Apoptosis and related proteins in placenta of intrauterine fetal death in prostaglandin f receptor-deficient mice

The present study investigated whether the increase of apoptosis in the placenta is associated with intrauterine fetal death in prostaglandin F receptor-deficient mice. Apoptosis was demonstrated within placental and decidual tissue by the TUNEL method. The majority of apoptosis was found in syncytiotrophoblast tissues. Enhanced TUNEL-positive staining in the syncytiotrophoblast layer was scattered in the placental tissues in clusters of apoptotic cells in the death group. Marked TUNEL-positive cells were identified in decidua of both groups. The rate of apoptosis in the placenta and decidua in the death group was higher than that in the survival group (P < 0.05). Immunohistochemical analysis showed that the level of active caspase-3 protein expression in the placenta in the death group was much higher than that in the survival group. The level of Bcl-2 protein expression in the placenta in the death group was much lower than that in the survival group. Western blot analysis demonstrated that increased expression of the active form of caspase-3 was detected in the placenta and decidua in the death group compared with that in the survival group. In contrast, a decrease in the expression of Bcl-2 was detected in the placenta and decidua in the death group compared with that in the survival group. Enhanced expression of Bax:Bcl-2 ratio was detected in placenta and decidua in the death group compared with that in the survival group. Thus, significantly increased apoptosis in the mouse placenta and decidua might be involved in the pathophysiologic mechanism of intrauterine fetal death.     

Adrenergic innervation of various sections of the heart in laboratory animals and man

By means of incubating slices in 2% glyoxylic acid solution, distribution of adrenergic fibers in the myocardium of various cardiac parts has been studied in the white rat, rabbit, cat, guinea pig and in the man. Both in the animals and in the man the distribution density of the adrenergic fibers of the myocardial plexuses in the auricle is higher than in the ventricle, and in the left half of the heart it is lower than in the right one. There are certain species differences in distribution of the adrenergic fibers. The density of the adrenergic fibers in the guinea pig myocardium is the highest, and in the white rat is is the lowest.     

Expression of IGF-I and -II mRNA in the brain and craniofacial region of the rat fetus

Insulin-like growth factors (IGF-I and -II) are present in the brain during development, with high levels of both being also found in the periphery particularly in the embryo. IGFs in the brain are believed to stimulate the proliferation of neuronal and glial precursors and their phenotypic differentiation. Using in situ hybridization, we have investigated the distribution of cells producing IGF-I and -II in the rat fetus during the second half of prenatal development with special emphasis on the peripheral and central nervous system. High levels of IGF-I mRNA were found in the olfactory bulb and in discrete neurons of the cranial sensory ganglia, notably in the trigeminal ganglion, as early as 13 days of gestation, in the pineal primordium of 18 day old fetuses, and in discrete groups of cells in the cochlear epithelium located laterally outside the forming spiral organ, in day 13 to 21 fetuses. High levels of IGF-II mRNA in the brain, besides the choroid plexus and the leptomeninges, were detected in hypothalamus, in the floor of the 3rd ventricle at all stages studied, in the pineal primordium at 18 days and in the pars intermedia of the pituitary or in the Rathke's pouch epithelium from which it is derived, with progressive fading towards the end of the gestation. In the peripheral nervous system the IGF-II mRNA was only found in association with the vascular endothelia of the ganglia. IGF-II mRNA in the nervous system was found in highly vascularized areas, meninges, blood vessels and choroid plexuses. It is thus associated with structures involved in the production of extracellular fluids and/or substrate transport and supply in the nervous tissues. A more specific role in the differentiation or fetal endocrine function should be considered for IGF-II in cells producing melatonin and melanocyte stimulating hormone (MSH) in the pineal and pituitary glands, respectively. The presence of IGF-I mRNA in the nervous system could be associated with fiber outgrowth and synaptogenesis in the cases of olfactory bulb and developing iris. The role of IGF-I in restricted populations of cells of the cochlear epithelium and in the pineal gland is unclear and requires further investigations including a search for IGF-I receptors in possible target cells. In the sensory ganglia, the presence of high levels of IGF-I mRNA eventually corresponds to the production, by post-translational processing, of the amino-terminal tripeptide of IGF-I, which might represent a neurotransmitter for these sensory neurons.     

