Venetoclax resistance in acute myeloid leukaemia-Clinical and biological insights

Venetoclax, an oral BCL-2 inhibitor, has been widely incorporated in the treatment of acute myeloid leukaemia. The combination of hypomethylating agents and venetoclax is the current standard of care for elderly and patient's ineligible for aggressive therapies. However, venetoclax is being increasingly used with aggressive chemotherapy regimens both in the front line and in the relapse setting. Our growing experience and intensive research demonstrate that certain genetic abnormalities are associated with venetoclax sensitivity, while others with resistance, and that resistance can emerge during treatment leading to disease relapse. In the current review, we provide a summary of the known mechanisms of venetoclax cytotoxicity, both regarding the inhibition of BCL-2-mediated apoptosis and its effect on cell metabolism. We describe how these pathways are linked to venetoclax resistance and are associated with specific mutations. Finally, we provide the rationale for novel drug combinations in current and future clinical trials.

Impact of Folinic Acid Dosing on Efficacy and Toxicity of High-Dose Methotrexate in Central Nervous System Lymphoma

INTRODUCTION

High-dose methotrexate (HDMTX)-based regimens are the treatment of choice in primary central nervous system lymphoma (PCNSL). Folinic acid (FA) rescue is used to mitigate the toxic effects of MTX on normal cells. However, the optimal dosing of FA in PCNSL remains uncertain.

METHODS

We analyzed the relationship between FA dosing and treatment efficacy and toxicity in a cohort of 36 PCNSL patients treated at our institute between the years 2014 and 2022. A combination of univariate and multivariate analyses using known prognostic factors were used to determine the association between FA dosing and treatment outcomes.

RESULTS

We found that higher per-treatment cumulative FA doses were associated with inferior progression-free survival (PFS), with a hazard ratio (HR) of 2.2 for each 100 mg/m2 increase in FA dose. We identified a threshold of 350 mg/m2/treatment, above which there was a significant reduction in PFS. Notably, lower FA doses did not result in increased toxicity.

CONCLUSION

Our findings suggest that optimizing FA dosing to avoid very high rescue doses may improve treatment outcomes in PCNSL patients receiving HDMTX. Further prospective studies are warranted to validate these findings.

Standardization of Molecular MRD Levels in AML Using an Integral Vector Bearing ABL and the Mutation of Interest

Quantitative PCR for specific mutation is being increasingly used in Acute Myeloid Leukemia (AML) to assess Measurable Residual Disease (MRD), allowing for more tailored clinical decisions. To date, standardized molecular MRD is limited to typical NPM1 mutations and core binding factor translocations, with clear prognostic and clinical implications. The monitoring of other identified mutations lacks standardization, limiting its use and incorporation in clinical trials. To overcome this problem, we designed a plasmid bearing both the sequence of the mutation of interest and the ABL reference gene. This allows the use of commercial standards for ABL to determine the MRD response in copy number. We provide technical aspects of this approach as well as our experience with 19 patients with atypical NPM1, RUNX1 and IDH1/2 mutations. In all cases, we demonstrate a correlation between response and copy number. We further demonstrate how copy number monitoring can modulate the clinical management. Taken together, we provide proof of concept of a novel yet simple tool, which allows in-house MRD monitoring for identified mutations, with ABL-based commercial standards. This approach would facilitate large multi-center studies assessing the clinical relevance of selected MRD monitoring.

