Abstract 1152: NKTR-255, a polymer-conjugated IL-15, dramatically improves ROR1 CAR-T cell persistence and anti-tumor efficacy in an autochthonous model of ROR1+ lung cancer

CAR-T cells have mediated remarkable clinical responses against hematological malignancies, but this success has yet to extend to solid tumors, where many factors in the tumor microenvironment (TME) inhibit their persistence and function. In a phase 1 trial at our Center, CAR-T cells targeting the tumor-associated antigen ROR1 in patients with non-small cell lung cancer (NSCLC) and triple negative breast cancer rapidly became dysfunctional and persisted poorly at tumor sites, ultimately failing to mediate objective responses. To evaluate strategies to improve ROR1 CAR-T efficacy, we adapted the KrasLSL-G12D/+;p53fl/fl (KP) autochthonous model of lung adenocarcinoma to express ROR1 (KPROR1). This aggressive model mimics the initiation, progression, and suppressive TME of human NSCLC. ROR1 CAR-T cells in KPROR1 mice rapidly declined in number, lost the ability to produce pro-inflammatory cytokines, and failed to significantly enhance tumor control, recapitulating the major barriers to CAR-T efficacy we observed in patients. NKTR-255 is a novel immunotherapeutic consisting of a polymer conjugated recombinant human interleukin-15 (rhIL-15) that could enhance the activity of CAR-T cells. NKTR-255 binds to the IL-15 receptor and IL-2/IL-15 receptor, thus maintaining the full potential spectrum of IL-15 biology while exerting a sustained effect on CD8+ memory T cell and NK cell expansion and persistence. We hypothesized that the combination of CAR-T cells and NKTR-255 would be feasible and safe and may extend the duration of efficacy of ROR1 CAR-T cells in ROR1+ lung tumors by improving their expansion and persistence. To test this, we treated tumor-bearing KPROR1 mice with control or ROR1 CAR-T cells with or without weekly injections of NKTR-255. NKTR-255 treatment resulted in a robust expansion of ROR1 CAR-T cells in the peripheral blood relative to vehicle-treated mice, which correlated with increased CAR-T cell infiltration into lung tumors. CAR-T cells in NKTR-255-treated mice also showed reduced signs of T cell exhaustion, including reduced expression of inhibitory receptors and enhanced ability to produce effector cytokines upon ex vivo re-stimulation. Importantly, combination therapy with both NKTR-255 and ROR1 CAR-T cells resulted in significantly improved tumor control relative to either treatment alone. Together, our work shows that NKTR-255 dramatically improves the persistence, function, and anti-tumor activity of ROR1 CAR-T cells in an aggressive autochthonous model of ROR1+ lung cancer. Our findings provide rationale to combine NKTR-255 with CAR-T cell therapy as a strategy to enhance the anti-tumor efficacy of CAR-T cells in patients with solid tumors.

Citation Format: W. Sam Nutt, Takahiro Miyazaki, Mario Marcondes, Stanley R. Riddell, Shivani Srivastava. NKTR-255, a polymer-conjugated IL-15, dramatically improves ROR1 CAR-T cell persistence and anti-tumor efficacy in an autochthonous model of ROR1+ lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1152.

Abstract 5115: Novel humanized anti-GD2 antibody inhibits GD2-mediated immunosuppression by targeting GD2+ breast cancer stem-like cells

Background: Breast cancer stem-like cells (BCSCs) are reported to be a major contributing factor for tumor growth and chemotherapy resistance in triple-negative breast cancer (TNBC). We reported that the disialoganglioside GD2 is highly expressed on BCSCs and that targeting GD2 with dinutuximab (chimeric anti-GD2 antibody) in combination with NK cells synergistically reduced tumor volumes in TNBC animal models. Here, we hypothesize that naxitamab targets GD2+ BCSCs and inhibits breast cancer (BC) growth by enhancing macrophage mediated phagocytosis and T cell mediated cytotoxicity. In addition, we explore whether addition of an investigational polymer-engineered IL-15 receptor-agonist, NKTR-255 treated NK cells, can further enhance this anti-GD2 mediated anti-cancer activity.

Methods: Naxitamab is a US FDA approved fully humanized anti-GD2 (hu3F8) monoclonal antibody for the treatment of pediatric neuroblastoma. We evaluated the effects of naxitamab treatment on macrophage mediated phagocytosis of BC cells using the live cell imaging system, IncuCyte®. Next, we compared the effects of NKTR-255 treated NK cells with recombinant human IL-15 (rIL-15) treated NK cells in naxitamab induced ADCC in GD2+ BC cells. We also performed immunohistochemistry (IHC) to examine GD2 expression and correlate it with T cell infiltration in primary TNBC patient samples with high and low GD2 levels. The effect of naxitamab treatment on T cell mediated cytotoxicity in BC cells was also observed.

Results: When compared to control, naxitamab treatment promoted macrophage mediated phagocytosis of Hs578T and HCC1395 cells in a dose dependent manner (p <0.001). Additionally, when co-cultured with healthy donor derived macrophages, we found a significant reduction in Hs578T spheroids treated with naxitamab in comparison to IgG control (p<0.001). Furthermore, we observed a significantly higher rate of apoptosis in GD2+ Hs578T and HCC1395 breast cancer cells treated with naxitamab and NK cells generated using NKTR-255, compared to rIL-15 treated NK cells (p<0.0001). Interestingly, IHC analysis showed that TNBC patients with high GD2 expression have significantly lower CD3+ T cell infiltration than patients with low GD2 expression (p<0.05). We also observed increased T cell mediated killing of BT549 and T47D cells treated with naxitamab in comparison to IgG control (p<0.001).

Conclusion: TNBC with high GD2 expression inhibits immune cell infiltration and naxitamab can inhibit BCSC growth by targeting GD2. Combination of naxitamab with macrophages induced macrophage mediated phagocytosis TNBC cells. NK cells were more stable and cytotoxic when generated with NKTR-255 vs. native IL-15, and naxitamab further enhanced NK cell mediated ADCC of GD2+ BCSCs. The increased T cell mediated killing of breast cancer cells treated with naxitamab further supports the immunomodulatory role of GD2.

Citation Format: Vivek Anand, Venkatesh Hegde, Maryam Siddiqui, Anudishi Tyagi, Bolutyfe Oderinde, Mario Marcondes, Willem Overwijk, Venkata Lokesh Battula. Novel humanized anti-GD2 antibody inhibits GD2-mediated immunosuppression by targeting GD2+ breast cancer stem-like cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5115.

957 NKTR-255+cetuximab in patients with solid tumors: interim safety and efficacy results from the phase 1b dose-escalation study

Background

NKTR-255 is an investigational IL-15Rα-dependent, polymer-conjugated, recombinant human IL-15 agonist designed to provide sustained pharmacodynamic (PD) responses without the need for daily dosing. NKTR-255 engages all IL-15 receptor binding complexes to expand, proliferate and activate natural killer (NK) and CD8+ T-cells. This Phase 1b/2 trial (NCT04616196) evaluates NKTR-255+cetuximab in highly refractory patients with head-and-neck squamous cell carcinoma (HNSCC) or colorectal cancer (CRC).

Methods

Successive cohorts received escalating doses of NKTR-255 (q3w) +cetuximab (250mg/m< sup >2</sup > weekly), 1 week after a loading dose of cetuximab alone. Safety (CTCAEv5.0; MTD/recommended Phase 2 dose [RP2D]) and efficacy (RECISTv1.1) were measured. PK/PD analyses were conducted, including assessment by flow cytometry/plasma cytokine analysis. Fold-change was calculated as treatment over baseline for NKTR-255 (baseline=1).

Results

As of August 15, 2021, 12 patients had received ≥1 dose of NKTR-255+cetuximab; (37–70 years; 92% male; HNSCC n=4, CRC n=8; NKTR-255 1.5µg/kg n=7, NKTR-255 3.0µg/kg n=5). Patients had received a median 3.5 lines of prior therapy for metastatic disease. 11 patients had no response to the most recent prior therapy. Of the 12 patients, seven remain on treatment, with five not yet reaching first scan. RP2D has not yet been reached; dose escalation is ongoing.

