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1.
Bioessays ; 45(9): e2300071, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37300287

RESUMO

Niels Kaj Jerne has proposed the "immune network theory" of interactions among anti-idiotypic antibodies, able to interfere with humoral responses to certain antigens. After the occurrence of the primary generation of antibodies, against an antigenic epitope, idiotypes of these antibodies induce anti-idiotypic antibodies that modulate the intensity of the first response, and so on. Adverse effects following SARS-COV-2 COVID-19 vaccines are occasionally similar to the symptoms of COVID-19 infection. Rare events linked to SARS-CoV-2 vaccines also resemble some rarely reported COVID-19 complications. Safety data from product information by European Medicines Agency suggest that spectra do overlap for four main vaccines. The proposition is that vaccine events and COVID-19 complications are related to anti-idiotypic antibodies whose spatial shape can lead to interactions with ACE2 molecules, in individuals with a prolonged Spike protein synthesis. The vaccines target cells by their affinity to the vaccine vector, or to engulf lipid nanoparticles. Anti-idiotypic antibodies shaped similarly to the Spike protein possibly interact with ACE2 molecules and cause diverse signs and symptoms.


Assuntos
COVID-19 , Humanos , Vacinas contra COVID-19/efeitos adversos , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2 , SARS-CoV-2 , Imunidade , Vacinação , Anticorpos Anti-Idiotípicos
2.
Bioessays ; 45(6): e2300023, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37042128

RESUMO

Hyperbaric oxygen (HBO) therapy still lacks proper interpretations of its many actions. This hypothesis is based on reports of temporarily elevated peripheral vascular resistance (PVR) during HBO sessions. Besides that, during HBO sessions, hyperoxygenated tissues can reduce their perfusion so much that CO2 can accumulate in them. Tissue perfusion depends on vascular innervation and on the balance between systemic constrictors and local dilators. During an HBO session, increased tissue oxygen levels suppress dilatory mechanisms. Tissue hyperoxygenation increases PVR, suggesting that the HBO action on an edematous tissue may be caused by an oxygen-induced disbalance among Starling capillary forces. The presented hypothesis is that oxygen-caused arteriolar constriction reduces the hydrostatic pressure in downstream capillaries. Thus, more tissue fluid is absorbed in vascular capillaries, under the condition that the plasma colloid osmotic pressure remains unaltered during the HBO session. Among several known mechanisms behind the HBO actions, the vasoconstriction has been listed as a therapeutic modality for the reduction of the tissue edema, for a crush injury, for burns (in an acute phase), and for the compartment syndrome. The Bell's palsy is among often listed indications for the HBO treatment, although evidence is poor and reports of randomized trials are scarce.


Assuntos
Oxigenoterapia Hiperbárica , Arteríolas , Capilares , Oxigênio
3.
Bioessays ; 43(3): e2000112, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33336824

RESUMO

This renin-angiotensin system (RAS) interpretation is focused on differences in tissue dependence on RAS and on the topological hierarchy that allows mediators to act only on downstream tissues. Dependence of tissues on RAS: Tested by expectation maximization clustering of the RNA human tissue expression (https://biogps.org/). ACE and vasoconstrictive AT1R clustered with the prorenin receptor. ACE2 and dilatory MAS1 clustered with nine RAS-related genes, highly expressed in: Liver; Cardiac_Myocytes; Skeletal_Muscle; Uterus; Kidney; Lung; Small_Intestine; Smooth_Muscle. RAS and stress accumulation: While prorenin is active after binding to its receptor, binding of soluble renin increases its enzymatic activity several times. Increased renin secretion multiplies the overall capacity for producing Ang I, leading to hypertension and increased vascular resistance. Coronavirus infection and comorbidities: Cardiorespiratory failure during infection is linked to the previously altered RAS role in lungs and myocardium. Reduced vasodilation by ACE2 lead to vasoconstriction and suboptimal tissue perfusion patterns. Also see the video abstract here https://www.youtube.com/watch?v=Jf0Iped-Mws.


