Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Yield from family screening in a national adolescent cardiac screening program

Introduction

Cascade family screening in patients with confirmed or suspected inherited cardiac disorders is now well established. This may refute or confirm a familial clinical diagnosis and is particularly relevant in young adolescent individuals as it may be too early to manifest a distinct phenotype.

Objectives

A large cohort of 2708 adolescents aged 14–16 years gave consent to participate in a national cardiac screening program (BEAT-IT). Individuals with suspected inherited cardiac disorders were extensively evaluated. Their relatives were also invited to undergo screening. This study reports the yield of this family cardiac screening program.

Methodology

Family members of probands with suspected or confirmed inherited cardiac conditions were offered cardiac screening. A standard clinical screening protocol for all first-degree family members included a resting 12-lead ECG and echocardiogram. Those with a channelopathy suspicion also underwent postural ECGs and exercise testing. Screening second-degree relatives was also performed in a cascade fashion when clinically indicated. Relatives with a normal baseline screen were offered surveillance if younger than 25 years or a proband clinical diagnosis. Those with an abnormal ECG and/or echocardiogram were referred for further evaluation.

Results

17 probands (63% females) were suspected of harbouring inherited heart disease. Another 2 were diagnosed with a clinical phenotype. The mean age was 15.3±0.58 years. All were Caucasian.

77 family members underwent cardiac screening, with a mean age of 42.5±16.43 at first evaluation. The majority were female (n=44, 57.1%). 12 (15.6%) had an abnormal ECG. 6 (7.8%) had an abnormal echocardiogram, with 2 (2.6%) consistent with cardiomyopathy. 8 (10.4%) were diagnosed with an inherited cardiac condition (n=2 HCM, n=1 DCM, n=5 LQTS). Another 7 (9.1%) are under surveillance because of a pathological ECG in the absence of a clinical phenotype.

The highest clinical yield was in the Long QT group (n=5, 55.6%). Family members (n=25) referred because of proband lateral TWI were the second most likely to require clinical follow-up because of a pathological ECG or a clinical diagnosis (n=7, 28.0%). Relatives referred because of isolated anterior TWI on the proband's ECG had the lowest diagnostic yield (n=17, 0%). After excluding families of probands with isolated anterior TWI (n=18), the overall clinical yield increased to 13.6%. Another 11.9% are under surveillance because of a pathological ECG.

Conclusion

The yield of family screening as part of a national cardiac screening program was 10.4%. This increases to 13.6% when excluding probands with anterior TWI, with 11.9% under surveillance because of a pathological ECG. To our knowledge, this is the first such study of its kind.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Beating Hearts MaltaResearch, Innovation and Development Trust (University of Malta)

The prevalence of short PR interval in adolescent athletes and non-athletes

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Malta Heart Foundation and Beating Hearts

Background

Little is known about the prevalence and clinical relevance of an isolated short PR interval in young individuals.

Objectives

To explore the PR interval in adolescent athletes and non-athletes and determine possible association with sex, age, ethnicity, athletic ability and sporting discipline.

Methods

Between 2017-2018, school children aged 14-17 years were invited to participate in a National cardiac screening programme comprised of a health questionnaire and a resting 12-lead ECG. An athlete was defined as an individual participating in >4 hours/week of organised sports. Sport disciplines were categorised as skill, power, mixed and endurance. A short PR interval was defined as <120ms.

Results

A total of 1619 (61.0%) non-athletes and 1036 (39.0%) athletes  (median age 15 years, 50.5% females, 93.0% Caucasian) participated in the screening program. Most athletes participated in mixed sports (62.2%).

The mean PR interval was shorter in non-athletes compared to athletes (136.65 ± 19.00ms vs 139.93 ± 19.86ms p < 0.001) and in females compared to males (135.98 ± 18.39ms vs 139.93 ± 20.20ms, p < 0.001). An isolated short PR interval was present in 405 (15.3%) individuals. Associated pre-excitation was present in an additional 5 cases (0.2%). A short PR interval was commoner in females (18.7% vs 11.7%, p < 0.001) and in non-athletes (16.6% vs 13.2%, p = 0.020). Age (p = 0.657) and ethnicity (p = 0.115) did not influence the presence of a short PR interval.

The presence of a short PR interval in adolescent athletes was independent of the sporting discipline category (p = 0.071), in both males (p = 0.400) and females (p = 0.233).  The absolute PR interval did not differ significantly between sporting categories (p = 0.065),  in both genders (males, p = 0.202, females, p = 0.279).

Symptoms that were suggestive of arrhythmias were present in similar proportions of individuals with short and normal PR intervals (18.8% vs 17.1%, p = 0.393). 

Conclusion

An isolated short PR interval was a frequent finding in this cohort, with a predilection for females and non-athletes. The high frequency of short PR in young individuals suggests that in the absence of pre-excitation or symptoms, further evaluation is not warranted. Long-term follow-up studies may further elucidate the clinical relevance of this phenomenon.

Steven Johnson Syndrome and Toxic Epidermal Necrolysis in a burn unit: A 15-year experience

INTRODUCTION

The diffuse epidermal exfoliation seen in Steven Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) is similar to skin loss in second degree burns, and many of these patients are referred for treatment at burn centers. Treatment can differ markedly from center to center, and mortality can range from 25% to 70%, including a considerable morbidity. However, our experience over a 15-year period from 2000 to 2015 with 40 patients found a mortality rate of only 10% (4/40). The purpose of this paper is to discuss our treatment algorithm as a model for other centers treating SJS/TENs patients.

METHODS

Records were reviewed for all patients admitted to the LAC+USC burn unit between 2000 and 2015 and 40 patients were identified with biopsy-proven SJS or TENS. These cases were reviewed for age, gender, initial and greatest TBSA, causative drug, pre-existing medical conditions, and morbidity and mortality. All data were entered into the SPSS statistical software package and all statistical analyses were performed using this program.

RESULTS

Our treatment algorithm focused on early referral to a specialty burn unit, immediate discontinuation of the offending drug, fluid resuscitation, nutritional supplementation, and meticulous wound care. Average time to transfer to a burn unit was 3.36 days. Silver-releasing antimicrobial dressings were applied to the affected skin surface and changed every 3 days. Mupirocin coated petroleum gauze was used for facial involvement. Steroids were tapered and discontinued if initiated at an outside facility (58% of patients), and starting after 2001, all patients received a course of IVIG. All patients received fluid resuscitation and the majority received supplemental tube feedings (69%). Average length of total stay was 17.1 days and length of ICU stay 15.9 days. While 44% were transferred to another facility for further rehabilitative care, 37% of patients discharge to home. In patients discharged home with complete resolution of skin lesions, time to healing was an average of 14 days.

DISCUSSION

With our 10% mortality rate in 40 patients, our study represents a relatively large study population while maintaining a relatively low mortality rate. The demographic data from our study largely aligns with the existing literature, and we therefore feel that our low mortality rate is due to our treatment algorithm, rather than to a less severe pathology in our patient population. This claim is supported by a standard mortality ratio of 1.68. This ratio proves a significantly improved mortality than would be expected based on disease severity on admission.