10 patients experienced an AE; one G5 AE occurred (due to progression). Seven patients reported NKTR-255-related AEs (all G1-2, except one G3 [which resolved in 24 hours]). Any-cause AEs in ≥20% were acneiform dermatitis, fatigue, and infusion-related reaction.

Treatment-induced transient changes in inflammatory cytokines, including IFNy, MCP-1 and IL-6, at 1.5µg/kg (n=3) peaked 4 hours post-infusion and resolved by 24-48 hours. Mean T1/2 of NKTR-255 (1.5µg/kg dose, first cycle) was 27.8 hours.

Dose-dependent expansion of NK and CD8+ T-cells was observed in peripheral blood. For NK cells, mean peak fold-change was ~4-fold and ~6-fold, and for CD8+ T-cells was ~2-fold and ~3-fold (1.5µg/kg and 3µg/kg dose levels, respectively). NK and CD8+ T-cells demonstrated increased Ki67+ proliferative ability.

As of August 15, four patients in the 1.5µg/kg NKTR-255 dose cohort were response-evaluable: one CRC patient (4 prior metastatic treatment lines) reported a confirmed PR (–52%) after 3 cycles; two HNSCC patients reported SD.

Conclusions

NKTR-255 was biologically active and led to expansion and proliferation of NK and CD8+ T-cells. Early dose-escalation data suggest that NKTR-255+cetuximab is safe and tolerable with preliminary anti-tumor activity. Updated data will be presented. NKTR-255, alone and in combination with daratumumab and rituximab, is also being evaluated in liquid tumors.

Acknowledgements

The authors thank the patients and their families involved in the trial.

Trial Registration

NCT04616196

Ethics Approval

The study was approved by site IRBs.

Consent

N/A

368 REVEAL: Phase 1 dose-escalation study of NKTR-262, a novel TLR7/8 agonist, plus bempegaldesleukin: local innate immune activation and systemic adaptive immune expansion for treating solid tumors

Background

NKTR-262 is a small-molecule agonist of toll-like receptors (TLR) 7/8. Given by intratumoral (IT) injection, NKTR-262 is retained within the tumor microenvironment (TME) and promotes an immunostimulatory milieu and tumor antigen release. Bempegaldesleukin (BEMPEG) is a CD122-preferential IL-2 pathway agonist, which increases proliferation and tumor infiltration of CD8+ T cells and natural killer (NK) cells. Preclinically, NKTR-262 plus BEMPEG combined innate immune signaling and enhanced antigen presentation, with sustained T-cell activation, resulting in tumor growth inhibition of treated and abscopal lesions.

Methods

This phase 1 dose-escalation study enrolled patients with relapsed/refractory, advanced/metastatic solid tumors (REVEAL; NCT03435640). Patients received escalating doses of NKTR-262 (0.03 mg to 3.84 mg IT) followed 3 weeks‘ later by BEMPEG (0.006 mg/kg IV) q3wk utilizing a 3+3 design. The primary endpoint was safety and tolerability, including definition of the recommended phase 2 dose (RP2D). Other endpoints included antitumor activity, pharmacodynamics, and pharmacokinetics.

Results

As of June 15, 2020, 36 patients were enrolled. One dose-limiting toxicity, transient transaminase elevation, was observed at the highest NKTR-262 dose (3.84 mg). The most frequent treatment-related adverse events were flu-like symptoms, fatigue, nausea, and pruritus, consistent with the known profile of BEMPEG. Early evidence of clinical activity was observed in patients with metastatic melanoma, with a disease control rate (partial response [PR] + stable disease) of 41.2% (7/17 patients), including two patients with PRs after progression on two prior immunotherapy regimens. Preliminary analyses showed dose-dependent induction of CXCL10 and type 1 interferon genes, consistent with TLR7/8 engagement. CD11c+ target cells were significantly more abundant in baseline melanoma biopsies than other tumor types (p<0.001). Induction of TLR7/8-responsive genes correlated with CD11c+ baseline density (p<0.05). Minimal TLR7/8-dependent changes in immune cell subsets or inflammatory cytokines were observed in peripheral blood, reflecting favorable TME modifications driven by retention of NKTR-262. Increased activation of CD4+, CD8+, and NK cells in blood were observed, consistent with BEMPEG mechanism of action.

Conclusions

NKTR-262 plus BEMPEG led to engagement of the entire immune activation cascade required for systemic tumor clearance. Robust TLR7/8 engagement supported the NKTR-262 mechanism of action, while the minimal toxicity profile underscored the benefit of local delivery of NKTR-262, and the BEMPEG combination induced systemic activation of T and NK cells. These data support the RP2D of NKTR-262 (3.84 mg IT) plus BEMPEG (0.006 mg IV) q3w, and the initiation of the phase 1b dose-expansion phase, which is exploring concurrent dosing, with or without nivolumab, in relapsed/refractory metastatic melanoma patients.

Trial Registration

NCT03435640

Ethics Approval

The study was approved by the institutional review board of each participating site.

Recommendations on vaccination for Latin American small animal practitioners: a report of the WSAVA Vaccination Guidelines Group

The World Small Animal Veterinary Association Vaccination Guidelines Group has produced global guidelines for small companion animal practitioners on best practice in canine and feline vaccination. Recognising that there are unique aspects of veterinary practice in certain geographical regions of the world, the Vaccination Guidelines Group undertook a regional project in Latin America between 2016 and 2019, culminating in the present document. The Vaccination Guidelines Group gathered scientific and demographic data during visits to Argentina, Brazil and Mexico, by discussion with national key opinion leaders, visiting veterinary practices and review of the scientific literature. A questionnaire survey was completed by 1390 veterinarians in five Latin American countries and the Vaccination Guidelines Group delivered continuing education at seven events attended by over 3500 veterinarians.

The Vaccination Guidelines Group recognised numerous challenges in Latin America, for example: (1) lack of national oversight of the veterinary profession, (2) extraordinary growth in private veterinary schools of undetermined quality, (3) socioeconomic constraints on client engagement with preventive health care, (4) high regional prevalence of some key infectious diseases (e.g. feline leukaemia virus infection, canine visceral leishmaniosis), (5) almost complete lack of minimal antigen vaccine products as available in other markets, (6) relative lack of vaccine products with extended duration of immunity as available in other markets, (7) availability of vaccine products withdrawn from other markets (e.g. Giardia vaccine) or unique to Latin America (e.g. some Leishmania vaccines), (8) accessibility of vaccines directly by pet owners or breeders such that vaccination is not delivered under veterinary supervision, (9) limited availability of continuing education in veterinary vaccinology and lack of compulsion for continuing professional development and (10) limited peer‐reviewed published scientific data on small companion animal infectious diseases (with the exception of leishmaniosis) and lack of support for such academic research.

In this document, the Vaccination Guidelines Group summarises the findings of this project and assesses in evidence‐based fashion the scientific literature pertaining to companion animal vaccine‐preventable diseases in Latin America. The Vaccination Guidelines Group makes some recommendations on undergraduate and postgraduate education and academic research. Recognising that current product availability in Latin America does not permit veterinarians in these countries to vaccinate according to the global World Small Animal Veterinary Association guidelines, the Vaccination Guidelines Group makes a series of “pragmatic” recommendations as to what might be currently achievable, and a series of “aspirational” recommendations as to what might be desirable for the future. The concept of “vaccine husbandry” is addressed via some simple guidelines for the management of vaccine products in the practice. Finally, the Vaccination Guidelines Group emphasises the global trend towards delivery of vaccination as one part of an “annual health check” or “health care plan” that reviews holistically the preventive health care needs of the individual pet animal. Latin American practitioners should transition towards these important new practices that are now well embedded in more developed veterinary markets.

The document also includes 70 frequently asked questions and their answers; these were posed to the Vaccination Guidelines Group during our continuing education events and small group discussions and should address many of the issues surrounding delivery of vaccination in the Latin American countries. Spanish and Portuguese translations of this document will be made freely available from the on‐line resource pages of the Vaccination Guidelines Group.