Rituximab versus obinutuzumab-based first-line chemoimmunotherapy for follicular lymphoma-a real-world multicenter retrospective cohort study

The GALLIUM study showed a progression-free survival advantage of 7% in favor of obinutuzumab vs. rituximab-based immunochemotherapies as first-line therapy in follicular lymphoma (FL) patients. Yet, the toxicity appears to be increased with obinutuzumab-based therapy. This is a multicenter retrospective-cohort study including adult FL patients comparing the toxicity of first-line rituximab vs. obinutuzumab-based chemo-immunotherapies (R and O groups, respectively). We compared the best standard-of-care therapy used per time period, before and after obinutuzumab approval. The primary outcome was any infection during induction and 6 months post-induction. Secondary outcomes included rates of febrile neutropenia, severe and fatal infections, other adverse events, and all-cause mortality. Outcomes were compared between groups. A total of 156 patients were included in the analysis, 78 patients per group. Most patients received bendamustine (59%) or CHOP (31.4%) as adjacent chemotherapy. Half of the patients received growth-factor prophylaxis. Overall, 69 patients (44.2%) experienced infections, and a total of 106 infectious episodes were recorded. Patients in the R and O groups had similar rates of any infection (44.8% and 43.5%, p = 1), severe infections (43.3% vs. 47.8%, p = 0.844), febrile neutropenia (15% vs. 19.6%, p = 0.606), and treatment discontinuation, as well as similar types of infections. No covariate was associated with infection in multivariable analysis. No statistically significant difference was evident in adverse events of grades 3-5 (76.9% vs. 82%, p = 0.427). To conclude, in this largest real-life study of first-line treated FL patients comparing R- to O-based therapy, we did not observe any difference in toxicity during the induction and 6 months post-induction period.

Venetoclax-based salvage therapy for adult patients with relapsed/refractory acute lymphoblastic leukemia

OBJECTIVES

Dysregulation of BCL-2 family members has been reported in acute lymphocytic leukemia (ALL), with various BH3-dependencies of the leukemic clone. We conducted a multicenter retrospective cohort of patients with relapsed/refractory B or T ALL, with ven-chemotherapy or ven-navitoclax combinations, to assess efficacy and safety.

METHODS

Seventeen patients were included in the analysis, median age was 32 years, with 6 B-ALL and 11 T-ALL patients. Nine patients received venetoclax combined with chemotherapy, and 13 patients received venetoclax in combination with navitoclax, vincristine and asparaginase, of which 5 were already exposed to venetoclax in previous lines.

RESULTS

ORR was 55% and 46% among the ven-chemotherapy and the ven-navitoclax-chemotherapy, respectively. Most of the responders proceeded to an allogenic bone marrow transplant in both cohorts. The most common adverse effects of the ven-navitoclax combination were infectious complications and hepatotoxicity.

CONCLUSIONS

Our data demonstrated the possible efficacy of ven-chemotherapy and ven-navitoclax in r/r ALL with moderate toxicity.

Utility of Galactomannan Screening for Early Detection of Invasive Aspergillosis in High-Risk Hemato-Oncology Patients

INTRODUCTION

Invasive aspergillosis (IA) affects mainly patients with hematological malignancies, and early diagnosis is crucial for timely treatment. Most diagnoses are based on clinical and mycological criteria, mostly galactomannan (GM) test in serum or bronchoalveolar fluid, which is performed in case of clinical suspicion or as routine screening in patients at high risk who are not receiving anti-mold prophylaxis, for early detection of IA. The aim of this study was to assess in a real-world setting the efficacy of biweekly serum GM screening for the early detection of IA.

METHODS

A retrospective cohort that included 80 adult patients treated at the Hematology Department, Hadassah Medical Center, 2016-2020, with a diagnosis of IA. Clinical and laboratory data were collected from patients' medical files and the rate of GM-driven, GM-associated, and non-GM-associated IA was calculated.

RESULTS

There were 58 patients with IA. The rate of GM-driven diagnosis was 6.9%, GM-associated diagnosis was 43.1%, and non-GM-associated diagnosis was 56.9%. The GM test as a screening tool had led to IA diagnosis in only 0.2% of screened serums with a number needed to screen in order to find 1 patient with IA of 490.

CONCLUSION

Clinical suspicion outweighs GM screening as a tool for early diagnosis of IA. Nevertheless, GM has an important role as a diagnostic tool for IA.