Socioeconomic and psychosocial factors mediate race differences in nocturnal blood pressure dipping

BACKGROUND

Reduced nocturnal blood pressure (BP) dipping is more prevalent among blacks living in the United States than whites and is associated with increased target organ damage and cardiovascular risk. The primary aim of this study was to determine whether socioeconomic and psychosocial factors help to explain racial differences in dipping. In order to address the limited reproducibility of dipping measures, we investigated this question in a sample of participants who underwent multiple ambulatory BP monitoring (ABPM) sessions.

METHODS

The study sample included 171 black and white normotensive and mildly hypertensive participants who underwent three ABPM sessions, each 1 month apart, and completed a battery of questionnaires to assess socioeconomic and psychosocial factors.

RESULTS

As expected, blacks showed less dipping than whites, after adjusting for age, sex, body mass index (BMI), and mean 24-h BP level (mean difference = 3.3%, P = 0.002). Dipping was related to several of the socioeconomic and psychosocial factors examined, with higher education and income, being married, and higher perceived social support, each associated with a larger dipping percentage. Of these, marital status and education were independently associated with dipping and together accounted for 36% of the effect of race on dipping.

CONCLUSIONS

We identified a number of socioeconomic and psychosocial correlates of BP dipping and found that reduced dipping among blacks vs. whites is partially explained by marital status (being unmarried) and lower education among blacks. We also present results suggesting that repeated ABPM may facilitate the detection of associations between dipping and other variables.

Relationship of hepatitis B or C virus prevalences, risk factors, and outcomes in renal transplant recipients: analysis of German data

BACKGROUND

Chronic liver disease resulting from hepatitis B (HBV) and hepatitis C (HCV) virus infections is still a major concern in kidney recipients. Our aim was to evaluate the prevalences, risk factors, and impact of HBV and HCV infections in adult renal transplant recipients in Germany.

MATERIALS AND METHODS

Data were collected on 1633 kidney recipients transplanted between 1989 and 2002 at the 21 German renal transplant centers participating in MOST, the prospective Multinational Observational Study in Transplantation. Subgroup analyses compared HBV- and HCV-positive patients vs those with HBV/HCV-negative serology at the time of transplantation.

RESULTS

The prevalences of 4.4% (n = 72) for HBV and 5.8% (n = 94) for HCV showed a marked decline over the last 15 years. Retransplantations were significantly more common among HBV+ (29%) and HCV+ (36%) than HBV-/HCV- patients (12%). HCV+ patients experienced significantly longer dialysis times and received significantly more pretransplantation blood transfusions. Between all groups, no significant differences were observed in acute rejection rate at 12 months or in renal graft function up to 5 years posttransplantation (mean glomerular filtration rate: HBV+, 57.3 mL/min; HCV+, 58.5 mL/min; HBV-/HCV-, 59 mL/min). No progressive elevations in liver enzymes and bilirubin were noted during the 5-year observation period.

CONCLUSIONS

HBV and HCV infections currently have a low prevalence among German kidney graft recipients. Long dialysis times, blood transfusions, and retransplantations were identified as risk factors for hepatitis infections. At 5 years posttransplantation, kidney and liver functions did not differ significantly between HBV+ and HCV+ vs HBV-/HCV- renal transplant recipients.

Improvement in long-term renal graft survival due to CMV prophylaxis with oral ganciclovir: results of a randomized clinical trial

Oral ganciclovir prophylaxis and intravenous preemptive therapy are competitive approaches to prevent cytomegalovirus (CMV) disease after renal transplantation. This trial compared efficacy, safety and long-term graft outcome in 148 renal graft recipients randomized to ganciclovir prophylaxis (N = 74) or preemptive therapy (N = 74). Hierarchical testing revealed (i) patients with CMV infection had more severe periods of impaired graft function (creatinine clearance(max-min) 25.0 +/- 14.2 mL/min vs. 18.1 +/- 12.5 mL/min for patients without CMV infection; p = 0.02),(ii) prophylaxis reduced CMV infection by 65% (13 vs. 33 patients; p < 0.0001) but (iii) creatinine clearance at 12 months was comparable for both regimes (54.0 +/- 24.9 vs. 53.1 +/- 23.7 mL/min; p = 0.92). No major safety issues were observed, and patient survival at 12 months was similar in both groups (5 deaths [6.8%] vs. 4 [5.4%], p = 1.0000). Prophylaxis significantly increased long-term graft survival 4 years posttransplant (92.2% vs. 78.3%; p = 0.0425) with a number needed to treat of 7.19. Patients with donor +/recipient + CMV serostatus had the lowest rate of graft loss following prophylaxis (0.0% vs. 26.8%; p = 0.0035). In conclusion, it appears that routine oral prophylaxis may improve long-term graft survival for most renal transplant patients. Preemptive therapy can be considered in low risk patients in combination with adequate CMV monitoring.

Cognition, psychosocial adjustment and coping in familial cases of velocardiofacial syndrome

Velocardiofacial syndrome (VCFS) is characterized by both physical manifestations and neuropsychiatric disabilities. About 6-28% of cases are familial. The aim of the present study was to compare the clinical characteristics of subjects with familial and nonfamilial VCFS, with a special focus on cognitive and psychiatric disabilities. In addition, the complexities of coping with the disease in families in which both a parent and children are affected were highlighted in case vignettes. Sixteen patients from six families with VCFS were compared to 63 subjects with nonfamilial VCFS for physical parameters, IQ, and rate of major psychiatric disorders. After controlling for the effect of age, IQ was significantly lower in the familial compared to the nonfamilial group of VCFS patients. Rate of psychiatric disorders was similarly high in both groups. The familial group had fewer cardiac and palate anomalies. A significant negative correlation was found between IQ and age. Most of the adults with familial VCFS were neuropsychiatrically disabled. Thus, although familial VCFS seems to be associated with a milder physical phenotype than nonfamilial VCFS, the neuropsychiatric deficits are significant in both types, at all ages.

A proposed method for assessing plasma hypertonicity in vivo

Indices of plasma hypertonicity, elevated plasma concentrations of solutes that draw fluid out of cells by osmosis, are needed to pursue hypertonicity as a possible risk factor for obesity and chronic disease. This paper proposes a new index that may be more sensitive to mild hypertonicity in vivo at a point in time than traditional measures. The index compares mean corpuscular volume (MCV) estimates from diluted (in solution by automated cell counter) and nondiluted blood (calculated from manual hematocrit, MCV=Hct/RBC*10(6)). A larger Auto vs Manual MCV (>2 fl) in vitro indicates hypertonicity in vivo if the cell counter diluent is isotonic with the threshold for plasma vasopressin (PVP) release and PVP is detectable in plasma (>0.5 pg/ml). To evaluate this principle of concept, hypertonicity was induced by 24-h fluid restriction after a 20 ml/kg water load in four healthy men (20-46 years). Unlike serum and urine indices, the MCV difference-&-PVP index detected hypertonicity in all participants.

