Neighbourhood species richness and drought-tolerance traits modulate tree growth and δ13 C responses to drought

Mixed-species forests are promoted as a forest management strategy for climate change adaptation, but whether they are more resistant to drought than monospecific forests remains contested. In particular, the trait-based mechanisms driving the role of tree diversity under drought remain elusive. Using tree cores from a large-scale biodiversity experiment, we investigated tree growth and physiological stress responses (i.e. increase in wood carbon isotopic ratio; δ13 C) to changes in climate-induced water availability (wet to dry years) along gradients in neighbourhood tree species richness and drought-tolerance traits. We hypothesized that neighbourhood species richness increases growth and decreases δ13 C and that these relationships are modulated by the abiotic (i.e. climatic conditions) and the biotic context. We characterised the biotic context using drought-tolerance traits of focal trees and their neighbours. These traits are related to cavitation resistance versus resource acquisition and stomatal control. Tree growth increased with neighbourhood species richness. However, we did not observe a universal relief of water stress in species-rich neighbourhoods. The effects of neighbourhood species richness and climate on growth and δ13 C were modulated by the traits of focal trees and the traits of their neighbours. At either end of each drought-tolerance gradient, species responded in opposing directions during dry and wet years. We show that species' drought-tolerance traits can explain the strength and nature of biodiversity-ecosystem functioning relationships in experimental tree communities experiencing drought. Mixing tree species can increase growth but may not universally relieve drought stress.

Early switch from run-in treatment with vemurafenib plus cobimetinib to atezolizumab after 3 months leads to rapid loss of tumour control in patients with advanced BRAFV600-positive melanoma: The ImmunoCobiVem phase 2 randomised trial

AIM

ImmunoCobiVem investigated whether a planned switch to atezolizumab after achieving tumour control during run-in with vemurafenib + cobimetinib improves progression-free survival (PFS) and overall survival (OS) compared to continuous targeted therapy (TT) in patients with previously untreated advanced BRAF^V600-mutated melanoma.

METHODS

In this multicenter phase 2 study, patients received vemurafenib plus cobimetinib. After 3months, patients without progressive disease (PD) were randomly assigned (1:1) to continue vemurafenib + cobimetinib (Arm A) or switch to atezolizumab (Arm B) until first documented PD (PD1). Primary outcome was PFS1 (time from start of run-in until PD1 or death). OS and safety were also assessed.

RESULTS

Of 185 patients enroled between November 2016 and December 2019, 135 were randomly assigned after the run-in period (Arm A, n = 69; Arm B, n = 66). Median PFS1 was significantly longer in Arm A versus Arm B (13.9 versus 5.9months; hazard ratio [HR] 0.55; 95% confidence interval [CI], 0.37-0.84; P_Stratified=0.001). Median OS was not reached in either arm (HR 1.22; 95%CI, 0.69-2.16; P_Stratified=0.389); 2-year OS was higher in Arm B versus Arm A (67%; 95%CI, 53-78 versus 58%; 95%CI, 45-70). Grade 3/4 AEs occurred in 55% of patients in Arm A and 64% in Arm B; treatment-related AEs led to discontinuation of any drug in 7% and 9% of patients, respectively.

CONCLUSION

In patients with BRAF^V600-mutated advanced melanoma who achieve tumour control with TT, early switch at 3months to atezolizumab led to rapid loss of tumour control but provided a numerical OS benefit at 2years compared with continued TT.

Source apportionment of circum-Arctic atmospheric black carbon from isotopes and modeling

Black carbon (BC) contributes to Arctic climate warming, yet source attributions are inaccurate due to lacking observational constraints and uncertainties in emission inventories. Year-round, isotope-constrained observations reveal strong seasonal variations in BC sources with a consistent and synchronous pattern at all Arctic sites. These sources were dominated by emissions from fossil fuel combustion in the winter and by biomass burning in the summer. The annual mean source of BC to the circum-Arctic was 39 ± 10% from biomass burning. Comparison of transport-model predictions with the observations showed good agreement for BC concentrations, with larger discrepancies for (fossil/biomass burning) sources. The accuracy of simulated BC concentration, but not of origin, points to misallocations of emissions in the emission inventories. The consistency in seasonal source contributions of BC throughout the Arctic provides strong justification for targeted emission reductions to limit the impact of BC on climate warming in the Arctic and beyond.

