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Papers by Jorge Herkovits
Academia Medicine
Although the relationship between environmental toxicity and infectious diseases is poorly studie... more Although the relationship between environmental toxicity and infectious diseases is poorly studied, it is probably more common than is recognized, since the chemical substances could be associated with pre-existing pathologies. For example, some conditions that influence the progression of COVID-19 could have toxicological causes such as cancer, endocrine, neurological, and inflammatory disorders, kidney failure, etc. This contribution highlights that SARS-CoV-2 and some high-volume organic and inorganic chemicals could also exert dysfunctions in the same homeostatic regulators such as HIF-1 and ACE2, with a potential synergistic effect that could affect the severity of COVID-19. This potential synergy is illustrated with adverse effects acquired through bioassays performed with free-living vertebrate embryos indicating that their use as sentinel organisms for environmental contamination could be beneficial both for the ecosystem and human health.
Bulletin of Environmental Contamination and Toxicology, Mar 1, 2002
International Journal of Environmental Research and Public Health, Dec 31, 2006
The water quality based toxics control is essential to evaluate the aggregate toxicity, bioavaila... more The water quality based toxics control is essential to evaluate the aggregate toxicity, bioavailability as well as for the detection and/or prediction of ecological impacts. Reconquista River valley is situated in the north area of Great Buenos Aires with a population of three million inhabitants. The river is loaded with industrial and municipal waste water. In the present preliminary study the authors report the toxicity found in surface water at a 6 sample stations (including a reference point and a stream) all of them downstream from mixing zone areas. The ecotoxicological study was performed with three native species (Bufo arenarum embryos, Cnesterodon decemmaculatus and a species of shrimp collected in an upstream reference site) during a 7 day renewal toxicity test conducted with 10 individuals (by duplicate) for each condition plus control. The results point out that the Bufo arenarum embryos test is the most sensitive to toxic substances as well as the better adapted species to the changing physico-chemical conditions of this river. The results obtained with embryos, expressed in Acute and Chronic Toxicity Units (according USEPA) range between <0.3--2 and <1--5 respectively (recommended magnitudes for industrial effluents according USEPA: 0.3 and 1 toxicity units respectively). Therefore, the toxicitymore » found in Reconquista River ecosystem was up to 6 times higher than the maximal value recommended for industrial effluents. It is noteworthy that in the place where toxicity starts to rise, a large number of dead fishes were found and from that place downstream, no macroorganisms were found in the river. The results confirm the high sensitivity of Bufo arenarum embryos for continental waters ecotoxicological studies and the possibility of using this test as a short-term chronic toxicity method for water quality-based toxics control.« less
Cellular and Molecular Life Sciences, Oct 1, 1986
Environmental Health Perspectives, Feb 1, 1996
Biological Trace Element Research, Feb 1, 1990
The protective effect of zinc against slight teratogenical action, exerted by low cadmium concent... more The protective effect of zinc against slight teratogenical action, exerted by low cadmium concentrations, was evaluated in Bufo arenarum embryos treated simultaneously with both cations or preincubated with Zn before Cd treatment. Data on survival, malformations, and delay in development pointed out that Zn could prevent the deleterious effects of Cd in previous and simultaneous treatments with that heavy metal.
Environmental Pollution, 2002
Test of early life stages are very sensitive to toxic effects and moreover a good predictive corr... more Test of early life stages are very sensitive to toxic effects and moreover a good predictive correlation between embryo-larval survival and independent ecological parameters such as species richness and diversity have been established. The main purpose of this preliminary study is to report that Bufo arenarum embryos are very sensitive to contaminants from a variety of sources such as leachates, industrial effluents, surface and ground water. The toxicity of 30 samples (five from each category plus controls of surface and ground water from reference places) was evaluated during a 14 day renewal toxicity test at 20 C, conducted with 10 embryos (by triplicate) from stage 23--25 onwards using six concentrations (V/V) of each sample of Holtfreter`s solution. For industrial effluents and leachates the results range from a concentration of 0.6% resulting in 24hs LC100 up to a sample which exert 20% of lethality after 14 days of treatment. The survival of controls and in samples from reference places was over 90% for 7 days and over 80% for 14 days. The results with Bufo arenarum embryos confirm that a 7 day Short-term Chronic Toxicity Test is appropriate for toxicity screening of industrial effluents (as it was established by EPA formore » whole effluent toxicity test for aquatic life protection performed with other species) as well as for leachates. On the other hand, for freshwater (surface and ground), it is convenient to extend the exposure period until 14 days in order to record situations of low, but significant levels of toxicity, which could be of particular value for surface as well as ground water quality criteria.« less
Complementary Therapies in Medicine, 1993
Comparative Biochemistry and Physiology Part A: Physiology, 1987
Academia Medicine, Oct 31, 2023
Although the relationship between environmental toxicity and infectious diseases is poorly studie... more Although the relationship between environmental toxicity and infectious diseases is poorly studied, it is probably more common than is recognized, since the chemical substances could be associated with pre-existing pathologies. For example, some conditions that influence the progression of COVID-19 could have toxicological causes such as cancer, endocrine, neurological, and inflammatory disorders, kidney failure, etc. This contribution highlights that SARS-CoV-2 and some high-volume organic and inorganic chemicals could also exert dysfunctions in the same homeostatic regulators such as HIF-1 and ACE2, with a potential synergistic effect that could affect the severity of COVID-19. This potential synergy is illustrated with adverse effects acquired through bioassays performed with free-living vertebrate embryos indicating that their use as sentinel organisms for environmental contamination could be beneficial both for the ecosystem and human health.