Generation of confluent cardiomyocyte monolayers derived from embryonic stem cells in suspension: a cell source for new therapies and screening strategies

BACKGROUND

Cellular cardiomyoplasty is evolving as a new strategy to treat cardiac diseases. A prerequisite is a reliable source of pure cardiomyocytes, which could also help in the exploitation of recent advances in genomics and drug screening. Our goal was to establish a robust lab-scale process for the generation of embryonic stem (ES)-cell-derived cardiomyocytes in suspension.

METHODS

A 71 ES cell clone carrying a construct consisting of the alpha-cardiac myosin heavy chain (alphaMHC) promoter driving the neomycin resistance gene was used for antibiotic-driven cardiomyocyte enrichment. Rotating suspension culture was established to initiate embryoid body (EB) formation. To track growth and differentiation kinetics, cell count and flow cytometry for SSEA-I, E-cadherin (stem-cell marker)and sarcomeric myosin (cardiomyocytes marker) was performed. Oct4 expression was measured via real time (RT)-PCR.

RESULTS

Cultures comprising 2.5-8 x 10(6) differentiating FS cells/mL were obtained after 9 days in rotating suspension. Upon G418 addition,vigorous contracting spheres, termed cardiac bodies (CB), developed. These cultures consisted of about 2.1 x 10(5) enriched cardiomyocytes/mL after 6- 10 days of selection. Suspensions comprising 90- 95%viable single cells were generated using an improved dissociation method. Seeding of cardiomyocytes with 7 x 10(4) cell/cm(2) resulted in a homogeneous monolayer of synchronously contracting cells. Myocyte specific immunohistochemistry indicated purity of > 99%.

DISCUSSION

We have established a reliable lab-scale protocol to generate cultures of highly enriched cardiomyocytes in suspension. This will facilitate development of larger-scale processes for stem-cell based cardiomyocyte supply. An improved method is provided to derive vital suspensions of cardiomyocytes, which could be utilized for transplantation as well as for drug screening purposes.

[Multifocal localization of tumors of Schwann cell origin]

Neurofibromatosis (disease of Von Recklinghausen) was considered to be a unique disease. Today, however, it is known that it consist of two clinically and genetically different diseases. Neurofibromatosis type 1 is a more frequent disease formerly known as peripheral, while neurofibromatosis type 2 (bilateral acoustic neurinoma) is significantly less frequent. In this case report we present a 30-year old female patient who had several tumours with the following localizations: 1. the pontocerebellar angulus; 2. the left foramen jugular; 3. the anterior part of the spinal canal; 4. the soft tissue of the neck; 5. falx cerebri. The tumor in the neck was removed completely by ENT surgeon while the others were partly removed by neurosurgeon. In this case report we described diagnostic and therapeutic problems in the treatment of this patient with the long-lasting hoarseness and difficult swallowing.

p53 Protects renal inner medullary cells from hypertonic stress by restricting DNA replication

We previously found that p53 upregulation by hypertonicity protected renal inner medullary collecting duct (mIMCD3) cells from apoptosis. The purpose of the present study was to investigate the mechanism by which p53 protects the cells. We now find that hypertonicity (NaCl added to a total of 500 mosmol) inhibits DNA replication and delays G(1)-S transition as concluded from analysis of cell cycle distributions and bromodeoxyuridine (BrDU) incorporation rates. Lowering of p53 with p53 antisense oligonucleotide attenuated such effects of hypertonicity, resulting in an increased number of apoptotic cells in S phase and cells with >4 N DNA. Results with synchronized cells are similar, showing that cells in the early S phase are more sensitive to hypertonicity. Immunocytochemistry revealed that p53 becomes phosphorylated on Ser(15) and translocates to the nucleus in S both in isotonic and hypertonic conditions. Caffeine (2 mM) greatly reduces the p53 level and Ser(15) phosphorylation, followed by a remarkable increase of DNA replication rate, by failure of hypertonicity to inhibit it, and by reduction of cell number during hypertonicity. Finally, inhibition of DNA replication by the DNA polymerase inhibitor aphidicolin significantly improves cell survival, confirming that keeping cells in G(1) and decreasing the rate of DNA replication is protective and that these actions of p53 most likely are what normally help protect cells against hypertonicity.

Day-to-day reproducibility of mental stress-induced abnormal left ventricular function response in patients with coronary artery disease and its relationship to autonomic activation

BACKGROUND

Mental stress (MS) results in left ventricular (LV) dysfunction in approximately half of the patients with symptomatic coronary artery disease (CAD) and is an adverse prognostic sign. The reproducibility of various MS tasks in inducing LV dysfunction and its relationship to autonomic activation in patients with CAD are not known. We studied the reproducibility on different days of 3 commonly used MS tasks on LV ejection fraction (LVEF), heart rate, blood pressure, and rate-pressure product and the relationship of reproducibility to autonomic activation as determined by heart rate variability in patients with chronic stable angina.

METHODS AND RESULTS

Ten patients with CAD and exercise-induced ischemia who had abnormal LVEF responses to at least one MS task from a battery of MS tasks (mental arithmetic, anger recall, and color Stroop test) while undergoing continuous ambulatory Holter and LV function monitoring underwent a second MS testing 4 to 8 weeks later, with no change in clinical status or cardiac medications in the interim. Autonomic tone was determined from indexes of heart rate variability (high frequency [HF] for parasympathetic activity and low frequency [LF] and low frequency/high frequency ratio [LF/HF] for sympathetic activity). MS tasks resulted in a small increase in heart rate (P <.0001), a modest increase in systolic blood pressure (P <.0001) and the rate-pressure product (P <.0001), and a small but statistically significant increase in LF (P <.002) and LF/HF (P <.0001), but no change in HF compared with baseline. These changes were highly reproducible over the 2 studies. With a fall in LVEF of 5% or greater considered as indicative of an MS-positive task, anger recall was the most effective and reproducible MS task in inducing LV dysfunction. MS-positive tasks were associated with a greater increase in systolic blood pressure (P =.005). Anger recall resulted in a trend toward a higher increase in systolic blood pressure (P =.08) than the other MS tasks. In MS tasks with inconsistent LVEF responses in the 2 studies (LV dysfunction present in one study but not in the other), there was significant parasympathetic withdrawal (P =.02) in MS-negative tasks but no difference in sympathetic activation. On the other hand, in MS tasks with consistent LV dysfunction on both occasions, there was no difference in parasympathetic or sympathetic activation. MS-positive tasks were not accompanied by chest pain or ST depression.

CONCLUSIONS

Of the commonly used MS tasks, anger recall produces LV dysfunction with the highest frequency and is the most reproducible task when retested 4 to 8 weeks later in patients with CAD. These data are relevant for planning studies of the effects of therapeutic interventions on MS-induced LV dysfunction.