Constraints on oceanic methane emissions west of Svalbard from atmospheric in situ measurements and Lagrangian transport modeling

Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year. We present a model-supported analysis of the atmospheric CH₄ mixing ratios measured by the different platforms. To address uncertainty about where CH₄ emissions actually occur, we explored three scenarios: areas with known seeps, a hydrate stability model, and an ocean depth criterion. We then used a budget analysis and a Lagrangian particle dispersion model to compare measurements taken upwind and downwind of the potential CH₄ emission areas. We found small differences between the CH₄ mixing ratios measured upwind and downwind of the potential emission areas during the campaign. By taking into account measurement and sampling uncertainties and by determining the sensitivity of the measured mixing ratios to potential oceanic emissions, we provide upper limits for the CH₄ fluxes. The CH₄ flux during the campaign was small, with an upper limit of 2.5 nmol m^-2 s^-1 in the stability model scenario. The Zeppelin Observatory data for 2014 suggest CH₄ fluxes from the Svalbard continental platform below 0.2 Tg yr^-1. All estimates are in the lower range of values previously reported.

The sources of atmospheric black carbon at a European gateway to the Arctic

Black carbon (BC) aerosols from incomplete combustion of biomass and fossil fuel contribute to Arctic climate warming. Models-seeking to advise mitigation policy-are challenged in reproducing observations of seasonally varying BC concentrations in the Arctic air. Here we compare year-round observations of BC and its δ(13)C/Δ(14)C-diagnosed sources in Arctic Scandinavia, with tailored simulations from an atmospheric transport model. The model predictions for this European gateway to the Arctic are greatly improved when the emission inventory of anthropogenic sources is amended by satellite-derived estimates of BC emissions from fires. Both BC concentrations (R(2)=0.89, P<0.05) and source contributions (R(2)=0.77, P<0.05) are accurately mimicked and linked to predominantly European emissions. This improved model skill allows for more accurate assessment of sources and effects of BC in the Arctic, and a more credible scientific underpinning of policy efforts aimed at efficiently reducing BC emissions reaching the European Arctic.

Individualized multimodal treatment strategy for anaplastic thyroid carcinoma-Case report of long-term remission and review of literature

INTRODUCTION

The prognosis of anaplastic thyroid cancer (ATC) is poor with a mean survival time of six months following diagnosis. Despite various attempts to modify common treatment modalities including surgery, external beam radiation and chemotherapy, an effective treatment is not available yet. We report, here, a patient who achieved long-term survival based on multimodal treatment, including in vitro evaluation of drug response of his tumor cells.

PRESENTATION OF CASE

A 42 years old male patient underwent total thyroidectomy with central and lateral neck dissection for ATC (pT4b, pN0 (0/36), L0, V0, Pn1, R0 cM0 - UICC-Stage: IV b). From the tumor tissue a primary cell culture was established. While the patient received a combined radio-chemotherapy cell viability assays were performed using Sorafenib, Vandetanib und MLN8054 (Aurora kinase inhibitor) as inhibitors. Cell viability was determined by MTT-assay after 72 and 144h of treatment.

DISCUSSION

All the three compounds affected cell viability in a time- and dose dependent manner. These effects were most pronounced by Sorafenib. Based on in vitro findings, the patient was treated daily with 400mg Sorafenib for 75days. 43 months after initial diagnosis, the patient had no evidence of disease as shown by MRI, CT and FDG-PET-CT imaging.

CONCLUSION

In the setting of multimodal treatment, in vitro drug evaluation of individual tumor cells of patients might be a promising tool to ameliorate the fatal prognosis of selected ATC patients.

