultrasound (US) examination of breast lesions.

MATERIALS AND METHODS

Forty-seven patients aged 23-71 years underwent color Doppler US before and after intravenous injection of a microbubble contrast agent. A 3-minute computer-assisted assessment of the color pixel density (CPD) was used to evaluate objectively the increase in the number of color Doppler US signals, the transit time of the microbubble bolus, and the potential additional differential diagnostic information.

RESULTS

Peak CPD at contrast agent-enhanced color Doppler US was 14.3% +/- 8.1 (mean +/- 1 standard deviation) for carcinomas and 9.3% +/- 4.9 for benign lesions (P = .04). The time to peak enhancement was shorter in carcinomas (38 seconds +/- 20) than in benign tumors (71 seconds +/- 48, P = .02). Final CPD was close or equal to baseline values. With the median of 13% for peak CPD as a threshold, the sensitivity for this parameter was 55%, the specificity was 79%, and the accuracy was 62% (P = .04). For a median time to peak of 50 seconds, the sensitivity was 84%, the specificity was 57%, and the accuracy was 76%.

CONCLUSION

After microbubble contrast agent injection, carcinomas and benign lesions behave differently in degree, onset, and duration of Doppler US enhancement. High interindividual variability and temporal variations in the Doppler US signal still limit the value of these criteria for prospective diagnosis.

Activated protein C resistance assay performance: improvement by sample dilution with factor V-deficient plasma

OBJECTIVE

To evaluate a modification of a commercially available reagent kit (COATEST APC Resistance Kit) for functional activated protein C (APC) resistance testing, and to determine the ability of the modified assay to demonstrate APC resistance in patients receiving warfarin.

DESIGN

Functional APC resistance testing was performed using both the first-generation COATEST APC Resistance Kit and a modified, or second-generation, version of the COATEST assay that uses predilution of the patient sample with factor V-deficient plasma. Factor V genotyping for APC resistance (FV R506Q) was performed using a well-characterized polymerase chain reaction-restriction fragment length polymorphism method.

SETTING

University medical center.

PATIENTS

Seventy-three individuals referred for hypercoagulability testing who were not receiving warfarin therapy and 29 patients with a history of venous thrombosis who were receiving warfarin therapy.

MAIN OUTCOME MEASURE

Sensitivity and specificity as determined by comparing functional APC resistance to the FV R506Q genotype.

RESULTS

In 73 patients referred for hypercoagulability testing, but not receiving warfarin therapy, a sensitivity of 0.86 and a specificity of 0.75 were obtained with the first-generation COATEST assay. In contrast, a sensitivity and specificity of 1.0 were obtained when the second-generation COATEST assay was employed. In 29 patients receiving warfarin, the first-generation assay exhibited a sensitivity and specificity of 0.88 and 0.95, respectively, whereas the sensitivity and specificity for the second-generation assay was 1.0.

CONCLUSIONS

Predilution of patient plasma with factor V-deficient plasma results in improved sensitivity and specificity of the COATEST APC Resistance Kit, thus offering a simple modification to enhance APC resistance determination in the routine clinical laboratory setting.

[Dynamic assessment of contrast medium enhancement in Doppler ultrasound imaging. Current status]

Findings in previous investigations have indicated that contrast-enhanced colour Doppler can be used to improve the demonstration of characteristic features of neovascularization in malignancies. However, the quantification of the increase in colour Doppler signals after Levovist in the cited study relied only on descriptive criteria defined by the investigator, resulting in a subjective scoring system. A computer-assisted method for quantitative analysis of colour pixel density is a novel approach for objective assessment of colour Doppler signal after contrast media administration. After microbubble contrast medium injection in 47 patients, carcinomas and benign lesions behaved differently regarding degree, onset and duration of Doppler enhancement. However, the high interindividual variability and the temporal variations of the Doppler signal still limit the value of these criteria for prospective diagnosis. Rapid image-acquisition techniques are needed in order to apply the necessary mathematical processing before the contrast kinetics can be used for diagnostic purposes.