Characterization of cytosolic sialidase from Chinese hamster ovary cells: part I: cloning and expression of soluble sialidase in Escherichia coli

The cDNA of Chinese hamster ovary (CHO) cell cytosolic sialidase was amplified by RT-PCR and cloned into the pGEX-2T plasmid vector encoding for glutathione S-transferase (GST). Screening revealed transformed Escherichia coli clones with the constructed plasmid encoding the CHO cell sialidase sequence. After isopropyl-beta-D-thiogalactopyranoside (IPTG) induction, SDS-PAGE of the total protein extracts revealed a new protein of about 70 kDa, correlating with the molecular weight of a fusion protein composed of the GST (26 kDa) and the cloned cytosolic CHO cell sialidase (43 kDa). A soluble fusion protein was purified from sonified E. coli homogenates by one-step affinity chromatography on Glutathione Sepharose 4B, which showed sialidase activity towards 4-methyl-umbelliferyl-alpha-D-N-acetylneuraminic acid (MUF-Neu5Ac) substrate. Induction of cells with 0.1, 0.5, and 1.0 mM IPTG revealed highest total protein amounts after induction with 1.0 mM IPTG, but highest specific activity for affinity chromatography purified eluates from cultures induced with 0.1 mM IPTG. Therefore, large scale production was performed by inducing cells during exponential growth in a 25 L bioreactor for 3 h with 0.1 mM IPTG after chilling the cell suspension to 25 degrees C. The amount of 26.46 mg of 40-fold purified GST-sialidase with a specific activity of 0.999 U/mg protein was obtained from crude protein extracts by one-step affinity chromatography. 2-Deoxy-2,3-dehydro-N-acetylneuraminic acid (Neu5Ac2en) and Neu5Ac were competitive inhibitors for the sialidase, the former being the more effective one using MUF-Neu5Ac as the substrate. The cytosolic sialidase is capable of desialylating a wide spectrum of different types of gangliosides using a thin-layer chromatography overlay kinetic assay without detergents. This is the subject of the accompanying paper (Müthing, J.; Burg, M. Carbohydr. Res. 2001, 330, 347-356).

Characterization of cytosolic sialidase from Chinese hamster ovary cells: part II. Substrate specificity for gangliosides

Cytosolic Chinese hamster ovary (CHO) cell sialidase has been cloned as a soluble glutathione S-transferase (GST)-sialidase fusion protein with an apparent molecular weight of 69 kD in Escherichia coli. The enzyme has then been produced in mg quantities at 25-L bioreactor scale and purified by one-step affinity chromatography on glutathione sepharose (Burg, M.; Müthing, J. Carbohydr. Res. 2001, 330, 335-346). The cloned sialidase was probed for desialylation of a wide spectrum of different types of gangliosides using a thin-layer chromatography (TLC) overlay kinetic assay. Different gangliosides were separated on silica gel precoated TLC plates, incubated with increasing concentrations of sialidase (50 degreesU/mL up to 1.6 mU/mL) without detergents, and desialylated gangliosides were detected with specific anti-asialoganglioside antibodies. The enzyme exhibited almost identical hydrolysis activity in degradation of GM3(Neu5Ac) and GM3(Neu5Gc). A slightly enhanced activity, compared with reference Vibrio cholerae sialidase, was detected towards terminally alpha(2-3)-sialylated neolacto-series gangliosides IV3-alpha-Neu5Ac-nLc4Cer and VI3-alpha-Neu5Ac-nLc6Cer. The ganglio-series gangliosides G(D1a), G(D1b), and G(T1b), the preferential substrates of V. cholerae sialidase for generating cleavage-resistant G(M1), were less suitable targets for the CHO cell sialidase. The increasing evidence on colocalization of gangliosides and sialidase in the cytosol strongly suggests the involvement of the cytosolic sialidase in ganglioside metabolism on intracellular level by yet unknown mechanisms.

Myocardial blood-flow response during mental stress in patients with coronary artery disease

Positron emission tomography was used to quantify changes in myocardial blood flow during mental stress in patients with and without coronary artery disease. Blunted augmentation of myocardial blood flow during mental stress was observed in regions without significant epicardial stenosis.

Protection of renal inner medullary epithelial cells from apoptosis by hypertonic stress-induced p53 activation

Acute hypertonicity causes cell cycle delay and apoptosis in mouse renal inner medullary collecting duct cells (mIMCD3) and increases GADD45 expression. Because the tumor suppressor protein p53 may be involved in these effects, we have investigated the role of p53 in mIMCD3 response to hyperosmotic stress. Acute elevation of osmolality with NaCl addition from the control level of 320 mosmol/kg to 500-600 mosmol/kg greatly increased the levels of total and Ser(15)-phosphorylated p53 within 15 min. However, similar elevation of osmolality with urea did not increase p53 levels. Our studies indicate that induced p53 is transcriptionally active because NaCl addition to 500-600 mosmol/kg stimulated transcription of a luciferase reporter containing a p53 consensus element and appropriately altered mRNA levels of known transcriptional targets of p53, i.e. increased MDM-2 and decreased BCL-2 levels. Elevating NaCl further to 700-800 mosmol/kg rapidly killed most of the cells by apoptosis. At these higher NaCl concentrations, p53 levels were further increased although Ser(15) phosphorylation and transcriptional activity were significantly lower than levels at 500-600 mosmol/kg. At NaCl-induced 500 mosmol/kg, apoptosis was rare in the presence of control, nonspecific oligonucleotide but highly prevalent upon addition of p53 antisense oligonucleotide that substantially reduced p53 levels. We conclude that induction of active p53 in mIMCD3 cells by hypertonic stress contributes to cell survival.

Tumor necrosis factor-alpha during continuous high-flux hemodialysis in sepsis with acute renal failure

Suppressed ex vivo endotoxin (ET)-induced production of the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), in isolated mononuclear cells (PBMCs) is associated with fatal outcome in severe sepsis. PBMCs from surviving patients, but not those from nonsurviving patients, recover their capacity to produce normal amounts of TNF-alpha. We tested the influence of two modalities of continuous renal replacement therapy (CRRT) on ex vivo-induced whole-blood production of TNF-alpha and inhibitory TNF-soluble receptor type I (TNFsRI) in 12 patients with acute renal failure and sepsis (APACHE II score 22 to 30).

METHODS

Standard continuous venovenous hemofiltration (CVVH; 36 liters of bicarbonate substitution fluid per day) was performed in 7 patients using polyamid hemofilters (FH66; Gambro). In an additional five patients, we performed daily 18 hours of high-flux hemodialysis (CHFD) using polysulfon F60S dialyzers (Fresenius) and 75 liters of bicarbonate dialysate using the GENIUS single-pass batch dialysis system. Samples were separated from the blood circuit as well as from the ultrafiltrate/spent dialysate lines at the start, during, and end of treatment. Whole-blood samples were incubated with 1 ng/ml of ET for three hours at 37 degrees C. Ultrafiltrate or dialysate samples were incubated with donor whole blood in the presence of ET to measure suppressing activity in ultrafiltrate and spent dialysate.

RESULTS

At the start of CRRT, ET-induced whole-blood TNF-alpha production was suppressed to approximately 10% of that in normal controls. During CVVH, median ET-induced TNF-alpha production increased from 0.35 ng/ml at the start to 1.2 ng/ml at three hours, but decreased to pre-CVVH levels at the end of a 24-hour period. In contrast, in patients on CHFD, the median ET-induced TNF-alpha production was 0.5 ng/ml at the start, 1.1 ng/ml at 3 hours, 1.6 ng/ml at six hours, and 1.5 ng/ml at the end of 18 hours of treatment. The ultrafiltrate obtained after three hours of CVVH did not contain suppressing activity. In CHFD, the spent dialysate as compared with fresh dialysate suppressed ET-induced TNF-alpha production in donor blood by 33% throughout the 18 hours of treatment. Whole-blood production of TNFsRI did not change significantly at any time point during CVVH or CHFD.

