scholarly journals Age changes in the tigroid substance of neutrons of the lateral preoptic nucleus of hypothalamus under different light modes

2021 ◽  
Vol 11 (10) ◽  
pp. 269-274
Author(s):  
R. Bulyk ◽  
V. Yosypenko ◽  
M. Kryvchanska ◽  
K. Vlasova ◽  
Y. Lukan
Keyword(s):  
Optical Density ◽  
Histochemical Staining ◽  
Light Deprivation ◽  
Preoptic Nucleus ◽  
Age Changes ◽  
Light Stimulation ◽  
Experimental Conditions ◽  
Old Rats

The article presents analysis of the results of the original histochemical studies of tigroid substance of neurons of the lateral preoptic nucleus of  hypothalamus in mature and old rats under the influence of different light modes. In all observations, the tigroid substance was located in the cytoplasm of neurons of the lateral preoptic nucleus of hypothalamus in the form of individual granular formations of different sizes and shapes. The amount of tigroid substance of neurons of the lateral preoptic nucleus of hypothalamus in mature rats is greater than in older rats. At the same time, it should be noted that different experimental conditions significantly affected the amount of tigroid substance in neurons of the lateral preoptic nucleus of hypothalamus in old rats. In particular, under conditions of light deprivation, the optical density of specific histochemical staining for tigroid substance in neurons of the lateral preoptic nucleus of hypothalamus increased significantly (p<0,001), and under conditions of light stimulation, on the contrary, probably decreased (p<0,001).

scholarly journals ONTOGENETIC ASPECTS OF MELATONIN RECEPTORS 1A DENSITY IN THE LATERAL PREOPTIC NUCLEUS OF THE HYPOTHALAMUS UNDER VARIOUS LIGHT CONDITIONS

2021 ◽  
Vol 74 (9) ◽  
pp. 2202-2206
Keyword(s):  
Circadian Rhythm ◽  
Immunohistochemical Staining ◽  
Melatonin Receptors ◽  
Polymeric System ◽  
Light Deprivation ◽  
Light Conditions ◽  
Preoptic Nucleus ◽  
Light Stimulation ◽  
Old Rats

The aim: To find out density of melatonin receptors 1A in the neurons of the lateral preoptic nucleus of the hypothalamus in mature and old rats under various light conditions. Materials and methods: The study was carried out on 72 albino mature and old rats with light conditions appropriate for the experiment. To find out circadian differences of melatonin receptors 1A the material for the study was taken at 2 p.m. and 2 a.m. Visualization of primary antibodies against melatonin receptors 1A (Abcam) was conducted by means of the polymeric system Dako and diaminobenzidine staining under the microscope Delta Optical Evolution 100. The intensity of staining was assessed on the digital copies of images according to computer microdensitometry method. Results: Immunohistochemical examinations conducted enable to suggest that melatonin receptors 1A in the neurons of the lateral preoptic nucleus of the hypothalamus respond to different light conditions. In particular, intensity of immunohistochemical staining to melatonin receptors 1A under conditions of light deprivation increases both in mature and old rats, but it decreases under conditions of light stimulation. The parameter is higher at 2 a.m. as compared with 2 p.m. Intensity of immunohistochemical staining to melatonin receptors 1A in the neurons of the lateral preoptic nucleus of the hypothalamus is always lower in old rats than in mature ones. Conclusions: Density of melatonin receptors 1A in the neurons of the lateral preoptic nucleus of the hypothalamus is subordinated to the circadian rhythm: it increases at night and decreases in the daytime. At the same time, light stimulation results in disorders of the rhythm and development of desynchronization.

scholarly journals Continuous Registration of Thrombin Generation in Plasma, Its Use for the Determination of the Thrombin Potential

1993 ◽  
Vol 70 (04) ◽  
pp. 617-624 ◽  
Author(s):  
H C Hemker ◽  
S Wielders ◽  
H Kessels ◽  
S Béguin
Keyword(s):  
Optical Density ◽  
Thrombin Generation ◽  
Time Course ◽  
Enzyme Concentration ◽  
Amidolytic Activity ◽  
Experimental Conditions ◽  
Time Integral ◽  
Α2 Macroglobulin ◽  
Substrate Conversion ◽  
Activity Curve

