Efficacy and Safety of Ensovibep for Adults Hospitalized With COVID-19 : A Randomized Controlled Trial

BACKGROUND

Ensovibep (MP0420) is a designed ankyrin repeat protein, a novel class of engineered proteins, under investigation as a treatment of SARS-CoV-2 infection.

OBJECTIVE

To investigate if ensovibep, in addition to remdesivir and other standard care, improves clinical outcomes among patients hospitalized with COVID-19 compared with standard care alone.

DESIGN

Double-blind, randomized, placebo-controlled, clinical trial. (ClinicalTrials.gov: NCT04501978).

SETTING

Multinational, multicenter trial.

PARTICIPANTS

Adults hospitalized with COVID-19.

INTERVENTION

Intravenous ensovibep, 600 mg, or placebo.

MEASUREMENTS

Ensovibep was assessed for early futility on the basis of pulmonary ordinal scores at day 5. The primary outcome was time to sustained recovery through day 90, defined as 14 consecutive days at home or place of usual residence after hospital discharge. A composite safety outcome that included death, serious adverse events, end-organ disease, and serious infections was assessed through day 90.

RESULTS

An independent data and safety monitoring board recommended that enrollment be halted for early futility after 485 patients were randomly assigned and received an infusion of ensovibep (n = 247) or placebo (n = 238). The odds ratio (OR) for a more favorable pulmonary outcome in the ensovibep (vs. placebo) group at day 5 was 0.93 (95% CI, 0.67 to 1.30; P = 0.68; OR > 1 would favor ensovibep). The 90-day cumulative incidence of sustained recovery was 82% for ensovibep and 80% for placebo (subhazard ratio [sHR], 1.06 [CI, 0.88 to 1.28]; sHR > 1 would favor ensovibep). The primary composite safety outcome at day 90 occurred in 78 ensovibep participants (32%) and 70 placebo participants (29%) (HR, 1.07 [CI, 0.77 to 1.47]; HR < 1 would favor ensovibep).

LIMITATION

The trial was prematurely stopped because of futility, limiting power for the primary outcome.

CONCLUSION

Compared with placebo, ensovibep did not improve clinical outcomes for hospitalized participants with COVID-19 receiving standard care, including remdesivir; no safety concerns were identified.

PRIMARY FUNDING SOURCE

National Institutes of Health.

The ESC ACCA EAPCI EORP acute coronary syndrome ST-elevation myocardial infarction registry

Aims 

The Acute Cardiac Care Association (ACCA)–European Association of Percutaneous Coronary Intervention (EAPCI) Registry on ST-elevation myocardial infarction (STEMI) of the EurObservational programme (EORP) of the European Society of Cardiology (ESC) registry aimed to determine the current state of the use of reperfusion therapy in ESC member and ESC affiliated countries and the adherence to ESC STEMI guidelines in patients with STEMI.

Methods and results 

Between 1 January 2015 and 31 March 2018, a total of 11 462 patients admitted with an initial diagnosis of STEMI according to the 2012 ESC STEMI guidelines were enrolled. Individual patient data were collected across 196 centres and 29 countries. Among the centres, there were 136 percutaneous coronary intervention centres and 91 with cardiac surgery on-site. The majority of centres (129/196) were part of a STEMI network. The main objective of this study was to describe the demographic, clinical, and angiographic characteristics of patients with STEMI. Other objectives include to assess management patterns and in particular the current use of reperfusion therapies and to evaluate how recommendations of most recent STEMI European guidelines regarding reperfusion therapies and adjunctive pharmacological and non-pharmacological treatments are adopted in clinical practice and how their application can impact on patients’ outcomes. Patients will be followed for 1 year after admission.

Conclusion 

The ESC ACCA-EAPCI EORP ACS STEMI registry is an international registry of care and outcomes of patients hospitalized with STEMI. It will provide insights into the contemporary patient profile, management patterns, and 1-year outcome of patients with STEMI.

Application of a One-Dimensional Computational Model for the Prediction of Deposition from a Dry Powder Inhaler

BACKGROUND

Accurate prediction of the regional deposition of inhaled dry powders as a function of powder properties and breathing pattern is a long-term research goal for pulmonary drug delivery. In the present work, deposition along the respiratory tract of dry powders of Fluticasone propionate and Salmeterol is predicted.