CONCLUSION

These data suggest that high-volume CHFD is superior to standard CVVH in removing a suppressing factor of proinflammatory cytokine production. As CVVH only transiently improves TNF-alpha production, it is most likely that the putative suppressing factor is removed because of saturable membrane adsorption in CVVH. In CHFD, there is a combination of adsorption and detectable diffusion into the dialysate. It remains to be shown whether a further increase in the volume of dialysate per day is able to not only improve but normalize the cytokine response and improve outcome in septic patients with acute renal failure.

Expression of interferon-inducible Mx-proteins in patients with IgA nephropathy or Henoch-Schönlein purpura

Both viral infections and dysregulated cytokine synthesis have been implicated in the pathogenesis of immunoglobulin A nephropathy (IgAN) and Henoch-Schönlein purpura (HSP). Mx proteins are specifically induced by type I interferons (IFN-alpha, -beta, -omega) and are very sensitive in detecting, for example, virus-induced, in vivo production of IFN-alpha/-beta, because the biological half-life of Mx (approximately 3 days) markedly exceeds that of IFN-alpha/-beta (20 to 90 minutes). Mx concentrations in leukocytes were measured by enzyme-linked immunosorbent assay (ELISA) in 79 blood samples of 35 patients with IgAN and five with HSP. No patient showed symptoms of infections at the time of the examination. Compared with normal leukocyte Mx concentrations (<2 mU/1,000 leukocytes), only 3 of 79 samples of IgAN/HSP patients showed mildly elevated Mx concentrations (range, 2.2 to 3 mU/1,000 leukocytes). By contrast, patients with increased endogenous IFN production (lupus erythematosus) or patients treated with IFN-alpha2 showed leukocyte Mx concentrations of up to 35 mU/1,000 leukocytes. In patients with IgAN and HSP, leukocyte Mx concentrations were not correlated with various clinical parameters. Immunohistochemically, no renal Mx expression could be detected in eight renal biopsy specimens of patients with various stages of IgAN, whereas control specimens (skin of patients treated with IFN-alpha2) showed abundant cellular Mx expression. Furthermore, human mesangial cells in vitro showed marked Mx production after exposure to IFN-alpha or IFN-beta. We conclude that, in patients with IgAN/HSP, no evidence of an activation or dysregulation of the type I interferon system can be detected.

Novel approach to specific growth factor inhibition in vivo: antagonism of platelet-derived growth factor in glomerulonephritis by aptamers

Mesangial cell proliferation and matrix accumulation, driven by platelet-derived growth factor (PDGF), contribute to many progressive renal diseases. In a novel approach to antagonize PDGF, we investigated the effects of a nuclease-resistant high-affinity oligonucleotide aptamer in vitro and in vivo. In cultured mesangial cells, the aptamer markedly suppressed PDGF-BB but not epidermal- or fibroblast-growth-factor-2-induced proliferation. In vivo effects of the aptamer were evaluated in a rat mesangioproliferative glomerulonephritis model. Twice-daily intravenous (i.v.) injections from days 3 to 8 after disease induction of 2.2 mg/kg PDGF-B aptamer, coupled to 40-kd polyethylene glycol (PEG), led to 1) a reduction of glomerular mitoses by 64% on day 6 and by 78% on day 9, 2) a reduction of proliferating mesangial cells by 95% on day 9, 3) markedly reduced glomerular expression of endogenous PDGF B-chain, 4) reduced glomerular monocyte/macrophage influx on day 6 after disease induction, and 5) a marked reduction of glomerular extracellular matrix overproduction (as assessed by analysis of fibronectin and type IV collagen) both on the protein and mRNA level. The administration of equivalent amounts of a PEG-coupled aptamer with a scrambled sequence or PEG alone had no beneficial effect on the natural course of the disease. These data show that specific inhibition of growth factors using custom-designed, high-affinity aptamers is feasible and effective.

Evolution of osmotic stress signaling via MAP kinase cascades

Cells respond to changes in osmotic pressure with compensatory molecular adaptations that allow them to re-establish homeostasis of osmotically disturbed aspects of cell structure and function. In addition, some cell types respond to osmotic stress by changing their phenotype or, if their tolerance threshold is exceeded, by initiating programmed cell death. To understand how cells achieve these different types of adaptive response to osmotic stress, it is necessary to identify the key elements of osmosensory signal transduction and to analyze the complex networks that process osmotic stimuli imposed upon cells by their environment. This review highlights mitogen-activated protein kinase (MAPK) cascades as important intracellular signal-transduction pathways activated in response to changes in osmolality. A unifying theme of osmotic stress signaling via MAPKs seems to be regulation of the cell cycle as part of the cellular stress response. This very important physiological capacity may have been conserved throughout evolution as a major function of MAPKs from many different subfamilies. The evidence for this conjecture is discussed, and our current knowledge about osmotic stress signaling pathways in yeast, animals and plants is briefly reviewed.

Selective histamine uptake rescues photo- and mechanoreceptor function of histidine decarboxylase-deficient Drosophila mutant

In insects, histamine is found both in the peripheral nervous system (PNS) and in the CNS and is known to function as a fast neurotransmitter in photoreceptors that have been shown to express selectively the hdc gene. This gene codes for histidine decarboxylase (HDC), the enzyme for histamine synthesis. Fast neurotransmission requires the efficient removal of the transmitter from the synaptic cleft. Here we identify in Drosophila photo- and mechanoreceptors a histamine uptake mechanism that can restore the function of these receptors in mutants unable to synthesize histamine. When apparent null mutants for the hdc gene imbibe aqueous histamine solution or are genetically "rescued" by a transgene ubiquitously expressing histidine decarboxylase under heat-shock control, sufficient amounts of histamine selectively accumulate in photo- and mechanoreceptors to generate near-normal electrical responses in second-order visual interneurons and qualitatively to restore wild-type visual and mechanosensory behavior. This strongly supports the proposal that histamine functions as a fast neurotransmitter also in a certain class of mechanoreceptors. A set of CNS-intrinsic neurons that in the wild type contain high concentrations of histamine apparently lacks this uptake mechanism. We therefore speculate that histamine of intrinsic neurons may function as a neuromodulator rather than as a fast transmitter.