Phase I study of TZT-1027, a novel synthetic dolastatin 10 derivative, for the treatment of patients with non-small cell lung cancer

PURPOSE

The purpose of this phase I study was to evaluate the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), the recommended dose for phase II study, pharmacokinetics, and antitumor activity of TZT-1,027 (soblidotin) in patients with non-small cell lung cancer (NSCLC) when administered every 3-4 weeks.

METHODS

Eligible patients had the following characteristics: stage III/b or IV NSCLC that was refractory to conventional therapy or for which no standard therapy was available; Eastern Cooperative Oncology Group (ECOG) performance status (PS) <or=2; adequate organ function; and age >or=20 and <75 years. The patients were administered TZT-1,027 in escalating doses from 0.5 to 5.6 mg/m(2). Pharmacokinetic samples were collected during each treatment course.

RESULTS

Forty-nine patients were enrolled. Three patients had DLTs, including neutropenia, neutropenia complicated by fever, myalgia, and neuropathic pain. The common toxicities included constipation, anorexia, alopecia, nausea, leukopenia, and neutropenia. One complete response and three partial responses were observed. The pharmacokinetic parameters (AUC and C (max)) of TZT-1,027 tended to increase linearly with dose.

CONCLUSIONS

DLTs included neutropenia, neutropenia complicated by fever, myalgia, and neuropathic pain. The MTD was 4.8 mg/m(2). The recommended phase II study dose of TZT-1027 is 4.8 mg/m(2) administered every 3-4 weeks.

A phase I safety and pharmacokinetic study of apomab, a human DR5 agonist antibody, in patients with advanced cancer

3582

Background: Apomab, a fully human affinity-matured IgG1 monoclonal antibody, is a DR5 pro-apoptotic receptor agonist that triggers the extrinsic pathway of apoptosis. DR5 is expressed both on malignant and normal cells; however, pre-clinical data indicate that DR5 activation stimulates apoptosis predominantly in malignant cells. This first-in-human study assessed the safety, pharmacokinetics (PK) and any early evidence of anti-cancer efficacy of Apomab. Methods: Patients with advanced treatment-refractory solid tumors received Apomab IV on Day1 (cycle 1 = 28 days, cycles 2–8 = 14 days) at 1, 4, 10, 15, or 20 mg/kg (stage 1); with cohort expansion at 10 mg/kg or the MTD (if lower) every 14 days (stage 2). Tumor assessments were made after 2, 4 and 8 cycles. Therapy continued past 2 cycles as permitted by on-going evidence of benefit, until disease progression or unacceptable toxicity occurred. Results: 26 patients ECOG PS ≤1 have been enrolled and treated through 20 mg/kg. The 20 (8M, 12F) with confirmed data (up to 15mg/kg) received a median of 2 cycles (range 1–8). All dose levels have been tolerable (<33% dose limiting (Grade 3 drug-related) toxicities in the first 2 doses + 24 hours). 2 disparate DLTs occurred among 11 patients treated at 10 mg/kg. 1 patient (ovarian cancer) had asymptomatic transaminitis (ALT and AST) at C1D5, reaching Grade 3 by D29, received no further Apomab with resolution by D53. 1 patient (colorectal cancer) had a pulmonary embolism C1D4. Six patients completed at least 4 cycles of Apomab, 4 completed 8 cycles. No objective responses have been seen but at 10 mg/kg 1 patient (appendiceal cancer) remains on study (stable disease) past 8 cycles and 1 patient (colorectal cancer) had 28% shrinkage of target lesions and symptomatic improvement after 4 cycles. PK of Apomab is dose-proportional at 1 and 4 mg/kg with a typical IgG1 half-life of ∼15–20 days. AUC/Css,min concentrations at >4 mg/kg are greater than those displaying activity in preclinical models. No HAHA responses have been seen to date. Conclusions: Apomab is well tolerated with a minor response seen in a colorectal cancer patient. Enrollment is continuing at 10mg/kg. Further safety and efficacy data will be presented.