PubMed, Feb 1, 1978
1. The development was studied of embryos in which dramatic deformations were produced by physica... more 1. The development was studied of embryos in which dramatic deformations were produced by physical means during the period in which they are highly susceptible to teratogenesis. 2. In spite of the deformations histogenesis as a whole as well as cytodifferentiation seems to be normal. 3. With only few exceptions the embryos showing dramatic deformations ultimately recover a normal morphology. 4. The shape recovering capacity raises the question whether morphogenesis and shape are not in fact more or less independent phenomena.
International Journal of Environmental Research and Public Health, Jun 30, 2007
Journal of Applied Toxicology, 2005
BioMed Research International, 2017
Ecotoxicology, Mar 15, 2012
Proceedings ... annual meeting, Electron Microscopy Society of America, Aug 1, 1978
SEM studies on amphibian gastrulation have shown the overall shape and arrangement of several cel... more SEM studies on amphibian gastrulation have shown the overall shape and arrangement of several cell types (e. g. bottle cells, mesodermal cells, ectodermal cells, etc. ) as well as the cellular activities in the blastocoel cavity during archenteron floor descent. The main purpose of the present communication is to show the internal structure of Bufo arenarum gastrula as viewed in sagittal dissection at the stage when the ventral blastoporal groove starts forming.Material and Methods: Bufo arenarum gastrula were fixed in 2, 5% glutaraldehyde in phosphate buffer for 2, 5 hrs. After removing the vitelline membrane the embryos were fractured and then dissected near the mid-sagittal plane. The specimens were dehydrated through an acetone series, dried according to the critical point technique, coated with evaporated gold-platinum and observed in a Jeol JSM-U3 scanning electron microscope operated at 5-15 kW.Observations: The internal structure of a Bufo arenarum gastrula at the ventral blastoporal groove stage is illustrated in Fig. 1. Blastocoel cavity (B), internal endodermal yolky cells (Y), prospective ectoderm (PE), archenteron (A), dorsal blastoporal lip (L), ventral blastoporal groove (V).
As a result of their aquatic embryonic and larval development, many species of amphibians are pot... more As a result of their aquatic embryonic and larval development, many species of amphibians are potentially affected by adverse environmental conditions. In this study the possibility of reducing the lethal effect of aluminum (ALC13, Mallinckrodt) in Bufo arenarum embryos by means of simultaneous zinc (ZnSO4) treatment is reported. The aluminum hazard was evaluated in a 7 day renewal toxicity testing study conducted with batches of 10 individuals (by quadruplicate) in six concentrations of aluminum plus the control at 20 C. The pH of the experimental solutions were measured. The LC100 expressed as Al(3 +) mg/L at 24 and up till 168 hours of treatment were 0.9 (the pH of the solution was 6.2 while in control Holtfreter solution the pH was 6.8). Therefore, aluminum exert a lethal effect on amphibian embryos in concentrations which reduce only slightly the pH of the maintaining solution. The lethal effect of aluminum could be reduced 100% by means of simultaneous treatment with 2 mg Zn(2 +)/L. The results point out the high sensibility of the amphibian embryos to aluminum (LC100/24hs:0.9mg Al(3 +)/L) and therefore, episodic increases in dissolved aluminum, usually concomitant with surface water pH decreases, could produce very harmful effects during embryonic stagesmore » of amphibians. The noteworthy beneficial effect of zinc against the lethal effect of aluminum could be of practical value in reducing the harmful effects exerted by aluminum. The conspicuous Al-Zn antagonism points out the need of biological test systems for recording the integrated effects of substances released to the environment.« less
Academia Medicine
Although the relationship between environmental toxicity and infectious diseases is poorly studie... more Although the relationship between environmental toxicity and infectious diseases is poorly studied, it is probably more common than is recognized, since the chemical substances could be associated with pre-existing pathologies. For example, some conditions that influence the progression of COVID-19 could have toxicological causes such as cancer, endocrine, neurological, and inflammatory disorders, kidney failure, etc. This contribution highlights that SARS-CoV-2 and some high-volume organic and inorganic chemicals could also exert dysfunctions in the same homeostatic regulators such as HIF-1 and ACE2, with a potential synergistic effect that could affect the severity of COVID-19. This potential synergy is illustrated with adverse effects acquired through bioassays performed with free-living vertebrate embryos indicating that their use as sentinel organisms for environmental contamination could be beneficial both for the ecosystem and human health.
