Incidence of T wave alternation after acute myocardial infarction and correlation with other prognostic parameters: results of a prospective study

Tachycardia induced alternation of the T wave (TWA) has been associated with arrhythmia morbidity in mixed patient populations. However, less is known concerning the general incidence of TWA and its usefulness in risk stratification early after acute myocardial infarction (MI). TWA was prospectively and systematically assessed in 140 consecutive patients 15 +/- 6 days after acute MI and prior to discharge. Results of TWA measurements were compared to other noninvasive risk markers, LV function, and coronary angiography. Sustained TWA was present at rest or inducible during exercise in 27% of patients. The patient-specific heart rate for the onset of TWA was 98 +/- 9 beats/min. After multivariate analysis, TWA correlated with age (P = 0.02) and LV function (P = 0.002) and occurred more often in patients after nonanterior MI (P = 0.03). Acute results of Holter monitoring, late potentials by signal-averaged ECG, and heart rate variability were unrelated to the TWA status. During follow-up (451 +/- 210 days) two major arrhythmic events occurred. The incidence of TWA early after MI is about 25%. TWA is related to age and LV function but not to other common arrhythmia markers. Although TWA does not appear to be related to excessive cardiac morbidity, evaluation of the prognostic significance of TWA requires further study.

Interferon alfa down-regulates CD81 in patients with chronic hepatitis C

CD81 protein has been shown to bind hepatitis C virus (HCV) envelope 2 (E2) glycoprotein in vitro and may act as a (co)receptor for HCV. Regulation of CD81 expression by interferon alfa (IFN-alpha) and ribavirin could thereby affect the response to antiviral therapy. In the present study, the effects of IFN-alpha and ribavirin on CD81 protein and CD81 mRNA were assessed in peripheral blood lymphocytes (PBL) and isolated human hepatocytes by fluorescence-activated cell sorter (FACS) analysis and real-time polymerase chain reaction (PCR), respectively. In addition, regulation of CD81 in PBL was investigated in 10 patients treated with combination therapy. Incubation with IFN-alpha (50 U/mL) down-regulated total CD81 in PBL (81.7 +/- 11.6% of control; P =.003) and in isolated human hepatocytes (91.6 +/- 8.1% of control; P =.034). Incubation with IFN-alpha with and without ribavirin (2.2 microg/mL) significantly reduced cell surface-associated CD81 protein (83.9 +/- 10.3% of control; P =.003). PBL of untreated patients chronically infected with HCV had significantly higher levels of total CD81 protein compared with PBL obtained from healthy donors (631.1 +/- 93.3 vs. 538.9 +/- 95.2 relative fluorescence units [RFU]; P =.030). Pretreatment cell surface-associated CD81 protein was lower in patients infected with genotype HCV-3 than those infected with HCV-1 (111.8 +/- 15.0 vs. 162.0 +/- 41.3 RFU; P =.019). Furthermore, cell surface-associated CD81 protein was lower 4 weeks after initiation of therapy in patients with an initial virologic response compared with initial virologic nonresponders (110.5 +/- 8.5 vs. 139.8 +/- 27.5 RFU; P =.057). In conclusion, IFN-alpha and ribavirin regulate CD81 expression in vitro and in vivo. CD81 expression correlates with HCV genotype and initial virologic response in patients with chronic hepatitis C.

Functional heterogeneity of ROMK mutations linked to hyperprostaglandin E syndrome

BACKGROUND

The renal K(+) channel ROMK (Kir1.1) controls salt reabsorption in the kidney. Loss-of-function mutations in this channel cause hyperprostaglandin E syndrome/antenatal Bartter syndrome (HPS/aBS), which is characterized by severe renal salt and fluid wasting.

METHODS

We investigated 10 HPS/aBS patients for mutations in the ROMK gene by single-strand conformation polymorphism analysis (SSCA) and direct sequencing. To assess the functional consequences, Ba(2+)-sensitive K(+) currents were measured in five mutants of the core region as well as one mutant with truncated C-terminus, using the two-electrode voltage-clamp technique after an injection of mutant cRNA into Xenopus oocytes.