No significant financial relationships to disclose.

A phase I study of R547, a novel, selective inhibitor of cell cycle and transcriptional cyclin dependent kinases (CDKs)

3528

Background: R547, a potent inhibitor of CDKs 1, 2, 4, 7, and 9, has shown broad antitumor activity in preclinical models. This phase Ia study assessed safety, pharmacokinetic (PK), and pharmacodynamic (PD) endpoints. Methods: R547 given as a 90 or 180 min infusion D1, D8 (21 day cycle). Key inclusion criteria: ECOG 0–2, adequate hematologic, hepatic, and renal function. Exclusion: brain metastases, NYHA III/IV CHF, CVA, current antihypertensive therapy. Blood samples on cycle 1, D1, D8 for PK and PD. PD endpoint is inhibition of retinoblastoma phosphorylation (pRB) in PBMCs. Results: 41 pts received R547 over dose range 8.6 - 195 mg/m2; 31 pts on 90 min and 10 pts on 180 min schedule. Mean age 53.4 yrs (20–81), 25F:16M. Mean R547 cycles 3.1(<1- 8) for 18 evaluable pts receiving doses ≥ 155 mg/m2. Toxicities: principal related events were nausea (54%), fatigue (34%), emesis (34%), headache (34%), and hypotension (32%). All of these limited to gr 1/ 2, except 4 gr 3 fatigue (1 in cycle 1) and 1 gr 3 nausea. DLTs: 90 min- gr 3 somnolence, gr 3 confusion, gr 3 fatigue, 1 pt each, all at 195 mg/m2; 180 min- 1 DLT of prolonged gr 3 pruritis at 195 mg/m2. PK: Mean AUC for 20 pts with PK receiving ≥ 155 mg/m2 R547 exceeds exposures efficacious in xenograft studies. At equivalent doses, the 180 min schedule produces equivalent AUC but 30% reduction of Cmax. PD: for pts with available data (n=21), an exposure-dependent decrease in pRB/total RB ratio was observed 1.5 to 24 hrs post R547. Activity: tumor regression in 1 pt with metastatic squamous ca skin; 8 additional pts received ≥ 4 cycles. Conclusions: Treatment with R547 is tolerable at a dose of 155 mg/m2 on D1, D8 (21 day cycle) for both 90 and 180 min schedules. Nausea, emesis, headache, and transient hypotension are manageable with anti-emetic, analgesic, and iv fluid support. The DLTs observed in the 90 min schedule have not occurred in pts receiving 180 min infusions, a schedule which maintains R547 exposure but reduces Cmax. Exposures predictive of preclinical efficacy have been achieved. Inhibition of a relevant PD marker (pRB) and antitumor activity have each been confirmed in the clinic. Phase II trials in advanced solid tumors and hematologic malignancies are planned.

No significant financial relationships to disclose.

Phase I combination study of trabectedin (T) and capecitabine (C) in patients with advanced malignancies

