Human Biological Tissues Research Articles

MULTI-CHANNEL MUELLER-MATRIX TOMOGRAPHY AS A METHOD OF DETERMINING THE VOLUME OF BLOOD LOSS IN FORENSIC MEDICAL PRACTICE

In connection with the extreme urgency of determining the volume of blood loss during the forensic examination of a corpse, the authors proposed a modern digital analysis method - multichannel Muller matrix tomography of human biological tissues. Aim of the work. To develop a complex of forensic criteria for accurate determination of the volume of blood loss using the method of multichannel polarization Müller-matrix tomography of histological sections of structured biological tissues (rectus abdominis muscle, skin). Material and methods. For the study, rectus abdominis muscle and skin samples were taken from 85 deceased individuals aged 18 to 56 years with varying degrees of blood loss. The results. The proposed method of researching changes in the values ​​of linear birefringence of fibrillar structures of the rectus abdominis muscle and skin of of cadavers as a result of acute internal and external blood loss showed the possibility of accurate determination within the volume of 0±2000 mm3. Conclusions. The method of multichannel differential Müller-matrix tomographic reproduction of a set of linear birefringence maps and histograms of distributions of random values ​​of the structural anisotropy parameter of histological sections of the rectus abdominis muscle and skin of the dead with different degrees of blood loss is sensitive within ΔV=0mm3÷2500mm3. The accuracy ranges of the multi-channel tomographic reproduction of LD maps within the range of ΔV=0mm3÷1000mm3 ↔86%-92% have been determined.

Reducing Inert Materials for Optimal Cell-Cell and Cell-Matrix Interactions within Microphysiological Systems.

In the pursuit of achieving a more realistic in vitro simulation of human biological tissues, microfluidics has emerged as a promising technology. Organ-on-a-chip (OoC) devices, a product of this technology, contain miniature tissues within microfluidic chips, aiming to closely mimic the in vivo environment. However, a notable drawback is the presence of inert material between compartments, hindering complete contact between biological tissues. Current membranes, often made of PDMS or plastic materials, prevent full interaction between cell types and nutrients. Furthermore, their non-physiological mechanical properties and composition may induce unexpected cell responses. Therefore, it is essential to minimize the contact area between cells and the inert materials while simultaneously maximizing the direct contact between cells and matrices in different compartments. The main objective of this work is to minimize inert materials within the microfluidic chip while preserving proper cellular distribution. Two microfluidic devices were designed, each with a specific focus on maximizing direct cell-matrix or cell-cell interactions. The first chip, designed to increase direct cell-cell interactions, incorporates a nylon mesh with regular pores of 150 microns. The second chip minimizes interference from inert materials, thereby aiming to increase direct cell-matrix contact. It features an inert membrane with optimized macropores of 1 mm of diameter for collagen hydrogel deposition. Biological validation of both devices has been conducted through the implementation of cell migration and cell-to-cell interaction assays, as well as the development of epithelia, from isolated cells or spheroids. This endeavor contributes to the advancement of microfluidic technology, aimed at enhancing the precision and biological relevance of in vitro simulations in pursuit of more biomimetic models.

A comparative study on the axial intensity of some laser beams spreading through human and mouse biological tissues

A comparative study on the axial intensity of some laser beams spreading through human and mouse biological tissues

Legal regulation of human somatic rights: transplantation of human organs and biological tissues in Ukraine and foreign countries