RESULTS

Three novel ROMK mutations were identified together with six mutations described previously. The mutations were categorized into three groups: (1) amino acid exchanges in the core region (M1-H5-M2), (2) truncation at the cytosolic C-terminus, and (3) deletions of putative promoter elements. While the core mutations W99C, N124K, and I142T led to significantly reduced macroscopic K(+) currents (1 to 8% of wild-type currents), the A103V and P110L variants retained substantial K(+) conductivity (23 and 35% of wild-type currents, respectively). Coexpression of A103V and P110L, resembling the compound heterozygous state of the affected individual, further reduced macroscopic currents to 9% of the wild-type currents. All mutants in the core region exerted a dominant-negative effect on wild-type ROMK1. The C-terminal frameshift (fs) mutation (H354fs) did not change current amplitudes compared with ROMK1 wild type, suggesting that a mechanism other than alteration of the electrophysiological properties may responsible for loss of channel activity.

CONCLUSIONS

Analysis of ROMK mutants linked to HPS/aBS revealed a spectrum of mechanisms accounting for loss of channel function. Further characterization of the molecular defects might be helpful for the development of new therapeutic approaches.

Vascularization of malignant and benign skin tumours measured by D-galactose-based signal-enhanced colour Doppler sonography

PURPOSE

Evaluation of colour Doppler criteria to differentiate between malignant and benign skin tumours on the basis of the degree of vascularization.

MATERIAL AND METHODS

The B-mode sonomorphology and the degree of vascularization in colour Doppler of 81 clinically potentially malignant tumours of cutaneous and subcutaneous structures were analyzed and quantified by number of intratumoral vessels per sonographic slice and percentage vessel area.

RESULTS

Of all criteria employed, counting the intratumoral vessels visible on one ultrasound slice after application of a signal-enhancing agent led to highest sensitivity (94%) of all used criteria but the specificity was poor (64%). The highest specificity (88%) and greatest diagnostic accuracy (86%) discriminating benign and malignant lesions were found using the criterion "percentage vessel area >5.0%" after all inflamed lesions had been excluded on the basis of clinical criteria. Plain colour Doppler increased the specificity up to 97%, although the sensitivity decreased simultaneously to max. 75%. Analysis of the B-mode morphology and spectral Doppler parameter of intratumoral vessels did not contribute to the differential diagnosis.

CONCLUSION

Signal-enhanced colour Doppler sonography is a valuable tool in the pretherapeutic assessment of cutaneous lesions. This method may be relevant for therapy and prognosis.

The electronic structure of the flavin cofactor in DNA photolyase

Density functional theory is used to calculate the electronic structure of the neutral flavin radical, FADH(*), formed in the light-induced electron-transfer reaction of DNA repair in cis,syn-cyclobutane pyrimidine dimer photolyases. Using the hybrid B3LYP functional together with the double-zeta basis set EPR-II, (1)H, (13)C, (15)N, and (17)O isotropic and anisotropic hyperfine couplings are calculated and explained by reference to the electron densities of the highest occupied molecular orbital and of the unpaired spin distribution on the radical. Comparison of calculated and experimental hyperfine couplings obtained from EPR and ENDOR/TRIPLE resonance leads to a refined structure for the FAD cofactor in Escherichia coli DNA photolyase. Hydrogen bonding at N3H, O4, and N5H results in significant changes in the unpaired spin density distribution and hyperfine coupling constants. The calculated electronic structure of FADH(*) provides evidence for a superexchange-mediated electron transfer between the cyclobutane pyrimidine dimer lesion and the 7,8-dimethyl isoalloxazine moiety of the flavin cofactor via the adenine moiety.