2079

Background: T binds to the minor groove of DNA, synergizes with functional nuclease excision repair and targets inducible transcription. T is active in several tumor types and exhibits preclinical synergy with C. The primary objective of this study is to determine the maximum tolerated dose (MTD) of T in combination with C. Secondary objectives include safety and pharmacokinetic (PK) analyses. Methods: Pts with advanced cancer, performance status 0–1 and adequate organ function are eligible. Pts received T starting at 0.4 mg/m2 over 3 hours on day 1 followed by C on days 2 through 15. The initial dose of C was 2000 mg/m2/day and was reduced to 1600 mg/m2/day due to GI dose-limiting toxicity. Dose escalation of T continued. Cycles are repeated every 3 weeks, with PK sampling included. Standard “3+3” dose escalation design, definitions of dose limiting toxicity (DLT), and dose modification for toxicity are implemented. Results: To date, 30 patients have received 112 cycles (range 1–12, median 4) of treatment at 7 dose levels. Two of 3 pts at dose level 4 (C 2000 mg/m2/d and T 0.9 mg/m2) and 2/6 pts at dose level 3 (C 2000 mg/m2/d and T 0.75 mg/ m2) developed gastrointestinal DLT (emesis, diarrhea, pancreatitis). C was subsequently reduced to 1600 mg/m2/d and a new T dose escalation was initiated at 0.6 mg/m2. Treatment has been well tolerated with C 1600 mg/m2/d and T up to the current dose of 0.9 mg/m2 (dose level 4a), with 1of 6 subjects experiencing grade 1 alkaline phosphatase. The most frequently reported related grade 3–4 adverse events (AEs) are diarrhea (23%), neutropenia (20%), nausea (16.6%), hand-foot syndrome (16.6%) and vomiting (13%). Anti-tumor activity to date includes a confirmed partial response lasting 8 months (m) in a patient with cholangiocarcinoma, and prolonged stable disease in 2 patients with breast cancer (6 and 7m), ovarian cancer (11m) and chondrosarcoma (9m). Conclusions: The combination of C 1600mg/m2/d and T up to 0.9mg/m2 is tolerable and has promising activity in several tumor types. Dose escalation of T continues at 1.1 mg/m2. Biologic and pharmacokinetic analyses will be presented.

[Table: see text]

Second malignancies after treatment for Hodgkin's disease

The occurrence of treatment-related second malignancy following Hodgkin's disease (HD) has now been recognized as a major problem. The purpose of this study was to review our experience with second malignancies in patients treated for Hodgkin's disease, comparing the results with the international literature data. Six hundred and sixty five patients with HD were treated in our department, between 1978 and 1996. Second neoplasm developed in 32 cases (4.8%). Seven secondary hematological malignancies were observed: four acute nonlymphocytic leukemias, two non-Hodgkin's lymphomas and one chronic myeloid leukemia. Among patients with second hematological malignancies, the mean age at diagnosis of HD was 44 years and the mean interval until the development of second malignancy was 6.1 years. Five patients received chemo- and radiotherapy and in two cases chemotherapy was used. Three of the seven patients are alive. Twenty-five patients have had solid tumors, affecting lung (5), breast (3), colon (3), stomach (2), urinary bladder (2), head-and-neck (1), thyroid gland (1), esophagus (1), liver (1), pancreas (1), furthermore, three sarcomas and two malignant melanomas were observed. Their mean age at the diagnosis of HD was 46 years and the mean period of latency was 8.3 years. Chemotherapy was applied to nine patients, 16 patients received both chemo- and radiotherapy. Eleven patients had solid tumors in the region irradiated earlier. Ten out of the 25 patients are alive, three patients' present state is unknown. Since alkylating agents increase the risk of leukemia and irradiation contributes mainly to other malignancies, future treatment protocols should attempt to reduce the most serious consequence of therapy without compromising the survival. It is necessary to investigate the impact of additional risk factors. Careful, lifelong observation is indicated for patients with HD, with special attention given to new clinical signs and symptoms.

Interaction of the G protein beta 3 subunit T825 allele and the IRS-1 Arg972 variant in type 2 diabetes

BACKGROUND

Type 2 diabetes mellitus is a common late-onset disease with a strong genetic component. It is characterized by insulin resistance which results from alterations in insulin signal transduction. The G protein beta 3 subunit 825T allele was recently found to be associated with hypertension and obesity which makes it a sensible candidate gene for type 2 diabetes.

METHODS

In a case-control study on 320 male patients and 962 male healthy controls we investigated the association of two candidate genes with diabetes, i.e. (i) the GNB3 825T allele, associated with a G protein beta 3 subunit splice variant and enhanced intracellular signal transduction, and (ii) the insulin receptor substrate-1 (IRS-1) 972Arg variant, which encodes a protein variant associated with cellular insulin resistance.

RESULTS

The GNB3 825T allele and the IRS-1 972Arg variant were significantly associated with diabetes (odds ratios for either variant 1.4 1.8). Odds ratios were 3 4 in males carrying both alleles.