The article examines the problems of legal regulation of transplantation of organs and tissues of the human body in Ukraine and foreign countries. Emphasis is placed on legal and ethical difficulties arising in the field of transplantology. It is noted that the right to «mechanize the body» has a number of specific features, namely: the specific nature of the object of these rights - the human body, which is the object of property rights and currently has mainly a monetary value expression; natural dependence on knowledge of biology, genetics, medicine, technology. Their existence and implementation are possible only with the help of achievements of scientific and technical progress; novelty, which has a different degree of expression, depending on the type of protected result of disposal of body or life; ambiguous attitude from the side of religion, morality, ethics, politics; inextricable connection with constitutional (fundamental) human rights in view of the special connection with personal (natural) rights and the peculiarity as an independent group of human rights; exclusivity in terms of its legal consequences in the process and as a result of their implementation. With any change in the physical embodiment of a person, the subjective aspect of legal relations changes, that is, many connections of various branches of legal regulation (civil, marital and family, constitutional, etc.) are affected; the degree of their recognition and implementation reflects the level of development of the state and society in general, etc. It is emphasized that individual somatic rights are reflected both in the legislation of Ukraine and in the legislation of foreign countries. For example, the right to transplant organs in national legislation is not used as a right to dispose of one's body, but as a certain necessity, a medical indication. In order to regulate the issue of organ donation, the legislation of individual states prescribes the practice of establishing special procedures for obtaining the donor's consent to extract a transplant from him (Belgium, Greece, Turkey). Given the lack of transplants for transplant operations, it is important to develop educational work at the state level, explaining to citizens the need to issue voluntary consents for the posthumous use of their donor material. It is worth making proposals for the development and adoption of the State Program of Ukraine aimed at the development of donation. This program should provide organizational, legal and preventive state measures for the promotion and development of legal donation in Ukraine; proposals for the development of a national legal mechanism aimed at encouraging voluntary posthumous donation, which would be based on the lifetime legally formalized consent of potential donors to the posthumous free use of their donor material.

Biomarkers of arsenic exposure in biogeochemical provinces

Introduction. One of the direct methods of assessing the impact of contaminants on public health is the use of biological markers that allow determining the presence of a substance or its metabolite in human biological tissues and the dose received from all sources of this substance. 
 The purpose of this study was to determine the dependence of arsenic content in biological samples (hair) 
 of exposed residents on the level of its content in drinking water and to substantiate the effectiveness of the use of this biomarker in the conditions of a hydrogeochemical province in the Republic of Dagestan.
 Material and methods. During this research the arsenic content in the hair of the exposed residents was measured with further comparison of the data obtained with its content in drinking groundwater. To determine the arsenic content in the hair of the exposed residents, an atomic absorption method was used with preliminary preparation of biosubstrate samples. Socio-demographic data were obtained from a questionnaire. Statistical data processing was carried out using Microsoft Excel.
 Results. In the course of this study, a correlation was revealed between the arsenic content in the hair of the exposed residents and its content in the drinking water consumed, and a direct proportional relationship between these values was also revealed. Thus, with an increase in the concentration of arsenic in water by 
 0.1 mg/l, the arsenic content in the hair increases by 0.14 mkg/g. So, using of the hair of exposed residents as a biomarker of long-term exposure is recommended to small doses of arsenic in a biogeochemical province.
 limitation of the study is the small sample size. However, this does not prevent the assessment of the effectiveness of using hair as a biomarker of arsenic exposure and preliminary conclusions for subsequent in-depth analysis of biomonitoring in the conditions of biogeochemical provinces.
 Conclusion. As a rule, the content of natural toxic elements is characterized by trace amounts in the conditions of biogeochemical provinces. Biomonitoring will reveal the level of stress on the body and timely apply preventive methods before the clinical signs of intoxication are revealed.

The Law On Human Trafficking For The Purpose Of Illegal Organ Trade

The merits and drawbacks of organ sales are vigorously debated in Indonesia. Nevertheless, some argue that the trade in human organs should be prohibited, a stance supported by Indonesian law. Both organ recipients and donors bear significant responsibility in organ trade, as financial gain serves as the primary motive for organ brokers and medical professionals alike. This research aims to conduct a Legal Analysis of Human Trafficking for the Purpose of Organ Illegal Trade. The methodology employed is a literature review through online searches on various journal platforms such as Google Scholar, Science Direct, and the Garuda Portal, focusing on national and international scientific journal articles. The search, limited to the last four years (2019-2023), employed subject-specific terms like "human organ trafficking," "person trafficking," or "positive law." The search excluded articles containing only conceptual discussions. The findings reveal that the buying and selling of organs are ethically reprehensible and illegal in the healthcare industry, as outlined in Health Law Number 36 of 2009. Although ethical kidney transplants using organs obtained through sales are impossible, specific considerations should be noted. The purchase and sale of human organs and/or biological tissue constitute a specialized crime, with Article 192 of Law Number 36 of 2009 specifying criminal punishments. Those found deliberately engaging in organ or body tissue trade, as defined in Article 64 paragraph (3), may face a maximum sentence of 10 years in prison and a fine of IDR 1,000,000,000 (one billion rupiah).