Risk factors and outcomes of COVID-19 in adult patients with hematological malignancies: A single-center study showing lower than expected rates of hospitalization and mortality

BACKGROUND

Studies addressing coronavirus disease 2019 (COVID-19) in patients with hematological malignancies have reported mortality rates of up to 40%; however, included predominantly hospitalized patients.

METHODS

During the first year of the pandemic, we followed adult patients with hematological malignancies treated at a tertiary center in Jerusalem, Israel, who contracted COVID-19, with the aim of studying risk factors for adverse COVID-19-related outcomes. We used remote communication to track patients managed at home-isolation, and patient questioning to assess the source of COVID-19 infection, community versus nosocomial.

RESULTS

Our series included 183 patients, median age was 62.5 years, 72% had at least one comorbidity and 39% were receiving active antineoplastic treatment. Hospitalization, critical COVID-19, and mortality rates were 32%, 12.6%, and 9.8%, respectively, remarkably lower than previously reported. Age, multiple comorbidities, and active antineoplastic treatment were significantly associated with hospitalization due to COVID-19. Treatment with monoclonal antibodies was strongly associated with both hospitalization and critical COVID-19. In older (≥60) patients not receiving active antineoplastic treatment, mortality, and severe COVID-19 rates were comparable to those of the general Israeli population. We did not detect patients that contracted COVID-19 within the Hematology Division.

CONCLUSION

These findings are relevant for the future management of patients with hematological malignancies in COVID-19-affected regions.

Desensitization protocol to lenalidomide: An effective and safe treatment modality for delayed hypersensitivity-induced rash in patients with multiple myeloma

INTRODUCTION AND OBJECTIVES

Lenalidomide is considered a standard of care in multiple myeloma (MM) Some MM patients will develop delayed hypersensitivity to lenalidomide, which can lead to treatment discontinuation. Desensitization to lenalidomide can help these patients to complete treatment courses. Here, we aimed to review lenalidomide-treated MM patients who developed delayed hypersensitivity-induced rash and were treated with desensitization.

METHODS

A retrospective analysis of medical files of MM patients, who were desensitized to lenalidomide due to delayed hypersensitivity rash. Patients were treated between 2018 and 2022 at Hadassah Medical Center, Jerusalem, Israel.

RESULTS

Search of patients yielded 16 patients that underwent desensitization to lenalidomide within the study period. The desensitization protocol consisted of a slow, 3-week-long protocol with lenalidomide's target doses of 10, 15, and 25 mg/day. Of the 16 patients, 10 (62.5%) succeeded to complete the protocol and thus were able to complete lenalidomide treatment cycles. One patient with unsuccessful desensitization was subsequently treated with first-generation IMiD thalidomide, with no rash appearing. None of the patients that were treated with desensitization had severe immune-mediated or non-dermatological adverse reactions.

CONCLUSIONS

Desensitization to lenalidomide is safe and effective. Discontinuation of lenalidomide in MM patients with delayed hypersensitivity and no contraindication to desensitization should be discouraged. Collaboration between hematologists and allergists is needed.

Venetoclax in Relapse/Refractory AL Amyloidosis—A Multicenter International Retrospective Real-World Study

Therapeutic options in relapsed refractory (R/R) light-chain (AL) amyloidosis patients are limited. Given the encouraging results in t(11;14) multiple myeloma and the high prevalence of t(11;14) in AL amyloidosis, venetoclax is an attractive treatment option in this setting. We report here the results of a multi-center retrospective study on 26 R/R AL amyloidosis patients treated off-label with venetoclax. The median lines of therapy prior to venetoclax was 3.5 (range 1–7), and 88% of our cohort had t (11;14). Twenty-two patients (85%) were previously treated with daratumumab. The overall hematologic response rate was 88%, 35% achieved a CR, and 35% achieved VGPR. The median event-free survival was 25 months (m) (95% CI 9.7 m-not reached), and the median overall survival was 33 m (95% CI 25.9–39.2 m). Most of the patients in this cohort are in ongoing deep responses and continuing venetoclax therapy. The treatment was relatively safe. One patient died due to infection, and there were two grade 3 infections in our cohort. Tumor lysis syndrome (TLS) was not seen in any patient. Dose reductions were frequent but did not affect the efficacy. These promising results require confirmation in a randomized controlled trial.