CONCLUSIONS

The results document an association of a hypertension susceptibility gene with type 2 diabetes which may partially explain the frequent coexistence of both disorders.

Early detection for colorectal cancer: new aspects in fecal occult blood screening

The authors report on promising diagnostic methods of occult intestinal bleeding and discusses the potential new strategy of early detection of colorectal carcinomas in respect to old and new diagnostic measures available. Because of the limited sensitivity and specificity of classical methods used for the demonstration of occult fecal blood, the authors recommend the introduction of new techniques and markers in screening practice. It is presumed that new discoveries in molecular biology will improve the accuracy of early colorectal cancer prevention. Their implementation into routine screening, however, will not take place in the near future. Until their realization, improved screening efficacy is expected from the use of more specific and sensitive blood tests.

The efficacy of a combination of etoposide, ifosfamide, and cisplatin in the treatment of patients with soft tissue sarcoma

BACKGROUND

Successful chemotherapy for patients with soft tissue sarcoma (STS) has been limited by a lack of active drugs. The most effective single agents are doxorubicin, dacarbazine, and, more recently, ifosfamide. Previously the most widely used combination has been CYVADIC (cyclophosphamide, vincristine, doxorubicin, and dacarbazine). In one randomized trial, ifosfamide was superior to cyclophosphamide; two nonrandomized studies also reported favorable results. Etoposide monotherapy was successful in 8%; the effectiveness of cisplatin was 5-23%. In view of these findings, the authors treated STS patients with an etoposide, cisplatin, and ifosfamide (VIP) combination.

METHODS

The eligibility criteria included histologically confirmed, inoperable, metastatic or locally recurrent STS; a World Health Organization (WHO) performance status of 0-2; a maximum age of 75 years; and progressive, measurable disease. A total of 104 patients were treated from January 1990 to June 1997. The median age of the patients was 42.4 years. The patients were treated with a combination of etoposide (100mg/m(2) for 5 days), ifosfamide (2000 mg/m(2) for 2 days), and cisplatin (20mg/m(2) for 5 days) once a month via a peripheral vein. The treatment response and the toxicity were assessed according to WHO criteria.

RESULTS

Of 104 evaluable patients, 47 responded. The overall response rate was 46% (complete response: 10%; partial response: 36%). In 43 patients the disease remained stable (41%). Remission duration was 4.6 months. Toxicity was moderate. The main adverse events were alopecia (100%), nausea and vomiting (73%), and leukopenia (29%).

CONCLUSIONS

This new combination is promising for the treatment of patients with advanced STS.

Reflections on oncology in central and eastern Europe

In the last two decades cancer mortality dramatically increased in the majority of Central and Eastern European countries. In the period from 1992 to 1995, the Hungarian male population had the highest death rate (265.0 of 100,000) due to malignancies among 46 countries worldwide. Hungarian women ranked third in cancer death rate among these countries (138.0 of 100,000). Several factors might be responsible for these figures: a) increases in environmental carcinogenic risk factors, b) unfavourable lifestyle changes in the population especially related to high tobacco consumption and dangerous drinking habits, c) lack or insufficiency detection, d) delay in diagnosis, e) inadequate therapeutic patient management, f) shortage of manpower, and g) unsatisfactory financial support. Efforts have been made to overcome these difficulties by: a) detail analysis of exogenous risk factors, b) review of lifestyle of the population, c) public education efforts for effective prevention, d) introduction of model screening programs, e) reorganization of cancer diagnosis and treatment services, and f) design and establishment of a National Cancer Control Program.