THE PECULIARITIES IN THE FORMATION OF GUNSHOT WOUNDS CHANNELS CAUSED BY 7.62 MM EXPANSIVE «HPBT» AND «SP» TYPE BULLETS

The aim of the study – to study the peculiarities of wound channel formation, causedby 7.62 mm «HPBT» and «SP» bullets, by means of experimental methods of forensicballistics with the use of human biological tissue simulators.Materials and methods. Experimental investigations were carried out under conditionsof the ballistic route of the National Scientific Center «Hon. Prof. M. S. Bokarius ForensicScience Institute». To determine the velocities of the fired bullets, the optoelectronicmeasuring complexes IBX-731.4 were used. Ballistic plasticine «Beschussmasse,6287156» was used as a simulator of human body tissues. The experimental shooting wascarried out with a TS.M308 model .308 «Winchester» sniper rifle. For the experimentalshooting 7.62 × 51 mm (.308 «Winchester») cartridges were used, which were filled with«SP» and «HPBT» bullets.Results. In the course of experimental shooting, the peculiarities of the formation ofdamage channels caused by 7.62 mm «SP» and «HPBT» bullets were determined. Basedon the results of experimental studies, it has been found that the bullets of these types ofthe same caliber and practically the same mass are able to cause different amounts ofbodily injury, which is primarily due to the peculiarities of the design of the bullets. SPtype bullets with a bare core cause more severe bodily injuries, they are less subject tofragmentation and in most cases retain a relatively heavy bottom part. As a consequence,such bullets are able to cause longer wound channels than other types of expansivebullets. HPBT-type bullets can also cause sufficiently large amounts of bodily injury,but because of their design, they are more prone to fragmentation when hitting thehuman body. In the course of the research it has been established that there are severalperipheral (secondary) channels in the area of the main wound channel. They are formeddue to destruction of the bullet and movement of its separate fragments away from themain direction, which leads to complication of diagnostics and further treatment of suchgunshot wounds.Conclusions. The use of 7.62 × 51 mm (.308 «Winchester») expansive «SP» and «HPBT»type bullets in the course of combat operations for firing modern sniper systems resultsto severe bodily injuries. Wounds caused by such bullets are characterized by significantin volume zones of direct traumatic necrosis (contusion), which significantly extend deepinto the tissues and structures of the human body and form even larger in size zonesof conditional necrosis (contusion) and morpho- functional changes. The formationnature of both the main wound channel and the peripheral wound channels, caused byfragments of bullet structural elements, depends on the velocity, design features andposition (projection) of the bullet at the moment of impact. Changes in biological tissuesin the area of wounds caused by these types of expansive bullets have rather complexarchitectonics, which significantly complicates the issue of clear delimitation of gunshotwound zones and adequate surgical intervention. The used investigation methods of thestriking properties of expansive bullets are suitable for predicting the severity and volumeof the caused injuries, as well as for determining the individual characteristic complex ofgunshot wounds signs caused by such bullets.

Histopathological considerations of transvaginally implanted polytetrafluoroethylene mesh in human biological tissues

Histopathological considerations of transvaginally implanted polytetrafluoroethylene mesh in human biological tissues

Potential release of trace metal ions from metallic orthodontic appliances and dental metal implants: A Review of in vitro and in vivo experimental studies

Metallic wear nanoparticles, corrosion products and trace metal ions release from metallic materials, e.g. metallic alloys and pure metals, implanted into the human and animal's body in orthodontic surgery is becoming a major cause for concern. Additionally, metallic wear nanoparticles can themselves undergo a corrosion process contributing to the total level of dissolved metal ions. This review briefly provides an overview of both metallic alloys and pure metals used in implant materials in dental surgery. A short section is dedicated to important biomaterials and their corrosive behavior in both real solutions and various types of media that model human and animal's biological fluids and tissues. The present review gives an overview of analytical methods, techniques and different approaches applied to the measurement of in vivo and in vitro trace metals released into body fluids and tissues from patients and animals carrying metal dental implants and metallic orthodontic appliances. Reference levels of ion concentrations in body fluids and tissues that have been determined by a host of studies are compiled, reviewed and presented in this paper. This review summarizes data, describing the potential toxicity of metal wear debris, free metallic ions and corrosion products release from metallic orthodontic appliances (metal surgical implants) in vivo and in vitro. Finally, a collection of published clinical data on in vivo and in vitro released trace metals from metal dental implants is included.