METHODS

A one-dimensional particle transport and deposition model is used, whose novelty is in the treatment of the alveolar space of each airway generation as an efficient mixing chamber. This assumption has been supported by simulations and measurements during the last 20 years. The model is applied to two popular pulmonary tree geometries, to investigate the effect of particle size on localized deposition and to estimate the uncertainty due to variations in airway size.

RESULTS AND CONCLUSIONS

Application of the model for the specific particle size distribution measured by a cascade impactor in the marketed product ELPENhaler, predicts the whole lung deposition (WLD), as well as the split between pulmonary (PU) and tracheobronchial (TB) deposition. Introduction in the model of modified particle size distributions with increased fractions of fine particles, indicates that the fine-particle dose is a satisfactory predictor of WLD but not of the PU/TB ratio.

Public knowledge, beliefs and practices in Greece about cancer etiology and prevention

This questionnaire survey of the parents of elementary schoolchildren in Greece assessed their self-reported knowledge, attitudes and practices towards smoking, diet and exposure to X-radiation. A random sample of 403 household units (379 fathers and 391 mothers) was selected from urban areas of Thessaloniki. Half of the parents who smoked (50.1%) did not ask for permission to smoke from other people and 66.0% regularly smoked in front of their children. On the other hand, 82.6% of smokers recognized the existence of a health risk to children from passive smoking. Parents overestimated the role of nuclear tests and accidents as factors in carcinogenesis. Two-thirds of parents did not know the beneficial role of the Mediterranean diet to health, and dietary intake analysis showed some departure from the traditional Mediterranean diet. A reconsideration of the policy regarding health education programmes concerning cancer prevention in Greece is needed.

Parecoxib sodium in the treatment of postoperative pain after Lichtenstein tension-free mesh inguinal hernia repair

PURPOSE

This prospective, randomized, double-blind study compared the analgesic efficacy and safety of parecoxib sodium versus lornoxicam and diclofenac, after Lichtenstein tension-free mesh inguinal hernia repair.

METHODS

Patients were randomly assigned to receive parecoxib 80 mg daily i.v. (Group A), lornoxicam 16 mg daily i.v. (Group B) or diclofenac 150 mg daily i.m. (Group C). Rescue analgesia in all groups consisted of pethidine 25 mg i.m. Pain was measured with an analogue scale (pain intensity score).

RESULTS

Patients treated with parecoxib 80 mg reported significantly lower summed pain intensity scores compared with lornoxicam and diclofenac-treated patients. Duration of analgesia was also significantly longer with parecoxib than with lornoxicam and diclofenac. Adverse events were significantly less common in the parecoxib and lornoxicam group, compared with diclofenac group.

CONCLUSIONS

Multiple-day administration of parecoxib 40 mg twice daily is more effective than equivalent doses of lornoxicam and diclofenac, and generally better tolerated than diclofenac after Lichtenstein tension-free mesh inguinal hernia repair.

Effects of ageing on the biomechanical properties of rat articular cartilage

Previous studies have demonstrated that male Sprague Dawley (SD) rats experience age-related bone loss with the same characteristics as that in ageing men. As articular cartilage, like bone, is a critical component of the health and function of the musculoskeletal system, the authors hypothesized that articular cartilage in the untreated male SD rats could be a suitable model for studying the age-related deterioration of articular cartilage in men. To test this hypothesis, male SD rats were killed at between 6 and 27 months. The right femur of each rat was removed. The effects of ageing on the structural integrity of the distal femoral articular cartilage were studied by biomechanical testing with a creep indentation apparatus. The aggregate modulus, Poisson's ratio, permeability, thickness, and percentage recovery of articular cartilage were determined using finite element/non-linear optimization modelling. No significant differences were observed in these biomechanical properties of the distal femoral articular cartilage as a function of age. Therefore, untreated male SD rats appear to be unsuitable for studying the age-related changes of articular cartilage as they occur in men. However, and more intriguingly, it is also possible that ageing does not affect the biomechanical properties of articular cartilage in the absence of cartilage pathology.

Knot security in simple sliding knots and its relationship to rotator cuff repair: how secure must the knot be?