[The effect of docetaxel on malignant tumors]

In recent years numerous molecular biological discoveries enlightened the various steps of the neoplastic transformation. Based on new targets, this development made it possible to synthetize new tumour inhibitory substances. Among them taxanes capable to block depolymerization of tubulin--which is an essential molecule in cell division--play an important role. Docetaxel (Taxotere) belongs to this group and is an active drug in the treatment of breast cancer. Moreover, platinum-resistant tumours may also respond to the therapy. It is important to note that even visceral (hepatic) metastases may express chemosensitivity. Results of combination chemotherapy seem to be also promising. The antitumour effect of Taxotere in NSCLC and other malignant neoplasms in under investigation. The toxicity of Taxotere may be successfully reduced by premedication of steroids. The necessary protective measures render the Taxotere therapy safe and of being perspectivistic.

Guanidinoacetate methyltransferase deficiency: new clinical features

Guanidinoacetate methyltransferase deficiency is a recently described inborn error of creatine biosynthesis that responds to treatment with oral creatine supplementation. The previously reported clinical features consist of developmental arrest and an extrapyramidal movement disorder. We describe a patient who presented with epilepsy, global developmental delay, and a persistently low plasma creatinine level. The diagnosis was established by measuring urinary guanidinoacetate and by demonstrating absence of the creatine/phosphocreatine peak in the patient's basal ganglia in 1H magnetic resonance spectroscopy. The clinical and biochemical abnormalities responded to creatine replacement.

Ionic control of beta cell function in nesidioblastosis. A possible therapeutic role for calcium channel blockade

A preterm female infant presented with intractable hypoglycaemia within 10 minutes of delivery. Normoglycaemia could be maintained only by the intravenous infusion of glucose at a rate of 20-22 mg/kg/min. Persistent hyperinsulinaemic hypoglycaemia of infancy was diagnosed from an inappropriately raised plasma insulin concentration (33 mU/l) at the time of hypoglycaemia (blood glucose < 0.5 mmol/l). Medical treatment with glucagon, somatostatin, and diazoxide led to only a modest reduction in the intravenous glucose requirement; a 95% pancreatectomy was performed and histological 'nesidioblastosis' confirmed. In vitro electrophysiological studies using patch clamp techniques on isolated pancreatic beta cells characterised the ionic basis for insulin secretion in nesidioblastosis. The beta cells were depolarised in low ambient glucose concentrations with persistently firing action potentials; these were blocked reversibly by the calcium channel blocking agent verapamil. Persistent postoperative hyperinsulinaemic hypoglycaemia was treated with oral nifedipine. This increased median blood glucose concentrations from 3.5 to 4.8 mmol/l and increased in duration the child's tolerance to fasting from 3 to 10.5 hours. These data allude to an abnormality in the ionic control of insulin release in nesidioblastosis and offer a new logical approach to treatment which requires further evaluation.

Bartter's syndrome associated with severe retinopathy and presenting as pseudohypoaldosteronism in a newborn

Various pathophysiological explanations for Bartter's syndrome have been put forward since the condition was first described in 1962. It is currently thought that reduced reabsorption of sodium chloride in the distal tubule of the loop of Henle and the collecting ducts leads to secondary hyperkaluria and hypokalaemic metabolic alkalosis. We describe a 9 1/2-year-old boy with Bartter's syndrome and severe retinopathy whose features may be those of a previously unrecognized disorder.

[Use of taxol in the management of malignant tumors]

Taxol is a novel cytostatic agent which inhibits the depolymerisation of microtubulin. The stabilization of this important substance leads to cellular arrest and consecutively apoptosis. Accordingly, taxol is capable to influence neoplastic growth in several malignancies. At present the following standard regimen is recommended: 175 mg/m2 taxol in a 3-hour i. v. infusion following corticosteroid + diphenhydramine + cimetidine premedication. Its antitumour activity has been proved especially in advanced ovarian and breast cancer. Encouraging results have been reported in various bronchial, testicular malignancies, lymphomas and leukemias. Clinical investigations in several other malignancies are ongoing.

Interferon-alpha for induction and maintenance in multiple myeloma: results of two multicenter randomized trials and summary of other studies

BACKGROUND

Interferon (IFN) treatment trials in multiple myeloma have yielded discordant results regarding response rates, maintenance duration, and survival times. Further randomized trials and global evaluations of available data are urgently needed for clarification.