Fluvastatin therapy improves microcirculation in patients with hyperlipidaemia

The purpose of this study was to investigate the effect of fluvastatin on the microcirculation of patients with hyperlipidaemia (low-density lipoprotein cholesterol > 160 mg/dL, triglycerides < 350 mg/dl) inadequately controlled by diet. After a dietary run-in of 4 weeks, patients were randomised in a double-blind study to receive fluvastatin 40 mg twice daily (n = 24) or placebo (n = 24) for 12 weeks. The effect on microcirculation was assessed using capillary microscopy and laser Doppler fluxmetry at the nailfold at baseline and at 6 and 12 weeks after initiation of therapy. Capillaroscopy showed that fluvastatin improved microcirculation, i.e. time to peak flow during postocclusive reactive hyperaemia dropped from 19.7 +/- 7.2 s at baseline to 12.3 +/- 9.5 s at week 6 (P < 0.01) and 10.6 +/- 6.5 s at week 12 (P < 0.0001). These results were confirmed using laser Doppler fluxmetry to study microcirculation in thermoregulatory capillaries at the same site. A significant decrease in total and LDL-cholesterol was achieved during fluvastatin therapy. In conclusion, fluvastatin therapy improves microcirculation in nutritive as well as thermoregulatory capillaries in hypercholesterolaemic patients within 6 weeks.

The design and implementation of a restorative care model for home care

PURPOSE

The increasing demand for geriatric home-based care makes it timely to examine how the existing system can become most effective and efficient in promoting the functional outcomes of older patients.

DESIGN AND METHODS

A multidisciplinary work group identified home care agency policies, misconceptions of older adults and their caregivers, and practice patterns of nurses, therapists, and home health aides that can impede patients' progress toward functional independence. This article describes the process that one home care agency used to remove these obstacles.

RESULTS AND IMPLICATIONS

The work group developed and implemented a restorative model of care that integrates the medical treatments for acute disease processes and the personal care and rehabilitative interventions directed toward chronic disabilities, to improve the functional outcomes of older adults receiving home care.

Anomalous elastic response of silicon to uniaxial shock compression on nanosecond time scales

We have used x-ray diffraction with subnanosecond temporal resolution to measure the lattice parameters of orthogonal planes in shock compressed single crystals of silicon (Si) and copper (Cu). Despite uniaxial compression along the (400) direction of Si reducing the lattice spacing by nearly 11%, no observable changes occur in planes with normals orthogonal to the shock propagation direction. In contrast, shocked Cu shows prompt hydrostaticlike compression. These results are consistent with simple estimates of plastic strain rates based on dislocation velocity data.

Bacterial populations colonizing and degrading rice straw in anoxic paddy soil

Rice straw is a major substrate for the production of methane, a greenhouse gas, in flooded rice fields. The bacterial community degrading rice straw under anoxic conditions was investigated with molecular methods. Rice straw was incubated in paddy soil anaerobically for 71 days. Denaturing gradient gel electrophoresis (DGGE) of the amplified bacterial 16S rRNA genes showed that the composition of the bacterial community changed during the first 15 days but then was stable until the end of incubation. Fifteen DGGE bands with different signal intensities were excised, cloned, and sequenced. In addition, DNA was extracted from straw incubated for 1 and 29 days and the bacterial 16S rRNA genes were amplified and cloned. From these clone libraries 16 clones with different electrophoretic mobilities on a DGGE gel were sequenced. From a total of 31 clones, 20 belonged to different phylogenetic clusters of the clostridia, i.e., clostridial clusters I (14 clones), III (1 clone), IV (1 clone), and XIVa (4 clones). One clone fell also within the clostridia but could not be affiliated to one of the clostridial clusters. Ten clones grouped closely with the genera Bacillus (3 clones), Nitrosospira (1 clone), Fluoribacter (1 clones), and Acidobacterium (2 clones) and with clone sequences previously obtained from rice field soil (3 clones). The relative abundances of various phylogenetic groups in the rice straw-colonizing community were determined by fluorescence in situ hybridization (FISH). Bacteria were detached from the incubated rice straw with an efficiency of about 80 to 90%, as determined by dot blot hybridization of 16S rRNA in extract and residue. The number of active (i.e., a sufficient number of ribosomes) Bacteria detected with a general eubacterial probe (Eub338) after 8 days of incubation was 61% of the total cell counts. This percentage decreased to 17% after 29 days of incubation. Most (55%) of the active cells on day 8 belonged to the genus Clostridium, mainly to clostridial clusters I (24%), III (6%), and XIVa (24%). An additional 5% belonged to the Cytophaga-Flavobacterium cluster of the Cytophaga-Flavobacterium-Bacteroides phylum, 4% belonged to the alpha, beta, and gamma Proteobacteria, and 1.3% belonged to the Bacillus subbranch of the gram-positive bacteria with a low G+C content. The results show that the bacterial community colonizing and decomposing rice straw developed during the first 15 days of incubation and was dominated by members of different clostridial clusters, especially clusters I, III, and XIVa.

