Reliability of Chair-side Monolithic CAD-CAM Generated Lithium Disilicate Single Crowns with Knife- Edge Finish Line: Up to 5-Year Retrospective Analysis of Clinical Performance

This clinical study evaluated the survival of monolithic lithium disilicate (MLD) single crowns. Between January-2010 and January-2015, 87 patients received 122 MLD (IPS e.max CAD) single crowns on natural teeth with knife-edge finish lines that were adhesively bonded (Maxcem Elite). MLD single crowns (N=122) were bonded on 60 molars (maxilla:35, mandible:25), 53 premolars (maxilla:27, mandible:26), 4 canines (maxilla:2, mandible:2), 3 laterals and 2 centrals (maxilla). One crown fracture, one retention loss and one endodontic complication were experienced (survival rate: 97.5%). MLD single crowns could be safely indicated on teeth with knife-edge preparations.

Hard and soft tissue changes in the rehabilitation of the anterior maxilla with triangular shape neck implants: a retrospective clinical study with a one-year follow up

Aim of this retrospective study was to evaluate the one-year clinical and radiographic outcomes of implants with a triangular shaped neck inserted immediately after tooth extraction in esthetic zones. Patients in which immediate postextraction implants were placed and restored in the anterior maxilla, who underwent a Cone Beam Computed Tomograpy (CBCT) at baseline and after 12-16 months were included. The socket was preserved using deproteinized bovine bone to fill the buccal gap, and a resorbable collagen membrane. One-year implant survival and prosthesis success were evaluated. Hard and soft tissue stability was assessed by measuring various parameters on CBCT images. Clinical evaluation was also performed and Pink Esthetic Score (PES) assessed. Data from baseline and one-year follow-up were statistically compared using paired tests and a significance threshold of p=0.05. Twenty patients (13 males, 7 females, mean age 50.42±11.35 years) were included. Each contributed with one implant. No implant was lost. A significant improvement in PES was detected. Excellent hard and soft tissue preservation was observed after one year of function. Immediate placement of implants with a triangular shaped neck after tooth extraction, can be a suitable solution even for areas with a high aesthetic demand, such as the anterior maxilla.

A randomized, controlled clinical trial to evaluate the immunogenicity of a PreS/S hepatitis B vaccine Sci-B-Vac™, as compared to Engerix B®, among vaccine naïve and vaccine non-responder dialysis patients

BACKGROUND

Dialysis patients have a suboptimal response to hepatitis B (HBV) vaccination. This study aimed to compare the immunogenicity of two vaccines: the third-generation Sci-B-Vac™ vs. the second-generation Engerix B^®. The cohort included two groups of dialysis patients: naïve and previously vaccinated non-responders. Primary endpoints were antibody titers ≥10 IU/L at 3 and 7 month post-vaccination. Secondary objectives were seroprotection rates in vaccine-naïve patients and in previously vaccinated non-responders.

METHODS

Eighty-six patients were assigned to vaccine (Sci-B-Vac™ or Engerix B^®) using computer-generated randomization, stratified by age, gender, diabetes, and previous HBV vaccination. Sci-B-Vac™ was administered in three doses, 10 μg, at 0, 1, and 6 months in naïve patients; or 20 μg in previously vaccinated non-responders. Engerix B^® included four doses, 40 μg at 0, 1, 2, and 6 months.

RESULTS

Each group had 43 patients. Seroconversion was 69.8% with Engerix B^® vs. 73.2% with Sci-B-Vac™. Antibody titers at 7 months were higher with Sci-B-Vac™ (266.4 ± 383.9, median 53.4) than with Engerix^® (193.2 ± 328.9, median 19). However, these differences were not significant, perhaps due to a suboptimal sample size.

CONCLUSIONS

This study suggests comparable immunogenicity for both vaccines. Thus, we cannot reject the null hypothesis that there is no difference in seroconversion by vaccine type. It is noteworthy that naïve patients were vaccinated with a standard dose of Sci-B-Vac™, while Engerix B^® was administered at a double dose. Similarly, although mean antibody titer levels in the Sci-B-Vac™ group were higher than in the Engerix^® group, this difference did not reach significance. Consequently, a future clinical trial should recruit a larger cohort of patients, using a standard double-dose protocol in both groups.

Morphological features of the maxillary incisors roots and relationship with neighbouring anatomical structures: possible implications in endodontic surgery

The purpose of this study was to investigate the relationship between the root apex of the upper incisors and neighbouring anatomical structures as well as the morphology of the root-end foramen after apicoectomy. Fifty-seven patients requiring endodontic surgical treatment for a maxillary anterior root were enrolled. A preoperative diagnostic computed tomography (CT) scan was analysed to determine: the distance between the anterior wall of the nasopalatine duct and the central (CI-ND) incisor root 4mm from the apex; and the distance between the floor of the nasal cavity and the tip of either the central (CI-NF) or the lateral (LI-NF) incisor root. After apicoectomy, root-end foramen endoscopic pictures were taken in order to characterize their morphology. Fifty-nine central and 26 lateral incisors were evaluated. The average CI-ND was 4.71 ± 1.26 (SD) mm. The average CI-NF was 10.62 ± 2.25 mm. The average LI-NF was 13.05 ± 2.43 mm. The foramen shape after apicoectomy was ovoid to circular in about 90% of cases in both central and lateral incisors. A sound knowledge of the anatomical relationships at the surgical site is essential for the clinician to perform a safe endodontic surgical procedure.

Preservation of an injured vital tooth using ultrasonic device and mineral trioxide aggregate

The purpose of this case report is to present a root fracture repair procedure for non devitalized injured tooth. One injured, non-endodontically treated maxillary anterior tooth in which an incomplete vertical root fracture involving only the buccal side was suspected, underwent an exploratory flap to visualize the pattern of bone loss and assess the type of root fracture. The pre-operative diagnosis was confirmed. A groove following fracture line was prepared using retro-tips driven by an ultrasonic device and sealed with Mineral Trioxide Aggregate (MTA), following filling of the bone defect with Calcium Sulphate. At 24 months follow up the case showed clinical and radiographic success. The present surgical approach showed preservation of function and vitality of tooth with a shallow incomplete vertical root fracture.

The influence of previous non-surgical re-treatment on the outcome of endodontic surgery

AIM

The aim of this study was to evaluate retrospectively if the outcome of periradicular surgery at four year follow-up can be affected by a previous orthograde re-treatment.

METHODS

Eighty-one patients with 118 endodontically treated teeth who underwent surgical retreatment were divided in three groups. In group OA endodontic re-treatment was feasible and was attempted but, owing to the persistence of clinical symptoms and radiographic lesion, apical surgery was performed 4.8 ± 3.5 months later. In group OF endodontic re-treatment was feasible but was not performed, with subsequent apical surgery. In group ONF endodontic re-treatment was unfeasible, and apical surgery was performed. The treatment outcome was assessed four years postsurgery according to clinical and radiographic criteria.