Assuntos
Enzima de Conversão de Angiotensina 2/genética , COVID-19/genética , Hipertensão/genética , Sistema Renina-Angiotensina/genética , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidade , Idoso , Angiotensina I/genética , Angiotensina I/metabolismo , Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/metabolismo , COVID-19/mortalidade , COVID-19/virologia , Regulação da Expressão Gênica , Humanos , Hipertensão/metabolismo , Hipertensão/mortalidade , Hipertensão/virologia , Pulmão/metabolismo , Pulmão/patologia , Pulmão/virologia , Miocárdio/metabolismo , Miocárdio/patologia , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/metabolismo , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Receptor Tipo 1 de Angiotensina/genética , Receptor Tipo 1 de Angiotensina/metabolismo , Receptor Tipo 2 de Angiotensina/genética , Receptor Tipo 2 de Angiotensina/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Renina/genética , Renina/metabolismo , Transdução de Sinais , Análise de Sobrevida
4.
Bioessays ; 42(10): e2000056, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32820542

RESUMO

This paper discusses possible mechanisms that might lead to misinterpretations of collected data and makes new evidence-based medicine (EBM) recommendations to oppose the previously accepted preventive measures, or treatment options. It is focused on the danger of the "red meat" consumption, and the question whether eating pungent food is good or bad for our health and finally whether the "bad luck" concept of getting several cancer types is valid or not. These three topics got and still have significant media attention. Several mechanisms are proposed as possible causes of these apparent conflicts. Some of them have already been recognized but sadly remained less known to medical readers and also to the general population. Also see the video abstract here https://youtu.be/owjoRXrNShA.


Assuntos
Neoplasias , Carne Vermelha , Ingestão de Alimentos , Humanos
5.
Acta Clin Croat ; 61(2): 239-247, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36818940

RESUMO

The aim was to identify immunohistochemical (IHC) markers able to predict recurrence of urinary bladder tumors. The method of multivariate adaptive regression splines (MARS) was applied to IHC data of 33 patients with urinary bladder cancer that relapsed one to six times (24 male and nine female, age 57-87 years). The MARS analysis was used to predict the total number of recurrences and the Ki-67 value by nine IHC markers (epidermal growth factor receptor (EGFR), HER2, HER3, E-cadherin, Ki-67, MLH1, MSH2, MSH6 and PMS2). Data were divided as initial tumors, first and subsequent recurrences, and tumors that relapsed within nine months of previous surgery or later. The IHC markers were semiquantitatively classified into four groups, as follows: 0 means no positive cells; 1, 10% of positive cells; 2, 11%-30% of positive cells; and 3, 31%-100% of positive cells. In predicting the overall number of recurrences, as a surrogate marker of tumor biology, the R2 value for all tumors was 0.423, for initial tumors 0.686, for first recurrence 0.700, and for subsequent recurrences only 0.233. The key predictors for initial tumors were HER2 and MSH2, while for the first recurrence it was EGFR. For quick recurrences (within nine months), the R2 was 0.474 with EGFR and HER3 as predictors, while for slow recurrences R2 was 0.640 due to EGFR and PMS2. In predicting the Ki-67 value of that tumor, the R2 value for all tumors was 0.300, for initial tumors 0.262, for first recurrence 0.360, and for subsequent recurrences only 0.533. The key predictors for first recurrences were EGFR and MSH6, and for subsequent recurrences HER2, EGFR and all Lynch markers. The R2 was 0.266 for quick recurrences and 0.370 for slow recurrences. The finding of E-cadherin was not found relevant by any of these MARS models. In conclusion, the MARS results associated multiple IHC markers with the number of recurrences and with Ki-67 values. It is important that differences in predictive markers were found between initial tumors and first recurrences, and between quick and slow recurrences, thus suggesting that tumor biology is different among these subgroups regarding the total number of recurrences and Ki-67 values.