Factor structure of the Reynolds Adolescent Depression Scale in a sample of school-based adolescents

Depression is a common health problem in the adolescent population. The Reynolds Adolescent Depression Scale (RADS) is used to measure depression in clinical and community adolescent samples. Although there is available evidence for the reliability and validity of the RADS, there is insufficient documentation of its factor structure. This study examined the factor structure of the RADS in adolescent boys and girls (m-144). Internal consistency reliability ranged from .91 to .94 based on grade level, and was .91 for boys and .93 for girls. Factor analysis resulted in a 5-factor solution. Interpretation of factors were as follows: (a) Factor I--generalized demoralization; (b) Factor II--despondency and worry; (c) Factor III--externalized somatocism; (d) Factor IV--anhedonia; and, (e) Factor V--self-worth.

Ultrasonic assessment of physiological echo-contrast agent distribution in brain parenchyma with transient response second harmonic imaging

OBJECTIVES

The present study was designed to provide normal data of transient response second harmonic imaging (TRSHI) examinations of cerebral echo contrast enhancement using different modes of electrocardiogram (ECG) gating and echo-contrast agent doses.

MATERIALS AND METHODS

Fifty-five patients were examined in an axial diencephalic plane of section using the transtemporal acoustic bone window. TRSHI examinations (ECG gating: systolic, frame-rate once every 2 cardiac cycles = "basical instrument setting") could be performed in 50 individuals with adequate insonation conditions after application of 4 g of a galactose-based microbubbles suspension in a concentration of 400 mg/ml. For comparison, diastolic ECG gating (20 patients), cardiac-cycle triggering frequency of once every 2 seconds (15 patients), or an echo contrast agent dose of 2 g Levovist (15 patients) were used. Analysis of peak intensities (PIs) and areas under the curve (AUCs) was done in posterior (region of interest [ROI]a) and anterior (ROIb) parts of the thalamus, in the lentiform nucleus (ROIc), and the white matter (ROId).

RESULTS

In 41 patients with basical instrument setting, characteristic time intensity curve (TIC) could be detected in all ROIs. In ROIa (90%) and ROIb (82%), focal contrast enhancement was most difficult to visualize, and in ROIc and ROId, characteristic TICs were observable in more than 90% of the examinations. Background subtracted PIs and AUCs were significantly higher in ROIc (mean PI: 12.2 +/- 8 acoustic units [AUs]; mean AUC: 598.8 +/- 451.1 AU x Cardiac cycles), and ROId (11.8 +/- 6.9; 559.2 +/- 404) as compared to ROIa (8.3 +/- 5.2; 368.9 +/- 242.7) and ROIb (7.1 +/- 4.7; 298.2 +/- 199.1) (P < .0001). Values for corresponding examinations with a diastolic ECG gating and a cardiac cycle triggering frequency of once every 2 seconds were not different as compared to the basical instrument setting. A 4 g Levovist dose increased the portion of typical TIC in all ROIs. PI of 4 g examinations were significantly higher in ROId and ROIb as compared to the 2 g examination.

CONCLUSION

Our findings indicate that TRSHI allows noninvasive assessment of focal cerebral contrast enhancement in the majority of patients with adequate insonation conditions. This study provides data about normal quantitative and qualitative TRSHI values in patients without cerebrovascular diseases. A dose of 4 g Levovist is recommended in those individuals with inaccurate echo contrast enhancement using the 2 g dose.

