Beyond image defined risk factors (IDRFs): a delphi survey highlighting definition of the surgical complexity index (SCI) in neuroblastoma.

PURPOSE: Preoperative evaluation of Image Defined Risk Factors (IDRFs) in neuroblastoma (NB) is crucial for determining suitability for upfront resection or tumor biopsy. IDRFs do not all carry the same weighting in predicting tumor complexity and surgical risk. In this study we aimed to assess and categorize a surgical complexity (Surgical Complexity Index, SCI) in NB resection. METHODS: A panel of 15 surgeons was involved in an electronic Delphi consensus survey to identify and score a set of shared items predictive and/or indicative of surgical complexity, including the number of preoperative IDRFs. A shared agreement included the achievement of at least 75% consensus focused on a single or two close risk categories. RESULTS: After 3 Delphi rounds, agreement was established on 25/27 items (92.6%). A severity score was established for each item ranging from 0 to 3 with an overall SCI range varying from a minimum score of zero to a maximum score of 29 points for any given patient. CONCLUSIONS: A consensus on a SCI to stratify the risks related to neuroblastoma tumor resection was established by the panel experts. This index will now be deployed to critically assign a better severity score to IDRFs involved in NB surgery.

Comparison of fetal and neonatal sonographic measurements of ventricular size in second- and third-trimester fetuses with or without ventriculomegaly: cross-sectional three-dimensional ultrasound study.

OBJECTIVES: To assess, in a population comprising normal fetuses and fetuses with primary or post-hemorrhagic ventriculomegaly, the reproducibility of measurement of neonatal ultrasound indices in the fetus and to compare the performance of various cut-offs of these parameters to diagnose ventriculomegaly and classify its severity. METHODS: This was a retrospective cross-sectional study including 182 singleton fetuses assessed by transvaginal neurosonography. The sample populations included 116 normal fetuses and 66 fetuses with primary (n = 56) or post-hemorrhagic (n = 10) ventriculomegaly. In all cases, the atrial width (AW) was measured according to standard protocols and the findings were compared with four sonographic indices developed in the neonate: the anterior horn width (AHW), the ventricular index (VI), the thalamo-occipital distance (TOD) and the fronto-occipital horn ratio (FOHR). Reproducibility of measurements was assessed using the intraclass correlation coefficient (ICC) and diagnostic accuracy of the neonatal indices was assessed against AW using areas under the receiver-operating-characteristics curves (AUC). RESULTS: The intra- and interoperator reproducibility of measurement of AW and the neonatal measurements was excellent, with ICCs > 0.99 for all measures. The association in the fetus of all four variables developed in the neonate with the degree of ventriculomegaly as defined by the AW was strong for severe ventriculomegaly (AW > 15.0 mm; all AUC > 0.95), whereas the separation of cases with mild ventriculomegaly (AW, 10.0-15.0 mm) from those with normal AW (< 10.0 mm) was less effective. CONCLUSIONS: When applied in the fetus, all four indices of ventriculomegaly developed in neonates (AHW, VI, TOD, FOHR) were associated strongly with fetal AW when the AW measurement indicated severe fetal ventriculomegaly. However, for mild ventriculomegaly, the association was weaker, probably due to the fact that, in the fetus, mild ventriculomegaly is not caused by obstruction of the ventricular system. Considering the similar performance of the four neonatal variables and the technical issues involved in determination of TOD and FOHR in the fetus, use of VI and AHW is preferred. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Frontal lobe growth is impaired in fetuses with congenital heart disease.