Histological comparison between wheat embryos developing in vitro from isolated zygotes and those developing in vivo

There is currently great interest shown in understanding the process of embryogenesis and, due to the relative inaccessibility of these structures in planta, extended studies are carried out in various in vitro systems. The culture of isolated zygotes in particular provides an excellent platform to study the process of in planta embryogenesis. However, very few comparisons have been made between zygotic embryos grown entirely in cultures and those grown in vivo. The present study analyses the differences and similarities between the in vitro and in vivo development of wheat zygotic embryos at the level of morphology and histology. The study was possible thanks to an efficient culture system and an appropriate method of preparing isolated wheat zygotes for microscopy. The in vitro embryos were fixed, embedded and sectioned in the two-celled, globular, club-shaped and fully differentiated stages. Embryos developing in vitro closely followed the morphology of their in planta counterparts and their cell types and tissues were also similar, demonstrating the applicability of the present culture system for studying the process of zygotic embryogenesis. However, some important differences were also detected in the case of in vitro development: the disturbance of or lack of initial polarity led to changes in the division symmetry of the zygotes and subsequently to the formation of uniform cells in the globular structures. Presumably, differences between the in vitro and in planta environments resulted in a lower level of differentiation and maturation in in vitro embryos and in abundant starch and protein accumulation in the scutellum.     

Concentrations of somatotropin and prolactin in the follicular fluid and blood serum of cows in different phases of the estrous cycle

Comparative investigations of somatotropin and prolactin contents in the fluid of antral follicles and blood serum of cows in different phases of the oestrous cycle were performed. The somatotropin concentration in the fluid was shown to rise with increasing the follicle diameters from 3-5 to 6-10 mm in the follicular phase and to decrease in follicles of diameter 11-20 mm in the luteal phase. The prolactin concentration was higher in the fluid of follicles 11-20 mm in diameter than in those of 3-5 mm in diameter in the follicular phase and did not depend on the follicle size in the luteal phase. Concurrently, the prolactin content in follicles 3-5 mm in diameter was higher in the luteal than follicular phase of the cycle. As compared to the follicular phase, an increase in the prolactin concentration in the bovine blood serum during the luteal phase was also found. The data obtained indicate that changes in the somatotropin and prolactin contents in the follicular fluid are related to processes regulating growth and development of antral follicles depending on the phase of oestrous cycle and to changes in the blood hormone concentrations as well.     

The effect of calcitonin on the mechanisms of urine formation and sodium excretion in normotensive and spontaneously hypertensive rats]

The effects of the pig calcitonin on the kidney excretory function in normotensive (NR) and spontaneously hypertensive rats (SHR) were examined. Calcitonin injection in the dose of 0.6 U/100 g of the body mass in NR and SHR in the conditions of 6-hour spontaneous diuresis caused the increase in the urination volume due to the inhibition of the tubular water reabsorption and growth of the glomerular filtration rate. The important role in the mechanism of the decrease in the water reabsorption in SHR plays the decrease in the content of vasopressin in the blood and urea in the kidney interstitium while in NR a more marked inhibition of the water reabsorption is caused by the decrease in the concentration of both urea and sodium in the kidney layers. The natriuretic effect of calcitonin was noticed only in NR.     