Assuntos
Biomarcadores Tumorais , Neoplasias da Bexiga Urinária , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Antígeno Ki-67 , Biomarcadores Tumorais/metabolismo , Proteína 2 Homóloga a MutS , Endonuclease PMS2 de Reparo de Erro de Pareamento , Neoplasias da Bexiga Urinária/patologia , Receptores ErbB/metabolismo
6.
Bioessays ; 41(9): e1900075, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31298432

RESUMO

An effort is made to frame memes within a human evolutionary context in which memes are complex emotion-related tools of enhanced learning and spread of language, art, culture and technology. The basic idea is that any information can become a meme if emotions are evoked in a recipient. The evolution of human brain with memetic capabilities thus produced modern humans.


Assuntos
Evolução Biológica , Mídias Sociais , Atitude , Comportamento , Emoções , Alimentos , Humanos
8.
Bioessays ; 39(10)2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28891269

RESUMO

Clinical trial results are often interpreted by inductive reasoning, in a trial design-limited manner, directed toward modifications of the current clinical practice. Deductive reasoning is an alternative in which results of relevant trials are combined in indisputable premises that lead to a conclusion easily testable in future trials.


Assuntos
Resolução de Problemas , Ensaios Clínicos como Assunto , Humanos
9.
Acta Clin Croat ; 57(4): 681-693, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31168206

RESUMO

- Paralumbar muscle performance and fatigue were evaluated by measuring electromagnetic activity during entire body vibration (EBV) in 44 healthy subjects. Physical fitness of subjects was estimated on a 5-degree scale. Electric activity was recorded in 200 seconds with 1 kHz sampling on the Biopac Student Lab during EBV. Data were used to produce time series for two vectors of the phase space and spatial axis: X (left-right), Y (up-down) and Z (ventral-dorsal). Time series were evaluated by calculating fractal dimension by the R/S algorithm. Movement of the electric field along the Y-axis showed changes (up-down) extracted in the first and second quarter of the measurement (p=0.02 and p=0.03, respectively). These changes were not specific for gender but showed dependence on subject age and fitness. The fractal dimension values by the R/S algorithm were larger in female subjects. Results suggested the electric field changes during EBV in the up-down direction to contain information on muscular performance and fatigue, not dependent on gender, but on the age and degree of overall physical fitness.


Assuntos
Músculos do Dorso/fisiologia , Campos Eletromagnéticos , Eletromiografia/métodos , Fadiga Muscular/fisiologia , Esforço Físico/fisiologia , Adulto , Algoritmos , Exercício Físico/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Aptidão Física/fisiologia , Fatores Sexuais , Vibração
10.
BMC Cancer ; 17(1): 231, 2017 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-28356061

RESUMO

BACKGROUND: Unexpected differences in Ki-67 values among HER2 & ER/PgR defined subgroups were found. This study aims to detect possible subdivisions beyond the conventional breast cancer types. METHODS: One thousand one hundred eighty consecutive patients with invasive ductal breast carcinoma were included and distributed in 16 subgroups (four HER2 phenotypes (0+, 1+, 2+ and 3+) times four ER/PgR phenotypes). Complex distributions of Ki-67 values were tested by expectation maximization (EM) clustering. RESULTS: Pooled Ki67 values of all patients showed the presence of three EM clusters (defined as LMA-low mitotic activity, IMA-intermediate mitotic activity and HMA-high mitotic activity) with expected mean Ki-67 values of 1.17%, 40.45% and 77.79%, respectively. Only ER-PgR- tumors significantly dispersed in three clusters (29.75% tumors in LMA, 46.95% in IMA and 23.30% in the HMA cluster), while almost no detected HMA tumors were of ER + PgR+ or ER + PgR- phenotypes. Among 799 ER + PgR+ patients distribution in clusters was HER2 dependent (p = 0.000243), due to increased number of IMA HER2 3+ tumors on the expense of LMA HER2 3+ tumors (52 IMA out of 162 HER2 3+ patients versus113 IMA out of 637 HER2 < 3+ patients). This was not found among ER + PgR- patients (p = 0.186968). Among ER-PgR- patients, HER2 overexpression also increased number of IMA tumor, but by reducing the number of HMA tumors (p < 0.000001). Here, difference between HER2 absent (0+) and HER2 3+ patients was evident (10 HMA out of 125 HER2 3+ patients versus 42 HMA out of 103 HER2 0+ patients). CONCLUSIONS: Results suggest that distributions of breast cancers in three clusters of mitotic activity depend on different mechanisms for ER + PgR+ and ER negative tumors. Although HER2 overexpression increases number of IMA tumors in both settings, in the former it is done by reducing number of LMA tumors, while in the latter it reduces the number of HMA tumors. Mitotic activity of ER + PgR- tumors seems unrelated to the HER2 status, possibly as an indicator that ER dysfunctionality in cancers that lack PgR expression. Among ER negative tumors, the absence of HER2 (0+) might be as important as the HER2 overexpression.