Neuroactive steroids induce GABA(A) receptor-mediated depolarizing postsynaptic potentials in hippocampal CA1 pyramidal cells of the rat

Intracellular recordings were performed in area CA1 pyramidal cells of rat hippocampal slices to determine the effects of certain steroids on inhibitory postsynaptic potentials/currents (IPSP/Cs) mediated by GABA(A) receptors. Following application of the steroids 5alpha-pregnan-3alpha,21-diol-20-one (5alpha-THDOC), alphaxalone and 5beta-pregnan-3alpha-ol-20-one (pregnanolone) hyperpolarizing PSPs developed into biphasic responses consisting of an early hyperpolarizing and a late depolarizing PSP sequence. Steroid-induced depolarizing PSPs could be elicited in the presence of antagonists to non-NMDA, NMDA, and GABA(B) receptors, indicating that these receptor types do not contribute significantly to the initiation of these responses. Depolarizing PSPs were completely blocked by both GABA(A) receptor antagonists bicuculline and t-butylbicyclophosphorothionat (TBPS) providing evidence for their mediation by GABA(A) receptors. The reversal potential of steroid-induced late inward PSCs, measured in single-electrode voltage clamp, was -29.9+/-5.3 mV, whereas the early outward current, which corresponded to the early hyperpolarizing component of PSPs, reversed at -68.2+/-1.5 mV. Depolarizing PSPs and late inward PSCs were sensitive to reduction of extracellular [HCO3-] and block of carbonic anhydrase by application of acetazolamide. The results suggest that certain neuroactive steroids can induce GABA(A) receptor-mediated depolarizing PSPs, which are dependent on HCO3-.

Prevention and Treatment of Hypertension Study (PATHS): effects of an alcohol treatment program on blood pressure

OBJECTIVE

To determine whether blood pressure is reduced for at least 6 months with an intervention to lower alcohol intake in moderate to heavy drinkers with above optimal to slightly elevated diastolic blood pressure, and whether reduction of alcohol intake can be maintained for 2 years.

DESIGN

A randomized controlled trial.

METHODS

Six hundred forty-one outpatient veterans with an average intake of 3 or more alcoholic drinks per day in the 6 months before entry into the study and with diastolic blood pressure 80 to 99 mm Hg were randomly assigned to a cognitive-behavioral alcohol reduction intervention program or a control observation group for 15 to 24 months. The goal of the intervention was the lower of 2 or fewer drinks daily or a 50% reduction in intake. A subgroup with hypertension was defined as having a diastolic blood pressure of 90 to 99 mm Hg, or 80 to 99 mm Hg if recently taking medication for hypertension.

RESULTS

Reduction in average weekly self-reported alcohol intake was significantly greater (P<.001) at every assessment from 3 to 24 months in the intervention group vs the control group: levels declined from 432 g/wk at baseline by 202 g/wk in the intervention group and from 445 g/wk by 78 g/wk in the control group in the first 6 months, with similar reductions after 24 months. The intervention group had a 1.2/0.7-mm Hg greater reduction in blood pressure than the control group (for each, P = .17 and P = .18) for the 6-month primary end point; for the hypertensive stratum the difference was 0.9/0.7 mm Hg (for each, P = .58 and P = .44).

CONCLUSIONS

The 1.3 drinks per day average difference between changes in self-reported alcohol intake observed in this trial produced only small nonsignificant effects on blood pressure. The results from the Prevention and Treatment of Hypertension Study (PATHS) do not provide strong support for reducing alcohol consumption in nondependent moderate drinkers as a sole method for the prevention or treatment of hypertension.

Transfer of endogenous pyrogens across artificial membranes?

Synthetic high-flux dialyzer membranes used in continuous veno-venous hemofiltration are permeable to middle molecular size endogenous pyrogens, the pro-inflammatory cytokines IL-1 beta and TNF-alpha. The quantities removed by sieving are, however, negligible in vitro as well as in vivo. Adsorption of cytokines to the membrane polymer is the major mechanism of pyrogen removal. Adsorption seems to be semispecific for pro-inflammatory cytokines because levels of anti-inflammatory mediators were not changed or even increased during CVVH. Thus, CVVH may change cytokine profiles in septic patients supporting the predominance of anti-inflammatory over pro-inflammatory activity in plasma. It remains to be demonstrated whether modifications of extracorporeal blood purification systems (high-volume CVVH, plasma separation + adsorption) are able to amplify the change in cytokine profiles and whether this change influences outcome of septic patients.

Endogenous fibroblast growth factor-2 mediates cytotoxicity in experimental mesangioproliferative glomerulonephritis

Fibroblast growth factor-2 (FGF-2) is released from mesangial cells in experimental mesangioproliferative glomerulonephritis induced with anti-Thy 1.1 antibody. To investigate the functional role of released FGF-2, rats received either neutralizing anti-FGF-2 IgG or a functional peptide antagonist of FGF-2 (FGF119-126) before or shortly after induction of anti-Thy 1.1 nephritis. In additional experiments, rats were treated with bolus injections of FGF-2 from 2 to 6 h after disease induction. The data showed that anti-FGF-2 therapy led to significant reductions of early mesangial cell injury (mesangiolysis, microaneurysm formation) and the subsequent mesangioproliferative changes (glomerular de novo expression of alpha-smooth muscle actin, mesangial cell proliferation, matrix accumulation, and platelet influx). Conversely, injections of FGF-2 augmented both mesangial injury and the subsequent mesangioproliferative changes. Studies on the mechanisms underlying the amplification of mesangial cell injury by FGF-2 showed that anti-FGF-2 therapy reduced cell death at 2 and 8 h after disease induction by 58 and 54%, respectively. This was associated with significant reductions in the number of glomerular H2O2- and OH -producing cells, as well as reduced glomerular production of nitric oxide. These data suggest that release of constitutively expressed FGF-2 after immune-mediated cell injury contributes to glomerular cell damage and thus identify FGF-2 as a novel mediator of cytotoxicity.

Effects of mental stress on left ventricular and peripheral vascular performance in patients with coronary artery disease

OBJECTIVES

We sought to investigate the mechanism of a mental stress-induced fall in left ventricular ejection fraction (LVEF) in patients with coronary artery disease.

BACKGROUND

Mental stress induces a fall in LVEF in a significant proportion of patients with coronary artery disease. This is accompanied by an increase in heart rate, blood pressure and rate-pressure product. Whether the mental stress-induced fall in LVEF is due to myocardial ischemia, altered loading conditions or a combination of both is not clear.

METHODS

Left ventricular (LV) function was studied noninvasively by serial equilibrium radionuclide angiocardiography and simultaneous measurement of peak power, a relatively afterload-independent index of LV contractility, in 21 patients with coronary artery disease (17 men, 4 women) and 9 normal subjects (6 men, 3 women) at baseline, during mental stress and during exercise. Peripheral vascular resistance (PVR), cardiac output (CO), arterial and end-systolic ventricular elastance (Ea, Ees,) and ventriculoarterial coupling (V/AC) were also calculated. Patients underwent two types of mental stress-mental arithmetic and anger recall-as well as symptom-limited semisupine bicycle exercise.