SummaryA method is described by which the time-course of thrombin generation in plasma can be obtained from a continuous optical density recording of p-nitroaniline (pNA) production in a 2:3 diluted plasma. A chromogenic substrate, methylmalonyl-methylanalyl-arginyl-pNA (SQ68), is used that is specifically split by thrombin but at a low rate. The thrombin that appears and disappears in the plasma does not split more than 5% of the substrate added, so the rate of substrate conversion is in good approximation proportional to the amidolytic activity in the plasma over the entire period of thrombin generation. The course of the enzyme concentration can be calculated from the amidolytic activity curve. It is shown that the thrombin generation curves obtained in this way are essentially identical to those obtained via the classical subsampling method.The presence of SQ 68 influences the amount of free thrombin that appears in plasma because it competitively inhibits the inactivation of thrombin by AT III and α2 macroglobulin. The inhibition of the thrombin peak by heparin, relative to an uninhibited control, remains unaltered by the presence of the substrate.From the course of thrombin activity and the prevailing decay constants, the course of prothrombin conversion velocity can be calculated. Prothrombin conversion was seen to be inhibited at high (>500 μM) substrate concentrations only, and experimental conditions are found under which the inhibition of the clotting process by the substrate is negligibleThe amidolytic activity is the sum of the activities of free thrombin and of the α2 macroglobulin-thrombin complex formed. Via a mathematical procedure the amount of SQ 68 that has been split by thrombin alone and not by the a2 macroglobulin-thrombin complex, can be derived from the course of the optical density.The total amount of SQ 68 eventually split by thrombin alone is proportional to the surface under the thrombin generation curve, i. e. to the time-integral of free thrombin. This value, that we call the thrombin potential (TP), directly indicates how much of any physiological substrate can potentially be split by the thrombin being generated in the plasma.

scholarly journals Effects of Multisession Anodal Electrical Stimulation of the Auditory Cortex on Temporary Noise-Induced Hearing Loss in the Rat

2021 ◽  
Vol 15 ◽  
Author(s):  
Iván Díaz ◽  
Ana Cecilia Colmenárez-Raga ◽  
David Pérez-González ◽  
Venezia G. Carmona ◽  
Ignacio Plaza Lopez ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Optical Density ◽  
Outer Hair Cell ◽  
Acoustic Trauma ◽  
Experimental Conditions ◽  
Compensatory Response ◽  
Epidural Stimulation ◽  
Efferent System ◽  
Efferent Neurons ◽  
Experimental Approaches

The protective effect of the efferent system against acoustic trauma (AT) has been shown by several experimental approaches, including damage to one ear, sectioning of the olivocochlear bundle (OCB) in the floor of the IV ventricle, and knock-in mice overexpressing outer hair cell (OHC) cholinergic receptors, among others. Such effects have been related to changes in the regulation of the cholinergic efferent system and in cochlear amplification, which ultimately reverse upon protective hearing suppression. In addition to well-known circuits of the brainstem, the descending corticofugal pathway also regulates efferent neurons of the olivary complex. In this study, we applied our recently developed experimental paradigm of multiple sessions of electrical stimulation (ES) to activate the efferent system in combination with noise overstimulation. ABR thresholds increased 1 and 2 days after AT (8–16 kHz bandpass noise at 107 dB for 90 min) recovering at AT + 14 days. However, after multiple sessions of epidural anodal stimulation, no changes in thresholds were observed following AT. Although an inflammatory response was also observed 1 day after AT in both groups, the counts of reactive macrophages in both experimental conditions suggest decreased inflammation in the epidural stimulation group. Quantitative immunocytochemistry for choline acetyltransferase (ChAT) showed a significant decrease in the size and optical density of the efferent terminals 1 day after AT and a rebound at 14 days, suggesting depletion of the terminals followed by a long-term compensatory response. Such a synthesis recovery was significantly higher upon cortical stimulation. No significant correlation was found between ChAT optical density and size of the buttons in sham controls (SC) and ES/AT + 1day animals; however, significant negative correlations were shown in all other experimental conditions. Therefore, our comparative analysis suggests that cochleotopic cholinergic neurotransmission is also better preserved after multisession epidural stimulation.