RESULTS

Seventy-six patients (112 teeth) could be evaluated at four years. In the ONF group five anterior maxillary teeth, belonging to three female patients, failed to heal. Three failures in three patients occurred in the OF group. No failure was recorded in the OA group. Three teeth in three patients were classified as uncertain healing in each group. The outcome of group OA resulted significantly better than the other treatment groups for both tooth-based and patient-based analysis. No significant effect was found as related to jaw, tooth type, presence of a post. A significant relation was found with gender (P=0.04). A negative correlation was found between outcome and age (Pearson's coefficient=-0.09), suggesting that the probability of failure increases with age.

CONCLUSION

Orthograde re-treatment prior to apical surgery could be considered a valid alternative to tooth extraction and not an over-treatment.

Magnification in modern endodontic practice

The use of magnification devices in endodontics is becoming more and more common, with the aim of improving the quality of treatment. The common magnification systems used in modern endodontics are the surgical operation microscope, fiber-optic endoscope, and surgical loupes. The benefits of using magnification devices for conventional endodontic treatment include the increased visualization of the treatment field, enhanced possibilities in locating canals, aid in the removal of separated instruments, diagnosis of root and tooth fractures, perforation repair, and case documentation. In endodontic surgery, the use of magnification improves the ability to locate, clean, and fill the root canal system, thus achieving a predictable outcome. Further evidence-based research might better clarify the advantages and limitations of using magnification in endodontic practice.

Endodontic treatment of a geminated maxillary second molar using an endoscope as magnification device

AIM

To describe endodontic treatment for a rare case of gemination.

SUMMARY

A case of complex endodontic treatment in a geminated tooth is presented. With the assistance of microinstruments and magnification devices, a geminated maxillary second molar was successfully treated. In such a case, ultrasonic tips and the use of an endoscope were essential to detect the peculiar anatomy of the tooth involved.

KEY LEARNING POINTS

Knowledge of anomalies concerning fused teeth is essential. Using an endoscope as a magnification device is useful during the inspection of pulp chambers. Ultrasonic tips are safe and useful to detect canal orifices.

Surgical decision making in coronally located vertical root fracture

AIM

The purpose of this study was to present an intrasurgical decision making in teeth showing clinical signs and symptoms of incomplete vertical root fracture.

METHODS

Sixteen patients with one tooth in which an incomplete vertical root fracture was diagnosed, involving only the buccal side, underwent a flap elevation procedure to visualize the pattern of bone loss and assess the type of root fracture. If the intraoperative diagnosis confirmed the presurgical one, a new root fracture repair technique was used. If the intraoperative diagnosis consisted of a complete or multiple fracture, the tooth was extracted and a postextraction implant insertion procedure was performed, in combination with the use of plasma rich in growth factors in order to enhance implant osseointegration.

RESULTS

A total of nine vertical root fracture repair procedures were performed. The mean patient follow-up was 22.5 months. All patients reported full satisfaction for mastication function and phonetics. One patient was not satisfied for the esthetic result. A total of seven implants were immediately inserted in fresh postextraction sockets, and loaded four months later. The mean patient follow-up was 25.2 months. Overall implant success and survival was 100% after one year of functional loading. All patients reported full satisfaction for mastication function, phonetics and esthetics.

CONCLUSIONS

Intraoperative diagnosis allowed to choose an appropriate surgical approach that led to excellent results in terms of clinical outcomes and patient satisfaction.

Effect of sodium hypochlorite with the addition of a proteolytic enzyme on postoperative discomfort: a multicenter randomized clinical trial

AIM

The purpose of this study was to compare the patient's postoperative discomfort when root canal irrigation was performed either with standard sodium hypochlorite or with sodium hypochlorite with the adjunct of a proteolytic enzyme.

METHODS

Two hundred patients were endodontically treated in two clinics. The type of irrigant to be used during root canal instrumentation was randomly assigned. Final irrigation was done using EDTA 17%. The canals were filled by warm vertical condensation with guttha-percha and the coronal seal was made using IRM. Patients were given a questionnaire to assess pain and swelling and the number of analgesics and other drugs taken during the first week after treatment.

RESULTS

A total of 166 questionnaires could have been evaluated. No significant difference was found between groups for pain, swelling and analgesics taken. Moderate pain and swelling was reported only in the first two days after treatment. No antibiotics use was reported. No guttha-percha excess beyond root apex was found by radiographic assessment.

CONCLUSIONS

The irrigating solution containing a proteolytic enzyme does not produce greater postoperative discomfort as compared to the conventional sodium hypochlorite in patients undergoing endodontic therapy.

Endoscopic management of a lateral root lesion. A case report

The aim of this study was to obtain periradicular tissue healing of a lateral root lesion using a microsurgical technique. The case report concerns a 52-year-old female patient, in general good health (ASA1), presented with the left maxillary canine (2.3) exhibiting acute, specific symptoms. A radiographic examination revealed the presence of a circumscribed radiolucent lesion associated with the mesial mid-root area of the 2.3 and the distal mid-root area of 2.2, both endodontically treated. Using an endoscope as a magnification device a surgical inspection of the middle-third of the root of 2.2 and 2.3 was made. A pathway between the periodontium and root-canal system was detected with an endodontic file on the middle-third of 2.3 root wall. A root-lateral cavity was prepared using retro-tips. An EBA cement was used as the root-end filling material. Following clinical and radiographic assessment at 36 months post-surgery, the case was classified as successful. This case report showed the utility of using an endoscope and micro-surgical instruments for diagnosis and surgical treatment of micro-anatomical root structures.

Arginine uptake is attenuated through modulation of cationic amino-acid transporter-1, in uremic rats

Endothelial cell dysfunction (ECD) is a common feature of chronic renal failure (CRF). Defective nitric oxide (NO) generation due to decreased endothelial NO synthase (eNOS) activity is a crucial parameter characterizing ECD. L-arginine is the sole precursor for NO biosynthesis. Among several transporters that mediate L-arginine uptake, cationic amino-acid transporter-1 (CAT-1) acts as the specific arginine transporter for eNOS. Our hypothesis implies that CAT-1 is a major determinant of eNOS activity in CRF. We studied glomerular and aortic arginine uptake, CAT-1, and CAT-2 messenger ribonucleic acid (mRNA) expression, and CAT-1 protein in: (a) rats 6 weeks following 5/6 nephrectomy (CRF), (b) sham-operated animals, and (c) rats with CRF treated orally with either atorvastatin or arginine in drinking water (modalities which have been shown to enhance eNOS activity and improve endothelial function). Both glomerular and aortic arginine transport were significantly decreased in CRF. Treatment with either arginine or atorvastatin abolished the decrease in arginine uptake in CRF rats. Using reverse transcriptase-polymerase chain reaction and Northern blotting, we found a significant increase in glomerular and aortic CAT-1 mRNA expression in CRF. Western blotting revealed that CAT-1 protein was decreased in CRF, but remained intact following arginine and atorvastatin administration. Renal and systemic arginine uptake is attenuated in CRF, through modulation of CAT-1 protein. These findings provide a possible novel mechanism to eNOS inactivation and endothelial dysfunction in uremia.