Action of cadmium on the elemental composition and cellular morphology of the hepatopancreas, kidneys and gonads of the mussel Mytilus edulis and scallop Mizuhopecten yessoensis

Studies have been made on the content and distribution of Cd, K, Mg, Ca, S and P in organs and cells of mussels and scallops before and after immersion in water containing cadmium chloride. In normal molluscs, the lowest content of Cd was found in the gonads; cadmium content of the hepatopancreas and kidney in the scallop is correspondingly 20 and 40 times higher than in the mussel. After immersion in water with cadmium (250 micrograms/l in summer experiments and 500 micrograms/l in spring ones), cadmium content of the hepatopancreas and kidney of the scallop was found to be also higher than that in the mussel, although the difference is less significant, being dependent on the season of year. The highest accumulation of cadmium (9.760 +/- 790 micrograms/g dry weight) was observed in the scallop kidney in summer period. After immersion in cadmium-containing water, the content of sulphur in the kidney and hepatopancreas increases, positive correlation being observed between the distribution of Cd and S. Exposure to cadmium results in the increase of Ca and Mg content in the gonads of scallops, as well as in the increase in Ca content of the gonads of mussels. Accumulation of cadmium in the gonads is rather small, maximum density of the material being observed histochemically in the gonadal wall. Morphological changes in the gonadal cells of mussels in summer period may be associated with the increase in cellular calcium.     

Development of hypothalamic control over thyrotropin secretion during human prenatal life]

It was shown in the tissue culture experiments that the human hypophysis secreted autonomously the thyrotrophin during the last three fourths of the prenatal life. The intensity of secretion is the highest in the end of the first third of this period, then it decreases, but during the last third it increases reliably again. During the second half of development the level of thyrotrophin in female foetuses in reliably higher than in the male ones. In the beginning of the second third of prenatal life, the hypothalamic factors decrease the autonomous thyrotrophin secretion twice in foetuses of both the sexes. In the end of the second third, sexual differences appear in their effect; they decrease reliably the autonomous thyrotrophin secretion in the male foetuses, whereas no such effect is observed in the female ones. The stimulating effect of the hypothalamic thyrotrophin releasing hormone manifests itself during the last third of prenatal life in foetuses of both the sexes. During the second half of prenatal life, the thyrotrophin concentration in blood of female foetuses is also reliably higher than in male foetuses. There is a positive correlation in female foetuses between the thyrotrophin concentration in blood and the level of hypophysial secretion under the effect of hypothalamic factors. Thyrotrophin is found in the cranial fluid of foetuses. In some cases its concentration in the cranial fluid is higher than in the blood. No correlation was found between the levels of the hormone in fluid and blood in female foetuses; a positive correlation was found in male foteuses.     

Changes of China agricultural climate resources under the background of climate change: IX. Spatiotemporal change characteristics of China agricultural climate resources

Based on the 1961-2007 ground surface meteorological data from 558 meteorological stations in China, this paper analyzed the differences of agricultural climate resources in China different regions, and compared the change characteristics of the agricultural climate resources in 1961-1980 (period I) and 1981-2007 (period II), taking the year 1981 as the time node. As compared with period I, the mean annual temperature in China in period II increased by 0.6 degrees C, and the > or = 0 degrees C active accumulated temperature in the growth periods of chimonophilous crops and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased averagely by 123.3 degrees C x d and 125.9 degrees C x d, respectively. In 1961-2007, the mean annual temperature increased most in Northeast China, and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased most in South China. The whole year sunshine hours and the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops in period II decreased by 125.7 h, 32.2 h, and 53.6 h, respectively, compared with those in period I. In 1961-2007, the annual sunshine hours decreased most in the middle and lower reaches of Yangtze River, while the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops decreased most in North China and South China, respectively. In the whole year and in the growth periods of chimonophilous and thermophilic crops, both the precipitation and the reference crop evapotranspiration in this country all showed a decreasing trend, with the largest decrement in the precipitation in the whole year and in the growth periods of chimonophilous and thermophilic crops in North China, the largest decrement in the reference crop evapotranspiration in the whole year and in the growth periods of thermophilic crops in the middle and lower reaches of Yangtze River, and the largest decrement in the reference crop evapotranspiration in the growth periods of chimonophilous crops in Northwest China. In 1961-2007, the climate in China in the whole year and in the growth periods of thermophilic crops showed an overall tendency of warm and dry, and the climate in the growth periods of thermophilic crops became warm and dry in Southwest China, North China, and Northeast China, but warm and wet in the middle and lower reaches of Yangtze River, Northwest China, and South China, whereas the climate in the growth periods of chimonophilous crops became warm and dry in North China, but became warm and wet in Northwest China.     