APPLICATION OF DIFFERENTIAL MULLER-MATRIX TOMOGRAPHY OF HISTOLOGICAL SECTIONS OF STRUCTURED BIOLOGICAL HUMAN TISSUES TO DETERMINE THE DEGREE OF BLOOD LOSS

In conducting a forensic medical examination of a corpse, in cases of acute blood loss, the decisive issue for investigators is to establish the amount of lost blood. However, this often remains a difficult task, since in the absence of a suitable quantitative system for measuring the volume of blood loss, forensic medical experts have to be guided by well-known morphological signs, which can be quite subjective. In conducting a forensic medical examination of a corpse, in cases of acute blood loss, the decisive issue for investigators is to establish the amount of lost blood. Therefore, it is important to find and develop new digital methods for determining the degree of blood loss. In order to solve this problem, the application of the method of multiparametric differential Mueller-matrix tomography of human biological tissues is proposed.
 Aim of the work. To develop a set of forensic criteria for the accurate determination of the volume of blood loss based on the data of differential Mueller-matrix tomography of histological sections of biological tissues with a fibrillar morphological structure.
 Materials and methods. Tissues with a fibrillar morphological structure (rectus abdominis muscle, skin) were collected from 60 cadavers of both sexes with varying degrees of blood loss from0 mm3to2500 mm3.The research was carried out by polarizing microscopy of histological sections of biological tissues in the standard location of the laser polarimeter.
 Results. Experimental measurements of distribution maps of linear birefringence of tissue sections with a fibrillar morphological structure with different degrees of blood loss were carried out. A linear range of changes in the magnitude of statistical moments of the 1st to 4th orders was established, which is associated with the degradation of linear birefringence of fibrillar networks of biological tissues.
 Conclusions. The effectiveness of applying the method of differential Mueller-matrix tomography of polycrystalline LD of the optically anisotropic component of structured biological tissues to changes in the level of blood loss of the deceased has been demonstrated. The sensitivity range ∆V=0÷1000 mm3 of this method is established.

The indigenous African cultural value of human tissues and implications for bio-banking.

Bio-banking in research elicits numerous ethical issues related to informed consent, privacy and identifiability of samples, return of results, incidental findings, international data exchange, ownership of samples, and benefit sharing etc. In low and middle income (LMICs) countries the challenge of inadequate guidelines and regulations on the proper conduct of research compounds the ethical issues. In addition, failure to pay attention to underlying indigenous worldviews that ought to inform issues, practices and policies in Africa may exacerbate the situation. In this paper we discuss how the African context presents unique and outstanding cultural thought systems regarding the human body and biological materials that can be put into perspective in bio-bank research. We give the example of African ontology of nature presented by John Samwel Mbiti as foundational in adding value to the discourse about enhancing relevance of bio-bank research in the African context. We underline that cultural rites of passage performed on the human body in majority of communities in Africa elicit quintessential perspective on beliefs about handling of human body and human biological tissues. We conclude that acknowledgement and inclusion of African indigenous worldviews regarding the human body is essential in influencing best practices in biobank research in Africa.

Fatal Methanol Poisoning Caused by Drinking Industrial Alcohol: Silesia Region, Poland, April-June 2022.

Methanol poisonings caused by drinking industrial alcohol remain a severe problem worldwide. Education on types of alcohol and their harmfulness and legal regulations limiting the industrial alcohol trade seem to be the keys to reducing the number of poisonings. Methanol distribution in different tissues after absorption is not well understood. This research aimed to quantify the methanol and formic acid distribution in body fluids and tissue material in post-mortem samples collected from 19 fatal victims of massive intoxication with industrial alcohol in the Silesia Region (Poland) who died between April and June 2022. The samples were analyzed using a gas chromatography-flame ionization detector (GC-FID), and correlation coefficients for methanol and formic acid were determined. The results show a wide distribution of methanol and formic acid in human post-mortem biological fluids (blood, urine, vitreous humor, bile, and cerebrospinal fluid) and tissues (muscle, kidney, liver, spleen, lung, and brain). The strongest correlation for methanol concentration in blood and body fluids/tissues was obtained in the cerebrospinal fluid (r = 0.997) and for formic acid in muscle tissue (r = 0.931). The obtained results may be a valuable tool in toxicological analysis and improve medical standards of early diagnosis and targeted treatment.