[A multicenter study of diagnostic criteria in ultrasound mammography. Statistical pitfalls and ways out of the data jungle]

This paper demonstrates the statistical processing of data from a multicentric study. Seventy-seven patients with a suspicious, solid breast mass were included in a two-center study, using clinical breast examination, mammography, and ultrasound. The assessment was formalized using a uniform evaluation sheet. The prospective results of the examinations were compared with the histologic report. The degree of interdependence between an examiner's diagnosis and diagnostic criteria used was assessed using the kappa statistics. We found that despite standardized assessment, the criteria used for differential diagnosis were at least partially different. The criteria valid for diagnosis at both centers were whether a mass fitted well into the surrounding tissue or led to destruction or architectural distortion, whether it was fixed to the surrounding tissues, as assessed by sonopalpation maneuvers, and whether it borders were sharp or unsharp.

Single cell RT-PCR analysis of ClC-2 mRNA expression in ureteric bud tip

Embryonic epithelia at the tip of the ureteric bud (UB) face the interspace between epithelial and mesenchymal cells and are fundamentally involved in reciprocal signaling during early nephrogenesis. To characterize their membrane conductive proteins, patch-clamp and single cell RT-PCR techniques were applied to embryonic rat UBs [embryonic day 17 (day E17)] microdissected from the outer cortex. Cells at the UB tip had a high whole cell conductance (14 +/- 2 nS/10 pF, n = 8). The main fractional conductance resembled that of Ca-activated Cl channels in nonepithelial cells, with its time-dependent activation at depolarizing and inactivation at hyperpolarizing voltages. A second Cl-selective current fraction, by contrast, activated slowly during strong hyperpolarization, suggestive of a ClC-2-mediated conductance. To determine the origin of this current, cytoplasm was harvested into the patch pipette, RNA was reverse transcribed, and cDNA encoding the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) housekeeper gene or the ClC-2 Cl channel was amplified by polymerase chain reaction (PCR). GAPDH and ClC-2 PCR products were identified in 23 and 8 (out of a total of 57) single cell cDNA samples, respectively. ClC-2 PCR products with two different lengths were obtained, which might be due to two alternatively spliced ClC-2 mRNA isoforms. This first and combined approach by patch-clamp and single cell RT-PCR techniques to embryonic epithelia indicates that 1) cells at the UB tip express a phenotype remarkably different from that of postembryonic collecting duct principal cells and that 2) ClC-2 is likely to have a key role in early nephrogenesis.

Doppler ultrasound in the diagnosis of breast lesions

This article reviews the current status of Doppler sonography in breast neoplasms. The results already reported in the literature all indicate that more vessels are displayed and higher flow velocities are measured in malignant tumors than in benign conditions. The potential role of Doppler sonography remains to be definitively determined. It appears that high measured flow velocities and markedly elevated number of detectable vessel density indicate malignancy. However, Doppler sonography does not make it possible to rule out cancer, since a subset of malignant tumors show few Doppler signals or none at all. The use of Doppler sonography for monitoring the results of treatment is currently being evaluated.