Diagnosis and ablation of atrial flutter using a high resolution, noncontact mapping system

The ablation of atrial flutter can sometimes be time consuming and unsuccessful using conventional catheter techniques especially in patients with recurrences after previous ablation procedures. Simultaneous high resolution mapping from multiple sites may overcome some of the limitations. Therefore, a new high resolution noncontact mapping system was used for diagnosis and ablation of atrial flutter in 15 patients. The mapping system consists of a catheter-mounted multielectrode array, an amplifier, and a computer workstation. Far-field potentials recorded by the multielectrode catheter are amplified, digitized, and sampled at 1.2 kHz, and digitally filtered to construct high resolution activation maps during tachycardia. Ablation catheters can be steered to target sites without fluoroscopy. In 12 of the 15 patients the analysis of the activation sequence during tachycardia showed a counter-clockwise, and in 1 of 15 patients a clockwise, rotating wavefront using the isthmus as part of the reentrant circuit. In two patients no tachycardia could be induced. In 3 of the 15 patients with previous conventional ablation procedures the gap in the line of block in the isthmus region was identified and marked on the animation model. The isthmus in the right atrium was ablated and isthmus block verified by the mapping system in all patients. No complications were observed. No recurrences of atrial flutter occurred during follow-up of 4 +/- 1.7 months. The total procedure and fluoroscopy time was 171 +/- 50.0 minutes and 24 +/- 12.7 minutes, respectively. In conclusion, the use of the new high resolution noncontact mapping system in patients with right atrial flutter is safe and highly effective. In patients with previously failed conventional ablation procedures the use of a noncontact mapping system may facilitate the identification of the gap in the line of block in the isthmus region and reablation of atrial flutter.

Phytochemical investigation of Aglaia andamanica

Four new compounds, the limonoid 24-epi-melianodiol (8), the tirucallane aglaiodiol (9), and the two cyclopentatetrahydrobenzopyran derivatives pyramidaglain A (11) and B (12) were isolated from the leaves of Aglaia andamanica Hiern (Meliaceae), together with the eleven known constituents beta-sitosterol, beta-sitosterol glucoside, cycloart-23E-ene-3 beta,25-diol (1), three flavonoids 5-hydroxy-3,4',7-trimethoxyflavone (2), retusin (3) and pachypodol (4), the tirucallane 24-epi-piscidinol A (5), the lignan yangambin (6), the limonoid melianodiol (7), the bisamide pyramidatine (10) and the amino acid N-methyl-trans-4-hydroxy-L-proline (13). All structures were established by means of detailed spectroscopic analysis.

Mutations in the chloride channel gene, CLCNKB, leading to a mixed Bartter-Gitelman phenotype

Gitelman syndrome is an inherited renal disorder characterized by impaired NaCl reabsorption in the distal convoluted tubule and secondary hypokalemic alkalosis. In clinical practice, it is distinguished from other hypokalemic tubulopathies by the presence of both hypomagnesemia and normocalcemic hypocalciuria. To date, only mutations in a single gene encoding the thiazide-sensitive NaCl cotransporter have been found as the molecular basis of GS. We describe three unrelated patients presenting with the typical laboratory findings of GS. Mutational analysis in these patients revealed no abnormality in the SLC12A3 gene. Instead, all patients were found to carry previously described mutations in the CLCNKB gene, which encodes the kidney-specific chloride channel ClC-Kb, raising the possibility of genetic heterogeneity. Review of the medical histories revealed manifestation of the disease within the first year of life in all cases. Clinical presentation included episodes of dehydration, weakness, and failure to thrive, much more suggestive of classic Bartter syndrome than of GS. The coexistence of hypomagnesemia and hypocalciuria was not present from the beginning. In the follow-up, however, a drop of both parameters below normal range was a consistent finding reflecting a transition from cBS to GS phenotype. The phenotypic overlap may indicate a physiologic cooperation of the apical thiazide-sensitive NaCl cotransporter and the basolateral chloride channel for salt reabsorption in the distal convoluted tubule.