Phase Ib: Preliminary clinical activity and immune activation for NKTR-262 [TLR 7/8 agonist] plus NKTR-214 [CD122-biased agonist] in patients (pts) with locally advanced or metastatic solid tumors (REVEAL Phase Ib/II Trial)

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Background: NKTR-262 is a novel intratumoral prodrug designed to promote tumor antigen release, an immune stimulatory environment, and antigen presentation. NKTR-214 increases CD8+ T cells and NK cells in the tumor microenvironment. The combination of NKTR-262 with NKTR-214 accesses innate and adaptive immunity to provide an abscopal response and systemic tumor immunity. The Phase 1b/2 REVEAL trial is enrolling. Methods: In a 3+3 Phase 1 design, pts who are relapsed/refractory to ≥1 CPI receive escalating doses of intratumoral (IT) NKTR-262 followed by combined q3w treatment of IT NKTR-262 and fixed-dose intravenous (IV) NKTR-214 (0.006 mg/kg). Phase 1 will evaluate PK, safety, efficacy, and determine recommended Phase 2 dose. Scans are conducted every 9 wks (± 1 wk). Peripheral blood (PB) and tumor tissue are collected to measure biomarkers of immune activation. In Phase 2 expansion, NKTR-262 + NKTR-214 ± IV nivolumab (360 mg) will be assessed in specific tumor cohorts of IO-naïve and experienced pts. Results: As of 06 Nov 2018, 11 pts had received at least one cycle of NKTR-262 + NKTR-214 therapy. 7/11 pts were efficacy evaluable with at least one on-treatment scan (4 MEL, 2 SARC, 1 CRC). 2/4 R/R melanoma pts had uPRs with 100% (scan 2) and 40% (scan 1) reductions in target lesions per RECIST 1.1, respectively. Both patients remain on treatment. Two SARC pts had stable disease at scan 1. No pts experienced G3 or higher TRAEs or immune-related adverse events (AEs). Most common G1-2 AEs were transient flu-like symptoms. Gene expression analysis of tumor and PB show dose-dependent induction (4 to 16-fold) of TLR target genes. Consistent with the mechanism of action for NKTR-214, PB flow cytometry shows an average 13-fold increase from baseline in Ki67+ CD8+T cells in 6 pts. Conclusions: NKTR-262 + NKTR-214 engage the immune activation cascade from local tumor antigen production to anti-tumor T cell response. Initial dose levels of NKTR-262 with fixed-dose NKTR-214 were well-tolerated with early evidence of clinical activity. These data support continued evaluation of the combination +/- nivolumab. Clinical trial information: NCT03435640.

Cardiac Lesions in 30 Dogs Naturally Infected With Leishmania infantum chagasi

The hearts of 30 dogs naturally infected with Leishmania infantum chagasi were evaluated histologically and immunohistochemically. Myocardial lesions were detected in all dogs, including lymphoplasmacytic myocarditis (27/30), myonecrosis (24/30), increased interstitial collagen (22/30), lepromatous-type granulomatous myocarditis (7/30), fibrinoid vascular change (3/30), and vasculitis (1/30). The parasite was detected in the hearts of 20 of 30 dogs. The number of parasitized cells correlated with the intensity of the inflammation and with the number of granulomas. The results indicate that cardiac lesions are prevalent in dogs with naturally occurring leishmaniasis even in the absence of clinical signs of cardiac disease.

Tumour necrosis factor-induced gene expression in human marrow stroma: clues to the pathophysiology of MDS?

Aberrant regulation of the tumour necrosis factor alpha gene (TNF) and stroma-derived signals are involved in the pathophysiology of myelodysplasia. Therefore, KG1a, a myeloid leukaemia cell line, was exposed to Tnf in the absence or presence of either HS-5 or HS-27a cells, two human stroma cell lines. While KG1a cells were resistant to Tnf-induced apoptosis in the absence of stroma cells, Tnf-promoted apoptosis of KG1a cells in co-culture experiments with stroma cells. To investigate the Tnf-induced signals from the stroma cells, we examined expression changes in HS-5 and HS-27a cells after Tnf exposure. DNA microarray studies found both discordant and concordant Tnf-induced expression responses in the two stroma cell lines. Tnf promoted an increased mRNA expression of pro-inflammatory cytokines [e.g. interleukin (IL)6, IL8 and IL32]. At the same time, Tnf decreased the mRNA expression of anti-apoptotic genes (e.g. BCL2L1) and increased the mRNA expression of pro-apoptotic genes (e.g. BID). Overall, the results suggested that Tnf induced a complex set of pro-inflammatory and pro-apoptotic signals in stroma cells that promote apoptosis in malignant myeloid clones. Additional studies will be required to determine which of these signals are critical for the induction of apoptosis in the malignant clones. Those insights, in turn, may point the way to novel therapeutic approaches.

Reciprocal influences between ambulatorial peritoneal dialysis and pulmonary function

The aim of this study was to verify if dialysis solution volumes used in patients on continuous ambulatory peritoneal dialysis (CAPD) interfere with pulmonary function and if the pulmonary volumes interfere with the lymphatic absorption of the peritoneal cavity. We submitted 10 CAPD patients with a mean age of 48 +/- 18 years and on CAPD for 35 +/- 27 months to the following evaluations: first, measurement of the lymphatic absorption from the peritoneal cavity; second, measurement of the hydrostatic intraperitoneal pressure; and third, expirometry with the peritoneal cavity full of dialysis solution and empty. There were no differences between the expirometry results obtained with the peritoneal cavity full and empty of dialysis solution, and the results were in accordance with the prediction for this population. The values did not correlate with the peritoneal lymphatic absorption of the peritoneal cavity. The cumulative lymphatic absorption of the peritoneal cavity after 4 h dialysis solution permanence was 197 +/- 93 ml, and the hydrostatic intraperitoneal pressure was 13.9 +/- 2.8 column centimeters of water. Neither of these correlated with pulmonary volumes. In conclusion, CAPD did not interfere with the pulmonary function, nor did the pulmonary function influence the lymphatic absorption of the peritoneal cavity of these patients.

Measurement of blood urea concentration during haemodialysis is not an accurate method to determine equilibrated post-dialysis urea concentration

BACKGROUND

The double-pool urea kinetic model requires the measurement of the blood urea concentrations 30 min after haemodialysis (C(t+30)) to calculate equilibrated Kt/V. However, it has been suggested that urea concentrations 30 min before the end of dialysis (C(t-30)) may be representative of C(t+30). The aim of this study was to validate this suggestion.

METHODS

Twenty-two patients underwent haemodialysis for 180, 210, and 240 min. For each patient in each dialysis session, urea exponential decay curve was calculated. Because we measured C(t+30), we calculated the time (T(c)) before the end of dialysis that blood urea concentrations would be the same as C(t+30). In an additional 33 patients, we measured blood urea concentrations at T(c) and in C(t+30).

RESULTS

We found that C(t-30) was significantly lower than C(t+30) independent of the duration of dialysis. However, there was a significant correlation between Kt/V(t-30) and Kt/V(t+30). The T(c) was 45 min before the end of dialysis. In the additional 33 patients, C(t-45) and C(t+30) were 54+/-17 and 52+/-17 mg/dl (NS), and Kt/V(t-45) and Kt/V(t+30) were 1.27+/-0.21 and 1.29+/-0.18 (NS), respectively. There were significant correlations between C(t-45) and C(t+30) (r=0.96; P<0.001), and between Kt/V(t-45) and Kt/V(t+30) (r=0.82; P<0.001). However, when measurements were analysed individually, 48% of the data points from C(t-45) vs C(t+30), and 42% of the data points from Kt/V(t-45) vs Kt/V(t+30) fell out of the 95% confidence interval of regression line.

CONCLUSIONS

Although C(t-45) is useful to estimate Kt/V when assessing mean values, it is not suitable when assessing patients individually. This study demonstrates that the best method to calculate equilibrated Kt/V was a blood sample for urea concentrations 30 min after haemodialysis.