Expression of glucose transporters in human peritoneal mesothelial cells

Glucose containing solutions, the basis of peritoneal dialysis fluids, affect the proliferation and regeneration of peritoneal mesothelial cells (MsC). The aim of this study was to examine mechanisms of glucose transport into MsC, that is, the expression of facilitative glucose transporters (GLUT) and the Na(+)-dependent glucose transporter (SGLT1) in human primary MsC and a transfected MsC line. Since expression of both transporters is differentiation dependent, we investigated the effects of cell differentiation induced by culturing MsC on membranes or by addition of hexamethylene bisacetamide (HMBA; 6 mM), which enhances SGLT1 expression in LLC-PK1 cells. Levels of mRNA for GLUT1 through GLUT4 and SGLT1 were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR). The presence of the corresponding proteins was examined by Western blotting and localized by immunofluorescence. Active, Na(+)-dependent glucose transport was assessed by alpha-methyl-D-[14C]glucopyranoside (AMG) with and without the SGLT1-specific inhibitor phlorizin and by patch clamp experiments in NaCl or choline-chloride, For Na(+) dependent glucose uptake choline chloride instead of NaCl served as negative control. Facilitative transport was assessed using 2-fluoro-2-deoxy-[14C]-D-glucose (FDG) with and without the inhibitors cytochalasin B or phloretin. Primary and transfected MsC express GLUT1 and GLUT3 mRNA while no transcripts were found for GLUT2 and GLUT4. No SGLT1 transcript was detectable in subconfluent cells. Semiquantitative RT-PCR analysis documented that the addition of the differentiation inducer HMBA to confluent cultures or growth of MsC on membranes for seven days produced a down-regulation of mRNA for GLUT1, no change for GLUT3, and a substantial increase for SGLT1 mRNA. Under these conditions MsC express SGLT1 protein and possess a Na(+)-dependent glucose uptake as assessed by AMG. Phlorizin (1 mM) inhibits AMG uptake by 30 to 40%. In patch clamp experiments the addition of extracellular glucose depolarized the membrane potential only in the presence of sodium. These results indicate that differentiated MsC express GLUT1, GLUT3, and SGLT1. Further characterization of these transport mechanisms and their regulation may help to understand the cellular effects of glucose on MsC in peritoneal dialysis.

Doppler sonography of breast tumours

BACKGROUND

Doppler sonography has been used in breast tumours mainly for differential diagnostic purposes. Since angiogenesis appears to be related to the patient's prognosis, Doppler sonography may also have prognostic implications.

CURRENT STATUS

CW Doppler was initially used, but is now obsolete. Contemporary studies are carried out using colour Doppler. Quantification of colour Doppler is not available on ultrasound platforms, but has been developed for off-line analysis by several investigators. Vascular density and flow velocities are found to be higher in malignant than in benign tumours. However, in some malignant lesions, flow may be undetectable. Though the actual role of the method in differential diagnosis is still controversial, it may improve diagnostic confidence when performed by an experienced examiner.

PERSPECTIVES

Future fields of application currently being explored include monitoring of preoperative chemotherapy and prognostic assessment. Developments in the field of contrast media and scanner technology may further improve the quantitative estimation of tumour blood flow.

Colour Doppler sonography in breast tumours: an update

The aim of our study was to reassess the diagnostic performance of image-based, computer-assisted colour Doppler quantification under routine conditions. We used a computer-assisted protocol that quantitatively characterises a colour Doppler image by the relative amount of colour pixels (colour pixel density, CPD) and the colour hues (numerically expressed by the mean colour value, MCV) in 44 patients with breast carcinoma and 49 patients with benign breast lesions. Studies were carried out over two periods by two examiners, subsequently in charge of breast ultrasound. During the first period, the sensitivity of the MCV was 92 %, the specificity 75 %; the sensitivity of the CPD was 80 %, the specificity 81 %. During the second period, the sensitivity of the MCV was 58 %, the specificity 77 %; the sensitivity of the CPD was 68 %, the specificity 71 %. Despite measures to create uniform examination conditions, the diagnostic performance of this method may decline under routine conditions.

Computer assisted retraining of attentional impairments in patients with multiple sclerosis

OBJECTIVE

To evaluate the efficacy of a computer based retraining of specific impairments of four different attentional domains in patients with multiple sclerosis.

METHODS

Twenty two outpatients with multiple sclerosis received consecutively a specific training comprising 12 sessions in each of the two most impaired attention functions. The baseline of attentional deficits, the performance after each training period, and the course of performance in the next nine weeks was assessed by a computerised attention test battery. Additionally, the impact of the training on daily functioning was evaluated with a self rating inventory.

RESULTS

Subgroups of patients with multiple sclerosis showing different patterns of attentional impairment could be separated. Significant improvements of performance could almost exclusively be achieved by the specific training programmes. The increase of performance remained stable for at least nine weeks. For quality of life patients reported less attention related problems in everyday situations.