Bulletin of Environmental Contamination and Toxicology, Mar 1, 2002
International Journal of Environmental Research and Public Health, Dec 31, 2006
The water quality based toxics control is essential to evaluate the aggregate toxicity, bioavaila... more The water quality based toxics control is essential to evaluate the aggregate toxicity, bioavailability as well as for the detection and/or prediction of ecological impacts. Reconquista River valley is situated in the north area of Great Buenos Aires with a population of three million inhabitants. The river is loaded with industrial and municipal waste water. In the present preliminary study the authors report the toxicity found in surface water at a 6 sample stations (including a reference point and a stream) all of them downstream from mixing zone areas. The ecotoxicological study was performed with three native species (Bufo arenarum embryos, Cnesterodon decemmaculatus and a species of shrimp collected in an upstream reference site) during a 7 day renewal toxicity test conducted with 10 individuals (by duplicate) for each condition plus control. The results point out that the Bufo arenarum embryos test is the most sensitive to toxic substances as well as the better adapted species to the changing physico-chemical conditions of this river. The results obtained with embryos, expressed in Acute and Chronic Toxicity Units (according USEPA) range between <0.3--2 and <1--5 respectively (recommended magnitudes for industrial effluents according USEPA: 0.3 and 1 toxicity units respectively). Therefore, the toxicitymore » found in Reconquista River ecosystem was up to 6 times higher than the maximal value recommended for industrial effluents. It is noteworthy that in the place where toxicity starts to rise, a large number of dead fishes were found and from that place downstream, no macroorganisms were found in the river. The results confirm the high sensitivity of Bufo arenarum embryos for continental waters ecotoxicological studies and the possibility of using this test as a short-term chronic toxicity method for water quality-based toxics control.« less
Cellular and Molecular Life Sciences, Oct 1, 1986
Environmental Health Perspectives, Feb 1, 1996
Biological Trace Element Research, Feb 1, 1990
The protective effect of zinc against slight teratogenical action, exerted by low cadmium concent... more The protective effect of zinc against slight teratogenical action, exerted by low cadmium concentrations, was evaluated in Bufo arenarum embryos treated simultaneously with both cations or preincubated with Zn before Cd treatment. Data on survival, malformations, and delay in development pointed out that Zn could prevent the deleterious effects of Cd in previous and simultaneous treatments with that heavy metal.
Environmental Pollution, 2002
Test of early life stages are very sensitive to toxic effects and moreover a good predictive corr... more Test of early life stages are very sensitive to toxic effects and moreover a good predictive correlation between embryo-larval survival and independent ecological parameters such as species richness and diversity have been established. The main purpose of this preliminary study is to report that Bufo arenarum embryos are very sensitive to contaminants from a variety of sources such as leachates, industrial effluents, surface and ground water. The toxicity of 30 samples (five from each category plus controls of surface and ground water from reference places) was evaluated during a 14 day renewal toxicity test at 20 C, conducted with 10 embryos (by triplicate) from stage 23--25 onwards using six concentrations (V/V) of each sample of Holtfreter`s solution. For industrial effluents and leachates the results range from a concentration of 0.6% resulting in 24hs LC100 up to a sample which exert 20% of lethality after 14 days of treatment. The survival of controls and in samples from reference places was over 90% for 7 days and over 80% for 14 days. The results with Bufo arenarum embryos confirm that a 7 day Short-term Chronic Toxicity Test is appropriate for toxicity screening of industrial effluents (as it was established by EPA formore » whole effluent toxicity test for aquatic life protection performed with other species) as well as for leachates. On the other hand, for freshwater (surface and ground), it is convenient to extend the exposure period until 14 days in order to record situations of low, but significant levels of toxicity, which could be of particular value for surface as well as ground water quality criteria.« less
Complementary Therapies in Medicine, 1993
Comparative Biochemistry and Physiology Part A: Physiology, 1987
Academia Medicine, Oct 31, 2023
Although the relationship between environmental toxicity and infectious diseases is poorly studie... more Although the relationship between environmental toxicity and infectious diseases is poorly studied, it is probably more common than is recognized, since the chemical substances could be associated with pre-existing pathologies. For example, some conditions that influence the progression of COVID-19 could have toxicological causes such as cancer, endocrine, neurological, and inflammatory disorders, kidney failure, etc. This contribution highlights that SARS-CoV-2 and some high-volume organic and inorganic chemicals could also exert dysfunctions in the same homeostatic regulators such as HIF-1 and ACE2, with a potential synergistic effect that could affect the severity of COVID-19. This potential synergy is illustrated with adverse effects acquired through bioassays performed with free-living vertebrate embryos indicating that their use as sentinel organisms for environmental contamination could be beneficial both for the ecosystem and human health.