Pregnancy in women on chronic dialysis. A single-center experience with 17 cases

Successful pregnancy outcome is an uncommon occurrence in women requiring chronic dialytic treatment, and the most adequate dialysis therapy in the management of these pregnant patients has not been established. During the period 1988-1995, we studied the outcome of 17 pregnancies in dialyzed females, with an average age of 28.2 +/- 5.9 years (range: 18-38 years). Seven women had adequate urine volume (>800 ml/24 h). Five patients started dialysis after conception and the remaining 12 pregnancies were diagnosed after 6-72 months on dialysis. Fourteen women were maintained on hemodialysis (HD) and 3 on continuous ambulatory peritoneal dialysis (CAPD). The HD schedule was increased to 3 h 5-6 times weekly, and CAPD was increased to six 2-liter exchanges/day. Mean serum urea was 78.6 +/- 27.4 mg/dl (range 45-110); serum creatinine was 6.5 +/- 3.7 mg/dl (3.3-9.8 mg/dl); and hematocrit was 28.9 +/- 3.3 vol% (22-35 vol%). Anemia was partially controlled with rHuEpo in 8 patients. Significant problems were polyhydramnios in 7 cases (5 HD/2 CAPD), oligohydramnios in 1 (HD), gestational diabetes in 2 (CAPD), premature labor with spontaneous abortion at the 19th, 22nd and 28th weeks of gestation (2 HD/1 CAPD), hypertension in 8 (7 HD/1 CAPD), and sterile eosinophilic peritonitis in 1 case (CAPD). Mean gestational age at delivery in 14 successful pregnancies (12 HD/2 CAPD) was 32.3 +/- 2.6 weeks (27-36 weeks) and mean baby weight was 1,400.7 +/- 579.1 g (range 720-2,650 g). No congenital fetal abnormality was observed. Respiratory distress was observed in 6 infants, with 2 deaths (1 HD/1 CAPD) in the first week after delivery. In this study, successful pregnancies were reported in 70.6% of dialyzed women with uremia, with hemodialysis having a rate of fetal survival of 78.6% and CAPD with 33.3%.

Outcome of acute renal failure associated with cardiac surgery in infants

OBJECTIVE

To analyze the impact of acute renal failure (ARF) on the evolution of infants undergoing cardiac surgery.

METHODS

We assessed 15 infants undergoing cardiac surgery who developed (ARF). Their demographic, clinical and surgical data, and evolution were analyzed.

RESULTS

Their mean age was 4.4+/-4.0 months (8 days to 24 months). Twelve infants were males, and 4 patients already had ARF at surgery. The primary cause of ARF was immediate acute cardiac dysfunction in 10 infants, cardiac dysfunction associated with sepsis in 2 infants, and isolated sepsis in 3 infants. All children depended on mechanical ventilation during their postoperative period, 14 infants used vasoactive drugs, and 11 had an infectious process associated with ARF. Thirteen infants required dialytic treatment. Eleven infants developed oluguric ARF, and all had to undergo peritoneal dialysis; of the 4 patients with non-oliguric, 2 required dialysis, the main indication being hypervolemia. Of these 13 dialyzed infants, 4 died in the first 24 hours because of the severity of the underlying cardiac disease (mean urea level of 49+/-20 mg/dl). The mortality rate for the entire group was 60%, and it was higher among the patients with oliguria ARF (73% vs 25%, p<0. 001). The cause of death was acute cardiac dysfunction in 6 infants (early type-1 ARF) and sepsis in the 3 remaining infants (late type-2 ARF).

CONCLUSION

The mortality rate of ARF associated with cardiac surgery in infants was hight, being higher among children with oliguria; peritoneal dialysis was indicated due to clinically uncontrolled hypervolemia and not to the uremic hypercatabolic state.

Intraperitoneal pressure and hernias in children on peritoneal dialysis

Abdominal wall hernias have been increasingly recognized in patients on continuous ambulatory peritoneal dialysis (CAPD). They are also more frequent in children than in adults. The aim of this study was to determine the influence of intraperitoneal pressure (IPP) on the development of hernias in children on CAPD, and if there was a difference between IPP in children and adults. We studied 14 children aged 11.2 +/- 3.2 years, body weight 31.1 +/- 9.4 kg, who had undergone CAPD for 16.2 +/- 14.4 months. Also, 10 adults were studied, aged 48 +/- 18 years, body weight 62.4 +/- 13.9 kg, on the CAPD program for 35 +/- 27 months. The IPP was measured via a column of dialysate in the peritoneal dialysis line, immediately before the drainage of the peritoneal cavity. The pressure was measured with the patients in the supine position, at the level of the umbilical cicatrix with the zero point located on the mean axillary line. IPP was measured at inspiration and at expiration, and the mean of these two measurements was calculated. The children were divided in two groups: group 1 (n = 7) without hernias and group 2 (n = 7) with hernias (5 umbilical and 2 inguinal). The IPP of all children was 9.5 +/- 2.9 cm H2O. The IPP was 8.1 +/- 2.6 and 10.9 +/- 2.6 cm H2O in groups 1 and 2, respectively (P = 0.003). The instilled volume for test was similar in both groups. The IPP of the adults was 13.8 +/- 2.8 cm H2O, which was significantly greater than that of the children (P = 0.001). In conclusion, hernia is a common complication in children on CAPD and its prevalence is affected by IPP. Other associated factors may be the presence of anatomically weak sites in the abdominal wall of the children, since IPP is lower in children than in adults.

Seasonal variation of blood pressure in maintenance hemodialysis

CONTEXT

Seasonal variation in arterial blood pressure has been reported in studies with hypertensive and normotensive subjects. However, the influence of seasonal change on blood pressure of hemodialysis patients has not been reported.

OBJECTIVE

To investigate the seasonal variation of blood pressure in Brazil, a tropical country, in patients on hemodialysis.

DESIGN

Prospective, cohort study.

SETTING

Dialysis unit of a tertiary medical center (a teaching hospital of the University of São Paulo School of Medicine, São Paulo).

PATIENTS

Sixteen patients with chronic renal failure undergoing hemodialysis.

OUTCOMES

Blood pressure, body weight, and ambient temperature were evaluated during 6 hemodialysis sessions carried out on 13 days during the four seasons.

RESULTS

The diastolic blood pressure was lower in summer than in fall and winter (95 +/- 8 vs 107 +/- 10 and 101 +/- 10 mmHg, respectively; p < 0.05). The same was observed with mean blood pressure (116 +/- 8 vs 130 +/- 11 and 124 +/- 9 mmHg, respectively; p < 0.01). On the other hand, the ambient temperature was higher in summer than in fall and winter (23.0 +/- 1.6 vs 19.5 +/- 3.0 and 15.8 +/- 1.9 degrees C, respectively; p < 0.01).

CONCLUSIONS

We concluded that for patients with chronic renal failure the blood pressure has a seasonal variation with higher pressures in fall and winter than in summer. Thus, further studies are needed to elucidate the impact of this observation on the adjustment of antihypertensive treatment and on morbidity and mortality in maintenance dialysis patients.

Glycosuria in glomerular diseases: histopathology and clinical correlations

There are doubts about the presence of glycosuria and the progress of glomerular disease. Some reports suggest that glycosuria could be an index of a more severe tubulointerstitial lesion. We investigated the presence of glycosuria in 60 patients with primary glomerular diseases: 17 patients (28%) had glycosuria and 43 patients (72%) were glycosuria free. The two groups were similar in age, arterial pressure and sex. Serum creatinine was higher in patients with glycosuria (2.0 +/- 1.7 vs 1.3 +/- 0.9 mg/dl, P < 0.05). The protein excretion rate was 7.5 +/- 3.7 vs 5.3 +/- 4.2 g/day (P > 0.05) in patients with and without glycosuria, respectively, while serum albumin was lower in patients with glycosuria (1.7 +/- 0.6 vs 2.7 +/- 1.0 g/dl, P < 0.05). Several histological forms were present in the group with glycosuria, with membraneous glomerulonephritis being the most frequent. Histological evidence of tubular atrophy and interstitial fibrosis prevailed in patients with glycosuria, suggesting a poor prognosis for these patients. We may conclude that the presence of glycosuria in patients with glomerular disease is associated with more pronounced tubular atrophy and interstitial fibrosis and therefore imply a poorer prognosis.