Monitoring Minimal Residual Disease in RUNX1-Mutated Acute Myeloid Leukemia

INTRODUCTION

Mutated RUNX1 is considered a poor prognostic factor and usually is mutually exclusive with NPM1 mutations. Monitoring of molecular markers for minimal residual disease provides a powerful tool to assess remission and guide clinical decisions.

METHODS

Newly diagnosed RUNX1-mutated AML patients, designated to intensive chemotherapy-based treatment or nonintensive regimens, were monitored for mutated RUNX1 transcript levels by qPCR with patient-specific primers. Samples were obtained along the treatment course and follow-up.

RESULTS

A clear correlation was observed between mutated RUNX1 levels and response to treatment as observed by flow cytometry and STR-based assessment.

CONCLUSION

We demonstrate the feasibility of RUNX1-based MRD to correlate with the clinicopathological status of leukemia. We further suggest how RUNX1 qPCR monitoring can influence clinical decision-making and contribute to improved personalized patient care.

Gilteritinib monotherapy for relapsed/refractory FLT3 mutated acute myeloid leukemia: a real-world, multi-center, matched analysis

Patients with FLT3-mutated relapsed or refractory (R/R) acute myeloid leukemia (AML) have a dismal prognosis. Gilteritinib is a FLT3 tyrosine kinase inhibitor (TKI) recently approved for patients with R/R AML. We aimed to characterize real-world data regarding gilteritinib treatment in FLT3-mutated R/R AML and to compare outcomes with matched FLT3-mutated R/R AML patients treated with chemotherapy-based salvage regimens. Twenty-five patients from six academic centers were treated with gilteritinib for FLT3-mutated R/R AML. Eighty percent were treated with a prior intensive induction regimen and 40% of them received prior TKI therapy. Twelve patients (48%) achieved complete response (CR) with gilteritinib. The estimated median overall survival (OS) of the entire cohort was eight (CI 95% 0-16.2) months and was significantly higher in patients who achieved CR compared to those who did not (16.3 months, CI 95% 0-36.2 vs. 2.6 months, CI 95% 1.47-3.7; p value = 0.046). In a multivariate cox regression analysis, achievement of CR was the only predictor for longer OS (HR 0.33 95% CI 0.11-0.97, p = 0.044). Prior TKI exposure did not affect OS but was associated with better event-free survival (HR 0.15 95% CI 0.03-0.71, p = 0.016). An age and ELN-risk matched comparison between patients treated with gilteritinib and intensive salvage revealed similar response rates (50% in both groups); median OS was 9.6 months (CI 95% 2.3-16.8) vs. 7 months (CI 95% 5.1-8.9) in gilteritinib and matched controls, respectively (p = 0.869). In conclusion, in the real-world setting, gilteritinib is effective, including in heavily pre-treated, TKI exposed patients.

Dose-adjusted EPOCH-R is not superior to sequential R-CHOP/R-ICE as a frontline treatment for newly diagnosed primary mediastinal B-cell lymphoma: Results of a bi-center retrospective study

Purpose

Primary mediastinal B‐cell lymphoma (PMBCL) is a rare subtype of diffuse large B‐cell lymphoma (DLBCL). Despite its aggressive course, PMBCL is considered curable. While in recent years dose‐adjusted (DA) EPOCH‐R (rituximab, etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin) has become widely endorsed as first‐line therapy for newly‐diagnosed PMBCL, the optimal treatment for this disease and the role of radiotherapy (RT) remains unclear. DA‐EPOCH‐R provides good clinical outcomes, albeit is associated with short‐ and long‐term toxicity. To address this issue, the current retrospective bi‐icenter analysis compared efficacy and toxicity of DA‐EPOCH‐R and a less toxic R‐CHOP/R‐ICE regimen used for the treatment of newly‐diagnosed PMBCL.