OBJECTIVES: The primary objective of this study was to assess whether fetuses with congenital heart disease (CHD) have smaller frontal brain areas compared with normal controls. The secondary objective was to evaluate whether there are any differences in frontal brain area between cases with different types of CHD, grouped according to their impact on hemodynamics. METHODS: This was a retrospective cross-sectional study, including 421 normal fetuses and 101 fetuses with isolated CHD evaluated between 20 and 39 gestational weeks at our fetal medicine and surgery unit in the period January 2016-December 2019. The study group was subdivided, according to the CHD hemodynamics, as follows: (1) hypoplastic left heart syndrome and other forms of functionally univentricular heart defect; (2) transposition of the great arteries; (3) conotruncal defects and other CHDs with large shunts; (4) right ventricular outflow tract obstruction, without a hypoplastic right ventricle; (5) left outflow tract obstruction; (6) others. The transventricular axial view of the fetal head was used as the reference view, on which the frontal lobe anteroposterior diameter (FAPD) and the occipitofrontal diameter (OFD) were measured, assuming the former to be representative of the area of the frontal lobes. The FAPD/OFD ratio was then calculated as FAPD/OFD × 100. These two variables (FAPD and FAPD/OFD ratio) were then evaluated and compared between the study and control groups. Adjustment for gestational age, both via multiple linear regression and by using a-posteriori matching based on the propensity score, was employed. RESULTS: In normal fetuses, FAPD showed a linear positive correlation with gestational age. In fetuses with CHD, the FAPD was shorter than in normal fetuses from the 20th gestational week onwards, with the difference increasing after 30 gestational weeks. FAPD/OFD ratio was significantly smaller in fetuses with CHD than in normal fetuses (P < 0.0001) at all gestational ages, with no apparent differences among the various CHD categories, all of which had smaller FAPD/OFD ratio compared with controls. CONCLUSIONS: Fetuses with CHD have a shorter FAPD and a smaller FAPD/OFD ratio compared with normal fetuses. This impaired growth of the frontal area of the brain seems to occur in all types of CHD, regardless of their impact on hemodynamics. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Hindbrain morphometry and choroid plexus position in differential diagnosis of posterior fossa cystic malformations.

OBJECTIVE: To assess the differential diagnostic significance of a series of quantitative and qualitative variables of the cerebellar vermis in fetuses with posterior fossa cystic malformation, including Dandy-Walker malformation (DWM), vermian hypoplasia (VH) and Blake's pouch cyst (BPC). METHODS: This was a retrospective study of confirmed cases of DWM, VH and BPC, diagnosed at the Fetal Medicine and Surgery Unit of the Federico II University between January 2005 and June 2013 or the Fetal Medicine and Surgery Unit of G. Gaslini Hospital between July 2013 and September 2017. All included cases had good-quality three-dimensional (3D) volume datasets of the posterior fossa, acquired by transvaginal ultrasound through the posterior fontanelle. The midsagittal view of the posterior fossa was the reference view for the study. We assessed brainstem-tentorium angle and brainstem-vermis angle (BVA), as well as craniocaudal (CCVD) and anteroposterior (APVD) vermian diameters and vermian area (VA), which were normalized by biparietal diameter (BPD) to take into account gestational age (CCVD/BPD × 100, APVD/BPD × 100 and VA/BPD × 100, respectively). Finally, the position of the fourth ventricular choroid plexus (4VCP) was defined as normal ('up') or abnormal ('down'), relative to the roof/cyst inlet of the fourth ventricle. RESULTS: We analyzed 67 fetuses with posterior fossa malformations (24 cases of DWM, 13 of VH and 30 of BPC). The mean gestational age at diagnosis was 23.6 weeks. Regardless of gestational age, the BVA differed significantly between the three groups, and the VA/BPD was able to differentiate between VH and BPC. In differentiating between VH and BPC, the greatest areas under the receiver-operating characteristics curve were those for VA/BPD ratio. The 4VCP position was down in all cases of DWM and VH, while it was up in all cases of BPC. CONCLUSIONS: Our data support the concept that VA/BPD ratio and 4VCP position may be used to differentiate between DWM, VH and BPC in the fetus. In our series, the position of the 4VCP had the highest accuracy, but a larger number of VH cases should be evaluated to confirm that an up position of the 4VCP indicates BPC while a down position indicates DWM or VH. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Childhood infectious diseases and risk of multiple myeloma: an analysis of the Italian multicentre case-control study.

Common childhood infectious diseases have been associated with a reduced risk of following haematopoietic malignancies, but investigations on multiple myeloma (MM) are scarce. Information about 213 MM cases and 1128 healthy controls were obtained from a multicentre population-based Italian case-control study. The association between chickenpox, measles, mumps, pertussis and rubella and the MM risk was estimated by unconditional logistic regression, adjusting for age, gender and residence area. No association was found between MM risk and any considered infectious disease. The number of infections was slightly inversely associated with the risk of MM, but statistical significance was not reached (OR 0.87, 95% CI 0.55-1.4 for 1-2 diseases vs. none and OR 0.68, 95% CI 0.41-1.1 for 3-5 diseases, respectively, P = 0.131). We did not find a clear evidence that common infections during childhood are associated with the subsequent risk of developing MM.