PubMed, Feb 1, 1978
1. The development was studied of embryos in which dramatic deformations were produced by physica... more 1. The development was studied of embryos in which dramatic deformations were produced by physical means during the period in which they are highly susceptible to teratogenesis. 2. In spite of the deformations histogenesis as a whole as well as cytodifferentiation seems to be normal. 3. With only few exceptions the embryos showing dramatic deformations ultimately recover a normal morphology. 4. The shape recovering capacity raises the question whether morphogenesis and shape are not in fact more or less independent phenomena.
International Journal of Environmental Research and Public Health, Jun 30, 2007
Journal of Applied Toxicology, 2005
BioMed Research International, 2017
Ecotoxicology, Mar 15, 2012
Proceedings ... annual meeting, Electron Microscopy Society of America, Aug 1, 1978
SEM studies on amphibian gastrulation have shown the overall shape and arrangement of several cel... more SEM studies on amphibian gastrulation have shown the overall shape and arrangement of several cell types (e. g. bottle cells, mesodermal cells, ectodermal cells, etc. ) as well as the cellular activities in the blastocoel cavity during archenteron floor descent. The main purpose of the present communication is to show the internal structure of Bufo arenarum gastrula as viewed in sagittal dissection at the stage when the ventral blastoporal groove starts forming.Material and Methods: Bufo arenarum gastrula were fixed in 2, 5% glutaraldehyde in phosphate buffer for 2, 5 hrs. After removing the vitelline membrane the embryos were fractured and then dissected near the mid-sagittal plane. The specimens were dehydrated through an acetone series, dried according to the critical point technique, coated with evaporated gold-platinum and observed in a Jeol JSM-U3 scanning electron microscope operated at 5-15 kW.Observations: The internal structure of a Bufo arenarum gastrula at the ventral blastoporal groove stage is illustrated in Fig. 1. Blastocoel cavity (B), internal endodermal yolky cells (Y), prospective ectoderm (PE), archenteron (A), dorsal blastoporal lip (L), ventral blastoporal groove (V).
As a result of their aquatic embryonic and larval development, many species of amphibians are pot... more As a result of their aquatic embryonic and larval development, many species of amphibians are potentially affected by adverse environmental conditions. In this study the possibility of reducing the lethal effect of aluminum (ALC13, Mallinckrodt) in Bufo arenarum embryos by means of simultaneous zinc (ZnSO4) treatment is reported. The aluminum hazard was evaluated in a 7 day renewal toxicity testing study conducted with batches of 10 individuals (by quadruplicate) in six concentrations of aluminum plus the control at 20 C. The pH of the experimental solutions were measured. The LC100 expressed as Al(3 +) mg/L at 24 and up till 168 hours of treatment were 0.9 (the pH of the solution was 6.2 while in control Holtfreter solution the pH was 6.8). Therefore, aluminum exert a lethal effect on amphibian embryos in concentrations which reduce only slightly the pH of the maintaining solution. The lethal effect of aluminum could be reduced 100% by means of simultaneous treatment with 2 mg Zn(2 +)/L. The results point out the high sensibility of the amphibian embryos to aluminum (LC100/24hs:0.9mg Al(3 +)/L) and therefore, episodic increases in dissolved aluminum, usually concomitant with surface water pH decreases, could produce very harmful effects during embryonic stagesmore » of amphibians. The noteworthy beneficial effect of zinc against the lethal effect of aluminum could be of practical value in reducing the harmful effects exerted by aluminum. The conspicuous Al-Zn antagonism points out the need of biological test systems for recording the integrated effects of substances released to the environment.« less