CONCLUSIONS

In patients with multiple sclerosis it seems worthwhile to assess attentional functions in detail and to train specific attention impairments selectively.

CFTR mRNA and its truncated splice variant (TRN-CFTR) are differentially expressed during collecting duct ontogeny

The collecting duct epithelium originates from the embryonic ureter by branching morphogenesis. Ontogeny-dependent changes of CFTR mRNA expression were assessed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in primary monolayer cultures of rat ureteric buds (UB) and cortical collecting ducts, microdissected at different embryonic and postnatal developmental stages. The amount of wild-type CFTR-specific PCR product in UB declined to 20% of the initial value between embryonic gestational day E15 and postnatal day P1. After birth the CFTR product increased transiently between P1 and P7 by a factor of 10 and decreased towards day P14. PCR products specific for TRN-CFTR, a truncated splice variant, however, were low in early embryonic cells, increased markedly between day E17 and P2, and reached a plateau postnatally. Therefore, mRNA encoding TRN-CFTR does not appear to have a specific embryonic-morphogenetic function. By contrast, such function is suggested for wild-type CFTR mRNA as its abundance was high in early embryonic nephrogenesis, as well as during a postnatal period shortly before branching morphogenesis is completed.

Analysis of mouse glomerular podocyte mRNA by single-cell reverse transcription-polymerase chain reaction

Selective investigation of glomerular podocytes is not possible using conventional methods in vivo. Analysis of glomerular epithelium-derived cells in culture yields dubious results because of the rapid dedifferentiation of podocytes. We developed a modification of the polymerase chain reaction (PCR) method previously used to analyze cultured neurons. Podocytes harvested from freshly dissected glomeruli are ideal target cells for this modified, single cell reverse transcription-PCR method to reproducibly identify specific mRNA species from resident intact podocytes in vivo.

Reciprocal expression of myelin-associated glycoprotein splice variants in the adult human peripheral and central nervous systems

The L- and S-MAG isoforms differ only at their C-terminus and are believed to be functionally distinct. To obtain information on the relative expression of these alternatively spliced isoforms in humans, we cloned an S-MAG cDNA fragment. The deduced amino-acid sequence of the human S-MAG C-terminus shows fairly conservative substitutions of 4 out of the 10 residues compared to the rodent peptide. Using reverse transcription and a competitive polymerase chain reaction, we show that, in contrast to rodents, the L-MAG splice variant predominates in adult human brain while, like in rodents, S-MAG transcripts are most abundant in peripheral nerve. The results obtained by Western blot analysis and immunohistochemistry are in good agreement with the findings at the mRNA level. Animal experiments may thus be more representative for the role of MAG in human nerve than in brain.

Epithelial nephrogenesis

The metanephric, or definitive, kidney forms as a result of inductive processes between tissues of two distinct embryologic origins, the metanephric mesenchymal blastema and the ureteric bud. After inductive signalling between these primordial tissues, mesenchymal cells aggregate next to the branching ureteric bud tip, convert to epithelial cells and differentiate into the diverse cell populations of the nephron. The ureteric bud enters branching morphogenesis and gives rise to the collecting duct system. Nephrogenesis has become a target system by which to study developmental processes including embryonic inductive interactions, mesenchyme-to-epithelium conversion, cell lineage pathways, epithelial cell polarization, branching morphogenesis and spatio-temporal expression of transcription factors. This review summarizes data on cellular and extracellular events during epithelial metanephrogenesis.