Influence of segmental chromosome abnormalities on survival in children over the age of 12 months with unresectable localised peripheral neuroblastic tumours without MYCN amplification.

BACKGROUND: The prognostic impact of segmental chromosome alterations (SCAs) in children older than 1 year, diagnosed with localised unresectable neuroblastoma (NB) without MYCN amplification enrolled in the European Unresectable Neuroblastoma (EUNB) protocol is still to be clarified, while, for other group of patients, the presence of SCAs is associated with poor prognosis. METHODS: To understand the role of SCAs we performed multilocus/pangenomic analysis of 98 tumour samples from patients enrolled in the EUNB protocol. RESULTS: Age at diagnosis was categorised into two groups using 18 months as the age cutoff. Significant difference in the presence of SCAs was seen in tumours of patients between 12 and 18 months and over 18 months of age at diagnosis, respectively (P=0.04). A significant correlation (P=0.03) was observed between number of SCAs per tumour and age. Event-free (EFS) and overall survival (OS) were calculated in both age groups, according to both the presence and number of SCAs. In older patients, a poorer survival was associated with the presence of SCAs (EFS=46% vs 75%, P=0.023; OS=66.8% vs 100%, P=0.003). Moreover, OS of older patients inversely correlated with number of SCAs (P=0.002). Finally, SCAs provided additional prognostic information beyond histoprognosis, as their presence was associated with poorer OS in patients over 18 months with unfavourable International Neuroblastoma Pathology Classification (INPC) histopathology (P=0.018). CONCLUSIONS: The presence of SCAs is a negative prognostic marker that impairs outcome of patients over the age of 18 months with localised unresectable NB without MYCN amplification, especially when more than one SCA is present. Moreover, in older patients with unfavourable INPC tumour histoprognosis, the presence of SCAs significantly affects OS.

Impact of a delayed presentation to the emergency department for acute renal colic on biochemical and clinical outcomes.

INTRODUCTION AND OBJECTIVE: To verify the impact of delay on biochemical and clinical outcomes for patients presenting to the emergency department (ED) with acute renal colic. MATERIALS AND METHODS: Data were retrospectively collected from three institutions of two European countries between 01 January and 30 April 2020. Patients who presented to the ED with unilateral or bilateral renal colic caused by urolithiasis confirmed by imaging tests during the study period were included. A presentation after 24 h since the onset of symptoms was considered a delay. Patients presenting before 24 h from the symptom onset were included in Group A, while the patients presenting after 24 h in Group B. Clinical and biochemical parameters and management were compared. RESULTS: A total of 397 patients who presented to ED with confirmed urolithiasis were analyzed (Group A, n = 199; Group B, n = 198. The median (IQR) delay in presentation was 2 days (1,5-4). At presentation, no statistically significant differences were found amongst the two groups of patients regarding presenting symptoms such as fever and flank pain, and the median serum levels of creatinine, C reactive protein and white blood cells. No differences were found in terms of conservative or operative management. CONCLUSION: Delay in consultation >24 h is not associated with worsening biochemical parameters and clinical outcomes. Most patients with acute loin pain do not necessarily need urgent attendance to the ED and may be managed in the outpatients.

Congenital central hypoventilation syndrome: genotype-phenotype correlation in parents of affected children carrying a PHOX2B expansion mutation.

Congenital Central Hypoventilation Syndrome (CCHS) is a rare genetic disorder. Although most CCHS associated PHOX2B mutations occur de novo, about 10% of the cases are inherited from apparently asymptomatic parents, thus confirming variable expressivity and incomplete penetrance of PHOX2B mutations. Three asymptomatic parents of children affected with CCHS, and found to carry the same PHOX2B expansion mutations as their siblings, were studied by overnight polysomnography and somatic mosaicism analysis. In one case, significant sleep breathing control anomalies were detected, while the other two resulted in normal. In tissue-specific allele studies, mosaicism with a comparatively low mutant allele proportion was showed in the two unaffected adult carriers. Accurate polysomnography and assessment of the degree of somatic mosaicism should be conducted in asymptomatic carriers of PHOX2B mutations, as they may unmask subclinical but significant anomalies.