Patients and Methods

The study included all patients with a histologically confirmed PMBCL diagnosis treated with DA‐EPOCH‐R or R‐CHOP/R‐ICE between 01/2013‐12/2020 at two tertiary medical centers. Patient demographic and clinical data were derived from institutional electronic medical records. The analysis included 56 patients: 31 received DA‐EPOCH‐R and 25 – R‐CHOP/R‐ICE.

Results

At a median follow‐up of 1.9 years (IQR 3.1 years), similar progression‐free survival (2.1 versus 2.4 years; p = 0.7667), overall survival (2.5 versus 2.7 years; p = 0.8047) and complete response (80%) were observed in both groups. However, DA‐EPOCH‐R was associated with significantly longer hospitalization required for its administration (p < 0.001) and a trend for higher frequency of infections, stomatitis, thrombotic complications and febrile neutropenia‐related hospitalizations.

Conclusion

DA‐EPOCH‐R and R‐CHOP/R‐ICE provide similarly encouraging outcomes in newly‐diagnosed PMBCL patients. R‐CHOP/R‐ICE is associated with lower toxicity and significantly reduced hospitalization. Our findings suggest that this regimen may be considered as an alternative to DA‐EPOCH‐R in this patient population.

COVID-19 among patients with hematological malignancies: a national Israeli retrospective analysis with special emphasis on treatment and outcome

This national Israeli multicenter retrospective study aimed to characterize the clinical course of COVID-19 infection among patients with hematological malignancies, with special emphasis on treatment efficacy and outcome. Clinical and laboratory data from haemato-oncological patients diagnosed with COVID-19 from 16 medical centers were centrally reported. Multivariate regression analyses were used to determine variables associated with severe disease, hospitalization, and mortality. In total, 313 patients were included: 103 (35.7%) developed severe/critical respiratory infection, 178 (61.4%) were hospitalized, and 60 (20.0%) died. Age > 70 years was associated with severe/critical disease (p = 0.036) and mortality (p = 0.023), hypertension with severe/critical disease (p = 0.046) and hospitalization (p = 0.001), active haemato-oncological treatment with hospitalization (p = 0.009), and remdesivir treatment was associated with decreased mortality (p = 0.021). Convalescent plasma, enoxaparin, and corticosteroids resulted in no clinical benefit. In conclusion, COVID-19 infection seems particularly severe in patients with hematological malignancies, and of all examined therapies, remdesivir appears to be the most effective.

LMO2 Confers Synthetic Lethality to PARP Inhibition in DLBCL

Deficiency in DNA double-strand break (DSB) repair mechanisms has been widely exploited for the treatment of different malignances, including homologous recombination (HR)-deficient breast and ovarian cancers. Here we demonstrate that diffuse large B cell lymphomas (DLBCLs) expressing LMO2 protein are functionally deficient in HR-mediated DSB repair. Mechanistically, LMO2 inhibits BRCA1 recruitment to DSBs by interacting with 53BP1 during repair. Similar to BRCA1-deficient cells, LMO2-positive DLBCLs and T cell acute lymphoblastic leukemia (T-ALL) cells exhibit a high sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. Furthermore, chemotherapy and PARP inhibitors synergize to inhibit the growth of LMO2-positive tumors. Together, our results reveal that LMO2 expression predicts HR deficiency and the potential therapeutic use of PARP inhibitors in DLBCL and T-ALL.

Viral neurotropism, peripheral neuropathy and other morphological abnormalities in bovine ephemeral fever virus-infected downer cattle

OBJECTIVE

This study assessed the neurotropism of bovine ephemeral fever (BEF) virus (BEFV) and described histomorphological abnormalities of the brain, spinal cord and peripheral nerves that may causally contribute to paresis or paralysis in BEF.