RESULTS

Nine patients (43%) had an absolute fall in LVEF of > or = 5% (Group I) in response to at least one of the mental stressors, whereas the remaining patients did not (Group II). Group I and Group II patients were similar in terms of baseline characteristics. Both groups showed a significant but comparable increase in systolic blood pressure (15+/-7 vs. 9+/-10 mm Hg, p=0.12) and a slight increase in heart rate (7+/-4 vs. 8+/-7 beats/min, p=0.6) and a comparable increase in rate-pressure product (2.2+/-0.9 vs. 1.9+/-1.2 beats/min x mm Hg, p=0.6) with mental stress. However, PVR increased in Group I and decreased in Group II (252+/-205 vs. -42+/-230 dynes x s x cm(-5), p=0.006), and CO decreased in Group I and increased in Group II (-0.2+/-0.4 vs. 0.6+/-0.7 liters/min, p=0.02) with mental stress. There was no difference in the change in peak power (p=0.4) with mental stress. With exercise, an increase in systolic blood pressure, heart rate, rate-pressure product and CO and a fall in PVR were similar in both groups. Of the two mental stressors, anger recall resulted in a greater fall in LVEF and a greater increase in diastolic blood pressure. Exercise resulted in a fall in LVEF in 7 patients (33%). However, exercise-induced changes in LVEF and hemodynamic variables were not predictive of mental stress-induced changes in LVEF and hemodynamic variables. Conclusions. Abnormal PVR and Ea responses to mental stress and exercise are observed in patients with a mental stress-induced fall in LVEF. Peripheral vasoconstrictive responses to mental stress contribute significantly toward a mental stress-induced fall in LVEF.

Recurrent immunoglobulin A nephropathy after renal transplantation: a significant contributor to graft loss

BACKGROUND

Although most transplanted patients with underlying IgA nephropathy (IgAN) develop histological recurrence, its clinical relevance is considered low.

METHODS

We performed a single-center analysis of 61 renal transplant patients with IgAN.

RESULTS

Forty-four percent of the patients showed a stable graft function. Progressive graft dysfunction apparently due to recurrent IgAN occurred in 23% of the patients (16% required dialysis). Five patients were retransplanted, and three again developed dialysis-dependent renal failure apparently due to recurrent IgAN. In 20% of the patients, chronic transplant dysfunction was due to other reasons, whereas no reason was identified in 13% of the patients. Neither findings before transplantation, the ACE genotype, the type of immunosuppression, nor the course after transplantation predicted transplant dysfunction due to recurrent IgAN. Follow-up after transplantation was longer in the group with dysfunction due to recurrent disease than in the group with dysfunction due to chronic rejection or in the stable group.

CONCLUSION

Recurrent IgAN is a clinically relevant problem in renal transplant patients. Its importance may have been underestimated in the past due to inadequate lengths of follow-up.

Gene-polymorphisms of angiotensin converting enzyme and endothelial nitric oxide synthase in patients with primary glomerulonephritis

The ACE D- and the ecNOS a-allele have been associated with an adverse prognosis in patients with glomerulonephritis (GN). Using genomic DNA we investigated by RT-PCR whether the two polymorphisms are useful prognostic markers in GN patients. In patients with primary GN (IgA-GN n = 70, membranous GN n = 23, FSGS n = 17, MPGN n = 6) neither the whole group nor disease-specific subgroups exhibited any alterations from the normal ACE genotype distribution. No significant associations were detected between the ACE genotype and the development of hypertension, antihypertensive therapy required, progression rate of the disease, age of diagnosis and the antiproteinuric response to ACE-inhibition. In 40 IgA-GN patients with ESRD no increased prevalence of the D-allele was noted. The distribution of the ecNOS-alleles in the above patients (a-allele 22%, b-allele 78%) was comparable to that of the normal controls. No association with any of the parameters mentioned above were detected in the case of the ecNOS-alleles.

CONCLUSIONS

In our Caucasian patients neither the determination of the ACE nor the ecNOS genotype offered any diagnostic or prognostic help.

Cationic dextran induces mesangioproliferative nephritis in rats independent of glomerular IgA deposition

BACKGROUND

Dextran-induced mesangioproliferative glomerulonephritis in mice and, as recently reported, in rats is used as a model of IgA nephropathy. The pathogenetic role of the glomerular IgA deposits in this model, however, is unclear since IgG is often deposited in parallel.

METHODS

Lewis rats were immunized with cationic DEAE-dextran. Following this, rats received 5 x/week i.v. injections of 3 mg DEAE-dextran each, from days 20 to 80 and were then followed until day 120.

RESULTS

Rats developed transient proteinuria (range 63-152 mg/24 h) and haematuria on day 80. Renal biopsies obtained at days 60, 80, 100 and 120 showed mild to severe mesangioproliferative changes at days 80 and 100 which did not persist at day 120. Electron-microscopy revealed mesangial immune deposits, signs of endothelial activation and vacuoles in mesangial cells and podocytes. Compared to normal, age-matched controls, in the nephritic rats significant (P < 0.05) increases were noted for glomerular total cellularity, alpha-smooth-muscle actin expression (a marker of activated mesangial cells), monocyte/macrophage counts, and matrix proteins. Using three different antibodies, no evidence of glomerular IgA deposition was detected at any time point. In contrast, glomerular IgG, IgM, C3, and occasional small C5b-9 deposits were present in nephritic rats. Circulating IgG but not IgA anti-dextran antibodies could be demonstrated in nephritic rats.

CONCLUSIONS

The data confirm that mesangioproliferative glomerulonephritis can be induced in rats by immunization and chronic challenge with cationic dextran. Our data also show that in rats glomerular IgG deposition rather than IgA, appears to play an important pathogenetic role in this mesangioproliferative glomerulonephritis model.

Treatment of experimental mesangioproliferative glomerulonephritis with non-anticoagulant heparin: therapeutic efficacy and safety

Treatment with conventional heparin is effective in experimental mesangioproliferative glomerulonephritis. However, the long-term effects and safety of this therapy, in particular in the presence of mesangiolysis, have not been assessed. In addition, this therapy has been hampered by bleeding complications. In the present study, therefore, we investigated the long-term effects of a short course of non-anticoagulant (NA) heparin treatment in the anti-Thy 1.1 mesangioproliferative glomerulonephritis, in which early immune-mediated mesangiolysis subsequently leads to mesangial hyperproliferation. Rats received continuous ip NA-heparin or vehicle during the active mesangioproliferative phase (Days 2 to 9; early treatment) or during the early resolution phase (Days 10 to 17; late treatment). Whereas NA-heparin in the early treatment group did not affect the glomerular macrophage, lymphocyte, or platelet influx, it did lead to significantly decreased glomerular cellularity, mesangial cell proliferation, alpha-smooth muscle actin, desmin expression (ie, markers of activated mesangial cells), and matrix accumulation as well as to persistent mesangiolytic lesions including microaneurysms. Despite this latter finding, at Day 120, NA-heparin-treated rats of the early treatment group showed significantly better renal function and less proteinuria and glomerulosclerosis than vehicle-infused rats. In contrast, late therapy with NA-heparin neither accelerated resolution of the nephritis or otherwise affected the course of the disease. We conclude that transient NA-heparin therapy is effective in mesangioproliferative glomerulonephritis, both acutely and long term, when it is initiated during the active phase of the disease. Also, NA-heparin therapy is safe even in glomerular diseases accompanied by mesangiolysis.