Assessment of trends and clinical presentation in the emergency department of patients with renal colic during the COVID-19 pandemic era. / Evaluación de las tendencias y presentación clínica de pacientes con cólico nefrítico que acuden al servicio de urgencias durante la era pandémica del COVID-19.

INTRODUCTION: We hypothesized that the recent COVID-19 pandemic may lead to a delay in renal colic patients presenting to the Emergency Department due to the fear of getting infected. This delay may lead to a more severe clinical condition at presentation with possible complications for the patients. MATERIAL AND METHODS: Retrospective review of data collected from three institutions from Spain and Italy. Patients who presented to Emergency Department with unilateral or bilateral renal colic caused by imaging confirmed urolithiasis during the 45 days before and after each national lockdown were included. Data collected included patients' demographics, biochemical urine and blood tests, radiological tests, signs, symptoms and the therapeutic management. Analysis was performed between two groups, Group A: patients presenting prior to the national lockdown date; and Group B: patients presenting after the national lockdown date. RESULTS: A total of 397 patients presented to Emergency Department with radiology confirmed urolithiasis and were included in the study. The number of patients presenting to Emergency Department with renal/ureteric colic was 285 (71.8%) patients in Group A and 112 (28.2%) patients in Group B (p<0.001). The number of patients reporting a delay in presentation was 135 (47.4%) in Group A and 63 (56.3%) in Group B (p=0.11). At presentation, there were no statistical differences between Group A and Group B regarding the serum creatinine level, C reactive protein, white blood cell count, fever, oliguria, flank pain and hydronephrosis. In addition, no significant differences were observed with the length of stay, Urology department admission requirement and type of therapy. CONCLUSION: Data from our study showed a significant reduction in presentations to Emergency Department for renal colic after the lockdown in Spain and Italy. However, we did not find any significant difference with the length of stay, Urology department admission requirement and type of therapy.

Internalization via Antennapedia protein transduction domain of an scFv antibody toward c-Myc protein.

We constructed a single-chain variable fragment miniantibody (G11-scFv) directed toward the transactivation domain of c-Myc, which is fused with the internalization domain Int of Antennapedia at its carboxyl terminus (a cargo-carrier construct). In ELISA experiments, an EC(50) for binding saturation was achieved at concentrations of G11-scFv-Int(-) of approximately 10(-8) M. Internalization of a fluoresceinated Fl-G11-scFv-Int(+) construct was observed in intact human cultured cells with confocal microscopy. After 5 h of incubation in medium containing 1 microM Fl-G11-scFv-Int(+) or Fl-G11-scFv-Int(-), fluorescence intensity was determined in individual cells, both for cytoplasmic and nuclear compartments: concentration levels of Fl-G11-scFv-Int(+), relative to the extracellular culture medium concentration, were 4-5 times higher in the cytoplasm, 7-8 times higher in the nucleus, and 10 times higher in the nucleoli. In the same experimental conditions, the Fl-G11-scFv-Int(-) construct was 3-4 times more concentrated outside of the cells than inside. Cell membranes kept their integrity after 5 h of incubation. The antiproliferative activity of our miniantibody was studied on HCT116 cells. Incubation with 4 microM G11-scFv-Int(+) for 4 days induced very significant statistical and biological growth inhibition, whereas Int alone was completely inactive. Miniantibodies capable of penetrating cell membranes dramatically broaden the potential for innovative therapeutic agents and attack of new targets.

Chemotaxis of 3T3 and SV3T3 cells to fibronectin is mediated through the cell-attachment site in fibronectin and a fibronectin cell surface receptor.