Atypical distal renal tubular acidosis confirmed by mutation analysis

In autosomal dominant distal renal tubular acidosis type I (dRTA) impaired hydrogen ion secretion is associated with metabolic acidosis, hyperchloremic hypokalemia, hypercalciuria, nephrocalcinosis, and/or nephrolithiasis. A retardation of growth is commonly observed. In this report we present a family with autosomal dominant dRTA with an atypical and discordant clinical picture. The father presented with severe nephrocalcinosis, nephrolithiasis, and isosthenuria but metabolic acidosis was absent. His 6-year-old daughter, however, suffered from metabolic acidosis, hypokalemia, and hypercalciuria. In addition, sonography revealed multiple bilateral renal cysts but no nephrocalcinosis. Mutation analysis of the AE1 gene coding for the renal Cl-/HCO3(-)-exchanger AE1 displayed a heterozygous Arg589Cys exchange in both patients but not in the healthy family members. This point mutation is frequently associated with autosomal dominant dRTA. Diagnosis of autosomal dominant dRTA is supported in this family by results of AE1 mutation analysis.

Ultrasonic evaluation of pathological brain perfusion in acute stroke using second harmonic imaging

OBJECTIVE

To evaluate the use of transient response second harmonic imaging (HI) by means of ultrasound to assess abnormalities of cerebral echo contrast agent enhancement in patients with acute stroke.

METHODS

The study comprised 25 patients with acute onset of hemispheric stroke (<24 h) with sufficient insonation conditions and 14 control subjects without cerebrovascular disease. All stroke patients had HI, extracranial and transcranial colour coded duplex examinations of the arteries supplying the brain, and clinical examinations (European stroke scale) performed in the acute phase, on day 2, and within 1 week. Acute CT was repeated within 1 week and facultatively accompanied by angiography. Examinations using HI were performed in an axial diencephalic plane of section using the transtemporal acoustic bone window. After bolus application of galactose based microbubbles, 61 ultrasound images with a cardiac cycling triggering frequency of once every 2 seconds were recorded and evaluated off line. Focal perfusion deficit was identified if no contrast enhancement was visualised in a circumscribed region of interest and insufficient temporal bone window was excluded. In cases of reappearance of contrast enhancement reperfusion was assessed.

RESULTS

Adequate cerebral contrast enhancement could be seen in 21 subjects. In seven, a large hemispheric deficit of contrast enhancement affecting the entire middle cerebral artery (MCA) territory was detectable; the lentiform nucleus was affected in three subjects. Assessment of cerebral contrast abnormalities was possible in two patients with superficial MCA infarctions but in none of the patients with lacunar ischaemias. None of the control persons had focal deficits of cerebral echo contrast enhancement. In all patients with complete MCA infarction and striatocapsular infarction, presumed ischaemic areas in HI examinations correlated with final CT findings. Overall sensitivity and specifity of HI examinations for predicting size and localisation of the infarction were 75 and 100%, respectively. During follow up, reappearance of contrast enhancement was determined in three patients, in two patients circulatory arrest due to malignant brain oedema with missing contrast enhancement in the entire cerebral hemisphere could be seen. Extent of contrast enhancement deficits significantly correlated with the clinical status on admission and after 1 week (p<0.01).

CONCLUSIONS

Second harmonic imaging is the first ultrasonic technique that enables visualisation of pathological cerebral echo contrast enhancement. Because this method identifies deficits of focal contrast enhancement in patients with acute stroke and allows estimation of the final infarct size and clinical prognosis, it may help to select and monitor patients for invasive therapies.

High incidence of sudden death with conduction system and myocardial disease due to lamins A and C gene mutation

We studied 54 living relatives from a large French kindred, among which 17 members presented with a cardiomyopathy transmitted on an autosomal dominant mode. Five of these individuals had clinical manifestations of muscle disease phenotypically consistent with Emery-Dreifuss muscular dystrophy. Genetic analysis of this kindred had demonstrated a nonsense mutation in the LMNA gene located on chromosome 1q11-q23. This gene encodes lamins A and C, proteins of the nuclear lamina located on the inner face of the nuclear envelope. We retrospectively determined the cause of death of 15 deceased family members, 8 of whom had died suddenly, 2 as a first and single manifestation of the disease. The six other cases had histories of arrhythmias and left ventricular dysfunction before dying suddenly, and three of them died despite the prior implantation of a permanent pacemaker. The mean age of onset of cardiac symptoms among affected living family members was 33 years (range 15-47 years), and the first symptoms were due to marked atrioventricular conduction defects or sinus dysfunction, requiring the implantation of permanent pacemakers in seven cases. Myocardial dysfunction accompanied by ventricular arrhythmias developed rapidly in the course of the disease and resulted in severe dilated cardiomyopathy requiring cardiac transplantation in three cases. In conclusion, in patients presenting a life-threatening familial or sporadic cardiac restricted phenotype similar to that described here, mutations in the lamins A and C gene should be looked for. In the genotypically affected individuals, cardiological and electrophysiological follow-up should be performed to prevent sudden death that could occur rapidly in the evolution of such disease.