气候变化背景下中国农业气候资源变化Ⅸ.中国农业气候资源时空变化特征

利用中国558个气象台站1961-2007年地面气象观测资料,分析了不同区域农业气候资源变化的差异,并分析和比较了1961-1980年(时段Ⅰ)和1981-2007年(时段Ⅱ)的农业气候资源变化特征.结果表明： 与时段Ⅰ相比,时段Ⅱ中国年均气温增加了0.6 ℃,喜凉作物生长期内≥0 ℃积温和喜温作物生长期内≥10 ℃积温分别平均增加123.3和125.9℃·d;1961-2007年,年均气温增幅最大的区域是东北地区,喜温作物生长期内≥10 ℃积温增幅最大的是华南地区.对全国而言,与时段Ⅰ相比,时段Ⅱ在全年、喜凉和喜温作物生长期内日照时数分别减少了125.7、32.2和53.6 h;1961-2007年,长江中下游地区年日照时数的减幅最多,喜凉和喜温作物生长期内日照时数减少量最大的地区分别是华北和华南地区;在全年、喜凉和喜温作物生长期内,中国的降水量和参考作物蒸散量总体均表现为减少趋势,其中,华北地区在全年、喜凉和喜温作物生长期内降水量的减幅均最大,长江中下游地区参考作物蒸散量在全年和喜温作物生长期内的减幅最大,西北地区参考作物蒸散量在喜凉作物生长期内的减幅最大.研究期间,中国气候在全年和喜温作物生长期内总体表现为暖干趋势,其中,喜温作物生长期内西南、华北和东北地区为暖干趋势,长江中下游、西北和华南地区为暖湿趋势,喜凉作物生长期内华北地区为暖干趋势,西北地区为暖湿趋势.     

The nature of the sex-linked differences in glutathione peroxidase activity and aerobic oxidation of glutathione in male and female rat liver

1. Glutathione peroxidase activity in the livers of sham-operated female rats was about 60% higher than in similarly treated male rats. The value in the ovariectomized female was about the same as that in the castrated or sham-operated male. 2. Glutathione peroxidase activity changed during the oestrous cycle. The highest value was in oestrus, and was about 50% higher than the lowest activity, which was found in dioestrus. The activity in proestrus and in metoestrus was respectively about 20 and 30% higher than in dioestrus. 3. In the pregnant female 1 or 2 days before term, glutathione peroxidase activity was about 20% higher than that in the female in oestrus. 4. Subcutaneous implants of both oestra-diol and progesterone in the gonadectomized rats increased the glutathione peroxidase activity approximately to the values found in the female at oestrus. 5. The rate of aerobic oxidation of GSH in the female rat liver was about 80% higher than in the male and about 110% higher than in the gonadectomized rats. Treatment of gonadectomized rats with subcutaneous implants of oestradiol and of progesterone increased the rate of oxidation of GSH by about 100%. 6. In the presence of azide the rate of GSH oxidation in the male and in the female was respectively about 3.5- and 2.1-fold that in the absence of azide. In castrated or ovariectomized rats the increase due to the presence of azide was about 2.4-fold. In the gonadectomized rats treated with oestradiol or progesterone the rate of GSH oxidation in the presence of azide was about 2.2-fold that in its absence. 7. The rate of lipid peroxidation in female was 15-30-fold that in male or in gonadectomized rats. Treatment of the gonadectomized rats with oestradiol or with progesterone increased the rate of lipid peroxidation up to values that were even higher than in the female. In the presence of GSH the formation of malonaldehyde from peroxides was virtually eliminated. 8. The results suggest that the sex-linked differences in glutathione peroxidase activity, in the rate of GSH oxidation and in the rate of lipid peroxidation are due to the female sex hormones. 9. It is suggested that both the catalase activity and the rate of hydrogen peroxide formation are higher in the male than in the female. 10. Sex-linked changes in glutathione peroxidase, in the rate of GSH oxidation and in the rate of lipid peroxide formation are discussed in relation to the metabolism of oestrogens in the liver and also to the possible nature of those sex-linked changes.     