Fibronectin (FN) is a multidomain extracellular matrix protein that induces attachment and chemotactic migration of fibroblastic cells. In this study we analyzed the molecular determinants involved in the FN-induced chemotactic migration of normal and SV40-transformed 3T3 cells. Two different monoclonal antibodies to the cell-binding site of FN blocked chemotaxis to a 140-kD FN fragment (Ca 140) containing the cell-binding domain. A monoclonal antibody to a determinant distant from the cell-binding site did not affect chemotaxis. A synthetic tetrapeptide, RGDS, which represents the major cell-attachment sequence, was able to compete with FN and the Ca 140 fragment in chemotaxis assays, but this peptide itself had no significant chemotactic activity. A larger peptide encompassing this sequence, GRGDSP, was chemotactic, while the peptide GRGESP, where a glutamic acid residue was substituted for aspartic acid, was inactive. Chemotactic migration could be prevented in a dose-dependent manner by a rabbit polyclonal antiserum to a 140-kD cell surface FN receptor. This antibody was more effective on normal than on transformed 3T3 cells. Neither the anti-FN receptor antiserum nor a monoclonal antibody to the cell-binding site of FN blocked migration induced by another potent chemoattractant, platelet-derived growth factor. These data indicate that FN-induced chemotaxis of 3T3 and SV3T3 cells is mediated via the RGDS cell-attachment site of FN and the 140-kD cell surface FN receptor. The interaction is specific and can be altered by transformation.

Long-term follow-up of neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome.

OBJECTIVE: The aim of this study is to describe the long-term neurological, neuropsychological and neuroradiological sequelae and to determine prognostic factors for neurological outcome in children with neuroblastoma-associated opsoclonus-myoclonus-ataxia (OMA) syndrome. METHODS: Data on medical history were collected for the study patients. Examinations with grading of neurological signs, neuropsychological tests and brain magnetic resonance imaging with spectroscopy were performed during a follow-up clinic. RESULTS: Fourteen subjects entered the study. All had localized neuroblastoma and they were evaluated after a median of 7.8 years. Patients with a chronic/multiphasic neurological course received steroids combined with intravenous immunoglobulins in the majority of cases. 71% presented neurological sequelae and 62% had a full-scale IQ below the normal range. All patients showed at least some deficit in the neuropsychological functions assessed (language, visual-motor integration, memory, attention and motor ability). Long-term deficits were more frequently detected in patients with an interval of more than 2 months between OMA onset and its diagnosis, even if in most comparisons statistical significance was not reached. Cerebellar atrophy, observed in 36% of patients, was not associated with the neurological outcome. CONCLUSIONS: Persisting disability is present in most children with neuroblastoma-associated OMA. However, our results support the role of an early diagnosis of OMA in reducing sequelae and encourage the use of new immunosuppressive therapies.

PHOX2A and PHOX2B genes are highly co-expressed in human neuroblastoma.

The detection of PHOX2B mutations in a small proportion of patients affected with either familial or sporadic neuroblastoma (NB), has arisen interest on the possible pathogenic role of this gene in the disease determination. In this light, we have carried out a quantitative expression analysis of PHOX2B and its paralogue PHOX2A on a panel of NB cell lines and NB tumour samples to identify a possible differential expression between NB cells and their normal counterpart (adrenal medulla cells). Our results revealed that both PHOX2A and PHOX2B are over-expressed in tumour samples and NB cell lines. Particularly, the expression levels of the two genes in NB cell lines show a highly significant correlation, suggesting their possible synergistic role or a coordinated expression regulation. Furthermore, PHOX2 gene over-expression in NB tumours and cell lines suggests these genes may be widely involved in NB development through either a direct mechanism of up-regulation or a failure in maintaining proper transcript levels after embryonic development.

Inhibition of a protein-protein interaction between INI1 and c-Myc by small peptidomimetic molecules inspired by Helix-1 of c-Myc: identification of a new target of potential antineoplastic interest.

c-Myc is a transcription modulator proto-oncogene. When overexpressed, it becomes an important contributor to the multi-hit process of malignant transformation. In two earlier papers in this journal (see refs. 19 , 20) we reported that retro-inverso peptidomimetic molecules inspired by the Helix-1 of c-Myc motif could be sequence-specific antiproliferative agents active in the low micromolar range. We also found that our peptides were not opening the four-alpha-helix Myc:Max bundle. Their antiproliferative activity in cancer cell lines needs the presence of side chains projecting outside of the bundle in the corresponding native H1 motif. This observation suggested interference with an external partner. In this study we investigated the INI1:Myc interaction. INI1 is a subunit of the SWI/SNF complex (component of the enhanceosome surrounding Myc:Max heterodimer). The INI1:Myc interaction was confirmed via pull down, ELISA, and fluorescence anisotropy assays. According to the length of INI1 fragments used, we calculated Kds ranging between 1.3x10(-6) and 4.8x10(-7) M. The three different techniques applied showed that the INI1:Myc interaction was also the target of our retro-inverso peptidomimetic molecules, which seem to bind specifically at INI1. A Myc binding, 21aa INI1 fragment (minimum interacting sequence), could inspire the synthesis of a new class of more selective c-Myc inhibitors.