Activated complement C3: a potentially novel predictor of progressive IgA nephropathy

In the search for a serologic marker of disease activity, we measured concentrations of activated C3 (actC3, that is, neoantigens developing after C3 activation on breakdown products), C4-C3 complexes and soluble C5b-9 (sC5b-9) in one or two plasma samples from adult patients with IgA nephropathy (IgAN, N = 50) or Henoch-Schönlein purpura (HSP, N = 4). As controls, 20 patients with non-immune renal disease, but comparable age, degree of proteinuria, renal dysfunction and prevalence of hypertension were studied. Compared to controls, actC3 levels were elevated in 30% of the patients with IgAN and one of the HSP patients. C4-C3 complexes were elevated in only 8% of the IgAN patients, and sC5b-9 levels were within the control range in all IgAN and HSP patients. In IgAN patients with elevated actC3 levels, proteinuria and hematuria were more pronounced than in those with normal levels. Elevated plasma concentrations of actC3 at the first presentation correlated with subsequent deterioration of renal function both in patients with initially normal and already impaired renal function (r = -0.56, N = 44, P = 0.003). The five IgAN patients with elevated actC3 on both occasions of obtaining plasma showed the most rapid loss of renal function. We conclude that mainly alternative pathway complement activation can be demonstrated in patients with IgAN and HSP. In IgAN patients the presence of complement activation is associated with more severe renal disease. Further studies are warranted to examine the clinical usefulness of actC3 as a predictor of the subsequent course of IgAN.

Role of interleukin-6 in mediating mesangial cell proliferation and matrix production in vivo

Mesangial cell proliferation and matrix overproduction characterize many progressive glomerular diseases. Based on currently available data, the role of interleukin-6 (IL-6) in mediating mesangial cell proliferation and matrix production is controversial. The present study attempts to clarify this issue by showing that: (1) IL-6 knock out mice develop a normal glomerular architecture and in particular a normal mesangium. (2) Mesangioproliferative glomerulonephritis induced by Habu snake venom is equally severe in IL-6 knock out mice as in control mice. (3) A continuous seven-day intraperitoneal infusion of 50 micrograms recombinant human IL-6 into rats with a prior minimal (subnephritogenic) injury to mesangial cells does not induce glomerular cell activation, cell proliferation, matrix production, leukocyte influx, platelet influx or proteinuria. (4) A continuous seven-day IL-6 infusion into rats with mesangioproliferative nephritis (anti-Thy 1.1 nephritis) increases matrix protein transcription in the absence of detectable effects on matrix protein accumulation and otherwise has no effect on the natural course of the disease. We conclude from these findings that IL-6 is not an important mediator of mesangial cell proliferation and matrix overproduction in vivo, and that currently little rationale exists to advocate anti-IL-6 therapy in mesangioproliferative disease states.

Differential regulation of the C3a and C5a receptors (CD88) by IFN-gamma and PMA in U937 cells and related myeloblastic cell lines

We have analyzed the induction of the receptor for the anaphylatoxic peptide C3a (C3aR) by the immunomodulator IFN-gamma, the phorbol ester PMA, and dibutyryl cAMP (Bt2cAMP) in comparison with the C5a receptor (C5aR, CD88). For U937 cells, IFN-gamma and Bt2cAMP up-regulated the C3aR to the same extent, whereas Bt2cAMP was 20-fold more effective in C5aR induction. PMA increased the expression of the C5aR, and acted synergistically with IFN-gamma. In contrast, PMA did not increase specific 125I-hC3a binding, and actually antagonized C3aR induction by IFN-gamma. Two related human cell lines of the myeloblastic/monocytic lineage, HL-60 and Mono Mac 6, showed inducibility of the C3aR similar to U937 cells. The two receptors showed subtle differences in signal transduction. Despite comparable numbers of both receptors, IFN-gamma potentiated activation of the C5aR but not the C3aR, as measured by an increase in free cytosolic Ca2+ upon ligand activation. Interestingly, Bt2cAMP-treatment led to a functional response to C3a in U937 cells. Such differences in receptor regulation and signaling might underlie the partly differing physiologic effects of C3a and C5a on, for example, chemotaxis, induction of oxidative burst, or immunoregulatory functions.

Differential regulation of the C3a and C5a receptors (CD88) by IFN-gamma and PMA in U937 cells and related myeloblastic cell lines

We have analyzed the induction of the receptor for the anaphylatoxic peptide C3a (C3aR) by the immunomodulator IFN-gamma, the phorbol ester PMA, and dibutyryl cAMP (Bt2cAMP) in comparison with the C5a receptor (C5aR, CD88). For U937 cells, IFN-gamma and Bt2cAMP up-regulated the C3aR to the same extent, whereas Bt2cAMP was 20-fold more effective in C5aR induction. PMA increased the expression of the C5aR, and acted synergistically with IFN-gamma. In contrast, PMA did not increase specific 125I-hC3a binding, and actually antagonized C3aR induction by IFN-gamma. Two related human cell lines of the myeloblastic/monocytic lineage, HL-60 and Mono Mac 6, showed inducibility of the C3aR similar to U937 cells. The two receptors showed subtle differences in signal transduction. Despite comparable numbers of both receptors, IFN-gamma potentiated activation of the C5aR but not the C3aR, as measured by an increase in free cytosolic Ca2+ upon ligand activation. Interestingly, Bt2cAMP-treatment led to a functional response to C3a in U937 cells. Such differences in receptor regulation and signaling might underlie the partly differing physiologic effects of C3a and C5a on, for example, chemotaxis, induction of oxidative burst, or immunoregulatory functions.

Genetic depletion of histamine from the nervous system of Drosophila eliminates specific visual and mechanosensory behavior

The role of histamine as a fast neurotransmitter of imaginal insect photoreceptors is firmly established. In adult Drosophila, histamine is also found in mechanosensory receptors of cuticular hair sensilla and in a small number of nonreceptor neurons in head and body ganglia. Here we investigate the function of histamine by immunohistochemical and behavioral analysis of mutants deficient in the hdc gene that codes for histidine decarboxylase. The allele hdcJK910 appears to be a null mutation, as histamine immunoreactivity is almost entirely eliminated. Homozygous flies are blind in various behavioral paradigms. Mutant larvae, on the other hand, show normal photokinetic responses. Thus, adult Drosophila photoreceptors most likely utilize only a single substance, histamine, as a neurotransmitter, whereas larval photoreceptors apparently employ a different transmitter. With the alleles hdcP211, hdcP217, and hdcP218, variable amounts of histamine are found in photoreceptors and mechanoreceptors, but no histamine could be detected in any of the nonreceptor neurons. These mutants show various degrees of visual and mechanosensory impairment, as determined by quantitative behavioral assays. We conclude that histamine is required for normal function of cuticular hair sensilla and for efficient grooming of the body surface. Thus, in Drosophila, histamine represents a major functional neurotransmitter for mechanosensory receptors.

Cytokines and glomerular injury

Since reports of the first data on cytokines in renal diseases about 10 years ago, the field has seen an explosive growth over the last decade. It is now realized that cytokines can be synthesized by many different types of cells, including glomerular cells, upon adequate stimulation and exert a wide range of actions mostly in an autocrine or paracrine fashion. Cytokines not only contribute to developmental processes, but also to the maintenance of normal tissue integrity and in particular to the initiation and modulation of tissue injury, healing, or scarring. This review summarizes some recent data on the role of cytokines in glomerular disease and describes some of the first experimental approaches to therapeutically interfere with cytokine actions.