Peripheral vascular disease and serum phosphorus in hemodialysis: a nested case-control study

BACKGROUND

Serum phosphorus (P) and the product of serum calcium x serum P (Ca x P), are frequently elevated in end-stage renal disease patients on maintenance hemodialysis (HD). Elevated P and Ca x P have been associated with vascular calcification in dialysis patients.

OBJECTIVE

[corrected] To examine the role of P and Ca x P as risk factors for incident peripheral vascular disease (PVD) in HD patients with pre-existing CVD.

METHODS

This nested case-control study is drawn from the 11 incident PVD events reported in the cohort of the Secondary prevention with antioxidants of cardiovascular disease in end-stage renal disease (SPACE): a randomized placebo-controlled trial. PVD was defined clinically and confirmed ultrasonographically. Each individual with a PVD event was matched for SPACE treatment group (vitamin E or placebo), age (in 4-year categories) and gender with two individuals who had no CVD end point during the follow-up period.

RESULTS

Serum P and Ca x P levels were significantly higher in PVD patients than in controls. In univariate logistic regression analysis, only serum P predicted PVD in this population (OR 2.02, 95% CI 1.07 - 3.81, p = 0.03). In multivariate analysis, adjustment was made for variables dissimilar by PVD status including underlying renal disease, diabetes, smoking, history of angina pectoris, prescription for vitamin D3, erythropoietin, calcium channel blockers and aspirin. In this model, serum P remained the only significant predictor of incident PVD (OR 2.4, 95% CI 1.01 - 5.74, p = 0.04).

CONCLUSIONS

Findings of the present study are consistent with a role for serum P and Ca x P in the pathogenesis of PVD in HD patients.

Orthostatic hypotension in the elderly: are the diagnostic criteria adequate?

Orthostatic hypotension (OH) is a common finding in the elderly. OH is defined as a fall of at least 20 mmHg in systolic blood pressure (BP) and/or 10 mmHg in diastolic BP upon assuming an upright posture. Some patients exhibit a fall in BP of less than the defined OH upon standing. The aim of this study was to estimate the prevalence of BP changes not defined as OH among elderly in-patients and to assess the relationship between these changes in the morning and the occurrence of OH during the day. Postural BP measurements were performed in 502 in-patients; in the morning, early afternoon, and in the evening. We defined intermediate postural drop (ID) in BP as a decrease of 10-19 mmHg in systolic BP and/or of 5-9 mmHg in diastolic BP. We observed that OH and ID occurred in 39.2 and 18.5% of the measurements in the morning, respectively. The prevalence of OH and ID was lower in the evening than in the morning (P<0.05) and afternoon (P<0.005). Postural BP changes in the morning correlated with those occurring later in the day. Patients who had ID in the morning had a 57% probability of having OH later during the day. In conclusions, ID is prevalent in elderly in-patients. ID in the morning predicts OH later in the day. Thus, postural BP drops below the OH range may be an important finding in the geriatric population.

Delayed branching of endothelial capillary-like cords in glycated collagen I is mediated by early induction of PAI-1

Development of micro- and macrovascular disease in diabetes mellitus (DM) warrants a thorough investigation into the repertoire of endothelial cell (EC) responses to diabetic environmental cues. Using human umbilical vein EC (HUVEC) cultured in three-dimensional (3-D) native collagen I (NC) or glycated collagen I (GC), we observed capillary cord formation that showed a significant reduction in branching when cells were cultured in GC. To gain insight into the molecular determinants of this phenomenon, HUVEC subjected to GC vs. NC were studied using a PCR-selected subtraction approach. Nine different genes were identified as up- or downregulated in response to GC; among those, plasminogen activator inhibitor-1 (PAI-1) mRNA was found to be upregulated by GC. Western blot analysis of HUVEC cultured on GC showed an increase in PAI-1 expression. The addition of a neutralizing anti-PAI-1 antibody to HUVEC cultured in GC restored the branching pattern of formed capillary cords. In contrast, supplementation of culture medium with the constitutively active PAI-1 reproduced defective branching patterns in HUVEC cultured in NC. Ex vivo capillary sprouting in GC was unaffected in PAI-1 knockout mice but was inhibited in wild-type mice. This difference persisted in diabetic mice. In conclusion, the PCR-selected subtraction technique identified PAI-1 as one of the genes characterizing an early response of HUVEC to the diabetic-like interstitial environment modeled by GC and responsible for the defective branching of endothelial cells. We propose that an upregulation of PAI-1 is causatively linked to the defective formation of capillary networks during wound healing and eventual vascular dropout characteristic of diabetic nephropathy.

Mesna: a novel renoprotective antioxidant in ischaemic acute renal failure

BACKGROUND

Reactive oxygen species (ROS) play a key role in renal ischaemia-reperfusion injury. After establishing the in vitro anti-oxidative potential of mesna, a sulfhydryl-containing compound, its effect on kidney function and morphology in a rat model of ischaemic acute renal failure (ARF) was examined.

METHODS

Mesna (180 mg/kg) was administered at different time points relative to ischaemia and/or reperfusion onset. Kidney function was assessed by glomerular filtration rate (GFR) and fractional sodium excretion (FE(Na)) before a 45-min period of unilateral renal artery clamping and following 90 min of reperfusion. Mesna was administered by bolus, 30 min before the induction of ischaemia, 5 min before ischaemia, 5 min before reperfusion, and 5 min after the onset of reperfusion.

RESULTS

Mesna improved function of the ischaemic kidney at each administration. When mesna was administered 5 min before the onset of reperfusion, GFR reached 90-100% of its pre ischaemic value and FE(Na) was improved by 75%. The beneficial effect of mesna was also demonstrated by light and electron microscopy. Kidneys treated with mesna 5 min before reperfusion resembled ischaemic non-reperfused kidneys and showed subtle morphological and ultrastructural changes compared with ischaemic-reperfused kidneys. Mesna had no haemodynamic effect on renal blood flow and did not induce any osmotic diuresis.

CONCLUSIONS

We suggest that mesna acts as an antioxidant. Its antioxidant potential together with optimal protection achieved when administered 5 min before reperfusion, supports the conclusion that mesna scavenges ROS generated at the onset of reperfusion, thus diminishing reperfusion injury and organ damage.

Hepatitis C infection in dialysis patients in Israel

BACKGROUND

Hepatitis C virus is the major cause of acute and chronic hepatitis in patients with end-stage renal disease receiving replacement therapy.

OBJECTIVES

To define the prevalence of HCV RNA in a population of patients on dialysis in Israel, to determine the relative risk of acquiring HCV infection while treated by hemodialysis or chronic ambulatory peritoneal dialysis, and to define the HCV genotypes in this population.

METHODS

During 1995 we studied 162 dialysis patients. Information was obtained regarding the mode of dialysis, years of treatment, number of blood transfusions, and results of serological testing for HCV, hepatitis B virus, and human immunodeficiency virus. Anti-HCV antibodies were tested by a third-generation microparticle enzyme immunoassay. HCV RNA was determined by polymerase chain reaction. HCV genotyping was performed by a hybridization assay.