METHODS

Four paralysed and six asymptomatic but virus-infected cattle were monitored, and blood and serum samples screened by qRT-PCR, virus isolation and neutralisation tests. Fresh brain, spinal cord, peripheral nerve and other tissues were qRT-PCR-tested for viral RNA, while formalin-fixed specimens were processed routinely and immunohistochemically evaluated for histomorphological abnormalities and viral antigen distribution, respectively.

RESULTS

The neurotropism of BEFV was immunohistochemically confirmed in the brain and peripheral nerves and peripheral neuropathy was demonstrated in three paralysed but not the six aneurological but virus-infected animals. Wallerian degeneration (WD) was present in the ventral funicular white matter of the lumbar spinal cord of a paralysed steer and in cervical and thoracic spinal cord segments of three paralysed animals. Although no spinal cord lesions were seen in the steer euthanased within 7 days of illness, peripheral neuropathy was present and more severe in nerves of the brachial plexuses than in the gluteal or fibular nerves. The only steer with WD in the lumbar spinal cord also showed intrahistiocytic cell viral antigen that was spatially distributed within areas of moderate brain stem encephalitis.

CONCLUSION

The data confirmed neurotropism of BEFV in cattle and documented histomorphological abnormalities in peripheral nerves and brain which, together with spinal cord lesions, may contribute to chronic paralysis in BEFV-infected downer cattle.

SRSF2 Mutations Contribute to Myelodysplasia by Mutant-Specific Effects on Exon Recognition

Mutations affecting spliceosomal proteins are the most common mutations in patients with myelodysplastic syndromes (MDS), but their role in MDS pathogenesis has not been delineated. Here we report that mutations affecting the splicing factor SRSF2 directly impair hematopoietic differentiation in vivo, which is not due to SRSF2 loss of function. By contrast, SRSF2 mutations alter SRSF2's normal sequence-specific RNA binding activity, thereby altering the recognition of specific exonic splicing enhancer motifs to drive recurrent mis-splicing of key hematopoietic regulators. This includes SRSF2 mutation-dependent splicing of EZH2, which triggers nonsense-mediated decay, which, in turn, results in impaired hematopoietic differentiation. These data provide a mechanistic link between a mutant spliceosomal protein, alterations in the splicing of key regulators, and impaired hematopoiesis.

Recurrent RAS and PIK3CA mutations in Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare histiocytic disorder that is challenging to diagnose and treat. We performed molecular analysis of BRAF in the largest cohort of ECD patients studied to date followed by N/KRAS, PIK3CA, and AKT1 mutational analysis in BRAF wild-type patients. Forty-six of 80 (57.5%) of patients were BRAFV600E-mutant. NRAS mutations were detected in 3 of 17 ECD BRAFV600E wild-type patients. PIK3CA mutations (p.E542K, p.E545K, p.A1046T, and p.H1047R) were detected in 7 of 55 patients, 4 of whom also had BRAF mutations. Mutant NRAS was present in peripheral blood CD14(+) cells, but not lymphoid cells, from an NRASQ61R mutant patient. Our results underscore the central role of RAS-RAF-MEK-ERK activation in ECD and identify an important role of activation of RAS-PI3K-AKT signaling in ECD. These results provide a rationale for targeting mutant RAS or PI3K/AKT/mTOR signaling in the subset of ECD patients with NRAS or PIK3CA mutations.

Somatic alterations and dysregulation of epigenetic modifiers in cancers

Genomic discovery efforts in patients with cancer have been critical in identifying a recurrent theme of mutations in epigenetic modifiers. A number of novel and exciting basic biological findings have come from this work including the discovery of an enzymatic pathway for DNA cytosine demethylation, a link between cancer metabolism and epigenetics, and the critical importance of post-translational modifications at specific histone residues in malignant transformation. Identification of cancer cell dependency on a number of these mutations has quickly resulted in the development of therapies targeting several of these genetic alterations. This includes, the development of mutant-selective IDH1 and IDH2 inhibitors, DOT1L inhibitors for MLL rearranged leukemias, EZH2 inhibitors for several cancer types, and the development of bromodomain inhibitors for many cancer types--all of which are in early phase clinical trials. In many cases, however, specific genetic targets linked to malignant transformation following mutations in individual epigenetic modifiers are not yet known. In this review we present functional evidence of how alterations in frequently mutated epigenetic modifiers promote malignant transformation and how these alterations are being targeted for cancer therapeutics.