Iron overload detection in rats by means of a susceptometer operating at room temperature.

Biosusceptometry is a non-invasive procedure for determination of iron overload in a human body; it is essentially an assessment of the diamagnetic (water) and paramagnetic (iron) properties of tissues. We measured in vivo iron overload in the liver region of 12 rats by a room temperature susceptometer. The rats had been injected with sub-toxic doses of iron dextran. A quantitative relationship has been observed between the measurements and the number of treatments. The assessment of iron overload requires evaluating the magnetic signal corresponding to the same rat ideally without the overload. This background value was extrapolated on the basis of the signal measured in control rats versus body weight (R(2) = 0.73). The mean iron overload values for the treated rats, obtained after each iron injection, were significantly different from the means of the corresponding control rats (p < 0.01). The in vivo measurements have been complemented by chemical analysis on excised livers and other organs (R(2) = 0.89). The magnetic moment of iron atoms in liver tissues was measured to be 3.6 Bohr magneton. Evaluation of the background signal is the limit to the measure; the error corresponds to about 30 mg (1 SD) of iron while the instrument sensitivity is more than a factor of 10 better.

Sequence specific peptidomimetic molecules inhibitors of a protein-protein interaction at the helix 1 level of c-Myc.

Our work is focused in the broad area of strategies and efforts to inhibit protein-protein interactions. The possible strategies in this field are definitely much more varied than in the case of ATP-pocket inhibitors. In our previous work (10), we reported that a retro-inverso (RI) form of Helix1 (H1) of c-Myc, linked to an RI-internalization sequence arising from the third alpha-helix of Antennapedia (Int) was endowed with an antiproliferative and proapoptotic activity toward the cancer cell lines MCF-7 and HCT-116. The activity apparently was dependent upon the presence of the Myc motif. In this work, by ala-scan mapping of the H1 portion of our molecules with D-aa, we found two amino acids necessary for antiproliferative activity: D-Lys in 4 and D-Arg in 5 (numbers refer to L-forms). In the natural hetero-dimer, these two side chains project to the outside of the four alpha-helix bundle. Moreover, we were able to obtain three peptides more active than the original lead. They strongly reduced cell proliferation and survival (RI-Int-VV-H1-E2A,S6A,F8A; RI-Int-VV-H1-S6A,F8A,R11A; RI-Int-VV-H1-S6A,F8A,Q13A): after 8 days at 10 muM total cell number was approximately 1% of the number of cells initially seeded. In these more potent molecules, the ablated side chains project to the inside in the corresponding natural four alpha-helix bundle. In the present work, we also investigated the behavior of our molecules at the biochemical level. Using both a circular dichroism (CD) and a fluorescence anisotropy approach, we noted that side chains projecting at the interior of the four alpha-helix bundle are needed for inducing the partial unfolding of Myc-H2, without an opening of the leucine zipper. Side chains projecting at the outside are not required for this biochemical effect. However, antiproliferative activity had the opposite requirements: side chains projecting at the outside of the bundle were essential, and, on the contrary, ablation of one side chain at a time projecting at the inside increased rather than decreased biological activity. We conclude that our active molecules probably interfere at the level of a protein-protein interaction between Myc-Max and a third protein of the transcription complex. Finally, CD and nuclear magnetic resonance (NMR) data, plus dynamic simulations, suggest a prevalent random coil conformation of the H1 portion of our molecules, at least in diluted solutions. The introduction of a kink (substitution with proline in positions 5 or 7) led to an important reduction of biological activity. We have also synthesized a longer peptido-mimetic molecule (RI-Int-H1-S6A,F8A-loop-H2) with the intent of obtaining a wider zone of interaction and a stronger interference at the level of the higher-order structure (enhanceosome). RI-Int-H1-S6A,F8A-loop-H2 was less active rather than more active in respect to RI-Int-VV-H1-S6A,F8A, apparently because it has a clear bent to form a beta-sheet (CD and NMR data).

DNA-damaging activity in vivo and bacterial mutagenicity of sixteen hydrazine derivatives as related quantitatively to their carcinogenicity.