Assuntos
Neoplasias da Mama , Carcinoma Ductal de Mama , Antígeno Ki-67/análise , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Neoplasias da Mama/classificação , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/classificação , Carcinoma Ductal de Mama/metabolismo , Carcinoma Ductal de Mama/patologia , Feminino , Humanos , Imuno-Histoquímica , Antígeno Ki-67/metabolismo , Receptor ErbB-2/análise , Receptores de Estrogênio/análise
11.
Lijec Vjesn ; 139(1-2): 12-7, 2017.
Artigo em Servo-Croata (Latino) | MEDLINE | ID: mdl-30148585

RESUMO

Treatment of oncological patients must be based upon multidisciplinary approach, and takes place in specialized oncological centers. By the end of a specific oncological treatment further follow-up is being managed mostly by the oncologists, but the role of the general practitioners becomes more important every day and therefore should be precisely defined. Nowadays, most of the existing follow-up guidelines are not being based on prospective studies, yet on the expert's opinion of a precise oncological center or specialists. The aim of the Croatian Society of Medical Oncology (CSMO) with these recommendations is to standardize and rationalize the diagnostic procedures' algorithm in follow­up of oncological patients after primary treatment, in patients with planocellular head and neck cancer, oesophageal cancer, gastric cancer and colorectal cancer.


Assuntos
Neoplasias Colorretais , Neoplasias Esofágicas , Neoplasias de Cabeça e Pescoço , Neoplasias Gástricas , Neoplasias Colorretais/terapia , Neoplasias Esofágicas/terapia , Seguimentos , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Oncologia , Guias de Prática Clínica como Assunto , Estudos Prospectivos , Neoplasias Gástricas/terapia
12.
Gen Physiol Biophys ; 35(4): 407-415, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27447399

RESUMO

This study is aimed to estimate spatial variability of normal QRS loops trajectories in successive cardiac cycles analyzed in XYZ phase space among 27 young and 27 older subjects, both male and female. Among young subjects, 10 individuals were professional football players, while the remaining 17 were students without regular physical activities. Modified three-axial leads (Frank's lead system) were used continually to record high-resolution ECG (1 kHz sampling rate) at rest during 200 seconds by Biopac Student Lab System. Variability of all the three spherical coordinates of the ventricular electrical vector in five characteristic positions regarding the R peak was analyzed. It was found that although fractal dimensions were not gender-dependent (p > 0.05), the calculated values in all tested five positions were greater in young than in older individuals (p < 0.05). Besides that, among young subjects, several fractal dimensions were greater in athletes than in physically inactive students (p < 0.05). These results suggest that the availability of possible phase space trajectories for QRS vector motion is related to individual physical activity and ageing, leaving less variability to physically inactive or older individuals. Recognizing noninvasive features of heart activity might help early detection of heart problems caused by aging and sedentary life style.