Prospective study of tetanus-induced acute renal dysfunction: role of adrenergic overactivity

To assess the mechanisms related to tetanus-induced acute renal failure (ARF), 30 patients with tetanus had their renal function prospectively studied and factors possibly related to renal changes were evaluated during four weeks of hospitalization. Fifty percent of these patients had a glomerular filtration rate (GFR) < or = 50 ml/min in the first or second week of hospitalization (Group I) and 50% had a GFR > 50 ml/min throughout the entire hospitalization period (Group II). Age, gender, tetanus incubation time and tetanus onset time, hospitalization time, use of nephrotoxic drugs, need for mechanical ventilation with intermittent positive pressure, and presence of systemic infection were similar in both groups. None of the patients presented with oliguria. Autonomic nervous system (ANS) overactivity, characterized by intense variations in systolic and diastolic blood pressure, by increased heart rate and elevated urinary metanephrine excretion, was higher in Group I compared with Group II. Plasma renin activity, serum creatinephosphokinase levels, and myoglobinuria were not significantly different between the two groups. These results strongly suggest that tetanus-induced ARF has a high prevalence, is characterized by early onset, and is probably related to ANS overactivity.

Haemodialysis without anticoagulant: haemostasis parameters, fibrinogen kinetic, and dialysis efficiency

BACKGROUND

Haemodialysis without anticoagulant is an alternative to systemic anticoagulation of patients at high risk of bleeding. However, reports have suggested that heparin-free haemodialysis might results in blood defibrination, and fibrin deposition in dialytic membrane with possible reduction in dialyser efficiency.

METHODS

Haemostasis parameters, fibrin-fibrinogen kinetic assessed by 125I-fibrinogen (125I-F) turnover and 125I-fibrinogen deposition within the dialyser membranes, and dialytic efficiency were studied in 10 stable chronic uraemic patients. Each patient was dialysed on two consecutive 4-h dialyses, once with each of two dialysis strategies: haemodialysis without anticoagulant and conventional haemodialysis using heparin as anticoagulant.

RESULTS

No significant changes were seen in mean platelet count, plasma fibrinogen, prothrombin time, and antithrombin III during haemodialysis without anticoagulation, and these parameters were not different from those in patients who underwent conventional haemodialysis. Compared with the predialysis values, a shortening of the mean aPTT from an initial mean value was noted (P < 0.05) in haemodialysis without anticoagulation at 60, 120 and 240 min. Fibrin-fibrinogen degradation products remained unchanged during conventional haemodialysis, but were increased after the 30th minute of haemodialysis without anticoagulation (P < 0.05), although all values were in normal range. The biological half-life of 125I-F in uraemic patients before the haemodialysis was 5.02 +/- 0.43 days (control). There was a significant fall in 125I-F half-life during haemodialysis without anticoagulation (2.56 +/- 0.58 days; P < 0.01) but not during conventional haemodialysis (4.77 +/- 0.97, NS). After use each dialyser was dismantled and 125I-F deposition within the membranes (M#5, M#12 and M#19) was measured. During haemodialysis without anticoagulation mean fibrin deposition in M# (28.74 +/- 10.50 x 10(3) counts), M#12 (26.42 +/- 9.06 x 10(3) counts), and M#19 (21.97 +/- 8.33 x 10(3) counts) was greater (P < 0.001) than that during conventional haemodialysis (1.70 +/- 0.92 x 10(3), 1.33 +/- 0.65 x 10(3), and 1.59 +/- 1.03 x 10(3) counts respectively). However, this greater deposition of fibrin on membranes during haemodialysis without anticoagulation did not change dialyser efficiency as assessed (haemodialysis without anticoagulation vs conventional haemodialysis) by change in serum urea (-53.96 +/- 3.38% vs -51.96 +/- 5.20%, NS), serum creatinine (-48.65 +/- 5.99% vs -49.59 +/- 6.65%, NS), serum potassium (-30.06 +/- 4.46% vs -27.64 +/- 2.81%, NS), serum bicarbonate (+25.91 +/- 1.39% vs +24.89 +/- 2.59%, NS) and haematocrit (+3.20 +/- 3.99% vs 2.15 +/- 2.01%, NS). The mean Kt/V was similar for conventional haemodialysis (0.870 +/- 0.074) and haemodialysis without anticoagulation (0.873 +/- 0.107).

CONCLUSION

In conclusion, although conventional haemostasis parameters remained unchanged during haemodialysis without anticoagulation, some degree of activation of coagulation system occurs, haemodialysis without anticoagulation was associated with greater decline in 125I-F half-life and greater fibrin deposition on dialyser membranes, but with no change in dialyser efficiency.

The role of experimental chronic renal failure and aluminium intoxication in cellular immune response

BACKGROUND

A positive correlation between successful kidney transplantation, few rejection episodes, greater susceptibility to infection and morbidity in patients with high tissue levels of aluminium (Al) indicate that the metal may play a role in the immune response. The aim of this study was to determine if experimental aluminium intoxication could result in significant changes in lymphocyte activity in uraemic and nonuraemic rats.

METHODS

Lewis rats were divided into four groups: normals (N), nephrectomized control (U), and Al-treated (N + Al) and nephrectomized Al-treated (U + Al), which received a cumulative dose of 30 mg Al over a 4-week period. Al quantification, histology, histochemical analysis and immunological assays were performed after Al intoxication.

RESULTS

High tissue levels of Al and positive histochemical staining in bones were seen in Al-treated rats. Bone histology revealed osteomalacia in U + Al rats. No statistical differences were observed in mixed lymphocyte cultures from controls and Al-treated rats, whereas U and Al-treated rats showed a decrease in lymphoproliferative response to mitogen and natural killer cell cytotoxic activity. A decreased helper T lymphocyte: cytotoxic T lymphocyte cell ratio and a reduction in interleukin-2 production were observed only in the U + Al group. A reduced number of total T lymphocytes was detected in the spleens of all Al-treated rats.

CONCLUSIONS

These findings suggest that aluminium toxicity may contribute to immunological impairment in chronic renal failure.

Peculiar electrolytic and hormonal abnormalities in acute renal failure due to leptospirosis

Hypokalemia in leptospirosis acute renal failure (ARF) was studied in nine patients with severe leptospirosis ARF and five patients with moderate leptospirosis ARF and compared with five patients with severe acute tubular necrosis (ATN) and eight healthy individuals. Urinary volumes of both the severe and moderate leptospirosis groups were higher than those of the severe ATN group. Leptospirosis groups had serum potassium levels lower than those found in the healthy and severe ATN groups. Serum sodium levels were lower in the severe leptospirosis group than in the moderate leptospirosis, the severe ATN, and the healthy groups. There was a positive correlation between the fractional excretion of sodium and potassium in the severe leptospirosis group as well as between serum creatinine and potassium levels in the pooled leptospirosis groups. Urinary pH in the severe and moderate leptospirosis groups was lower than in the severe ATN group. Aldosterone levels were higher in the severe leptospirosis group than in the healthy individuals. Cortisol levels were higher in the leptospirosis groups than in the healthy subjects. These results strongly suggest that hypokalemia in leptospirosis ARF is due to renal potassium wasting potentialized by aldosterone and cortisol, requiring that special attention is given to potassium replacement as well as to volume repletion in the treatment of leptospirosis ARF.

Reduced humoral immunity in uremic mice genetically selected for high antibody response

Biozzi's Selection IV-A mice, genetically selected for 25 generations for high and low antibody response to sheep red blood cells (SRBC), 2-3 months old, were made uremic by subtotal nephrectomy and characterized for antibody production against the selection antigen. T cell activity was evaluated in vitro by lymphocyte proliferation and interleukin 2 (IL 2) production in response to the super antigen staphylococcal enterotoxin B (SEB). Total and IgM antibody titers (log2) were similar in uremic and non-uremic low responder mice (total antibody: 4.0 +/- 0.6 vs 3.6 +/- 0.6; IgG: 3.0 +/- 0.7 vs 2.4 +/- 0.4), while uremic high responders presented with non-uremic animals (total antibody: 10.8 +/- 1.6 vs 13.0 +/- 0.2; IgG: 10.3 +/- 1.5 vs 11.7 +/- 0.3). T cell proliferation and IL 2 production were similar in uremic and non-uremic groups after SEB stimulation. The results indicate a genetic effect on sensitivity to humoral immune response modulation by uremic status, with deficient antibody production despite a normal T cell proliferative response to mitogen stimulation in short-duration renal failure in high responder mice.