RESULTS

HCV RNA was detected in 18% of the HD group and 7% of the CAPD group. The number of HCV RNA-positive patients was significantly higher in the HD than the CAPD group (P < 0.05). HCV RNA-positive HD patients were treated longer than the HCV RNA-negative patients (P < 0.02).

CONCLUSIONS

Third-generation immunoassay proved to be highly sensitive (94%) and specific (91%) in identifying HCV RNA positivity. Several HCV subtypes were detected, 1b being the most frequent. Identification and isolation of infected HCV patients may minimize its spread in dialysis units and prevent cross-infection.

Effect of cyclosporin A on DNA repair and cancer incidence in kidney transplant recipients

Cancer incidence is enhanced in transplant recipients. Decreased DNA repair ability is associated with increased cancer incidence. Transplanted patients with cancer were found to have reduced DNA repair. We hypothesized that immunosuppressive therapy may impair DNA repair and thus contribute to the increased cancer incidence in transplanted patients. The objectives of this study were (1) to investigate the effect of two immunosuppressive treatment protocols on DNA repair in kidney transplant recipients; (2) to evaluate the cancer incidence in these patients; and (3) to study the in vitro effect of cyclosporin A (CsA), azathioprine, and prednisolone-separately and in various combinations-on DNA repair. Three groups were studied: (1) a control group; (2) patients treated with azathioprine and prednisone (double-therapy group); and (3) patients treated with CsA, azathioprine, and prednisone (triple-therapy group). The two patient groups did not differ in age, gender, time on dialysis before transplantation, or kidney function or in the number of acute rejections. However, the interval from transplantation to the DNA repair study was shorter in the triple-therapy group (P <.01). DNA repair was induced in peripheral blood mononuclear cells (PBMCs) by ultraviolet irradiation and expressed as tritiated thymidine uptake by these cells. DNA repair in the triple-therapy group was 679 +/- 64 cpm/10(6) cells, significantly less than that in the control group (1049 +/- 69 cpm/10(6) cells, P <.02). In the double-therapy group, DNA repair was similar to that in the control group. The follow-up period was shorter in the triple-therapy group (116 +/- 19 months vs 174 +/- 29 months, P <.01). Five tumors developed in the triple-therapy group, but only one developed in the double-therapy group (P =.05). The in vitro study showed a dose-dependent reduction in PBMC DNA repair by CsA. Azathioprine and prednisolone reduced DNA repair slightly, but CsA reduced DNA repair significantly more than either one or a combination of them. In summary, triple therapy was associated with impaired PBMC DNA repair and increased cancer incidence. CsA was responsible in large part for the reduction in DNA repair ability found in the in vitro and in vivo studies. This may have partly contributed to the enhanced cancer incidence in the kidney transplant recipients.

Sonographic features of dialysis-related amyloidosis of the shoulder

This study evaluated the diagnostic role of ultrasonography in dialysis-related amyloidosis in shoulders of chronically hemodialyzed patients. Fourteen shoulders of 12 long-term hemodialysis patients were examined. All patients had been on dialysis for at least 10 years. All patients had varying degrees of pain and limitations of movement in the studied shoulders. Dialysis-related amyloidosis was the presumed diagnosis in all patients. Any patient with a history of any disease, other than dialysis-related amyloidosis, capable of producing a pathologic shoulder condition was excluded. The following parameters were studied: supraspinatus and biceps tendon thickness, tendon tears, synovial thickening, and the presence of hypoechoic material around tendons and within bursae. All shoulders had a nonhomogeneous thickening, greater than 7 mm, of the supraspinatus tendon. Seven shoulders (50%) had abnormal thickening of the biceps tendon (4 mm or greater), and two shoulders had abnormal thickening of the subscapularis tendon. Hypoechoic deposits were seen in the subdeltoid bursae and biceps sheaths in five and six shoulders, respectively. Three shoulders showed partial tears of the supraspinatus tendon, one shoulder showed a tear in the biceps tendon, and one shoulder had a tear in the subscapularis tendon. Ultrasonography is an excellent imaging modality in diagnosing the presence of dialysis-related amyloidosis in symptomatic shoulders of long-term hemodialysis patients, without having to resort to invasive procedures. The results of previous studies have been confirmed and new ultrasonographic findings described. Of particular interest is the involvement of the subscapularis tendon in dialysis-related amyloidosis. Repeat ultrasonography can become an important way to follow-up progression of shoulder dialysis-related amyloidosis in hemodialyzed patients.

Secondary prevention with antioxidants of cardiovascular disease in endstage renal disease (SPACE): randomised placebo-controlled trial

BACKGROUND

Excess cardiovascular mortality has been documented in chronic haemodialysis patients. Oxidative stress is greater in haemodialysis patients with prevalent cardiovascular disease than in those without, suggesting a role for oxidative stress in excess cardiovascular disease in haemodialysis. We investigated the effect of high-dose vitamin E supplementation on cardiovascular disease outcomes in haemodialysis patients with pre-existing cardiovascular disease.

METHODS

Haemodialysis patients with pre-existing cardiovascular disease (n=196) aged 40-75 years at baseline from six dialysis centres were enrolled and randomised to receive 800 IU/day vitamin E or matching placebo. Patients were followed for a median 519 days. The primary endpoint was a composite variable consisting of: myocardial infarction (fatal and non-fatal), ischaemic stroke, peripheral vascular disease (excluding the arteriovenous fistula), and unstable angina. Secondary outcomes included each of the component outcomes, total mortality, and cardiovascular-disease mortality.

FINDINGS

A total of 15 (16%) of the 97 patients assigned to vitamin E and 33 (33%) of the 99 patients assigned to placebo had a primary endpoint (relative risk 0.46 [95% CI 0.27-0.78], p=0.014). Five (5.1%) patients assigned to vitamin E and 17 (17.2%) patients assigned to placebo had myocardial infarction (0.3 [0.11-0.78], p=0.016). No significant differences in other secondary endpoints, cardiovascular disease, or total mortality were detected.

INTERPRETATION

In haemodialysis patients with prevalent cardiovascular disease, supplementation with 800 IU/day vitamin E reduces composite cardiovascular disease endpoints and myocardial infarction.

Haemolysis in haemodialysis patients: evidence for impaired defence mechanisms against oxidative stress

BACKGROUND

Uraemic patients have a decreased ability to withstand oxidative stress. It is postulated that their antioxidant capacity is reduced, yet the mechanism remains unclear. Recently 33 haemodialysis (HD) patients were exposed to chloramine contamination in the water supply. This led to haemolysis in 24 patients, while nine were unaffected. In the former group haemoglobin decreased from 11.7+/-1.1 to 8.5+/- 1.4 g/dl (P<0.0001) and returned to 11.4+/-0.9 g/dl (P<0.0001) following recovery. During haemolysis, haptoglobin was 38.4+/-10.6 vs 138.1+/-8.3 ng/dl (P<0.0001) following recovery.

METHODS

To explore the factors affecting the severity of haemolysis we studied extracellular and intracellular anti-oxidant defence mechanisms 3 months after recovery. In 29 patients and 20 controls we determined plasma glutathione (GSH), and the erythrocyte enzymes glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Rx), and superoxide dismutase (SOD). Serum malondialdehyde (MDA) was measured as a marker of oxidative stress.