Assuntos
Envelhecimento/fisiologia , Diagnóstico por Computador/métodos , Eletrocardiografia/métodos , Futebol Americano/fisiologia , Sistema de Condução Cardíaco/fisiologia , Frequência Cardíaca/fisiologia , Algoritmos , Feminino , Fractais , Humanos , Masculino , Pessoa de Meia-Idade , Oscilometria/métodos , Reconhecimento Automatizado de Padrão/métodos , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
13.
Coll Antropol ; 40(1): 63-4, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27301240

RESUMO

A proposition is made that when two independent traits show similar regional patterns of incidence among modern European regions, a plausible expectation is that these two, otherwise unrelated traits, have simultaneously been spread by migration of our ancestors. As a potential example for the proposed concept, distribution of patients with Dupuytren's contracture is here compared with the reported European distribution of Y-Chromosome Haplogroup I, a genetic marker linked to the last glaciation period.


Assuntos
Cromossomos Humanos Y/genética , Contratura de Dupuytren/epidemiologia , Contratura de Dupuytren/genética , Haplótipos/genética , Migração Humana , População Branca/genética , Europa (Continente)/epidemiologia , Humanos , Masculino , População Branca/estatística & dados numéricos
14.
Future Oncol ; 11(16): 2307-14, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26260809

RESUMO

Adverse effects of targeted drugs on normal tissues can predict the cancer response. Rash correlates with efficacy of erlotinib, cetuximab and gefitinib and onset of arterial hypertension with response to bevacizumab, sunitinib, axitinib and sorafenib, possible examples of 'Black Swan' events, unexpected scientific observations, as described by Karl Popper in 1935. The proposition is that our patients have individual intrinsic variants of cell growth control, important for tumor response and adverse effects on tumor-unrelated tissue. This means that the lack of predictive side effects in healthy tissue is linked with poor results of tumor therapy when tumor resistance is caused by mechanisms that protect all cells of that patient from the targeted drug effects.


Assuntos
Antineoplásicos/uso terapêutico , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Antineoplásicos/efeitos adversos , Ensaios Clínicos como Assunto , Medicina Baseada em Evidências , Humanos , Terapia de Alvo Molecular/efeitos adversos , Prognóstico , Resultado do Tratamento
15.
J Theor Biol ; 340: 232-7, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24080235

RESUMO

Based on avian and mammalian fossils found in the northeastern Chinese province of Liaoning and physiological traits linked to homeothermy, a hypothesis of evolution of homeothermic animals is proposed. It is based on the importance of muscle function in cold environment, as a strong selection pressure that favors endothermic metabolism during periods of cold climates. The presented hypothesis postulates that in progressively cooling environment, animals will develop thermal insulation, increased basal metabolism if food is available, and torpor when food is scarce. Since late Permian, Triassic and Cretaceous global temperatures were high, an exceptional place that gradually became cold was needed for the homeothermy evolution. South China Craton is here proposed as a plausible candidate for that role since it drifted across the Paleo-Tethys ocean, from equator to high northern latitudes in a journey that lasted from 250 to 200Myr ago. After this small continent collided with North China Craton some 200Myr ago, the already cold-adapted animals had spread to large, mostly empty spaces on the North China Craton, due to their evolutionary advantage of making active living in the cold environment. The most advantageous early homeothermic animals went further north to the cold Liaoning to start an oasis that delivered modern birds during next 50Myr. Modern mammals possibly evolved somewhere in the cold vicinity. This made Liaoning and similarly cold places the cradles of early birds and early mammals since for the following millions of years these places remained too cold for poikilotherms to enter and warm enough for homeotherms to dwell, until the Cretaceous-Paleogene extinction event and subsequent global cooling that diminished poikilotherms. Homeothermy was probably even more important as a survival advantage in cooler climates of Paleogene, when mammals and birds became dominant animals. This interpretation is probably supported by a recent report that a small primate Archicebus achilles dated ~55Myr ago was found in the more south central China Hubei Province, while Hadrocodium wui, extinct mammaliaform that lived 195Myr ago in what is now the Yunnan province in southwestern China. The final confirmation of the proposed scenario would be to find somewhere in South China avian fossils older than those found in Liaoning, or to find the cradle of early mammals somewhere in Northern China.