The role of experimental aluminum intoxication in allogeneic immunoresponse

To evaluate the immunological properties of aluminum (Al) in experimental Al intoxication in rats, we performed heart transplantation and in vitro experiments. Lewis (Lew) rats were intoxicated with intraperitoneal injections of AlCl3. heart transplants were performed using Brown-Norway (BN) rats as donors. Isotransplants and normal Lew were used as controls. No differences in survival were observed. Unidirectional mixed lymphocyte cultures (MLC) and Concanavalin A (Con A)-stimulated cultures were prepared using spleen cells from normal and Al-intoxicated Lew rats. No differences were found in unidirectional MLC. Intoxicated cells showed a less intense response to con A than did normal cells. In conclusion, we could not detect an immunosuppressive role of Al intoxication in experimental cardiac transplantation or in MLC. However, the depressed Con A blastogenic response of Al-intoxicated cells may reflect an immunological role yet to be defined.

[Microneurography: technique to study cardiovascular regulation by the sympathetic nervous system in humans]

Microneurography is a valuable and safe method for direct intraneural recording of sympathetic nerve activity to muscle and skin in humans. The technique and its application for the study of autonomic function will be briefly discussed. The regulation of muscle sympathetic nerve activity will be focused in different clinical situations and or stimuli, such as: essential hypertension, mineralocorticoid induced hypertension, exercise mental arithmetic stress, cold pressor test, hyperinsulinemia, oral alcohol ingestion.

[Comparative and double-blind study of the efficacy and safety of cilazapril compared to nifedipine retard in the treatment of mild and moderate arterial hypertension]

PURPOSE

To evaluate the antihypertensive efficacy and safety of cilazapril compared to nifedipine retard in mild to moderate hypertension.

METHODS

forty randomized out-patients with mild moderate hypertension, diastolic pressure (DP) between 95 and 115 mmHg, with placebo for 15 days were randomized and allocated for treatment, double-blind, once daily with cilazapril 2.5 mg (n = 20) or nifedipine retard 20 mg (20 = n) for four weeks. The non-responders (DP > 90mmHg) had the dosage increased twice, b.i.d., while responders were maintained up to 10 weeks. Clinical visits were performed before, at baseline and every two weeks and the laboratory test was performed after placebo run-in, 4th and 10th weeks of treatment.

RESULTS

The blood pressure (BP) were similar between groups at the end of the placebo (cilazapril 151 +/- 14/103 +/- 5 - nifedipine 157 +/- 17/108 +/- 7mmHg, p > 0.05). DP decreased already at second weeks (cilazapril 95 +/- 9 - nifedipine 96 +/- 11mmHg, p < 0.05, compared to week 0) in both groups at the end of study with no difference inter groups. BP normalization was obtained in 58% of the patients with cilazapril and in 61% in the nifedipine group. Adverse biochemical effects were not observed in any group. Six (16%) patients of the cilazapril and 15 (39%) of nifedipine related collateral events, although no difference were observed between groups.

CONCLUSION

Cilazapril 2.5 to 25mg normalized BP in 58% of mild and moderate hypertension patients, and this efficacy was similar to sustained-release nifedipine 20 to 40mg. Cilazapril had no adverse effects on the biochemical parameters with low incidence of collateral effects.

Aluminium-related osteodystrophy and desferrioxamine treatment: role of phosphorus

We investigated (1) the prevalence of aluminium overload among 96 patients with symptomatic bone disease haemodialysed from 1987 to 1989 in the Sao Paulo area, Brazil; (2) the effect of 6 months desferrioxamine (DFO) treatment (1-2g/week). All patients underwent a first bone biopsy. Aluminium overload (extent of stainable bone aluminium more than 20% trabecular surface) was observed in 74 of 96 patients. Forty overloaded patients were divided into patients with high bone formation rate (BFR) (group 1; n = 17) and patients with low BFR (group 2; n = 23), and had a second biopsy after DFO therapy. In both groups aluminium surface was reduced after treatment (P < 0.001), osteoblast surface (P < 0.02-P < 0.01) and plasma parathyroid hormone (iPTH) (P < 0.01) increased. In group 1 BFR remained high. In group 2 BFR remained low in 16 patients (2a) and increased in seven (P < 0.02) (2b). In group 2a plasma phosphorus was below that in group 2b patients, before (P < 0.03) and after (P < 0.01) DFO. The histological features of group 2a patients resembled hypophosphataemic osteomalacia, those of group 2b patients aluminium osteodystrophy. These data show a high prevalence of aluminium overload in Brazilian patients. Low-dose DFO therapy was safe, decreased bone pain, prevented fractures, and reduced stainable bone aluminium. Bone lesions only partially improved, suggesting that low phosphorus intake and/or plasma calcitriol concentrations may have prevented improvement of bone formation and mineralization.

Nephrotoxicity of human Bence Jones protein in rats: proteinuria and enzymuria profile

The effect of intravenous administration of 80 mg purified human Bence Jones protein twice weekly for 5 weeks was investigated in male Wistar rats (N = 7; 2 months old). A state of immunological tolerance was demonstrated by the absence of a B-cell response (plaque-forming cells and hemagglutination titers) and by the absence of detectable antigen or antibody deposition in glomeruli, as indicated by light and electron microscopy. No rise in blood urea level was detected (33.9 +/- 4.3 vs 32.8 +/- 1.3 mg%). There was an increase in proteinuria (5.3 +/- 0.9 vs 32.8 +/- 4.0 mg/day), mainly due to Bence Jones protein excretion (0 vs 29.2 +/- 5.2 mg/day), with a slight but significant increase in albuminuria (0.2 +/- 0.1 vs 1.0 +/- 0.2 mg/day). There was a significant increase of lysosomal N-acetyl-beta-D-glucosaminidase in the urine (6.1 +/- 1.3 vs 72.7 +/- 18.8 mU/mg in creatinine). Lysosomal accumulation of Bence Jones protein in proximal tubular cells was evidenced by immunoelectronmicroscopy with protein A-gold. These results clearly showed proximal tubular dysfunction induced by chronic Bence Jones protein administration, without interference of autologous immune response as demonstrated by immunological state of tolerance.

[Effect of treatment with chlorthalidone on reduction of left ventricular mass in patients with systemic arterial hypertension]

PURPOSE

To evaluate the effects of the use of chlorthalidone on left ventricular mass of patients with mild and moderate systemic arterial hypertension (SAH).

METHODS

Twenty-nine patients with mild and moderate SAH were studied with mean age of 48.4 years and 16 men. Clinical evaluation, systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR), in supine and standing positions, were obtained before and every 3 weeks, after 2 with placebo, during 12 weeks of treatment with 50mg of chlorthalidone each 48 hours. Laboratory data (hemogram, sodium, potassium, urea creatinine, glucose, hepatic aminotransferases and urinalysis) were done before and at end of study. Echocardiographic study was performed by M-mode before and after 6 and 12 weeks of treatment, and obtained the following data: diastolic diameter (DdLV), diastolic septum (DSTLV) and posterior wall thickness (PWTLV) of left ventricle. The left ventricular mass (LVM) was calculated by the formula: LVM = (DSTLV+PWTLV+DdLVE)3 - (DdLV)3 x 1.05/body surface, in g/m2.

RESULTS

A significant reduction of SBP (p < 0.0001), DBP (p < 0.001) in supine and standing positions. HR did not show statistical difference. At echocardiographic study, M-mode, was observed a significant reduction of LVM after 12 weeks of treatment (181 +/- 67 to 156 +/- 34 g/m2, p < 0.01).

CONCLUSION

Chlorthalidone was effective to control blood pressure and to reduce LVM of patients with SAH.

Snakebite-induced acute renal failure: an experimental model

Acute renal failure (ARF) has been frequently reported after bites from the Viperidae snake family. The lack of a reproducible animal model has hampered the study of renal damage mechanisms. Intravenous injection of rats with 0.4 mg/kg of Bothrops jararaca venom produced functional and morphologic changes similar to those observed in human snakebite-induced ARF. There was an acute and significant decrease in the glomerular filtration rate, diuresis, and renal plasma flow. Serum fibrinogen levels decreased significantly. There was intravascular hemolysis, as shown by a significant decrease in hematocrit, and an increase in plasma lactate dehydrogenase levels and free hemoglobin. Blood pressure and serum creatine phosphokinase levels were not affected. Light and electron microscopy showed massive fibrin deposition in glomerular capillaries, proximal and distal tubular necrosis, and hemolyzed red blood cell casts in renal tubules. Based on these findings, a model of snakebite-induced ARF was achieved. Ischemia related to glomerular coagulation and intravascular hemolysis were the most important pathogenic factors causing a decrease in the glomerular filtration rate, although a direct venom nephrotoxicity cannot be excluded.