RESULTS

Plasma GSH was lower in patients as compared to controls (5.49+/-0.26 vs 7.4+/-0.5 micromol/l, P<0.005). There was an inverse correlation between GSH and the degree of haemolysis (r=-0.42, P<0.02). Patients had higher GSH-Rx (4.64+/-0.15 vs 3.97+/-0.12 U/gHb, P<0.02), lower GSH-Px (29. 7+/-1.85 vs 35.5+/-1.62 U/gHb, P<0.001), and similar SOD (0.63+/-0. 02 vs 0.51+/-0.02 U/mgHb) as compared to controls. There was no correlation between the enzyme levels and the degree of haemolysis. MDA was higher in patients (2.37+/-0.07 vs 0.97+/-0.1 nmol/ml, P<0. 0001). There was a correlation between MDA and the years patients were on HD (r=0.43, P<0.02).

CONCLUSIONS

These data indicate that HD patients have an impaired anti-oxidant response, which may be attributed in part, to plasma GSH deficiency. Patients with the lowest plasma GSH levels are more susceptible to oxidative stress and consequent haemolysis.

Glomerular hemodynamics in severe obesity

Differential solute clearances were used to characterize glomerular function in 12 nondiabetic subjects with severe obesity (body mass index >38). Nine healthy subjects served as the control group. In the obese group, glomerular filtration rate (GFR) and renal plasma flow (RPF) exceeded the control value by 51 and 31%, respectively. Consequently, filtration fraction increased. The augmented RPF suggested a state of renal vasodilatation involving, mainly or solely, the afferent arteriole. Albumin excretion rate and fractional albumin clearance increased by 89 and 78%, respectively. Oral glucose tolerance tests were suggestive of insulin resistance. Insulin resistance was positively correlated with GFR (r = 0.88, P<0.001) and RPF (r = 0.72, P <0.001). Mean arterial pressure was higher than in the control group. Fractional clearances of dextrans of broad size distribution tended to be lowered. The determinants of the GFR were estimated qualitatively by using a theoretical model of dextran transport through a heteroporous membrane. This analysis suggests that the high GFR in very obese subjects may be the result of an increase in transcapillary hydraulic pressure difference (DeltaP). An abnormal transmission of increased arterial pressure to the glomerular capillaries through a dilated afferent arteriole could account for the augmentation in DeltaP.

Erythropoietin, folic acid deficiency and hyperhomocysteinemia: is there a possible relationship in chronically hemodialyzed patients?

AIMS

To examine the possible relationships between recombinant human erythropoietin (rhEPO) therapy, serum folic acid and homocysteine levels in a cohort of stable, chronically hemodialyzed patients.

MATERIAL AND METHODS

The study was cross-sectional in its first phase and consisted of 3 groups of subjects (group 1:6 healthy controls; group 2:7 dialyzed patients not receiving rhEPO; group 3: 14 patients on rhEPO therapy). Hematological and biochemical parameters were taken after an overnight fast in all subjects. The second phase of the study was prospective, and included 8 dialyzed patients, and investigated the effects of a 6-month period of folic acid supplementation (10 mg, 3 times a week) on the same parameters examined in the first phase of the study.

RESULTS

In the first part of the study hemoglobin levels were near-normal, or normal, in all patients. No differences in hemoglobin or hematocrit values were observed in the 3 groups. 80% of all hemodialyzed patients had low serum folic acid levels, irrespective of whether they were receiving rhEPO. Serum erythropoietin level was elevated in group 3 (23.3+/-10.4 mIU/ml). In group 2, serum erythropoietin level was not different from that of the healthy controls (13.5+/-11.2 vs. 8.0+/-5.4 mIU/ml, p = n.s.). Total serum homocysteine levels were elevated in all dialyzed patients (group 2: 24.7+/-9.2 micromol/l; group 3: 31.6+/-14.4 micromol/l), with a significant difference seen when comparing controls and those dialyzed patients on rhEPO therapy (8.7+/-2.2 vs. 31.6+/-14.4 micromol/l; p<0.05). Significant correlations (ANOVA) were observed between serum erythropoietin and folic acid levels (r = -0.382; p = 0.049), and between folic acid and homocysteine levels (r = -0.560; p = 0.002). In the second part of the study folic acid supplementation led to a highly significant reduction in homocysteine levels (20.9+/-4.9 vs. 11.9+/-2.5 micromol/l; p<0.0005). Two of 3 patients receiving rhEPO therapy, had rhEPO discontinued after commencing folic acid, as hemoglobin levels remained adequate, even without rhEPO.

CONCLUSIONS

In hemodialyzed patients, the presence of a near-normal hemoglobin level, irrespective of rhEPO therapy, implies efficient erythropoiesis. Without adequate folic acid reserves, folic acid deficiency may develop in these patients and this will aggravate already high homocysteine levels. Therefore, folic acid supplementation is warranted in hemodialyzed patients, especially in those patients with hemoglobin levels approaching normal. This treatment is safe and effective in reducing homocysteine levels, especially when given in high doses for prolonged periods of time.

Lymphocytic intracellular calcium in a patient with complicated verapamil overdose

Overdose with calcium channel blockers (CCBs) may lead to serious complications. CCBs act by blocking calcium entry into the cell, thus lowering intracellular calcium ([Ca2+]i). [Ca2+]i during CCB overdose has not yet been reported. We measured [Ca2+]i in lymphocytes of a patient with acute verapamil overdose with a complex clinical picture. A 59-year-old woman was admitted after a suicidal ingestion of 7200 mg of a sustained-release verapamil preparation. She presented with hypotension, complete atrioventricular block, stupor, hypokalemia, and hyperglycemia. Acute oliguric renal failure, acute pancreatitis, and the adult respiratory distress syndrome further complicated her medical course. Treatment was supportive and she recovered completely. Intracellular calcium ([Ca2+]i) was measured in the patient's lymphocytes using a spectrofluorometer with the calcium-sensitive dye Fura-2-acetoxymethyl ester. Thirty nine hours after the ingestion, [Ca2+]i was low at 52 nM (compared with 80 nM in a healthy control subject). Lymphocytic [Ca2+]i did not respond to stimulation with phytohemagglutinin (PHA). Fourteen days after the verapamil overdose, after the patient had recovered completely, lymphocytic [Ca2+]i was still low at 55 nM. At this time, there was an incomplete response to PHA in the lymphocytes. Three months after the ingestion, [Ca2+]i was normal, with a normal response to PHA. Verapamil overdose may run a complex clinical course, but full recovery is to be hoped for with full supportive care. Cellular intoxication, as reflected by low lymphocytic [Ca2+]i, is prolonged and lags behind the clinical recovery by weeks.

Successful intradialytic parenteral nutrition after abdominal "Catastrophes" in chronically hemodialysed patients

OBJECTIVE

To assess the therapeutic contribution of intradialytic parenteral nutrition (IDPN) in four acutely ill, hypercatabolic, hemodialysed patients. All underwent major surgery, complicated by infection and malnutrition.