Assuntos
Adaptação Fisiológica , Evolução Biológica , Aves/fisiologia , Mamíferos/fisiologia , Animais , Metabolismo Basal , China , Clima , Temperatura Baixa , Fósseis , Humanos , Modelos Biológicos , Termogênese , Fatores de Tempo
16.
J Theor Biol ; 363: 164-8, 2014 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-25150458

RESUMO

This paper puts forward a new hypothesis to interpret the high carrier frequency of CFTR mutations in individuals of European descent. The proposed heterozygote advantage factor is related to the specific climate conditions in Europe during the last 50 ky that might have heavily compromised the respiratory function of our ancestors in Eurasia. A large part of the last 50 ky was cold, and the coldest period was the Last Glacial Maximum (LGM) (26.5 to 19 kya). The global climate was dry with a dust-laden atmosphere (20 to 25 times more dust than the present level). High levels of atmospheric dust started more than 40 kya and ended less than 10 kya. Secretion of airway fluid is usually related to the submucosal tissue hydration, while salt reabsorption relies on activation of CFTRs that allow ENaCs to absorb salt and water. The water loss by evaporation depends on the air humidity and flow rate. Salt accumulation in the mucus is normally prevented by reabsorption of Na(+) and Cl(-) by epithelial cells if the presence of functional CFTRs is normal. If one gene for CFTR is mutated, the number of functional CFTRs is reduced and this limits the capacity of salt reabsorption by epithelial cells. This means that evaporation makes the airway fluid more hypertonic, and osmotic forces bring more water from the interstitial space, thus leading to a new balance in mucosal fluid traffic. Increased osmolarity and volume of airway fluid can be more moveable in cases when evaporation and dust exposure is increased. If both CFTR genes are mutated, low number of functional CFTRs diminishes salt resorption of epithelial cells. Salt accumulated in the mucous fluid within respiratory ducts, as previously described. The hypertonic ductal content forces more water and some electrolytes to enter the airway fluid from the interstitial fluid, and evaporation leads to further concentration of thick immobile mucus. The proposed interpretation is that CFTR mutations have spread among our ancestors that roamed the central Eurasia after the LGM. The heterozygote individuals might have benefitted from the limited water resorption in their respiratory mucosa that allowed improved airway cleansing.


Assuntos
Adaptação Biológica/genética , Evolução Biológica , Fibrose Cística/genética , Fibrose Cística/história , Fibrose Cística/fisiopatologia , Heterozigoto , Respiração/genética , Clima , Poeira , História Antiga , Humanos , Modelos Biológicos , População Branca/genética
17.
Theor Biol Med Model ; 11: 47, 2014 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-25335870

RESUMO

Considering evolution of terrestrial animals as something happening only on flat continental plains seems wrong. Many mountains have arisen and disappeared over the geologic time scale, so in all periods some areas of high altitude existed, with reduced oxygen pressure (pO2) and increased aridity. During orogeny, animal species of the raising terrain can slowly adapt to reduced oxygen levels.This review proposes that animal evolution was often driven by atmospheric oxygen availability. Transitions of insect ancestors and amphibians out of water are here interpreted as events forced by the lack of oxygen in shallow and warm water during Devonian. Hyperoxia during early Carboniferous allowed giant insects to be predators of lowlands, forcing small amphibians to move to higher terrains, unsuitable to large insects due to reduced pO2. In arid mountainous habitats, ascended animals evolved in early reptiles with more efficient lungs and improved circulation. Animals with alveolar lungs became the mammalian ancestors, while those with respiratory duct lungs developed in archosaurs. In this interpretation, limb precursors of wings and pneumatised bones might have been adaptations for moving on steep slopes.Ural mountains have risen to an estimated height of 3000 m between 318 and 251 Mya. The earliest archosaurs have been found on the European Ural side, estimated 275 Myr old. It is proposed that Ural orogeny slowly elevated several highland habitats within the modern Ural region to heights above 2500 m. Since this process took near 60 Myr, animals in these habitats fully to adapted to hypoxia.The protracted P-Tr hypoxic extinction event killed many aquatic and terrestrial animals. Devastated lowland areas were repopulated by mammaliaformes that came down from mountainous areas. Archosaurs were better adapted to very low pO2, so they were forced to descend to the sea level later when the lack of oxygen became severe. During the Triassic period, when the relative content of O2 reduced to near 12%, archosaurs prevailed as only animals that could cope with profound hypoxia at the sea level. Their diverse descendants has become dominant terrestrial animals, until the K-Pg extinction due to meteor impact.