Sixteen hydrazine derivatives (hydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, phenylhydrazine, procarbazine, isoniazid, isocarboxazid, nialamide, 2,4-dinitrophenylhydrazine, phenelzine, hydralazine, dihydralazine, carbamylhydrazine, mebanazine, iproniazid, and 1-carbamyl-2-phenylhydrazine) were tested for DNA-damaging activity by the alkaline elution technique and for mutagenic activity in the Salmonella-microsome (Ames) test. The first nine compounds listed (56%) were found to induce a significant DNA fragmentation in the liver and/or in the lung of i.p.-treated male Swiss mice. The DNA-damaging potency varied over an approximately 30-fold range. Thirteen of the first 14 compounds listed (81% of the total), isocarboxazid being inactive, were positive in the Ames test, with a broad range of activity towards the five bacterial strains of Salmonella typhimurium used (TA1535, TA100, TA1537. TA1538, and TA98) and of metabolic behavior in the presence of S-9 mix containing rat liver, mouse liver, or mouse lung postmitochondrial preparations from Aroclor-treated animals. The mutagenic potency varied over an almost 7000-fold range. For 11 of the 16 hydrazine derivatives tested, homogeneous carcinogenicity data (induction of pulmonary tumors in mice chronically treated p.o.) were available from literature. Elaboration of these data showed that carcinogenic potency varied over an approximately 1900-fold range. The five most potent carcinogens were all positive in the DNA damage test. Their carcinogenic potency varied over a 130-fold rage and their DNA-damaging potency varied over a 22-fold range. DNA-damaging potency seemed to vary on a more compressed scale, but regression analysis indicated the existence of a strong positive correlation between in vivo DNA-damaging and carcinogenic potencies, while a lack of correlation was found between mutagenic and carcinogenic potencies. There was no correlation between DNA-damaging and mutagenic potencies.

Damage and repair of DNA in cultured mammalian cells with N-diazoacetylglycine amide.

N-Diazoacetylglycine amide, a diazochetoalkane, has been studied in vitro for DNA damage and repair in cells of a cloned subline from a BALB/c mouse. To our present knowledge, none of these compounds have been investigated for such activities. At nontoxic levels, a prolonged dose-dependent unscheduled DNA synthesis was observed by autoradiography. DNA damage was studied by sedimentation through alkaline sucrose gradients after the cells were lysed on the gradients. Treatment of the cells for 1 hr with nontoxic doses of N-diazoacetylglycine amide resulted in slower sedimentation of DNA. The number of single-strand breaks appeared rather linearly dose dependent for a large range of concentrations. Breaks were at their maximum after 1 hr of treatment, and no further increase in the number of breaks was seen. Some repair of the breaks probably occurs, but repair was sluggish even 68 hr after treatment. A significant part of the breaks was observed after incubation at 4 degrees in an ethylenediaminetetraacetate hypotonic solution. This seems to indicate that the compound does not require metabolic activation. Nontoxic doses of N-diazoacetylglycine amide and other similar derivatives exert mutagenic and carcinogenic activities. The presence of DNA damage and the difficulty in its repair at such doses could be related to both of these biological properties.

Physicochemical alterations in the conformation of rat liver chromatin induced by carcinogens in vivo.

Administration of methylating carcinogens such as methyl methanesulfonate (120 mg/kg), dimethylnitrosamine (5 mg/kg), or methylnitrosourea (80 mg/kg) to rats resulted in an increased ellipticity in circular dichroism spectra and in an enhanced ability to bind ethidium bromide in the liver chromatin. Although shearing of the chromatin preparations increased both the ellipticity and number of binding sites for ethidium bromide, the carcinogen-induced effects were noticeable whether or not chromatin was sheared. Although the doses of the 3 carcinogens used in these studies are equivalent in their ability to induce strand breaks in liver DNA at 4 hr, their effects on the induction of conformational changes in liver chromatin are different. For example, methyl methanesulfonate induced the minimum conformational changes in liver chromatin at 4 hr, whereas methylnitrosourea induced the maximum changes at 4 hr. Methyl methanesulfonate and dimethylnitrosamine, on the other hand, induced maximum changes at 3 days. The conformational changes induced by methyl methanesulfonate and methylnitrosourea, and not by dimethylnitrosamine, tend to be repaired by 14 days.