DESIGN

A retrospective clinical study.

SETTING

An in-center hemodialysis unit, at a tertiary referral hospital.

PATIENTS

Patient 1: a young woman, with a good renal transplant. Developed gastric lymphoma, which required gastrectomy. After cessation of immunosuppression, "lost" her kidney and returned to hemodialysis. Received IDPN for 4 months and recovered well from severe malnourishment. Patient 2: an elderly, malnourished man, on continuous ambulatory peritoneal dialysis (CAPD). Developed biliary peritonitis and bacteremia. In a 3-month period, the patient had four operations. Maintained on IDPN for 4 months. Patient 3: a young and obese man, who suffered from life-threatening staphylococcal aureus peritonitis, resulting in widespread bowel adhesions. Underwent repeated aspirations of purulent ascites, laparoscopy, and explorative laparotomy. IDPN was administered for 4 months and stopped on the patient's request. Patient 4: a young man, who after cadaveric renal transplantation remained hospitalized for 6 months because of acute rejection and peritoneal and retroperitoneal abscesses. Had major surgery performed seven times. Received IDPN for 6 months, and is now well.

RESULTS

All four patients benefited from 4 to 6 months of IDPN, as an integral part of intensive supportive and nutritional treatment. Weight loss was halted, as patient appetite returned and oral nutrition became adequate. Estimated daily protein intake reached 1.2 g/kg, while caloric intake rose to nearly 30 kcal/kg/d (Table 3). Mean serum albumin levels increased from 25.5 g/L +/- 0.9 g/L to 38.0 g/L +/- 1.5 g/L. No adverse side effects were seen from IDPN.

CONCLUSION

IDPN is a worthwhile part of treatments used in the catabolic, postoperative hemodialysed patient. It is safe and efficient when used over a 6-month period in trying to attenuate existing, or worsening malnutrition in these patients. It should be commenced at an early stage in these patients, after attempts at oral nutritional support have been deemed inadequate.

H2O2 induces DNA repair in mononuclear cells: evidence for association with cytosolic Ca2+ fluxes

Cellular DNA repair systems are induced whenever DNA is damaged. Reactive oxygen species (ROS) are generated, in vivo, in the tissues as a result of regular cellular metabolism or after exposure to oxidizing agents, such as ultraviolet (UV) irradiation. It has been suggested that ROS mediate DNA damage. The objectives of the study were as follows: (1) to investigate whether hydrogen peroxide (H2O2), the commonly occurring cellular ROS, induces DNA repair as a response to the damage it probably causes; (2) to evaluate whether H2O2-induced DNA repair, if present, is signaled through a Ca2(+)-dependent pathway via the tyrosine kinase signal transduction. H2O2 was found to induce DNA repair in human peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner. The recovery of RNA synthesis, which occurred after DNA repair, confirmed that transcribable DNA was repaired. The inhibition of tyrosine kinase activity by genistein reduced the DNA repair significantly. Furthermore, H2O2 caused a dose-dependent significant rise in cytosolic calcium ((Ca2+)i). H2O2 also induced a small rise in (Ca2+)i of cytosolic Ca2(+)-depleted cells, probably reflecting the release of Ca2+ from internal stores. Genistein inhibited both Ca2+ influx and Ca2+ release from internal stores. In summary, H2O2 induced a DNA repair synthesis that was in part Ca2+ dependent and signaled via tyrosine kinase. The changes in DNA repair paralleled changes in (Ca2+)i. The H2O2-induced (Ca2+)i rise was mostly the result of influx, but to some degree it was also due to the translocation of Ca2+ from internal stores.

Follow-up experience in pediatric liver transplantation in an academic, non-transplant-based gastroenterology group

As pediatric liver transplantation has become relatively common since the early 1980s, most long-term follow-up care has shifted from transplant centers to the pediatric gastroenterologists at referring institutions. We reviewed our experience with 16 patients who have undergone liver transplantation at eight institutions from 1987 to 1996. Our initial follow-up visit took place at an average 4.1 months after the transplant. The mean duration of follow-up was 41 months. During this period 11 hospitalizations at the transplant center occured, including five that were to rule out lymphoma or post-transplant lymphoproliferative disease. At the Schneider Children's Hospital, NY, USA, 158 outpatient visits were recorded. Forty-two hospitalizations occurred. Twenty of the hospital admissions were accounted for by two patients. Forty-nine outpatient/inpatient surgical or diagnostic procedures were performed, including 15 percutaneous liver biopsies. In only one biopsy was there a disagreement in the histologic diagnosis between our pathologist and the pathologist at the transplant center. In conclusion, comprehensive follow-up care can be provided by an academic hospital-based gastroenterology group in conjunction with a transplant center.

The peritoneal membrane in peritoneal dialysis patients: estimation of its functional surface area by applying stereologic methods to computerized tomography scans

The surface area of the peritoneal membrane in contact with dialysate is an important determinant of solute transport across the peritoneum. Yet there is no method for its estimation in peritoneal dialysis patients. In this study, stereologic methods were applied to computerized tomography (CT) imaging of the peritoneal membrane to estimate the peritoneal membrane surface area. The method was first validated by implementing stereologic methods on a phantom of known surface area. The phantom was a distorted bottle filled with contrast media. Series of thin helical CT sections were performed, and random sections were obtained after reconstruction. A transparent counting grid was placed over the random sections. The surface area was estimated using 9, 18, and 36 random sections. To calculate the coefficient of variation (CV) of the method, 20 different combinations of 9, 18, and 36 random sections were used. With 36 random sections, the error in estimation of the bottle's surface area was -9.4% to +8.8%. The CV was 5.0%. Decreasing the number of sections used to 18 and 9 yielded a CV of 7.8 and 12.3%, respectively. This method was then applied to the peritoneal membrane, which was visualized by instilling dialysate containing contrast media into the peritoneal cavity of peritoneal dialysis patients. The estimated peritoneal membrane surface area of six patients was 0.55 +/- 0.04 m2. This novel method permits the measurement of the peritoneal membrane surface area with a high degree of accuracy.

Calcium balance during pulse alfacalcidol therapy for secondary hyperparathyroidism in CAPD patients treated with 1.0 and 1.25 mmol/L dialysate calcium

Hypercalcemia frequently occurs in continuous ambulatory peritoneal dialysis (CAPD) patients treated with calcium carbonate and vitamin D metabolites. To reduce the incidence of this complication, it has been proposed to use dialysate solutions with a low calcium concentration. However, there is concern that these solutions may lead to a negative calcium balance. We measured calcium balance in 13 CAPD patients with secondary hyperparathyroidism who were treated with calcium carbonate and alfacalcidol, 2 microg twice weekly, while using 1.0- (1.0 group) and 1.25-mmol/L (1.25 group) dialysate calcium solutions. Calcium absorption was measured after the administration of Ca47. Results for the 1.0 (n = 6) and 1.25 (n = 7) groups included fractional calcium absorptions of 0.14 (range, 0.09 to 0.27) and 0.08 (range, 0.03 to 0.40; P = not significant [NS]) and calcium absorptions of 380 +/- 92 and 331 +/- 83 mg/d (P = NS). Dialysate calcium losses were 93 +/- 20 and 91 +/- 26 mg/d, and total calcium losses (dialysate and urine) were 106 +/- 16 and 108 +/- 40 mg/d (P = NS). Calcium balance was positive in all patients (274 +/- 92 and 223 +/- 65 mg/d; P = NS). These data suggest that the use of 1.0- and 1.25-mmol/L calcium solutions in conjunction with calcium carbonate and pulse alfacalcidol therapy is associated with a positive calcium balance in CAPD patients.