PATIENTS AND METHODS

256 patients participated in a randomized trial, 125 on IFN + VMCP, and 131 on VMCP alone. 100 patients were randomized to IFN maintenance (n = 46) or were untreated controls (n = 54). Global evaluations are based on 1,518 patients in induction and 924 in maintenance trials.

RESULTS

The induction trial demonstrated a significantly (p < 0.05) lower rate of progressive disease under IFN + VMCP (10.6%) than under VMCP (22.9%), but this benefit was limited to stage I or II patients. Median progression-free survival was longer in the IFN + VMCP arm (23.2 months vs. 15.8 months); median overall survival did not differ significantly (38.9 vs. 30.2 months). The IFN maintenance treatment trial showed significantly superior results in the IFN arm versus controls (median maintenance duration: 17.8 months and 8.2 months (p < 0.01), survival: 50.6 and 34.4 months (p < 0.05), respectively). Previous IFN treatment increased the benefits of IFN maintenance therapy. Adverse effects of IFN during induction were hematologic toxicity, fever, and infections, requiring dose reductions. Toxic effects of IFN maintenance treatment were mild. Global evaluations of randomized trials showed small but significant benefits of combined IFN induction therapy and significantly prolonged maintenance duration and survival under IFN maintenance.

CONCLUSIONS

Presently available data support the use of IFN maintenance treatment because it significantly prolongs maintenance duration and survival. IFN added to induction chemotherapy resulted in minor improvements at the expense of increased toxicity, highlighting the need for better induction regimens.

Randomized comparison of fluorouracil and leucovorin therapy versus fluorouracil, leucovorin, and cisplatin therapy in patients with advanced colorectal cancer

BACKGROUND

Because of experimental and preliminary clinical evidence that additional modulation of the biochemical pharmacology and cytotoxicity of 5-fluorouracil (5-FU) and leucovorin (LV) may be possible by combination of these agents with cisplatin (CDDP), the authors undertook a prospective randomized trial in patients with colorectal cancer.

METHODS

Between 1989 and 1992, 138 patients with advanced measurable colorectal cancer previously unexposed to chemotherapy were randomly assigned to treatment with either 5-FU (425 mg/m2) and LV (20 mg/m2) for 5 days, or the combination of 5-FU and LV in the same daily dose plus cisplatin (20 mg/m2), each drug given for 4 consecutive days. In both treatment arms, courses were administered every 28 days, if toxicity allowed, for a total of 6 months or until evidence of tumor progression.

RESULTS

The overall responses (complete and partial response) were 19% and 28% for the 5-FU/LV and the 5-FU/LV/CDDP treatment arms, respectively. Although the three-drug combination appeared superior to 5-FU/LV for time to progression or death (8.5 versus 5.2 months; P = 0.042), there was no evidence that the adoption of cisplatin will translate into a definite survival advantage. A comparative analysis of the toxicities experienced by the patients in the two treatment groups showed a comparable rate, although severe side effects (P < 0.05), specifically stomatitis (P = 0.013), were noticed more frequently in patients treated with 5-FU/LV for 5 days.

CONCLUSIONS

These results suggest that the therapeutic index of 5-FU/LV in metastatic colorectal cancer may be improved with the addition of cisplatin. However, the somewhat better therapeutic activity and lower incidence of severe gastrointestinal side effects have to be weighed against additional pharmaceutical charges and the need for a more intense antiemetic regimen.

Present research trends in cancer chemotherapy

Those research trends which are currently in the focus of interest of various research groups are summarized. The main tendency is to look for new molecular targets and to synthesize new antitumour drugs. Moreover, new research concepts emerge out of which differentiation induction, inhibition of MDR and study of apoptosis seem to be promising. Among clinical approaches megachemotherapy, neoadjuvant treatment and progress in supportive therapy are the main research directions. Last but not least, quality of life issues of the cancer patient are of particular importance.