Reduced glucose metabolism in the frontal cortex and basal ganglia of multiple sclerosis patients with fatigue: a 18F-fluorodeoxyglucose positron emission tomography study

To investigate the pathophysiology of fatigue in MS, we assessed cerebral glucose metabolism (CMR-Glu) in 47 MS patients using PET and 18F-fluorodeoxyglucose. Applying the Fatigue Severity Scale (FSS), we first compared MS patients with severe fatigue (MS-FAT, n = 19, FSS > 4.9) and MS patients without fatigue (MS-NOF, n = 16, FSS < 3.7) on a pixel-by-pixel basis using Statistical Parametric Mapping (SPM95). Second, we compared FSS values of all 47 patients covering the whole range of this scale with CMRGlu using an analysis of covariance (SPM95). In addition, we determined global CMRGlu by region-of-interest analysis. Sixteen healthy subjects served as control subjects (CON). Global CMRGlu was significantly lower in both MS groups compared with CON (CON 43.3 +/- 6.9 mumol/100 mL/min, MS-FAT 34.7 +/- 4.4, MS-NOF 35.4 +/- 4.5) but was not related to fatigue severity. Comparing the two MS groups, SPM95 analysis revealed predominant CMRGlu reductions bilaterally in a prefrontal area involving the lateral and medial prefrontal cortex and adjacent white matter, in the premotor cortex, putamen, and in the right supplementary motor area of MS-FAT. In addition, there were CMRGlu reductions in the white matter extending from the rostral putamen toward the lateral head of the caudate nucleus. FSS values were inversely related to CMRGlu in the right prefrontal cortex. CMRGlu in the cerebellar vermis and anterior cingulate was relatively higher in MS-FAT than in MS-NOF patients. CMRGlu of both regions showed positive correlations with FSS values. Our data suggest that fatigue in MS is associated with frontal cortex and basal ganglia dysfunction that could result from demyelination of the frontal white matter.

[Diagnosis and differential diagnosis in multiple sclerosis]

The diagnosis of multiple sclerosis (MS) relies on the occurrence of characteristic symptoms, on the patient's history and on the correct interpretation of nowadays very sensitive but not very specific auxillary examinations. This paper reviews the diagnostic criteria and typical signs and symptoms of the disease. The significance of cerebrospinal fluid (CSF) analysis, magnetic resonance imaging (MRI) and evoked potentials is discussed, with emphasis on their predictive value concerning the development of MS after a first episode with symptoms suggestive of MS. A wide range of other diseases mimicking MS, like infectious, autoimmune, granulomatous, metabolic and hereditary diseases is reviewed. A checklist for important points in patient history and further investigations is proposed.

A mutation in the puff region of VP2 attenuates the myocarditic phenotype of an infectious cDNA of the Woodruff variant of coxsackievirus B3

Coxsackievirus B3 (CVB3) infections induce myocarditis in humans and mice. Little is known about the molecular characteristics of CVB3 that activate the cellular immunity responsible for cardiac inflammation. Previous experiments have identified an antibody escape mutant (H310A1) of a myocarditic variant of CVB3 (H3) that attenuates the myocarditic potential of the virus in mice in spite of ongoing viral replication in the heart. We have cloned full-length infectious cDNA copies of the viral genome of both the wild-type myocarditic H3 variant of CVB3 and the antibody escape mutant H310A1. Progeny viruses maintained the myocarditic and attenuated myocarditic potential of the parent viruses, H3 and H310A1. The full sequence of the H3 viral cDNA is reported and compared with those of previously published CVB3 variants. Comparison of the full sequences of H3 and H310A1 viruses identified a single nonconserved mutation (A to G) in the P1 polyprotein region at nucleotide 1442 resulting in an asparagine-to-aspartate mutation in amino acid 165 of VP2. This mutation is in a region that corresponds to the puff region of VP2. Nucleotide 1442 of the H3 and H310A1 cDNA copies of the viral genome was mutated to change amino acid 165 of VP2 to aspartate and asparagine, respectively. The presence of asparagine at amino acid 165 of VP2 is associated with the myocarditic phenotype, while an aspartate at the same site reduces the myocarditic potential of the virus. In addition, high-level production of tumor necrosis factor alpha by infected BALB/c monocytes is associated with asparagine at amino acid 165 of VP2 as has been previously demonstrated for the H3 virus. These findings identify potentially important differences between the H3 variant of CVB3 and other previously published CVB3 variants. In addition, the data demonstrate that a point mutation in the puff region of VP2 can markedly alter the ability of CVB3 to induce myocarditis in mice and tumor necrosis factor alpha secretion from infected BALB/c monocytes.