The femoral artery-femoral vein polytetrafluoroethylene graft: a 14-year retrospective study

BACKGROUND

The use of the femoral vessels for permanent haemodialysis access has been neglected during the last two decades. Since 1981 femoral artery-vein loop polytetrafluoroethylene grafts have been constructed in our chronic haemodialysis patients. This study examines results obtained in patients with this particular graft over the last 14 years.

METHODS

This clinical study is retrospective in nature. Overall 35 patients, with 37 femoral grafts, are included. Inclusion and exclusion criteria for this type of graft are given and the surgical procedure detailed.

RESULTS

Seven patients had femoral grafts used as primary dialysis access. Twenty-eight patients had femoral grafts used after multiple access failures. There was no perioperative mortality. Immediate thrombotic non-function of the graft occurred in three patients. In the long term no patient death was related to the femoral grafts. Twenty-seven (73%) grafts had no long-term complications. The leading cause for graft 'loss' was patient death; in the first year 10 grafts were lost, eight because of patient death. All eight patients died with functioning grafts. Median graft survival was 21 months in all patients and 28 months in non-diabetic patients. Twenty-seven (73%) grafts were patent at the end of the first year, 33% of grafts were still patent after 5 years. Worsening claudication occurred in four patients; one diabetic required foot amputation. Four patients had late graft thrombosis; only two patients had bacteraemia originating from the femoral graft. Urea reduction ratio greater than 60% was measured in 87.5% of patients.

CONCLUSION

The femoral artery vein graft is a good primary and secondary haemodialysis access. Both infection and thrombosis rates are low and graft survival is comparable, if not superior to, that of upper-limb grafts. The graft is easy to cannulate, can be used early, is easily protected, and is cosmetically acceptable.

Postoperative rhabdomyolysis in patients with end-stage renal failure

Four patients with end-stage renal failure on intermittent hemodialysis in whom rhabdomyolysis developed after major surgery are described. This possibly underdiagnosed complication was manifested by extreme hyperphosphatemia, hypocalcemia, and elevated creatine phosphokinase levels. Serum myoglobin levels further supported the diagnosis. The metabolic abnormalities reached a peak on the fourth postoperative day. The possible precipitating factors included opiates used for anesthesia and postoperative pain control, anesthetic agents, and surgical position. The preferred treatment option is increasing dialysis to control hyperphosphatemia and hypocalcemia.

Hypercalcemia during pulse vitamin D3 therapy in CAPD patients treated with low calcium dialysate: the role of the decreasing serum parathyroid hormone level

Oral pulse therapy with vitamin D is effective in suppressing parathyroid hormone (PTH) secretion in continuous ambulatory peritoneal dialysis patients with secondary hyperparathyroidism (2'hpt). However, this treatment often leads to hypercalcemia. The goals of the study were: (1) to examine whether the incidence of hypercalcemia decreases when dialysate calcium is reduced from 1.25 to 1.0 mmol/L; (2) to determine the relative role of the factors involved in the pathogenesis of hypercalcemia; and (3) to study the efficacy of a low oral pulse dose of alfacalcidol in preventing the recurrence of 2'hpt. Fourteen continuous ambulatory peritoneal dialysis patients with 2'hpt were treated with pulse oral alfacalcidol and calcium carbonate and dialyzed with a 1.0-mmol (n = 7) or a 1.25-mmol (n = 7) dialysate calcium. The response rate (87%) and the incidence (71%) and severity of hypercalcemia were similar in both groups. In the early response stage, PTH decreased by 70% in both groups, and serum ionized calcium (iCa) increased from 1.18 +/- 0.02 to 1.27 +/- 0.04 mmol/L (P < 0.005) in the 1.0 group and from 1.19 +/- 0.02 to 1.29 +/- 0.02 mmol/L in the 1.25 group (P < 0.005). Nine of the 12 responders had a further decrease in serum PTH, which was associated with an additional increase in iCa from 1.28 +/- 0.02 to 1.47 +/- 0.04 (P < 0.005). Multivariate analysis showed that the early increase in iCa was positively correlated with alfacalcidol dosage (r = 0.69). In contrast, the late increase in iCa was mostly accounted for by the decrease in serum PTH (r = -0.93). This occurred while calcium carbonate, alfacalcidol dosage, and serum 1,25 hydroxy D3 remained unchanged compared with the early response stage. Finally, an alfacalcidol dose of 1 microg twice weekly was unable to maintain serum PTH at an adequate level in the long term. These data show that a reduction in dialysate calcium from 1.25 to 1.0 mmol does not reduce the occurrence of hypercalcemia and suggest that lowering serum PTH reduces the ability of the bone to handle a calcium load within a few weeks, thus causing hypercalcemia.

Excretion of epidermal growth factor in human adult polycystic kidney disease

In chronic renal failure, epidermal growth factor (EGF) excretion is decreased. In this study, asymptomatic adult polycystic kidney disease (APKD) patients with a relatively preserved glomerular filtration rate were examined. Excretion of EGF was studied in 6 patients with APKD (median age 42 years; serum creatinine [median] 95 [range-80-133] mumol/l) and compared with that of 28 healthy controls. EGF was determined in a spot morning urine by using a specific radioimmunoassay, and expressed in relation to creatinine excretion. Excretion of EGF in APKD was (median) 157 (range-13-359) and in the controls (median) 546 (range-238-1199) pmol/mmol creatinine (p < 0.001). Low excretion of EGF in APKD patients with preserved kidney function suggests a distal abnormality at an early stage of the disease, prior to the development of renal failure.

Detection of serum amyloid A-derived proteins in formalin-fixed paraffin-embedded tissues: reliability of the method and expansion of its spectrum

To further assess the reliability of the Shtrasburg method for detection of amyloid A in formalin-fixed, paraffin-embedded tissues and to expand the spectrum of the amyloid proteins analyzed by this method, we studied formalin-fixed, paraffin-embedded amyloid-containing tissues obtained from patients with the following types of amyloidosis: amyloid A, light chain, transthyretin, calcitonin, beta2 microglobulin, and senile seminal vesicle. The tissue samples were deparaffinized, processed, and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the Western blot technique. Only specimens from patients with amyloid A amyloidosis gave protein bands: a single 8.5-kd band in lanes of all tissues studied, except thyroid tissue, which displayed two bands of about 5 and 10 kd. Other types of amyloid failed to show any protein band. These findings suggest that the Shtrasburg method is sensitive, specific, and reliable and may have an important role in the diagnosis of amyloidosis.