Effect of Ta Content on Microstructure and Phase Transformation Temperatures of Ti75.5-Nb25.5 (%at.) Alloy

β-titanium shape memory alloys are used as shape memory-based biomedical applications and superelastic materials because they are made up of non-toxic components. Also, their behaviors are more semilar with that of human bone and dental biological tissues, such as biocompatibility, superior corrosion resistance, low density, and low modulus of elasticity. In the current study, the effect of Ta additive on the physical properties of Ti-Nb alloy has been investigated. Ti-Nb-Ta alloy samples were produced such that the Tantalum (Ta) element was substituted instead of Niobium (Nb), and the induction arc melting was used to melting the mixed powders. To investigate the crystal structure, microstructure, and phase transformation temperatures of all samples, the X-Ray Diffraction (XRD), Scanning Electron Microscopic (SEM), and Diffraction Scanning Calorimetry (DSC) measurements have been used. Both β-rich and α peaks were observed in the XRD and SEM measurements. Also, the DSC results revealed that the Ti-Nb-Ta alloys have only austenite transformation temperatures and their phase austenite phase transformation were decreased by the effect of Ta additive, additionally, the enthalpy change in〖 E〗_3 sample ( Ti_75.5 Nb_22.5 Ta_2 (%at)) has the highest value, while E_4 sample ( Ti_75.5 Nb_21.5 Ta_3 (%at)) has the lowest respective value.

Laser polarimetry of human biological tissues as an effective method of differential diagnosis, using the prostate gland as an example

Laser polarimetry of human biological tissues as an effective method of differential diagnosis, using the prostate gland as an example

APPLICATION OF DIFFUSIVE TOMOGRAPHY METHOD OF BIOLOGICAL PREPARATIONS IN FOREIGN MEDICAL DIFFERENTIAL DIAGNOSIS OF ALCOHOLIC AND ALCOHOLOGEN POISONING

The article presents the results of the study of forensic effi cacy of diff erential diagnosis of alcohol and carbon monoxide poisoning, as well as establishing the age of death in these cases by diff use tomography of fl uctuations of linear fl uctuations of linear birefringence of human biological tissues.
 Aim of the work. Investigation of the eff ectiveness of the method of diff use tomography of biological products and polycrystalline blood fi lms in the forensic diff erential diagnosis of alcohol and carbon monoxide poisoning and determining the age of death in these cases.Materials and methods. The object of the study were histological samples of human internal organs (brain, myocardium) and polycrystalline blood fi lms in cases of death from ethanol poisoning, carbon monoxide and coronary heart disease (control group) with diff erent ages (6 to 48 hours). The study was performed using the method of diff use tomography of fl uctuations in the parameters of optical anisotropy of layers of biological tissues and fl uids.Results. The eff ectiveness of analytical determination of the age of death in cases of ethanol and carbon monoxide poisoning by analyzing the range of linear changes in the magnitude of statistical moments of 1-4 orders of magnitude, ranging from 24 to 60 hours. The accuracy of determining the age of death is 0.5 hours.Conclusion. The eff ectiveness of the method of diff use tomography of fl uctuations of linear birefringence of layers of biological tissues and fl uids in diff erentiating the cause of death in cases of ethanol and CO poisoning, as well as diagnosing the age of death in these cases.

Optical Scanning System for Imaging of Heterogeneity in Biological Tissues

A non-invasive hand-held optical probe for imaging of biological tissues consists of nine units. Each unit is equipped with one red LED and three photodetectors placed at distances 7, 12, and 17 mm from the source along the x-axis. For testing, three phantoms of paraffin wax are embedded with solid inhomogeneity placed at various depths. Human biological tissues consisting of right index finger, four fingers of the same hand, and a part of the forearm below elbow joint are used. The data on optical backscattering are collected by moving the probe on the surface of phantom/tissue and after processing the respective images are obtained. Three images of the index finger show the tissue structural variation in various layers, which are in agreement with anatomical details and radiograph of the finger. The tissue details of four fingers are in agreement with that of individual finger. Similarly, the three images of the forearm show the structural variation. These observations suggest that the present technique may be used to detect tissue compositional changes below the skin.