Expression of IGFBP-2, -3, and -4 mRNA during differentiation of Caco-2 colon epithelial cells

Local production of insulin-like growth factor (IGF)-binding proteins (IGFBP) determines the availability of the IGF to the cell and thus regulates IGF action. To find out whether specific patterns of IGFBP gene expression and IGFBP secretion were related to cell growth vs. cell differentiation, expression of IGFBP during long-term culture (21 days, n = 5) of the colon carcinoma cell line Caco-2 was investigated at the mRNA and protein levels. Markers of cell proliferation (increase in DNA, RNA, and protein content) and of differentiation [alkaline phosphatase (AP) activity; creatine kinase (CK) activity] were measured in parallel during long-term culture. IGFBP-2 mRNA expression correlated significantly with markers of proliferation (P < 0.05), whereas IGFBP-3 mRNA expression or IGFBP-3 secretion correlated with markers of differentiation (AP: r = 0.83, P < 0.001; CK: r = 0.45, P < 0.01). Similarly, IGFBP-4 mRNA expression correlated significantly with markers of differentiation (AP: r = 0.34, P < 0.05; CK: r = 0.35, P < 0.05). We hypothesize that IGFBP-3 and -4 are related to differentiation of Caco-2 cells, whereas IGFBP-2 is related to proliferation in Caco-2 cells.

[Multiple sclerosis: therapy with recombinant beta-1b interferon: initial results with 30 multiple sclerosis patients in northwest Switzerland]

Recombinant interferon beta-1b has been registered with the Swiss health authorities since August 1995. Due to a special arrangement with health insurances it has been possible to prescribe this medication since spring 1995. We report on our experience with the first 30 consecutively treated multiple sclerosis patients. Indication, adverse event profile and clinical response to treatment are described. The most common side effects were local injection site reactions (63%), influenza-like symptoms (50%) and fatigue (33%). As compared to the prestudy period we observed a 49% reduction in the exacerbation rate. Compliance was excellent, possibly due to strict selection and extensive information about possible effects and side effects.

Coordinate expression of insulin-like growth factor II (IGF-II) and IGF-II/mannose-6-phosphate receptor mRNA and stable expression of IGF-I receptor mRNA during differentiation of human colon carcinoma cells (Caco-2)

Insulin-like growth factor II (IGF-II) has been implicated in the differentiation of skeletal muscle cells. In this study the putative role of IGF-II in epithelial cell differentiation was investigated. The expression of IGF-II, IGF-I receptor and IGF-II/mannose-6-phosphate receptor (IGF-II/M6P receptor) mRNA during spontaneous differentiation of the colon carcinoma cell line Caco-2 was measured. In addition, differentiation of Caco-2 cells during the cell culture period (days 1-21 in culture) was studied in parallel using morphological (light and scanning electron microscopy) and biochemical markers of growth (DNA, RNA and protein content, and beta-actin mRNA and glyceraldehyde phosphate dehydrogenase mRNA expression) and differentiation (alkaline phosphatase activity, carcinoembryonic antigen content). A putative correlation between the markers of growth and differentiation and IGF gene expression was studied using linear regression analysis. Expression of IGF-II mRNA and IGF-II/M6P receptor mRNA correlated significantly with the progress of differentiation, while the IGF-I receptor was stably expressed throughout the culture period and exhibited a crucial role for the survival of Caco-2 cells, as shown by blocking experiments employing the monoclonal anti-IGF-I receptor antibody alpha-IR3. We hypothesize that: IGF-II mRNA and IGF-II/M6P receptor mRNA are expressed in a coordinate fashion during the differentiation of Caco-2 cells; coordinate expression of IGF-II and of IGF-II/M6P receptor mRNA might point to a role for IGF-II as a growth stimulant and for the IGF-II/M6P receptor for a regulator of IGF-II bioavailability in differentiating cells; alternatively, high IGF-II/M6P receptor mRNA and protein expression in differentiated cells but low IGF-II binding to the IGF-II/M6P receptor point to an important intracellular role of this receptor type in differentiated colon epithelial cells; the IGF-I receptor mRNA is stably expressed during the differentiation process of Caco-2 cells; the IGF-I receptor protein seems to be a prerequisite for the survival of Caco-2 cells.