Assuntos
Adaptação Fisiológica , Evolução Biológica , Hipóxia/fisiopatologia , Oxigênio/análise , Altitude , Animais , Federação Russa
18.
Theor Biol Med Model ; 11: 10, 2014 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-24506945

RESUMO

Since cell membranes are weak sources of electrostatic fields, this ECG interpretation relies on the analogy between cells and electrets. It is here assumed that cell-bound electric fields unite, reach the body surface and the surrounding space and form the thoracic electric field that consists from two concentric structures: the thoracic wall and the heart. If ECG leads measure differences in electric potentials between skin electrodes, they give scalar values that define position of the electric field center along each lead. Repolarised heart muscle acts as a stable positive electric source, while depolarized heart muscle produces much weaker negative electric field. During T-P, P-R and S-T segments electric field is stable, only subtle changes are detectable by skin electrodes.Diastolic electric field forms after ventricular depolarization (T-P segments in the ECG recording). Telediastolic electric field forms after the atria have been depolarized (P-Q segments in the ECG recording). Systolic electric field forms after the ventricular depolarization (S-T segments in the ECG recording). The three ECG waves (P, QRS and T) can then be described as unbalanced transitions of the heart electric field from one stable configuration to the next and in that process the electric field center is temporarily displaced. In the initial phase of QRS, the rapidly diminishing septal electric field makes measured potentials dependent only on positive charges of the corresponding parts of the left and the right heart that lie within the lead axes. If more positive charges are near the "DOWN" electrode than near the "UP" electrode, a Q wave will be seen, otherwise an R wave is expected. Repolarization of the ventricular muscle is dampened by the early septal muscle repolarization that reduces deflection of T waves. Since the "UP" electrode of most leads is near the usually larger left ventricle muscle, T waves are in these leads positive, although of smaller amplitude and longer duration than the QRS wave in the same lead. The proposed interpretation is applied to bundle branch blocks, fascicular (hemi-) blocks and changes during heart muscle ischemia.


Assuntos
Eletrocardiografia/métodos , Coração/fisiologia , Humanos , Modelos Teóricos
19.
Theor Biol Med Model ; 11: 29, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24917206