A proposed aquatic plant community biotic index for wisconsin lakes

The Aquatic Macrophyte Community Index (AMCI) is a multipurpose tool developed to assess the biological quality of aquatic plant communities in lakes. It can be used to specifically analyze aquatic plant communities or as part of a multimetric system to assess overall lake quality for regulatory, planning, management, educational, or research purposes. The components of the index are maximum depth of plant growth; percentage of the littoral zone vegetated; Simpson's diversity index; the relative frequencies of submersed, sensitive, and exotic species; and taxa number. Each parameter was scaled based on data distributions from a statewide database, and scaled values were totaled for the AMCI value. AMCI values were grouped and tested by ecoregion and lake type (natural lakes and impoundments) to define quality on a regional basis. This analysis suggested that aquatic plant communities are divided into four groups: (1) Northern Lakes and Forests lakes and impoundments, (2) North-Central Hardwood Forests lakes and impoundments, (3) Southeastern Wisconsin Till Plains lakes, and (4) Southeastern Wisconsin Till Plains impoundments, Driftless Area Lakes, and Mississippi River Backwater lakes. AMCI values decline from group 1 to group 4 and reflect general water quality and human use trends in Wisconsin. The upper quartile of AMCI values in any region are the highest quality or benchmark plant communities. The interquartile range consists of normally impacted communities for the region and the lower quartile contains severely impacted or degraded plant communities. When AMCI values were applied to case studies, the values reflected known impacts to the lakes. However, quality criteria cannot be used uncritically, especially in lakes that initially have low nutrient levels.

Cultured porcine urinary bladder epithelial cells as a screening model for genotoxic effects of aromatic amines: characterisation and application of the cell culture model

Isolated epithelial cells from porcine urinary bladders were maintained in dividing long-term monolayer cultures, and were used as a model system for the urinary bladder in toxicological studies in vitro. To examine the state of differentiation during the culture period, the culture system was characterised morphologically by light and transmission electron microscopy and by immune fluorescence labelling with antibodies against cytokeratins 7,13 and pan. The cultured cells were identified as urothelial epithelium by their polarised structure, and by their expression of several uroepithelial specific morphological features, such as fusiform vesicles, tight junctions and an asymmetric apical cell membrane. Additionally, the cells were labelled with anti-cytokeratin 7,13 and pan antibodies, and negatively with anti-vimentin antibodies. The maintenance of suitable culture conditions was shown by the stable enzyme activities of (gamma-glutamyltranspeptidase, alkaline phosphatase and acid phosphatase over a culture period of 4 weeks. A good viability of the cultured cells under the chosen culture conditions was shown by the presence of low amounts of lactate dehydrogenase (< of = 5%) in the culture medium. The activities of the chosen marker enzymes for cell differentiation (gamma-glutamyltranspeptidase), lysosomes (acid phosphatase) and luminal membranes (alkaline phosphatase) were relatively stable over the observed culture period. Enzyme activities involved in metabolism of xenobiotics were determined, to define the ability for metabolism in cultured cells compared with bladder tissue in situ. Several constitutive phase I and II enzyme activities were found to be stable during the culture period, indicating that the cultured cells should be able to metabolise xenobiotics in a comparable manner to the urothelium in vivo. The cytotoxic effects of xenobiotics were investigated and IC50 values were determined by means of lactate dehydrogenase leakage and inhibition of neutral red uptake. The induction of sister chromatid exchanges was used as a parameter for the genotoxic effects of several xenobiotics. This cell culture system was found to be a very good screening system for the testing of substances that affect the bladder, especially aromatic amines.