Factor V R506Q gene mutation analysis by PCR-RFLP: optimization, comparison with functional testing for resistance to activated protein C, and establishment of cell line controls

Resistance to activated protein C (APC) has been recently identified as a highly prevalent risk factor for the development of venous thrombosis. In the majority of cases, APC resistance correlates with the presence of a single point mutation in the factor V gene (FV R506Q). The mutation is present in 3% to 5% of the general population and in up to 50% of patients with a personal and family history of venous thrombosis. In the current study, the authors have optimized and implemented for clinical diagnosis a method for detection of FV R506Q using the polymerase chain reaction coupled with restriction fragment length polymorphism analysis (PCR-RFLP). Forty-one healthy adults and 139 patients referred for hypercoagulability testing were genotyped and their APC resistance ratios determined using commercially available reagents (COATEST APC Resistance Kit). Comparative analysis indicated that if functional APC resistance was defined as per manufacturer's guidelines, a significant number of individuals with a normal factor V genotype were categorized as APC resistant and conversely, a significant number of individuals heterozygous for FV R506Q were categorized as non-APC resistant. These results indicate that comparative functional and genotypic analyses in the individual clinical laboratory setting are critical for establishing normal ranges and cut-off values for functional APC resistance due to FV R506Q. To facilitate molecular evaluation of APC resistance, Epstein-Barr virus (EBV) immortalized B-lymphocyte cell lines were established from individuals heterozygous and homozygous for FV R506Q.

Differential expression of perforin in muscle-infiltrating T cells in polymyositis and dermatomyositis

Polymyositis (PM) and dermatomyositis (DM) are the prototypical inflammatory diseases of skeletal muscle. In PM, CD8+ T cells invade and destroy muscle fibers, whereas humoral effector mechanisms prevail in DM. We studied the expression of the cytotoxic mediator perforin in inflammatory cells in PM and DM muscle by semiquantitative PCR, immunohistochemistry and confocal laser microscopy. Similar levels of perforin mRNA were expressed in PM and DM, and abundant perforin-expressing CD3+CD8+ and CD3+ CD4+ T cells were observed in both diseases. However, there was a striking difference in the intracellular localization of perforin. In DM, perforin was distributed randomly in the cytoplasm of the inflammatory T cells. In contrast, 43% of the CD8+ T cells that contacted a muscle fiber in PM showed perforin located vectorially towards the target muscle fiber. The results suggest (a) that the random distribution of perforin in the cytoplasm of muscle-infiltrating T cells observed in DM reflects nonspecific activation, and (b) that the vectorial orientation observed only in PM reflects the specific recognition via the T cell receptor of an antigen on the muscle fiber surface, pointing to a perforin- and secretion-dependent mechanism of muscle fiber injury.

Detection of clonal immunoglobulin heavy-chain gene rearrangements in cases of suspected lymphoproliferative disorders: comparison of polymerase chain reaction and Southern blot analysis

Demonstration of clonality is supportive of a diagnosis of malignancy in cases of lymphoproliferative disorders. Determination of clonality at the molecular level is currently accomplished by Southern analysis; however, the polymerase chain reaction offers a potential alternative that is rapid, simple, and less expensive. To test its feasibility as a diagnostic test, we amplified the DNA from 121 suspected lymphoproliferative disorders submitted for gene rearrangement studies. In comparison to Southern analyses, a sensitivity of 70% and specificity of 96% were obtained. To test the effect of primer variability in the joining region of the heavy-chain gene, we substituted a more degenerate primer but found no changes in sensitivity or specificity. We conclude that the polymerase chain reaction has current application with minute or fixed specimens and may generally serve as a rapid, initial evaluation for B-cell clonality, followed by Southern analysis in negative cases. However, higher overall sensitivity must be achieved before this technique can replace Southern analysis as the method of choice in determining clonal gene rearrangements.