Distribution of glycosaminoglycans in rat renal tubular epithelium

Polyanionic constituents of the glomerular capillary wall have been previously shown to have a primary role in the control of glomerular filtration. In the study presented here, the distribution and biochemical nature of polyanionic constituents in proximal (PT) and distal (DT) tubules have been investigated as possible determinants of tubulointerstitial function. For histochemical localization of sialic acid, paraffin sections were treated with Arachis hypogaea lectin (PNA) before and after neuraminidase treatment. Electron microscopic characterization of glycosaminoglycans (GAG) was performed on thin LR-white sections, using cationic colloidal gold (CCG) as an histochemical probe, and GAG-degrading enzymes. Without neuraminidase, PNA binded to collecting ducts but not to PT or DT. Neuraminidase pretreatment resulted in intense PNA binding to the tubulointerstitial blood vessels but only in mild apical tubular binding, which implies a lack of sialoglycoconjugates in the tubular basolateral membranes. In contrast, all PT and DT showed intense CCG binding to basolateral, but not to apical, membranes. All basement membranes showed CCG labeling, with considerable variations in labeling densities between PT (124 +/- 8.8/micron 2) and DT (52 +/- 1.8/micron 2), as well as between tubules and Bowman's capsule (P < 0.0001). Heparinase III treatment induced an almost complete loss of CCG binding in all basement and basolateral membranes, whereas chondroitinase ABC treatment led to a lesser but significant loss (P < 0.0001). The results indicate that rat tubulointerstitium expresses polyanionic constituents, consisting mainly of heparan and chondroitin sulfate. The role of these anionic sites in tubular function has yet to be clarified.

Case report: severe hyponatremia after water intoxication: a potential cause of rhabdomyolysis

A 28-year-old woman, treated for schizophrenia, developed severe hypotonic hyponatremia (serum Na: 109 mEq/L) after several days of compulsive water drinking. The patient was admitted in a coma and required intensive supportive therapy. Rhabdomyolysis quickly followed with high serum creatine phosphokinase levels and myoglobinuria. A high volume alkaline diuresis was initiated. Renal failure or compartment syndrome did not complicate the clinical picture. The mechanisms causing water intoxication and hyponatremia are discussed as are the possible pathogenetic explanations behind acute hyponatremia and rhabdomyolysis.

Acute necrotizing pancreatitis, lactic acidosis and prolonged hypoglycemia in a hemodialysed patient--a logical but unfortunately fatal combination

A hemodialysed patient with abdominal pain, severe lactic acidosis and prolonged hypoglycemia is described. The diagnosis of acute necrotizing pancreatitis was delayed and the patient died from both systemic and peripancreatic complications of the acute pancreatitis. The article deals with the problem of diagnosing acute pancreatitis in an end-stage renal failure (ESRF) patient; on the possible surgical options open to the physician in the management of acute pancreatitis and on a pathophysiological explanation behind both the lactic acidosis and hypoglycemia in this patient.

Adenocarcinoma at ureterosigmoidostomy junction in a renal transplant recipient 15 years after conversion to ileal conduit

In recent years, adenocarcinoma of the colon mucosa has become a recognized complication of ureterosigmoidostomy and in most cases the tumor arises at the site of ureterocolonic anastomosis. We report a case of a 29-year-old renal transplant recipient who developed two colonic carcinomas at the site of ureterosigmoidostomy 25 years after the urinary diversion and 15 years after conversion to an ileal conduit. This case emphasizes the need for a careful life-long follow-up of all patients who undergo ureterosigmoidostomy.

Effect of nifedipine on the renal functional reserve in cyclosporine-treated renal-transplant recipients

Cyclosporine decreases renal perfusion and impairs the renal hemodynamic response to a protein load. High-dose nifedipine has been shown to elevate renal plasma flow (RPF). We measured the renal functional reserve of 6 cyclosporine-treated renal-transplant recipients following intravenous administration of an amino acid solution, before and 2 weeks after therapy with high-dose nifedipine (up to 120 mg/day). Pretreatment renal functional reserve was nil Following administration of nifedipine, RPF increased by 22% (p < 0.01), filtration fraction decreased by 14% (p < 0.005) and renal vascular resistance declined by 39% (p < 0.005). Renal functional reserve remained unchanged. High-dose nifedipine increases renal perfusion but does not restore renal functional reserve in cyclosporine-treated renal-transplant recipients.

Effects of erythropoietin on glucose tolerance in hemodialysis patients

Erythropoietin (EPO) therapy is widely used to correct the anemia of end-stage renal disease. It has been reported that this treatment affects various hormonal systems. The aim of the present study was to evaluate the effects of EPO therapy on glucose tolerance. Anemia was corrected with EPO in 10 patients on chronic hemodialysis therapy. Oral glucose tolerance tests (OGTT) were performed before and after correction of anemia. The following measurements were made: the areas under the glucose curves (AUCglue), the areas over basal glucose values (OABVglue), the areas under the insulin curves (AUCins) and the areas over basal insulin values (AOBVins). Hemoglobin concentration increased from 70 +/- 1.4 milligrams to 111 +/- 1 milligram. Fasting plasma glucose, insulin and glucagon levels were were not affected by correction of the anemia. Following administration of EPO, AOBVglue increased by 19%, from 2101 +/- 243 to 2508 +/- 230 mmol.min/l (p < 0.02), while AOBVins remained unchanged. AUCins and AUCglue remained unchanged. These data show that correction of anemia with EPO in hemodialyzed patients causes an increase in the glycemic response to an oral glucose load while not affecting the insulin response.

Activation of procollagenase IV by cytochalasin D and concanavalin A in cultured rat mesangial cells: linkage to cytoskeletal reorganization

The secretion and activation of procollagenase IV were studied in cultured rat mesangial cells. Under resting conditions, mesangial cells secrete predominantly a protein that, by gel zymography, exhibits gelatinase activity and also reacts with an anti-72-kd procollagenase IV antibody raised against a conserved region of the activation site of the enzyme. Cytochalasin D or concanavalin A treatment of mesangial cells causes disruption of actin stress fibers and results in the activation of procollagenase IV, yielding two lower molecular mass forms with gelatinase activity. Concanavalin A-induced actin filament disruption and procollagenase IV activation can be blocked by alpha-methyl-D-mannopyranoside but not by D(+)-galactose. Procollagenase IV as well as the activated forms all exhibit Ca2+ and Zn2+ dependency, characteristic of metalloproteinases. Mesangial cells in culture also secrete a specific tissue inhibitor of metalloproteinase, TIMP-2. Cytochalasin D treatment of mesangial cells reduces TIMP-2 expression. Cytochalasin D and concanavalin A both inhibited the serum-induced contraction of collagen gels embedded with mesangial cells. It was concluded that cytochalasin D-induced cytoskeletal disruption in mesangial cells may activate procollagenase IV by inhibiting TIMP-2 expression and that there is a concanavalin A-binding site on mesangial cells that is part of a transmembrane signaling system altering mesangial cell cytoskeletal organization and metalloproteinase secretion and activation.