We sought to determine which simple sliding knot configurations would have adequate strength for rotator cuff repair. Four knot configurations were tied with both No. 1 polydioxanone suture and No. 2 Ethibond suture (Ethicon, Somerville, NJ) using 3 different tying techniques: hand-tie, standard knot pusher, and cannulated double-diameter knot pusher. The knots were then tested to failure on a materials testing system. The weakest standard knot configuration was S=S=S=S. The other 3 knot configurations (S//S//S//S, SxSxSxS, and S//xS//xS//xS) generally failed in the 35 to 50 N range. Ultimate strength in this range can be shown to be adequate to withstand, without suture failure, a maximal contraction of a repaired rotator cuff tear within the rotator crescent, assuming certain conditions are met (suture anchors placed 1 cm apart, 2 sutures per anchor). More complex knots are not necessary for adequate knot security. However, the same configuration with only 1 suture per anchor will not be strong enough because the suture will fail under maximum physiological load. This study shows that we can predict the adequacy of a given knot configuration under maximum physiological loading conditions.

Electric field-mediated DNA encapsulation into large liposomes

Large, ethidium bromide-loaded liposomes electrically pulsed in the presence of externally added DNA display the bright fluorescence of DNA-ethidium bromide complexes. Sonication of these liposomes increases the fluorescence of trapped DNA-ethidium bromide complexes by no more than about 40%. These results are thus in agreement with a mechanism involving electropores for DNA uptake but do not support an alternative mechanism, invoking invagination and pinching-off of the lipid bilayer, through which internalized DNA is shielded from the liposome contents.

Cytoindentation for obtaining cell biomechanical properties

A novel biomechanical testing methodology was developed to obtain the intrinsic material properties of an individual cell attached to a rigid substrate. With use of a newly designed cell-indentation apparatus (cytoindenter), displacement-controlled indentation tests were conducted on the surface of individual MG63 cells and the corresponding surface reaction force of each cell was measured. The cells were modeled with a linear elasticity solution of half-space indentation and the linear biphasic theory on the assumption that the viscoelastic behavior of each cell was due to the interaction between the solid cytoskeletal matrix and the cytoplasmic fluid. To obtain the intrinsic material properties (aggregate modulus, Poisson's ratio, and permeability), the data for experimental surface reaction force and deformation were curve-fitted with use of solutions predicted with a linear biphasic finite element code in conjunction with optimization routines. The MG63 osteoblast-like cells had a compressive aggregate modulus of 2.05+/-0.89 kPa, which is two to three orders of magnitude smaller than that of articular cartilage, six to seven orders smaller than that of compact bone, and quite similar to that of leukocytes. The permeability was 1.18+/-0.65 (x10(-10)) m4/N-s, which is four to six orders of magnitude larger than that of cartilage. The Poisson's ratio was 0.37+/-0.03. The intrinsic material properties of the individual cell in this study can be useful in precisely quantifying mechanical stimuli acting on cells. This information is also needed for theories attempting to establish mechanotransductional relationships.

Loop security as a determinant of tissue fixation security

Secure arthroscopic repair of rotator cuff tears and Bankart lesions requires tight knots (knot security). Equally important, but usually overlooked, is the tightness of the suture loop (loop security). This study compared loop security in knots tied with No. 1 PDS suture using three different methods: (1) hand-tied, (2) single-hole standard knot pusher, and (3) cannulated double-diameter knot pusher. The results of this study show that the double-diameter knot pusher maintained tight suture loops that were equivalent in circumference to hand-tied loops and were significantly tighter than suture loops tied with a standard single-hole knot pusher. This study highlights the fact that loop security is equally important to knot security in tissue fixation.

The effects of diabetes mellitus on the material properties of human metatarsal bones

While some investigations have focused on the effect of diabetes on the material properties of connective tissue in both the human and animal model, no study to date has investigated the effects of the disease process on human metatarsal bones. This investigation compared the material properties of human metatarsal bones from young diabetic donors (51.3 +/- 8 years) and older nondiabetic donors (72.3 +/- 10 years). The results demonstrated no significant differences between the two groups. This would seem to suggest that the effects of aging are comparable to the effects of diabetes on the structural integrity of human metatarsal bones.

Variations in the mechanical properties of cartilage from the canine scapulohumeral joint

OBJECTIVE

To measure the intrinsic material properties of scapulohumeral joint cartilage in adult dogs and determine whether regional differences exist within or between the humeral and glenoid cartilages.