Effect of feeding on glomerular filtration rate and proteinuria in conscious aging rats

1988 ◽  
Vol 255 (2) ◽  
pp. F250-F256 ◽  
Author(s):  
B. Corman ◽  
S. Chami-Khazraji ◽  
J. Schaeverbeke ◽  
J. B. Michel
Keyword(s):  
Glomerular Filtration Rate ◽  
Food Intake ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Renin Angiotensin System ◽  
Experimental Conditions ◽  
Angiotensin System ◽  
System Activity ◽  
Renin Angiotensin ◽  
Old Rats

Food intake increases glomerular filtration and proteinuria in adult rats. That this postprandial hyperfiltration could be age dependent was investigated in 3-, 10-, 20-, and 30-mo-old rats. Glomerular filtration rate and protein excretion were measured in fed or 24 h fasted conscious animals. In the 3-mo-old rats food ingestion increased renal filtration by 45% from 1.17 +/- 0.08 to 1.73 +/- 0.11 ml.min-1.g kidney wt-1 (n = 6). As the animals became older, the differences between fed and fasted periods became smaller: in 30-mo-old rats glomerular filtration rate was 0.85 +/- 0.03 and 1.01 +/- 0.06 ml.min-1.g kidney wt-1 (n = 6) in fasted and fed conditions, respectively. Proteinuria, which was mainly albuminuria, increased slightly with age and was more markedly reduced by acute food restriction in the 30-mo-old than in the 3-mo-old rats. Because the renin-angiotensin system activity decreases with age, its role in postprandial hyperfiltration was assessed by measuring glomerular filtration in 3-mo-old animals whose angiotensin II converting-enzyme activity was chronically inhibited by daily administration of perindopril. In such experimental conditions there was no longer a difference in renal filtration between fed and fasted rats. These data indicate that 1) postprandial increase in glomerular filtration is to some extent related to the renin-angiotensin system activity; 2) short-term reduction of food intake reduces proteinuria even in senescent rats, although the feeding dependence of the glomerular filtration is blunted with age.

METABOLIC CHANGES IN TESTICULAR CELLS FROM RATS AFTER LONG-TERM EXPOSURE TO 37 °C IN VIVO OR IN VITRO

1980 ◽  
Vol 85 (3) ◽  
pp. 471-479 ◽  
Author(s):  
F. F. G. ROMMERTS ◽  
F. H. DE JONG ◽  
J. A. GROOTEGOED ◽  
H. J. VAN DER MOLEN
Keyword(s):  
Sertoli Cells ◽  
Leydig Cells ◽  
Biochemical Properties ◽  
Effect Of Temperature ◽  
Seminiferous Tubules ◽  
Experimental Conditions ◽  
Testicular Cells ◽  
Old Rats

Biochemical properties of isolated Leydig cells, Sertoli cells and spermatocytes from rat testes have been investigated after in-vivo or in-vitro exposure of these cells to abdominal temperature (37 °C). The rate of production of testosterone and pregnenolone by isolated Leydig cells from cryptorchid and normal testes from mature rats was not different. Production of pregnenolone by mitochondria prepared from cryptorchid testes was 6·7 times higher than production by mitochondria from normal testes. Sertoli cells prepared from immature rats and incubated in vitro at 32 or 37 °C showed, on day 1 of the culture period, an initial twofold increase in the secretion of androgen-binding protein which was absent after 6 days in culture. In contrast, incorporation of [3H]leucine into secreted proteins was stimulated twofold on day 1 as well as by day 6 of culture. Secretion of oestradiol was increased 30-fold by day 6 when compared with the level found on day 1 when cells had been cultured at 37 °C and the increased secretion of oestradiol was maintained for approximately 2 days when the temperature of incubation was decreased to 32 °C Spermatocytes isolated from seminiferous tubules incubated for 20 h at 37 °C were active in the synthesis of RNA. No degeneration of these cells was observed in testes of 25-day-old rats 5 days after experimental cryptorchidism, whereas under similar conditions massive degeneration of spermatocytes was shown in the testes of mature rats. These results suggest that the effects of temperature on the different testicular cells greatly depend on the experimental conditions used to study the effect of temperature.

Identification of amino acid transport systems stimulated by FSH in rat testes

1985 ◽  
Vol 106 (3) ◽  
pp. 291-294 ◽  
Author(s):  
A. da Cruz Curte ◽  
G. F. Wassermann
Keyword(s):  
Transport Systems ◽  
Independent System ◽  
Experimental Conditions ◽  
Bicarbonate Buffer ◽  
Immature Rat ◽  
Aminoisobutyric Acid ◽  
System A ◽  
System L ◽  
Sodium Dependent ◽  
Old Rats