Genetic control of multiple sclerosis: increased production of lymphotoxin and tumor necrosis factor-alpha by HLA-DR2+ T cells

Lymphotoxin (LT) and tumor necrosis factor-alpha (TNF-alpha) play an important role in the pathogenesis of multiple sclerosis (MS). MS is associated with the HLA-DR2, Dw2, DQ6 HLA class II haplotype. Because both LT and TNF-alpha are encoded in the HLA region, the HLA association of MS may be related to the production of these cytokines. To test this hypothesis, we investigated the production of LT, TNF-alpha, and interferon-gamma (IFN-gamma) by CD4+ T-cell lines (TCLs) specific for myelin basic protein (MBP) or tetanus toxoid (TT) isolated from MS patients and normal controls. After stimulation with specific antigen but not mitogen, TCLs from HLA-DR2+ donors produced significantly more LT and TNF-alpha than TCLs from DR2- donors. In contrast, HLA-DR2+ and DR2- TCLs did not differ in the production of IFN-gamma, a cytokine also produced by T cells but not encoded in the HLA region. Increased secretion of LT and TNF-alpha was unrelated to the specificity (MBP vs TT), MHC restriction (HLA-DR2 vs other DR molecules), or source (MS vs normal) of the TCLs. There was no significant association of the cytokine production with individual LT or TNF-alpha alleles, indicating that the increased production of these cytokines may be linked to other polymorphic genes in this region. The results suggest that the association of MS with HLA-DR2 implies a genetically determined propensity of T cells to produce increased amounts of LT and TNF-alpha.

The role of CD8+ T lymphocytes in coxsackievirus B3-induced myocarditis

Coxsackievirus infections have previously been shown to cause acute or chronic myocarditis in humans, and several mouse models have been established to study the pathology of this disease. Myocardial injury may result from direct viral effects and/or may be immune mediated. To determine the relative roles of these processes in pathogenesis, we have compared coxsackievirus B3 (CVB3) infections of normal and immuno-compromised transgenic knockout (ko) mice. CVB3 was able to infect all strains used (C57BL/6, CD4ko, and beta-microglobulin ko [beta 2Mko]), and following intraperitoneal injection, two disease processes could be distinguished. First, the virus caused early (3 to 7 days postinfection) death in a viral dose-dependent manner. Immunocompetent C57BL/6 mice were highly susceptible (50% lethal dose = 70 PFU), while immunodeficient transgenic ko mice were less susceptible, showing 10- and 180-fold increases in the 50% lethal dose (for CD4ko and beta 2Mko mice, respectively). Second, a histologic examination of surviving CD4ko mice at 7 days postinfection revealed severe myocarditis; the inflammatory infiltrate comprised 40 to 50% macrophages, 30 to 40% NK cells, and 10 to 20% CD8+ T lymphocytes. The infiltration resolved over the following 2 to 3 weeks, with resultant myocardial fibrosis. In vivo depletion of CD8+ T lymphocytes from these CD4ko mice led to a marked reduction in myocarditis and an increase in myocardial virus titers. beta 2Mko mice, which lack antiviral CD8+ T cells, are much less susceptible to early death and to the development of myocarditis. We conclude that our data support a strong immunopathologic component in CVB3-induced disease and implicate both CD4+ and CD8+ T cells. Compared with immunocompetent animals, (i) mice lacking CD4+ T cells (CD4ko) were more resistant to virus challenge, and (ii) mice lacking CD8+ T cells (beta 2Mko and in vivo-depleted CD4ko) showed enhanced survival and a reduced incidence of the later myocarditis. Nevertheless, the picture is complex, since (iii) removal of the CD4+ component, while protecting against early death, greatly magnified the severity of myocarditis, and (iv) removal of the CD8+ cells from CD4ko mice, although protecting against early death and later myocarditis, led to markedly increased virus titers in the heart. These data underscore the complex balance between the costs and benefits of effective antiviral immune responses.