SAMPLES

Paired shoulder joints from 7 clinically normal adult dogs.

PROCEDURE

An automated indentation apparatus was used to obtain the intrinsic mechanical properties of the cartilage at 7 sites on each joint surface.

RESULTS

Topographic variations in mechanical properties of the glenoid and humeral cartilages were observed. The largest aggregate modulus (HA) for the humerus was seen at the caudocentral site (0.92 MPa) and for the scapula was seen at the centrocenter site (0.84 MPa). The mean shear modulus (mu) of humeral cartilage (0.23 MPa) was significantly greater than that of the glenoid cartilage (0.19 MPa). The mean Poisson's ratio (v) of humeral cartilage (0.24) was significantly smaller than that for the glenoid cartilage (0.29). Mean humeral cartilage aggregate modulus (0.71 MPa) was larger than the value for glenoid cartilage (0.67 MPa), but these differences were not significant. There were no significant differences in the compressive stiffness of the opposing cartilage in the canine scapulohumeral joint.

CONCLUSIONS

Differences in mechanical properties between opposing humeral and glenoid cartilages are not a cause of cartilage injury in the scapulohumeral joint of adult dogs. The mechanical properties of cartilage from young dogs with open physes and incomplete subchondral bone plates may be different from those of adult dogs.

Comparison of the mechanical performance of trochanteric fixation devices

The transtrochanteric surgical approach to the hip is commonly used, especially for revision hip surgery. Failure of the trochanter to heal can lead to hardware failure, persistent pain, and limp. Rigid internal fixation is needed in this approach to achieve an adequate rate of healing. Newer cable and cable grip systems have been designed to improve trochanteric fixation, but have not been compared to the older Charnley wire fixation techniques. In this study, an in vitro mechanical method previously used to test wire fixation methods was used to compare wire, cable, and cable grip fixation methods. A quasistatic mechanical distraction device was used to compare structural stiffness, load to clinical failure, energy to clinical failure, and maximum load resisted by the fixation devices. The cable grip system was found to be stiffer, to resist a larger load to mechanical failure at 1-cm displacement, and to absorb a greater amount of energy to clinical failure when compared with the other systems. These data suggest that use of the cable grip fixation method should result in improved clinical success compared with the Charnley wire technique.

Estimating the level of knowledge of Greek students on cancer aetiology and ways of prevention

The aim of the present research was to establish the perception of the relative importance of various environmental risk factors for cancer among Greek students. A questionnaire was used to assess the students' knowledge on cancer causation. The factors examined included smoking habits, drinking, geophysical factors, pollution, dietary factors, and the students' awareness of the contribution of these factors to the generation of the disease. In addition, we examined the students' attitude to the factors as cancer risk determinants. A random sample of 1,136 students was selected from the matriculated students of various departments of the Aristotelian University of Thessaloniki. We found a relative important lack of knowledge on subjects related to the generation of the disease.

Enzymatic synthesis of butyryl-rutin ester in organic solvents and its cytogenetic effects in mammalian cells in culture

Enzymic acylation of a flavonoid, rutin, with trichloroethylbutyrate (TCEB) has been performed by subtilisin protease in anhydrous pyridine solution. The addition of a hydrophobic compound on rutin is expected to change the hydrophilic/hydrophobic balance of the molecule, giving new properties to this compound. This work aimed at investigating the various cytological properties of the rutin-ester and compared them with those of the native molecule. No difference in the levels of sister chromosomes exchange (SCE) between rutin and rutin-ester treated cells at doses varying from 25 to 200 micrograms/mL was found. On the contrary impressive difference in the induced frequency of micronuclei (MN) between rutin and rutin ester treated cells was observed, for example, at a dose of 100 micrograms/mL of rutin were 3.5% MN counted, whereas for a similar dose treatment with rutin-ester a frequency of 8% of MN was found. The fact that rutin-ester is causing significantly higher levels of MN than the rutin alone can be considered as a manifestation of a higher action of the agent on the chromosome owing to its easier penetration in to the cell after its esterification.