ABSTRACT Testes of 12-day-old rats preincubated (90 min) and incubated (60 min) with FSH in Krebs–Ringer bicarbonate buffer (KRB) increased their uptake of [14C]methylaminoisobutyric acid and [14C]aminoisobutyric acid. The hormone was ineffective in sodiumfree KRB. Transport of [14C]aminoisobutyric acid in the presence of methylaminoisobutyric acid (MeAIB; 30 mmol/l) was not stimulated by FSH, and uptake of [14C]cycloleucine was not increased by FSH in any of the experimental conditions used. It was concluded that in immature rat testes FSH affects only the sodium-dependent system which permits the transport of MeAIB (transport system A) and has no effect on the sodium-independent system which prefers leucine (system L) or the sodium-dependent system which does not transport MeAIB (system ASC). J. Endocr. (1985) 106, 291–294

scholarly journals Spontaneous cerebellar activity and its role in neurotoxicity

2017 ◽  
Vol 70 (9-10) ◽  
pp. 283-289
Author(s):  
Ljiljana Martac ◽  
Gordana Stojadinovic ◽  
Branka Petkovic
Keyword(s):  
Cerebral Cortex ◽  
Fractal Dimension ◽  
Spontaneous Activity ◽  
Spectral Power ◽  
Aluminium Chloride ◽  
Control Group ◽  
Experimental Conditions ◽  
Electrocortical Activity ◽  
Chloride Hexahydrate ◽  
Old Rats

Introduction. In performed experiments, the parietal electrocortical activity of the cerebral cortex and the activity of the cerebellar cortex were simultaneously recorded. The main purpose was to compare their spontaneous activity, as the recording was conducted during anesthesia. Material and Methods. We used 2-3 months old rats weighing 200 - 350 g. Two groups of rats with same characteristics were made. The first group of 15 rats (control group) was recorded under anesthesia and there was a change in spectral power in accordance with frequency ranges. The second group of 30 rats was recorded under the same experimental conditions, but the rats were treated intraperitoneally by aluminium chloride hexahydrate solution or with 1.5% solution of aluminium chloride hexahydrate per os. Discussion. Changes in spontaneous activity of the cerebellum during aluminium intoxication were compared with control values. It was shown that lesion and neurotoxicity during stable anesthesia led to desynchronization of the cerebellar activity. This is described by the change in fractal dimension of cerebellar electrocortical activity. The assumption is that the inhibition caused by anesthetic is compensated during aluminium intoxication. Conclusion. The cerebellum plays a role in compensation through changes in spontaneous activity. This response involves an increase in the value of fractal dimension of cerebellar electrocortical activity which is reduced in neurotoxicity.

scholarly journals Study on Smoke Detector Characteristics Using Fire Simulations

2021 ◽  
Vol 35 (4) ◽  
pp. 8-14
Author(s):  
Ga-Hyeon Lee ◽  
Sung-Eun Lee ◽  
Si-Kuk Kim ◽  
Seung-Chul Lee
Keyword(s):  
Optical Density ◽  
Preliminary Data ◽  
Performance Testing ◽  
Wood Smoke ◽  
Smoke Detector ◽  
Experimental Conditions ◽  
Smoke Detectors ◽  
Fire Detector ◽  
Technical Specifications ◽  
Fire Experiments

To reduce the damage caused by fire detector malfunctions, we investigated the standards and literature pertaining to fire detectors in Korea. The domestic standards cite UL's technical specifications, which provide only the standards and types of combustible materials; however, additional research is needed because no facilities related to the experiments are investigated and no fire experiments have actually been conducted. In this study, we refer to UL 268, which is similar to the domestic standards, as well as detailed experimental conditions and methods to improve smoke detector performances; we also use wood as the combustion material from among the fire sources specified in UL 268. Experiments were conducted to measure the sensitization rates using an optical density meter and repeated to match the wood smoke profile standard provided in UL 268. Furthermore, we compared the smoke concentrations detected by the smoke detectors in the fire experiments with those from fire simulations using FDS software to confirm the detector characteristics. Through these comparisons, we show that this research could be used as preliminary data for performance testing of detectors using UL 268.

scholarly journals The State of Oxidative Metabolism in the Cardiac and Skeletal Muscle Tissue in Conditions of Light Deprivation

2020 ◽  
Vol 5 (5) ◽  
pp. 319-323
Author(s):  
M. Sh. Hilmutdinova ◽  
◽  
L. D. Chebotar ◽  
O. M. Larycheva
Keyword(s):  
Skeletal Muscle ◽  
Muscle Tissue ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Superoxide Anion Radical ◽  
Skeletal Muscle Tissue ◽  
Light Deprivation ◽  
Experimental Conditions ◽  
Intact Group ◽  
Femoris Muscle