The cause of the activation of an epidemic process of intestinal infections in the 70s]

In the seventies a considerable rise in dysentery morbidity was observed in all republics of the USSR, in the whole of the USSR, in Bulgaria and in the German Democratic Republic. An increase in cholera morbidity in the world, as well as in the number of countries affected by this infection, was registered. A tendency towards a rise in virus hepatitis incidence was observed in the USSR. The dynamic study of the ozone content in the stratosphere, solar activity, disturbances in the magnetic field of the Earth, air temperature for the period of 1967-1980 was carried out. Strong and moderate correlation between dysentery and air temperature in summer was established. The maximum morbidity level in the USSR in 1972 was probably the consequence of unusually high air temperature in summer.     

Effect of alternating magnetic field on the composition and level of lipids in radish seedlings

The effects of alternating magnetic field (AMF) with the frequency of 50 Hz on the dynamics of unfolding of cotyledon leaves, the composition and level of polar and neutral lipids and their component fatty acids (FA) were studied in 5-day-old radish seedlings (Raphanus sativus L. var. radicula D.L., cv. Rozovo-krasnyi s belym konchikom) grown in the light and in the dark. AMF weakened the inhibitory effect of light on unfolding of cotyledon leaves. In the light, the total content of lipids, as well as the level of polar and neutral lipids, in the seedlings in AMF was greater than in control material. In polar lipids, the total amount of glyco-and phospholipids increased; in neutral lipids, the level of triacylglycerols rose. The ratio between phospholipids and sterols (PhL/S) increased. In the dark, the total content of lipids and the level of neutral lipids in the seedlings in AMF were lower than in control material, and the ratio PhL/S decreased. In control material, there were no differences in the relative total content of unsaturated FA in the light and in the dark, whereas the level of linolenic acid was higher in the light than in the dark. AMF induced a decrease in the content of linolenic acid in the light and a rise in the dark; the level of erucic acid in the light decreased. The ratio between unsaturated and saturated FA decreased both in the light and in the dark. It was concluded that AMF with the frequency of 50 Hz was an adjusting agent considerably changing the content of lipids in the radish seedlings in the light and in the dark.     

The vestibular nuclei in the domestic hen (Gallus domesticus). VII.--Afferents from the spinal cord

Lesions of different parts of the spinal cord at different levels in the hen have been made and the resulting degeneration in the vestibular complex has been studied in silver impregnated sections. Spinovestibular fibres originate from cervical as well as lumbosacral levels of the cord and run in the dorsal part of the lateral funiculus. The spinovestibular fibres from all levels of the spinal cord terminate ipsilaterally in the nucleus Deiters ventralis, the nucleus Deiters dorsalis, the medial nucleus and rostrally in the descending nucleus. The spinovestibular fibres terminating in the above nuclei are few in number while spinovestibular fibres terminating bilaterally in the caudal part of the descending nucleus are much more abundant. In a few cases HRP injections in the vestibular complex resulted in labelled cells in upper cervical segments of the spinal cord localized in lamina VII. The findings are discussed in the light of data concerning the spinovestibular pathway in mammals.     