Analysis, Sources and Study of the Biological Consequences of Electromagnetic Pollution

The actions and health effects of electromagnetic fields in the radio frequency (RF) domains, referred to as radio frequencies and HV transmission networks have been studied for several decades. Following the appearance of questions and debates within the population, the actions and potential effects of radiofrequency and HV transport networks on health, in connection with the development of new wireless technologies, are generating a certain revival of interest. Thus, the increasing exposure to electromagnetic fields and the concerns of the public have led health organizations to undertake large-scale research programs to respond to the concerns expressed. These research programs have contributed to significantly increasing the number of studies on the actions and effects of electromagnetic pollution as well as their consequences on living beings. The objective of our research is focused on the analysis, sources, and study of the biological consequences of electromagnetic pollution. To do this, we have used physical laws and theorems, in particular Maxwell-Ampère, Maxwell-Gauss, Maxwell-Faraday, and Ohm’s law, to model the interactions between electromagnetic fields and living matter. In this article we have chosen the approach based on the electrical model of human biological tissue, taking into account on the one hand the physical phenomena of the propagation of an electromagnetic microwave plane wave in the range from 0 to 300GHz and on the other hand, the experimental values to simulate the relaxations α, β and γ and the impedance of the biological tissue faced with the variation of the frequency of propagation of the electromagnetic waves to identify the biological consequences relating thereto. The results obtained in the literature show the linear dependence of bio-impedance on frequency, these observations suggest that the tissue can be physiologically stressed at high frequencies. This can cause biological consequences for humans. The 2D simulation based on the proposed model has been developed as well as the verification of the consistency of the different mathematical models, by comparing the fractal dimensions of the results of the program with those of the figures obtained experimentally.

Pleiotropic Outcomes of Glyphosate Exposure: From Organ Damage to Effects on Inflammation, Cancer, Reproduction and Development.

Glyphosate is widely used worldwide as a potent herbicide. Due to its ubiquitous use, it is detectable in air, water and foodstuffs and can accumulate in human biological fluids and tissues representing a severe human health risk. In plants, glyphosate acts as an inhibitor of the shikimate pathway, which is absent in vertebrates. Due to this, international scientific authorities have long-considered glyphosate as a compound that has no or weak toxicity in humans. However, increasing evidence has highlighted the toxicity of glyphosate and its formulations in animals and human cells and tissues. Thus, despite the extension of the authorization of the use of glyphosate in Europe until 2022, several countries have begun to take precautionary measures to reduce its diffusion. Glyphosate has been detected in urine, blood and maternal milk and has been found to induce the generation of reactive oxygen species (ROS) and several cytotoxic and genotoxic effects in vitro and in animal models directly or indirectly through its metabolite, aminomethylphosphonic acid (AMPA). This review aims to summarize the more relevant findings on the biological effects and underlying molecular mechanisms of glyphosate, with a particular focus on glyphosate's potential to induce inflammation, DNA damage and alterations in gene expression profiles as well as adverse effects on reproduction and development.

Разработка инновационных материалов для судебной экспертизы

In the production of experimental studies related to the modeling of the behavior of human soft tissues in such widespread types of forensic examinations as forensic ballistic, tracological, forensic examination of cold and throwing weapons, forensic medical-use bioimitators. Human corpses, animal carcasses, and their living individuals are used as such objects, but in recent decades, with the development of chemistry and chemical technology, various artificial substitutes have become increasingly widespread – colloidal systems based on gelatin, soap, mixtures of petroleum petrolatum, as well as specialized compositions. Among the main advantages of using soft tissue substitutes are the following: visibility of the results obtained, availability of synthetic materials, uniformity of structure, reproducibility of experimental results with a statistically reliable amount, as well as, if necessary, the possibility of varying mechanical parameters for physical modeling of the characteristics of human biological tissues within the framework of an expert experiment. The paper proposes a technology for obtaining a reusable synthetic compound that allows modeling the properties of human soft tissues. The synthetic compound provides the transfer of general patterns of morphology of the formed gunshot injuries, similar to gunshot wounds on biological materials.

Analysis of the temperature influence on thermophysical properties in the three-dimensional numerical modeling of heat transfer in human biological tissue in the presence of a cancerous tumor

Analysis of the temperature influence on thermophysical properties in the three-dimensional numerical modeling of heat transfer in human biological tissue in the presence of a cancerous tumor