Higher salt consumption, digoxin-like factor, and nifedipine response are associated with salt sensitivity in essential hypertension

In addition to demonstrating evidences of increased sympathetic nervous system activity and marked left ventricular hypertrophy in salt-sensitive hypertensives, our group has also reported increased weight gain with salt overload in these patients. The increased weight gain suggests volume expansion, a situation already shown to increase plasma levels of a Na, K-ATPase inhibitor. Therefore, in the present study, digoxin-like factor (DLF) serum levels, spontaneous salt ingestion, nifedipine hypotensive effect, and plasma renin activity were evaluated in essential hypertensive subjects. Thirteen essential hypertensive outpatients were studied sequentially on an ad lib diet, a low salt diet (LSD = 30 mEq Na/day), and a high salt diet (HSD = LSD + 171 mmol/L NaCl/day), 1 week each. On the seventh day of LSD and HSD, DLF levels, mean blood pressure (MBP) response to nifedipine (10 mg sublingual), and plasma renin activity were measured. The MBP percent change from the seventh day of LSD to the seventh day of HSD (salt sensitivity) ranged from -13.7 to 20.9%. A positive correlation (r = 0.64, P < .01) was observed between salt sensitivity and 24-h urinary sodium excretion with an ad lib diet. The DLF serum levels correlated with the salt sensitivity both on LSD (r = 0.50, P < .05) and on HSD (r = 0.53, P < .05). Salt sensitivity was positively correlated with the difference of response to nifedipine between HSD and LSD (r = 0.78, P < .001). Plasma renin activity correlated inversely with DLF on LSD (r = -0.51, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Nephrotic syndrome associated with hepatointestinal schistosomiasis

Schistosomal nephropathy has long been related to the hepatosplenic form of schistosomiasis. In the last few years, 24 patients with hepatointestinal schistosomiasis and the nephrotic syndrome were studied. Aiming at evaluating a possible etiologic participation of schistosomiasis in the development of the nephropathy, this group was comparatively studied with a group of 37 patients with idiopathic nephrotic syndrome. Both groups had a different distribution of the histologic lesions. In the group with schistosomiasis there was a statistically significant prevalence of proliferative mesangial glomerulonephritis (33.3%), whereas in the control group there was prevalence of membranous glomerulonephritis (32.4%). On immunofluorescence, IgM was positive in 94.4% of the patients with schistosomiasis versus 55.0% in the control group (P < 0.01). In the group with schistosomiasis, 8 patients evidenced mesangial proliferative glomerulonephritis and 5, membranoproliferative glomerulonephritis. In both histological types immunofluorescence showed IgM and C3 granular deposits in the glomeruli. The data in this study suggests that mesangial proliferative and membranoproliferative glomerulonephritis, with glomerular granular IgM and C3 deposits, represent the renal lesions of the schistosomiasis associated nephropathy.

Late evaluation of glomerular filtration rate, proteinuria, and urinary acidification after acute tubular necrosis

Fourteen patients were studied 2 to 36 months after acute tubular necrosis. It was observed that 43% of the patients had decreased glomerular filtration rate. These patients were older and had lower urinary excretion of ammonium and titratable acidity. Proteinuria greater than 150 mg/day, without reaching a nephrotic level, was found in 92% of the patients. The presence of oliguria, the demand of dialysis, and the acute tubular necrosis etiology were not statistically different among the patients who recovered their glomerular filtration rate either totally or partially.

IgA nephropathy: acute renal failure, acute tubular necrosis, and features of postinfectious acute glomerulonephritis

From 1976 to 1987 on our Nephrological Unit, 57 patients with IgA nephropathy (IgAN) proven by renal biopsies were found. Three of those presented with acute tubular necrosis (ATN) and glomerulitis, without extrarenal predisposing cause in two; and showed, as prominent manifestation, a severe acute renal failure syndrome (ARFS), needing dialytic treatment. All three had hematuria, which was macroscopic in two and microscopic in one. Thus the prevalence of the association of glomerulitis and ATN was about 5.2%. There was complete recovery of renal functions in all three patients, but the usual symptomatology of IgAN. Two patients presented polymorphonuclear neutrophils infiltration of glomerular capillaries and in one of them, electron-dense deposits on the epithelial side of glomerular basement membrane ("humps") were observed, as well as those identified in the mesangial area. The glomerular polymorphonuclear neutrophils infiltration and endothelial cells proliferation (cases 1 and 3), the presence of "humps" (case 1), high antistreptolysin O (ASO) titers (cases 1 and 2), and low serum complement levels (case 1), suggest the possibility that antigens able to cause postinfectious glomerulonephritis (streptococcal or not) could induce in some individuals, by another immunopathogenetic route, mixed histopathological and clinical features of IgAN and postinfectious glomerulonephritis.

Nodular diabetic glomerulosclerosis without diabetes mellitus

A 66-year-old white man presented with severe chronic renal failure. He had no past or present symptomatic glucose intolerance nor a family history of diabetes mellitus. Several fasting plasma glucose determinations, hemoglobin Alc and an oral glucose tolerance test were normal. Funduscopic ophthalmoscopy and retinal fluorescein angiography did not demonstrate diabetic retinopathy. The kidney biopsy showed nodular diabetic nephropathy, with increased mesangial matrix, thickened glomerular basement membrane, and afferent and efferent glomerular arteriolar hyalinization. The diagnosis of nodular diabetic nephropathy was made in this patient in the absence of past or present or familial evidence of diabetes mellitus.

Left ventricular hypertrophy is more marked in salt-sensitive than in salt-resistant hypertensive patients

Besides the duration and severity of hypertension, several other factors have been shown to be related to left ventricular hypertrophy (LVH) in essential hypertension. The present study was conducted to examine the influence of salt sensitivity on LVH. Fifteen essential hypertensive ambulatory patients were submitted to a low-salt (30 mEq of Na/day for 7 days) and a high-salt (200 mEq of Na/day for 7 days) diet after 12 weeks on placebo. Daily urine collection was obtained during the whole study. After the placebo period, all patients were submitted to a complete clinical and laboratory investigation that included an echocardiogram (M-mode and two-dimensional). Five patients were salt-sensitive (mean blood pressure (BP) increase from the seventh day of the low- to the seventh day of the high-salt diet greater than 10%). No differences in weight, sex ratio, and duration of hypertension were obtained between salt-sensitive and -resistant patients. The initial BP was higher in the salt-sensitive patients. However, the difference was small and without statistical significance. The left ventricular weight was higher in the salt-sensitive than in salt-resistant patients (148 +/- 51 vs. 109 +/- 32 g/m2, p less than 0.05). The left ventricular end-diastolic diameter was also higher in the salt-sensitive patients (50 +/- 10 vs. 43 +/- 6 mm, p less than 0.05). The interventricular septum and posterior wall thicknesses were higher in salt-sensitive patients, although they did not reach statistical significance. In conclusion, salt-sensitive essential hypertensive patients are at a higher risk to develop LVH.

[Treatment of essential hypertension and hypercholesterolemia with or without hypertriglyceridemia, with low dose of bezafibrate (200 mg/day)]

Twenty patients with essential hypertension, 5 with dyslipidemia type IIa and 15 with that of type IIb, were treated with bezafibrate, 200 mg/day. As control group, 20 normo or dislipemic patients with essential hypertension receiving no hypolipidemic drugs, and chosen at random, showed no significant changes of the mean values of serum total cholesterol and triglycerides at three evaluations made in a period of about six months. Six patients were males (60 +/- 4 years) and 14 females (57 +/- 2 years). The levels of cholesterolemia and triglyceridemia were evaluated before the administration of the drug and on the 28th and 56th day of its use. The mean initial value of total cholesterol (n = 20) was 334 +/- 10 mg/dl, lowering significantly (P less than 0.01) to 274 +/- 7 mg/dl and 279 +/- 11 mg/dl. Initial triglyceridemia level (n = 15) was 544 +/- 85 mg/dl, decreasing significantly (P less than 0.01) to 234 +/- 36 and 245 +/- 36. Percentual mean decrease of cholesterolemia was respectively 16 +/- 4% and 14 +/- 5% and that of triglyceridemia was 46 +/- 8% for both evaluations. Side effects of the drug were not seen with the indicated dose. The therapy was useful to lower the dislipemic values of the essential hypertensive patients, in spite of no consistent changes in their diet and physical activity and of its use for a short period.