Physiological levels of hydrostatic pressure alter morphology and organization of cytoskeletal and adhesion proteins in MG-63 osteosarcoma cells

The response of human MG-63 osteosarcoma cells to physiological levels of hydrostatic pressure was studied. Cell cultures were subjected to a 20-min, 4-MPa hydrostatic pressure pulse. Adhesion was measured at 20 min and 2 h post-hydrostatic pressure. Morphometric measurements of cell shape and immunofluorescent assays of cytoskeletal and adhesion proteins were done pre- and post-hydrostatic pressure. Pressure-treated cells showed increased adhesion (resistance to deadhesion by trypsinization)-with increased recovery time. Indirect immunofluorescence demonstrated increased heterotypic adhesion receptor at cell-cell interfaces and increased alpha 3, beta 1-integrin at cell-substrate interfaces. Indirect immunofluorescence demonstrated depolymerization of alpha-tubulin, vimentin, and actin during the pressure pulse. Actin reorganization was slower than that of alpha-tubulin and vimentin, with stress filaments not well organized even after 1 h postpressure. The depolymerization of alpha-tubulin, vimentin, and actin observed at relatively low levels of hydrostatic pressure suggests disintegration of the integrin-cytoskeletal attachment complex. The increased resistance of the cells to trypsinization and the increase in both heterotypic adhesion receptor and the alpha 3, beta 1-integrin at cell interfaces suggest that cells compensate for loss of cytoskeletal integrity by increasing attachment to both adjacent cells and the extracellular matrix.

Metsovo-tremolite asbestos fibres: in vitro effects on mutation, chromosome aberration, cell transformation and intercellular communication

Samples of Metsovo-tremolite asbestos, previously found to be the causative agent of endemic pleural calcification and an increased level of malignant pleural mesothelioma in a rural area of north-western Greece (Metsovo area), were tested in various in vitro toxicity test systems. It was found that asbestos fibres of this type were strong inducers of micronuclei and numerical chromosomal abnormalities while they induced low levels of chromosomal aberrations in mammalian cells in culture. Furthermore, this type of asbestos can induce a low level of in vitro transformation of Syrian hamster embryo cells. The fibres had no effect on gap-junctional cell-cell communication (followed by the dye-transfer method) and did not induce any mutations in the Salmonella typhimurium strain TA102 which is known to be sensitive to the action of various oxidative agents. These results support the hypothesis generated from studies on other types of asbestos that such fibres induce tumours by causing chromosomal mutations.

Temperature and time effects on mutagen production in cooked lamb meat

Basic extracts isolated from lamb meat treated at various temperatures were tested for mutagenicity in Salmonella typhimurium strain TA98 in the presence of S9 mix. Samples of ground lamb patties were cooked for 10 min per side at 100, 150, 200, 250 and 300 degrees C. Low cooking temperatures resulted in products with low levels of mutagenicity. At temperatures greater than 150 degrees C the mutagenic activity of the cooked meat increased to reach a maximum at 300 degrees C. In another series of experiments, lamb patties were cooked at 250 degrees C for 2, 4, 6, 8, 10 and 12 min. Short cooking times (rare products) caused no mutagenic activity and uncooked ground meat showed no activity. Prolonged cooking appeared to increase the mutagenicity of the products with a maximum value at 10 min. The results indicate that the formation of mutagens depends on both cooking temperature and cooking time. The level of mutagenicity tends to increase with the degree of charring.

Mutagenicity, sister chromatid exchange inducibility and in vitro cell transforming ability of particulates from Athens air

Airborne particulates were collected over a period of twelve months by the use of Hi-Vol samplers in the basin of Athens, Greece. N-Hexane extracts were tested in a battery of in vitro tests for their ability to induce mutation in bacteria as well as mutation, sister chromatid exchange and morphological transformation in cultured mammalian cells. Positive results were found for mutagenicity with Salmonella strain TA98 in the Ames assay, for sister chromatid exchange induction in CHO cells and for transformation in BALB/c 3T3 cells in culture. They also showed weak non-dose-related induction of ouabain resistance in BALB/c 3T3 cells. The contribution of oxidizing and nitrating agents found in the Athens atmosphere, together with sunlight UV irradiation in the formation of direct acting mutagens and potential carcinogens from ambient polycyclic aromatic hydrocarbons, is suggested.