RESUMO

BACKGROUND: A previous theoretic model (Tumour Biol 2013;34:1-7.) that breast tumor types differ in the relative rate of tissue invasion was elaborated and developed on a consecutive case series. METHOD: Histologic data of 68 ductal breast cancer in situ (DCIS) and 1180 invasive ductal cancer (IDC) patients were collected and analyzed. RESULTS: ER+PgR- phenotype was more common in Luminal B2 than among the pooled Luminal A&B1 (p = 0.0002), and more frequent in Luminal B1 than in Luminal A (p = 0.0167). The same phenotype was associated with the age older than 54 years in Luminal B1 and in B2 patients. HER2 type cancers were more frequent in older patients (p = 0.0038).Tumor progression from DCIS to IDC was found 39% faster than the average in Luminal B1 tumors, supporting the clinical importance of this tumor type. A rare combination of low Ki-67 in HER2 type cancers (only 14% of HER2 type cancers) showed very slow transition to IDC (occurring at only 53.55% of average progression rate), while triple-negative cancers progressed faster than the average, despite Ki-67 value (104.63% for low and 114.27% for high Ki-67 tumors).In three tumor types with positive steroid receptors the ER+PgR- phenotype showed slower IDC transition than the ER+PgR+ phenotype of the same tumor type (difference in progression rate was 38% for Luminal A, 46% for Luminal B1 and 67% for Luminal B2 with Ki67 > 14%).Triple-negative tumors in younger patients exceeded the expected average progression rate by 24%, while in HER2 type tumors, the rate of tissue invasion was in younger patients 20% lower than the expected value. CONCLUSIONS: The relative rate of tissue invasion differed substantialy among our patients. Differences depended on tumor types, steroid expression phenotypes and age. The dysfunctional ERs in the ER+PgR- phenotype showed slower rates of tissue invasion, suggesting that ligand binding to functional breast tumor ERs, beside promoting the PgR expression, possibly also promotes tumor transition to the invasive phase.In triple-negative tumors, an age dependent premenopausal mechanism possibly acted as an accelerator of tissue invasion, while faster tissue invasion by HER2-overexpressed tumors in older patients possibly depended on an unidentified mechanism that takes more time to be acquired, so it was less present in premenopausal patients.


Assuntos
Neoplasias da Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Modelos Biológicos , Invasividade Neoplásica , Neoplasias da Mama/metabolismo , Carcinoma Intraductal não Infiltrante/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo
20.
Tumour Biol ; 34(1): 1-7, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23208673

RESUMO

This paper is based on the idea that ductal breast cancer in situ (DCIS) precedes the invasive breast cancer (invBC), although the triple-negative invBCs almost lack their DCIS precursor. Reported incidences of breast tumor types in DCIS and in invasive BCs suggest that probabilities of tumor progression might differ among tumor types, and these differences can have some impact on our patients. Reported data from several papers on incidences of the four breast tumor types-luminal A, luminal B, HER2, and triple negative-are used to compare tumor-type incidences for DCIS and for the invasive BC. The pooled distributions differed (Χ (2) = 97.05, p < 0.0001), suggesting a strong selection pressure that reduces the number of triple-negative DCIS lesions at the time of breast tumor diagnosis. Reported shares of DCIS in all newly diagnosed breast cancers range in large screening trials from 9 to 26 %, so in making a population model, three values are arbitrarily chosen: one DCIS out of ten breast cancers (the 10 % share), one DCIS out of seven breast cancers (one seventh or the 14.3 % share), and one out of five (the 20 % share). By using these shares and the pooled data of tumor-type incidences, values are calculated that would be expected from a hypothetical population in which types of DCIS and invasive BC are distributed accordingly to the reported incidences. The model predicts that the shares of breast cancer tumor types in the modeled population (DCIS plus invasive BCs) are 39 % for luminal A, 20 % for luminal B, 11 % for HER2 positive, and 30 % for the triple-negative cancers. Some 59 % of all breast tumors are expected to be hormone receptor positive, and HER2 to be overexpressed in 31 %. Simulated probabilities of tumor progression were used to calculate the number of tumor progression t(1/2) that has passed before the time of diagnosis. Calculated relative t(1/2) durations in the modeled population suggest that the triple-negative DCIS cases were fastest in tumor progression, three times faster than the HER2-positive tumors and near twice as fast as luminal A. Luminal A is the model slower than luminal B DCIS, suggesting that although their progression depends on estrogen exposure, HER2 overexpression in luminal B tumors adds some speed in tumor progression. The model results suggest that quick tumor progression might be the main feature of the triple-negative breast tumors, leading to seldom triple-negative DCIS at the time of breast cancer diagnosis. Applying approach of the presented model to the real data from a well-defined population seems warranted.


Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Biomarcadores Tumorais , Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Carcinoma Intraductal não Infiltrante/metabolismo , Progressão da Doença , Receptores ErbB/metabolismo , Feminino , Humanos , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo
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