The epidemiological analysis of monitoring of the immune status in liquidators of consequences of the Chernobyl accident for early identification of risk groups and diagnostics of oncological diseases. Report 2. Dependence of frequency and changes in the immune status on risk factors of radiation accident

Malignant neoplasms (MN) have been found to develop most frequently in the liquidators of entry into the ChNPP zones in 1986 (43.75%), as well as among the liquidators who worked for long, one quarter of whom participated in liquidation of the consequences of failure (LCF) in 1986. Specific features of the immune status depending on the timing of participation in LCF and the year of entry into the ChN PP zone have been established. Changes in the immune system in the persons with a confirmed diagnosis of MN who took both a non-permanent and permanent part in liquidating the consequences of the ChNPP failure in 1986 had the same character of deviations and differed in the magnitudes of deviations of immunological parameters. Continuous participation in the period of extreme conditions and a greater exposure to the radiation factor led to the increased content of CD8(+)-T-cells, CD16(+)-lymphocytes and activated T-lymphocytes, as well as to the reduced index of immune regulation, decreased content ofCD3-16/56+(NK)-cells (%) and the total IgE and to a greater deficiency of B-lymphocytes. Distinctions in the groups of liquidators who participated in LCF in 1986 and 1987 have been revealed. The greatest deviations in the IS indicators were found in liquidators-87. A similar effect came to light in case of a continuance in the ChNPP zones in 1986 and 1987; however, the degree of deviation of the content of CD4(+)-T-lymphocytes (41), CD8(+)-T-lymphocytes (1) and the immune regulation index (41) were remarkably higher in liquidators-87. A continuous stay in the ChNPP zones in 1987 led to the deficiency of CD4(+)-T-lymphocytes, increased values of CD8(+)-T-lymphocytes, a decreased index of CD4+/CD8+, as well as to the change in the ratio between NK-T and NK cells, increased numbers of CD95+, HLA-DR+ and activated T-lymphocytes, and a lower level of the total IgE. Long-term participation in LCF didn't cause any enhanced expression of cellular activation markers in liquidators-86. Specific features of changes in IS depending on a dose of external gamma-irradiation have been established. Increase in the frequency of MN among liquidators, in relation to the number of examinees in each age group, with age has been revealed. Distinctions in the age dynamics of IS in liquidators in the presence and in the absence of MN manifested themselves in a stable level of values of CD3+, CD4+, CD8(+)-T-lymphocytes, immune regulation index, CD95+, serum IgA at the age between 40 and 70 years old with a subsequent reduction in indicators and increase in the content of CD8(+)-T-lymphocytes with age in the absence of MN; continuous increase of CD3-16/56(+)-NK-cells in the presence of MN and decrease in the values after 70 in the absence of MN. Also revealed in IS of the both age groups of liquidators over 70 with and without MN was the deficiency of the T-cell component (CD3+, CD4(+)-T-lymphocytes, CD4+/CD8+ index) and the increase in absolute values of CD8(+)-T-lymphocytes. The growing deficiency of CD4(+)-T-lymphocytes during monitoring against the background of ever rising values of CD8(+)-T-lymphocytes leading to the weakening of the immune regulation due to progressing disorders of the T-lymphocyte regulatory subpopulation distribution can serve an indicator for the adverse prognosis of the life expectancy in the presence of MN.     

Activity of NAD- and NADP-dependent malate dehydrogenase isoenzymes in the myocardium of rabbits with alloxan diabetes]

Isoenzymes NAD-and NaDP MDH were detected in the cardiac muscle of rabbits by disc electrophoresis in polyacrylamide gel. Alloxan diabetes proved to be accompanied by a significant reduction in the activity of mitochondrial NADP MDH (in the reaction of malic decarboxylation) and its increase in cytozol. The activity of NAD-MDH (in the reaction of oxyacetate reduction) was also decreased in various isoenzymes in the myocardium (particularly in the mitochondria) in diabetes. Insulin restored the correlation of the activities of the isoenzymes NAD- and NADP-MDH in the cytostructures of the myocardium disturbed in diabetes.     