The article considers the features of oxidative metabolism of cardiac and skeletal muscle tissue in the changed photoperiod, under the influence of round-the-clock light deprivation in combination with the introduction of exogenous melatonin. Material and methods. The experimental study was performed on male Wistar rats. Two groups were formed for research: intact and experimental. The animals of the intact group were in standard housing and feeding conditions, without changes in light regime. The animals of the experimental group for 30 days were in conditions of round-the-clock light deprivation on the background of the introduction of melatonin at a dose of 1.0 mg/kg body weight. Results and discussion. The level of production of reactive oxygen species was evaluated by the formation of a superoxide anion radical. To assess the prooxidant-antioxidant system in the homogenate of the studied tissues was determined by the concentration of thiobarbituric acid reactive substances. The efficiency of the enzyme link was evaluated by catalase and superoxide dismutase activity. We revealed an increase in the production of superoxide anion radical due to the activity of phagocytes compared to the intact group in the heart muscle under conditions of light deprivation on the background of the introduction of melatonin. In skeletal muscle tissue homogenate the production of superoxide anion radical by the mitochondrial electron transport chain production is likely was reduced compared to the intact group. Light deprivation on the background of exogenous administration of melatonin reduces the intensity of production of reactive oxygen species, which is confirmed by a decrease in the level of superoxide anion radical in the homogenate of the quadriceps femoris muscle tissues of experimental animals. Melatonin as an antioxidant reduces the production of superoxide anion radical by mitochondrial oxidation in the quadriceps femoris muscle. In this case, the excess melatonin stabilizes the fluidity of the membrane, reducing its permeability, which may indicate the protective properties of this substance. Conclusion. Thus, modeling the conditions of excess melatonin modifies the generation of superoxide anion radical from various sources. The above experimental conditions contribute to multidirectional changes in the quantitative generation of the superoxide anion radical in the heart and skeletal muscles. Changes in the indicators of prooxidant-antioxidant status in the homogenate of the studied tissues under the selected experimental conditions were not detected

ENZYME IMMUNOASSAY PROTOCOL OPTIMIZATION FOR T-2 TOXIN INDICATION

2020 ◽  
Vol 15 (4) ◽  
pp. 551-560
Author(s):  
N.N. Mishina ◽  
◽  
I.N. Shtyrov ◽  
E.I. Semenov ◽  
N.M. Vasilevskiy ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Optical Density ◽  
Development Stage ◽  
Test System ◽  
Enzyme Linked Immunosorbent Assay ◽  
Experimental Conditions ◽  
First Case ◽  
Dependent Signal ◽  
Density Values ◽  
Enzyme Label

T-2 toxin is one of the most common and toxic trichothecene mycotoxins – secondary metabolites of molds that develop on cereals and some other crops. This article discusses the development stage of a test system for the determination of T-2 toxin based on enzyme-linked immunosorbent assay (ELISA), which uses an enzyme label – a conjugate of anti-rabbit goat antibodies with peroxidase. An important step in the creation of any ELISA-based test system is the preliminary titration of reaction components. The aim of the work was to determine the optimal concentration of the conjugate of antispecies antibodies in an indirectly competitive enzyme-linked immunosorbent enzyme immunoassay with the indication of T-2 toxin. A number of dilutions of the antivirus conjugate were examined: 1 : 1000; 1 : 2000; 1 : 3000; 1 : 4000; 1 : 5000; 1 : 7500; 1 : 10000; 1 : 12 500; 1 : 15,000; 1 : 17,500; 1 : 20,000; 1 : 30 000. In the ELISA staging protocol, calibration solutions of T-2 toxin at concentrations of 0.0 were used; 2.5; 5, 10, 20, 40, 80, 160 ng/ml and specific polyclonal rabbit antibodies to the T-2-BSA conjugate. Based on the average optical density values, calibration plots were constructed using the percentage of signal absorption from the zero standard. When evaluating the results of the study, the criterion for choosing the dilution of the conjugate of anti-species antibodies was considered the greatest, at which the best linearity of the grading plot is achieved and the level of its non-specific reaction with the zero standard would be the lowest. It was established that the optimal variants of dilutions of the conjugate of anti-species antibodies under the same experimental conditions tested were 1: 4000, 1 : 5000 and 1 : 12 500. Dose-dependent signal absorption was observed in all concentrations of anti-species antibodies. Dilutions of the conjugate of anti-species antibodies 1 : 1000–1 : 3000 and 1 : 17 500–1 : 30 000 were not taken into account, since the optical density of most wells was higher than the optimal boundaries in the first case (> 3.9) and lower in the second (< 0.4). Based on the foregoing, optimal dilution of the conjugate of anti-species antibodies was selected 1 : 12 500.

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