Mutagenicity and clastogenicity of the antineoplastic agents homo-azasteroidal ester of p-bis(2-chloroethyl)aminophenyl acetic acid and chlorambucil

The mutagenic and clastogenic effects of the antineoplastic agents homo-aza-steroidal ester (ASE) and chlorambucil (CBC) were tested for their ability to induce mutations in the Salmonella/microsome system and SCE in CHO cells in culture. ASE was found to be positive in strains TA1535 and TA100 and in the newer strain TA102 with and without metabolic activation, while CBC caused histidine reversion in strain TA102 after the addition of mammalian liver microsomal extract (S9). In addition, both agents were found to be strongly positive for SCE induction. The mutagenic and clastogenic actions of both agents were of a dose-response type.

Synthesis of a new nor-aza-steroidal ester of p-N,N-bis-(2-chloroethyl)aminophenylbutyric acid and in vitro study of its mutagenicity and clastogenicity

A new nor-aza-steroidal ester of chlorambucil has been synthesized. The study of the mitotic index in CHO and HeLa cells treated with this compound showed that it may be a cytostatic drug. It was also found that treatment of CHO cells with a dose as low as 5 micrograms/ml induces a large number of sister chromatid exchanges. A great number of abnormal metaphases has been observed when CHO cells were treated with the compound at a dose of 25 micrograms/ml. When the compound was tested in the Ames/Salmonella microsome assay, it was found to be mutagenic in strains TA100 and TA1535, both with and without metabolic activation.

Mutagenic and clastogenic effects of organic extracts from the Athenian drinking water

Organic extracts of chlorinated drinking water collected from the water distribution system of Athens, Greece, were tested in parallel for their ability to cause mutations in the Salmonella His+ reversion system and sister chromatid exchanges (SCE) and chromosomal aberrations in CHO cells. They were found to induce His+ revertants in frequencies similar to those detected previously with drinking water extracts from other areas around the world. We observe that organic samples from surface drinking water induce SCE and chromatid type abnormalities in CHO cell cultures while samples collected from ground drinking water did not. These findings confirm that chlorinated surface drinking water contains substances which are mutagenic and clastogenic and may be carcinogenic in humans.

Chromosome damage and SCE induced by the cytostatic factor homo-aza-steroidal ester of P-bis (2-chloro-ethyl) amino phenyl acetic acid in CHO cells in culture

The cytogenetic effects of homo-aza-steroidal ester (ASE) on Chinese hamster ovary (CHO) cells in vitro are reported. It was found that treatment of cells with a dose as low as 0.025 micrograms/ml of ASE causes a significant number of abnormal metaphases containing mostly chromatid-type aberrations. Similarly, significant frequencies of SCE were induced with only 0.075 micrograms/ml of ASE.

The implications of S-phase exchanges for the mechanisms of radiosensitivity in trisomy 21

Human lymphocytes obtained from four patients with Down syndrome and from two normal individuals were irradiated with X-rays during their S phase and examined for chromatid type aberrations. It is suggested that the significantly increased frequency of asymmetrical chromatid interchanges found in trisomic cells is related to an altered DNA repair system. This altered repair system is probably responsible for the increased frequency of chromosome aberrations that can be induced in these cells by x-rays and the increased tendency for leukemia observed in Down syndrome as well.

Induction of sister chromatid exchanges and chromosome aberrations in cultured mammalian cells by N-nitrosocimetidine

N-Nitrosocimetidine (NC) induces significant numbers of sister chromatid exchanges (SCE) and chromosome aberrations in cultured Chinese hamster ovary (CHO) cells even at a concentration of 1.2 x 10(-7) M. Its effectiveness in SCE induction is about two thirds that of the gastric carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). These results constitute further evidence that NC possesses carcinogenic activity.

Decreased repair of x-ray induced DNA single-strand breaks in lymphocytes in Down's syndrome

Gamma-ray irradiation introduces single and/or double strand breaks into the DNA molecule of the cells. In the case of mammalian cells, these breaks are being repaired in general during the first hr following exposure to ionizing radiation. The article reports on the results obtained from testing the ability of cultured lymphocytes from patients with Down's syndrome to repair radiation-induced DNA single-strand breaks. The ability to repair was deduced from the study of the DNA sedimentation profiles in alkaline sucrose gradients. It was found that lymphocytes from Down's syndrome patients are less efficient in repairing single-strand DNA breaks than are lymphocytes from normal individuals. This significantly increased fraction of unrepaired DNA strand breaks might be associated with the unusually high level of radiation-induced chromosome aberrations as compared with normals.