Immunohistochemical detection of lactoferrin of human milk in the tissues of the human and the fetus

By means of the indirect immunoperoxidase method in deparaffinized slices a comparative investigation on distribution of the female milk lactoferrin (LF) in tissues of the mature person and in the fetus has been performed. LF is revealed in cells of the neutrophil line of the mature person and of the fetus and in the secretory epithelium of some organs of the mature person (in the mammary, submandibular and parotid salivary glands, in the bronchial mucous membrane glands in the fundal and pyloric glands of the stomach). In all the cases investigated LF is revealed in the cells producing serous secrete: in the cells of the serous terminal parts and in the serous semilunar mixed terminal parts of the salivary glands, in the serous cells of the bronchial glands and in the chief cells of the gastric mucous membrane glands. In the fetal secretory epithelium of the organs LF is not found. As LF is revealed in the secretory epithelium of the mature person and is not revealed in the corresponding epithelium of the fetus, it should be considered as a marker of the cells, that reach certain degree of differentiation.     

河北夏蝗大发生与气象条件的关系

利用合成分析和秩相关系数2种方法,分析了河北2种生态类型蝗区中夏蝗LocustamigratoriaL.发生程度与气象条件的关系,以确定影响夏蝗大发生的关键气象因子。结果表明:2个类型蝗区大发生年以前一年5月至当年夏蝗出土以前的气温偏高、降水偏少为主;前一年6月下旬、7月上旬、8月上旬、8月中旬气温、6月上旬降水、当年3月下旬降水、4月下旬气温为沿海蝗区关键影响因子,前一年7月上旬和8月下旬气温、5月中旬降水及当年2月中、下旬气温、4月下旬和5月上旬气温为洼淀蝗区的关键影响因子。     

Dark Leaf Respiration in Light and Darkness of an Evergreen and a Deciduous Plant Species

Dark respiration in light as well as in dark was estimated for attached leaves of an evergreen (Heteromeles arbutifolia Ait.) and a deciduous (Lepechinia fragans Greene) shrub species using an open gas-exchange system. Dark respiration in light was estimated by the Laisk method. Respiration rates in the dark were always higher than in the light, indicating that light inhibited respiration in both species. The rates of respiration in the dark were higher in the leaves of the deciduous species than in the evergreen species. However, there were no significant differences in respiration rates in light between the species. Thus, the degree of inhibition of respiration by light was greater in the deciduous species (62%) than in the evergreen species (51%). Respiration in both the light and darkness decreased with increasing leaf age. However, because respiration in the light decreased faster with leaf age than respiration in darkness, the degree of inhibition of respiration by light increased with leaf age (from 36% in the youngest leaves to 81% in the mature leaves). This suggests that the rate of dark respiration in the light is related to the rate of biosynthetic processes. Dark respiration in the light decreased with increasing light intensity. Respiration both in the light and in the dark was dependent on leaf temperature. We concluded that respiration in light and respiration in darkness are tightly coupled, with variation in respiration in darkness accounting for more than 60% of the variation in respiration in light. Care must be taken when the relation between respiration in light and respiration in darkness is studied, because the relation varies with species, leaf age, and light intensity.     

An analysis of interhemispheric interrelationships in the visual cortex of cats based on the law of contrast perception of light]

The dependence of EP amplitude on the intensity of photic stimuli before and after section of the callosal body may be fully defined by the equation of the contrast law of light perception. Analysis of the nature of interhemispheric relationships by means of contrast law has shown that both reciprocal depressing and reciprocal facilitating interhemispheric relationships may exist in the primary visual cortical projection zone, and reciprocal facilitating interhemispheric influences in the secondary visual projection zone. Similarity of interhemispheric relationships has been recorded in the primary visual cortex in cats and in the secondary one, in rats, as well as in the socondary visual cortical zone in cats, and in the primary, in rats. Interhemispheric reciprocal influences in the whole range of stimuli intensities are distributed more uniformly in cats than in rats. Cats may perceive a wider range of intensity of photic stimuli than rats. In cats as in rats, the effectiveness of processing of the photic stimuli contrast is greater in the secondary visual cortical projection zone than in the primary one.