Progressive hypervolemia despite hypoproteinemia and massive edema formation in rats with nephrotoxic serum nephritis

Blood volume and whole kidney and single nephron function were evaluated 2 and 10 days after nephrotoxic serum nephritis (NSN) induction in Wistar rats. Progressive proteinuria, hypervolemia and edema were observed in NSN rats. Sodium retention was associated with a progressive depression of single nephron glomerular filtration rate and elevated fractional tubular reabsorption rates. Since hypervolemia rather than hypovolemia was observed in this study, edema formation must have been a consequence of intrarenal rather than extrarenal phenomena.

Essential hypertension and histocompatibility antigens. A linkage study

It is well established that genetic and environmental factors are involved in the etiology of essential hypertension. The presence of genes predisposing to essential hypertension in the human leukocyte antigen (HLA) complex is controversial because studies of an association between HLA antigens and essential hypertension have failed to yield consistent results. Our aim in the present study was to further investigate this issue through the method of linkage analysis. Analysis of 96 hypertensive siblings distributed in 31 families indicated a significant distortion (p = 0.0009) of the normal segregation pattern of inheritance of HLA haplotypes. Thus, our data indicate that at least one of the genes responsible for genetic predisposition to essential hypertension is located very near or within the HLA complex.

[Histopathologic study of primary glomerulopathies: retrospective analysis of 197 renal biopsies (1985-1987)]

The histopathological prevalence of primary glomerular diseases in patients aged 14 to 70 years (105 males, 92 females) was analysed: 140 (71%) were aged from 14 to 35 years and 57 (29%) were older than 35 years, the difference being significant (p less than 0.001). The following data were found at our Nephrological Unit: the prevalence of focal glomerular sclerosis was 37.1%; of the membranous glomerulonephritis 16.2%; of the IgA nephropathy 8.6%; of the membranoproliferative glomerulonephritis 6.1%; of the minimal change disease 5.1%. The acute diffuse glomerulonephritis, the rapidly progressive glomerulonephritis and the chronic glomerulonephritis showed the same prevalence of 4.6%, and the mesangial proliferative glomerulonephritis and the kidney in Alport's syndrome that of 3.6%. Diagnosis was not defined by renal biopsy in 6.1% of the patients. Failures to achieve diagnosis were due to biopsies with less than 5 glomeruli on optic microscopy or losses affecting the immunofluorescence procedures. It was concluded that the highest prevalence was that of the focal glomerular sclerosis, found in more than one third of the patients. It was followed by the prevalence of the membranous glomerulonephritis which occurred in about one sixth of our cases. The prevalence of IgA nephropathy, minimal change disease, membranoproliferative glomerulonephritis and of other primary glomerulopathies were low. The prevalence of focal glomerular sclerosis was significantly higher (p less than 0.001) in the younger group of patients (14-35 years) than in the older one; the same fact was seen in the prevalence of the proliferative histopathological forms of glomerulonephritis (p less than 0.025), grouping IgA nephropathy, membranoproliferative glomerulonephritis, rapidly progressive glomerulonephritis and mesangial proliferative glomerulonephritis.

[Continuous ambulatory peritoneal dialysis: efficient treatment for children with terminal uremia]

We have reviewed records of 12 children underwent CAPD between January 84 and May 88, ranging in age from 7 month to 16 years (mean age 8.9 +/- 4.9 years). CAPD treatment lasted from 3 to 24 months (average 10.3 months). Exchanges of dialysis fluid were performed by parents (8 cases) or children (3); mean volume was 41.7 +/- 8.7 ml/kg/exchange (range 32-58 ml/kg). During 132 patient months of treatment laboratory data showed a good metabolic control expect a tendency to hypoalbuminemia. There were 3 catheter changes. Complications were: peritonitis (15 episodes or one infection every 8.8 patient/treatment/months), hypertension (5 cases), hypervolemia (2), cuff extrusion (4), local exit site (5) and tunnel (2) infections and hernias (2). CAPD has been continued in 3 children; 6 other received renal transplantation, one was switched to hemodialysis and 2 died. This study has demonstrated that CAPD was an effective treatment for renal failure in children waiting renal transplant. Cuff extrusion and hypoalbuminemia were common complications in our children.

[Peritonitis in intermittent peritoneal dialysis: microbiological aspects and the antibiogram]

Peritonitis is the most frequent complication in patients on peritoneal dialysis and bacteria are the major causative agents. Initial antibiotic therapy may be "blind" but the antimicrobial agent used should be related to the infecting organism and its sensitivities. This study was initiated in order to evaluate the microbiological characteristics and sensitivity of bacteria isolated from pre and post peritoneal dialysis effluents. Positive growth of microorganisms was observed in 52 out of 503 cultures. Staphylococcus aureus and Staphylococcus epidermidis were identified most frequently (29 per cent each). Antibiograms showed high sensitivity to aminoglycosides (netilmicin and amikacin) and to second and third generation cephalosporin. Vancomycin and netilmicin were the best choices for Staphylococcal infection. A high bacterial resistance to ampicillin, co-trimoxazole, cephalothin and gentamicin was verified. Characteristics of organisms causing peritonitis in patients on intermittent peritoneal dialysis is very important, for selection of the initial antibiotic therapy.

[Primary IgA mesangial nephropathy (Berger's disease): clinico-pathological study]

From 1976 to December 1984 IgA nephropathy (IgAN) was diagnosed in 40 patients at the Nephrology Division of the Hospital das Clínicas, São Paulo University. In order to estimate the incidence of the disease in our city, we reviewed the kidney biopsies of the year 1984: IgAN constituted 6.5% of all biopsies of primary glomerular nephropathies. Of the 40 patients 67.5% were males and 32.5% females. Their age varied between 4 and 49 years and 72.5% were in the 2nd and 3rd decades of life at the beginning of the disease. From the racial standpoint, 82.5% of the patients were white, 10% were yellow and 7.5% black. The most frequent clinical manifestation, presented by 62.5% of patients, was macroscopic hematuria in close association with an acute infectious process. In the remaining 37.5% of cases the clinical picture of the disease was very variable, and did not evoke the diagnosis of IgAN. The initial laboratory investigation showed proteinuria in 92.5% of patients; it was under 1g/24h in 40%, it ranged from 1 to 3g/day in 37.5% and was over 3.5g/24h in 15% of them. Hematuria was present in all 40 cases and the red cells displayed moderate dismorphism. Glomerular filtration rate, evaluated by creatinine clearance in 39 patients, was over 90 ml/min/1.73m2 in 70%, ranged between 50 and 89 ml/min/1.73m2 in 7.5% and was under 25 ml/min/1.73m2 in 20% of them. Total complement CH50 was found normal in 79.4% and was slightly reduced in 20.6%. The C3 fraction showed slight reduction in 9.5% and C4 was found normal in all instances. Serum IgA was increased in 21% of the cases. All patients were submitted to percutaneous renal biopsy. Proliferative mesangial lesions were found in 82.5% of cases; they were focal in 42.5% and diffuse in 40%. In 15% of the patients, the glomeruli were entirely normal on light microscopy. In one case they were crescent-shaped, exhibiting 82% of the glomeruli this form. The immunofluorescence findings were quite uniform, with granular deposits occupying only the mesangium, with a global and diffuse distribution in all glomeruli. IgA was the dominant immunoglobulin deposited in the 40 cases and C3 was also found in the same localization and distribution in all biopsies, generally with a lesser intensity than IgA. IgG was present in 85% of cases and IgM in 32.5% of the biopsies, in the majority of them with the intensity of traces.(ABSTRACT TRUNCATED AT 400 WORDS)