Pathology of Runting in Farmed Saltwater Crocodiles (Crocodylus porosus) in Australia

Extremely poor growth of some individuals within a birth cohort (runting) is a significant problem in crocodile farming. We conducted a pathological investigation to determine if infectious disease is associated with runting in farmed saltwater crocodiles ( Crocodylus porosus) and to look for evidence of other etiologies. In each of 2005 and 2007, 10 normal and 10 runt crocodiles, with an average age of 5.5 months and reared under identical conditions, were sampled. Laboratory testing included postmortem; histological examination of a wide variety of tissues (with quantitation of features that were noted subjectively to be different between groups); hematology; serum biochemistry (total protein, albumin, globulins, total calcium, phosphorus, and iron); bacterial culture of liver and spleen (2005 only); viral culture of liver, thymus, tonsil, and spleen using primary crocodile cell lines (2007 only); and serum corticosterone (2007 only). The only evidence of infectious disease was mild cutaneous poxvirus infection in 45% of normal and 40% of runt crocodiles and rare intestinal coccidia in 5% of normal and 15% of runt crocodiles. Bacterial and viral culture did not reveal significant differences between the 2 groups. However, runt crocodiles exhibited significant ( P < .05) increases in adrenocortical cell cytoplasmic vacuolation and serum corticosterone, decreased production of bone (osteoporosis), and reduced lymphoid populations in the spleen, tonsil, and thymus. Runts also exhibited moderate anemia, hypoalbuminemia, and mild hypophosphatemia. Taken together, these findings suggest an association between runting and a chronic stress response (hyperactivity of the hypothalamic-pituitary-adrenal axis).

[Quantitative recording of renal function with magnetic resonance tomography]

AIM

To show the potential of various methods in magnetic resonance imaging for the evaluation of renal function.

MATERIAL AND METHODS

A combined assessment of renal morphology, renal hemodynamics and function is proposed. Various techniques are explained, including multiphasic 3D gadolinium MR angiography, MR phase-contrast flow measurements, quantitative perfusion measurements with intravascular contrast agents, and MR renography and MR urography. The use of these techniques is demonstrated for renovascular diseases.

RESULTS

The combined use of these techniques allows renal artery stenosis to be accurately detected and evaluation of renal blood flow, perfusion, glomerular filtration rate, and renal excretion. Based on true quantitative parameters, the hemodynamic and functional significance of the stenosis can be assessed. Renovascular diseases can be differentiated from renoparenchymal disease.

CONCLUSION

For the assessment of renal function, functional magnetic resonance imaging techniques are an important alternative to nuclear medicine. The predictive value regarding the effect of revascularization is currently under investigation.

The sustained antihypertensive effect of chronic cerebroventricular infusion of angiotensin antagonist in spontaneously hypertensive rats

The angiotensin antagonist [Sar1-Ile8]angiotensin II was infused into the lateral ventricles of mature spontaneously hypertensive and normotensive Wistar-Kyoto rats. Infusions were maintained at rats of 1200 ng/h for 6 days, and blood pressure was measured daily in the unanesthetized state. Blood pressure reduction occurred promptly and only in the hypertensive animals. This antihypertensive effect persisted for several days after discontinuation of the infusion. In contrast, iv infusion of the angiotensin antagonist at comparable doses failed to alter blood pressure in any significant fashion. These data suggest that the brain isorenin system participates in the maintenance of hypertension in the spontaneously hypertensive rat.