COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: II. SURFACE TEMPERATURE, VASCULARIZATION, AND IN VITRO RESPIRATION OF THE SKIN

1959 ◽  
Vol 37 (11) ◽  
pp. 1247-1253 ◽  
Author(s):  
O. Héroux
Keyword(s):  
Oxygen Uptake ◽  
Surface Temperature ◽  
Respiratory Rate ◽  
Environmental Conditions ◽  
Cold Temperature ◽  
Dorsal Skin ◽  
Adult Rats ◽  
White Rats ◽  
Different Types

The effect of cold temperature on the skin was studied on white rats exposed to two different types of environmental conditions. Two groups of adult rats kept in individual cages were continuously exposed for 3 months to constant cold temperature (18° and 6 °C) in the laboratory (indoor rats) while other groups of the same colony kept in groups of 10 were exposed for the same length of time to the fluctuating environmental conditions prevailing outside (outdoor rats).Indoor rats acclimated to 18 °C and 6 °C showed the same increase in the number of opened capillaries in the ears over the number observed in controls acclimated to 30 °C. "Summer and winter" outdoor rats showed the same number of capillaries as the "18 °C or 6 °C" indoor rats. Signs of injury healing such as thicker epidermis and larger nuclei were found in the ears of all the "6 °C" rats but in none of the "winter" rats. While the skin temperature measured at + 6 °C was slightly higher (0.4 to 1.0 °C) in rats acclimated at 6 °C than in those at 30 °C, it was lower (1.3 to 2.9 °C) in "winter" than in "summer" rats. After 28 days of acclimation, the rate of oxygen uptake of the dorsal skin of the foot was lower in "6 °C" than in "30 °C" rats but after 84 days it was significantly higher in the cold-acclimated rats. Similarly, after 3 months, the respiratory rate of the dorsal skin of the foot was higher in "winter" rats than in "summer" rats.

COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: II. SURFACE TEMPERATURE, VASCULARIZATION, AND IN VITRO RESPIRATION OF THE SKIN

1959 ◽  
Vol 37 (1) ◽  
pp. 1247-1253 ◽  
Author(s):  
O. Héroux
Keyword(s):  
Oxygen Uptake ◽  
Surface Temperature ◽  
Respiratory Rate ◽  
Environmental Conditions ◽  
Cold Temperature ◽  
Dorsal Skin ◽  
Adult Rats ◽  
White Rats ◽  
Different Types

The effect of cold temperature on the skin was studied on white rats exposed to two different types of environmental conditions. Two groups of adult rats kept in individual cages were continuously exposed for 3 months to constant cold temperature (18° and 6 °C) in the laboratory (indoor rats) while other groups of the same colony kept in groups of 10 were exposed for the same length of time to the fluctuating environmental conditions prevailing outside (outdoor rats).Indoor rats acclimated to 18 °C and 6 °C showed the same increase in the number of opened capillaries in the ears over the number observed in controls acclimated to 30 °C. "Summer and winter" outdoor rats showed the same number of capillaries as the "18 °C or 6 °C" indoor rats. Signs of injury healing such as thicker epidermis and larger nuclei were found in the ears of all the "6 °C" rats but in none of the "winter" rats. While the skin temperature measured at + 6 °C was slightly higher (0.4 to 1.0 °C) in rats acclimated at 6 °C than in those at 30 °C, it was lower (1.3 to 2.9 °C) in "winter" than in "summer" rats. After 28 days of acclimation, the rate of oxygen uptake of the dorsal skin of the foot was lower in "6 °C" than in "30 °C" rats but after 84 days it was significantly higher in the cold-acclimated rats. Similarly, after 3 months, the respiratory rate of the dorsal skin of the foot was higher in "winter" rats than in "summer" rats.

SEASONAL ADJUSTMENTS IN CAPTURED WILD NORWAY RATS: III. PRODUCTION OF ADRENAL STEROIDS IN VITRO

1963 ◽  
Vol 41 (1) ◽  
pp. 1147-1153
Author(s):  
J. S. Willmer ◽  
O. Héroux
Keyword(s):  
Environmental Conditions ◽  
Rattus Norvegicus ◽  
Seasonal Effect ◽  
Seasonal Adjustment ◽  
Adrenal Steroids ◽  
Steroid Secretion ◽  
Adrenal Steroid ◽  
White Rats ◽  
Norway Rats

The in vitro adrenal steroid secretion of wild Norway rats (Rattus norvegicus) captured during the winter differed in quantity, but not in quality, from that of similar rats captured during the summer. Whereas there was no evident seasonal effect on adrenal weight either in males or in females, adrenals of both sexes secreted at a faster rate during the winter than during the summer, this increase involving the four groups of steroids characterized chromatographically during both seasons and in both sexes; the predominant steroid secreted was corticosterone. This seasonal adjustment in adrenal activity is similar to that observed in white rats kept in group cages exposed outdoors to the natural summer and winter environmental conditions, but it differs from that found in white rats cold-acclimated in the laboratory, in which adrenal activity is lower than normal after cold acclimation.

COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: I. METABOLIC AND INSULATIVE CHANGES

1959 ◽  
Vol 37 (3) ◽  
pp. 473-478 ◽  
Author(s):  
O. Héroux ◽  
F. Depocas ◽  
J. S. Hart
Keyword(s):  
Metabolic Rate ◽  
Constant Temperature ◽  
Environmental Conditions ◽  
Resting Metabolic Rate ◽  
Thermal Acclimation ◽  
Cold Temperature ◽  
Metabolic Rates ◽  
Temperature Range ◽  
White Rats ◽  
Physiological Adjustments

Physiological adjustments to cold temperature have been compared in white rats exposed either to the outdoor fluctuating environmental conditions or to the indoor constant temperature conditions. While the metabolic adjustments such as increased peak metabolism and decreased shivering were similar in outdoor and indoor rats exposed to cold, the adjustments in insulation and thermoneutral metabolic rates were quite different. The pelage insulation increased in the rats kept outside during the winter but remained unchanged in the rats kept in a constant temperature room maintained at 6 °C. The resting metabolic rate measured at 30 °C increased in the 6 °C acclimated rats but not in the winter-exposed animals. Over the temperature range +30 °C to −15 °C, while the indoor cold-acclimated rats had a higher metabolic rate than their controls acclimated to 30 °C, the winter rats had a lower metabolism than their summer controls.

SEASONAL ADJUSTMENTS IN CAPTURED WILD NORWAY RATS: III. PRODUCTION OF ADRENAL STEROIDS IN VITRO

1963 ◽  
Vol 41 (5) ◽  
pp. 1147-1153 ◽  
Author(s):  
J. S. Willmer ◽  
O. Héroux
Keyword(s):  
Environmental Conditions ◽  
Rattus Norvegicus ◽  
Seasonal Effect ◽  
Seasonal Adjustment ◽  
Adrenal Steroids ◽  
Steroid Secretion ◽  
Adrenal Steroid ◽  
White Rats ◽  
Norway Rats

The in vitro adrenal steroid secretion of wild Norway rats (Rattus norvegicus) captured during the winter differed in quantity, but not in quality, from that of similar rats captured during the summer. Whereas there was no evident seasonal effect on adrenal weight either in males or in females, adrenals of both sexes secreted at a faster rate during the winter than during the summer, this increase involving the four groups of steroids characterized chromatographically during both seasons and in both sexes; the predominant steroid secreted was corticosterone. This seasonal adjustment in adrenal activity is similar to that observed in white rats kept in group cages exposed outdoors to the natural summer and winter environmental conditions, but it differs from that found in white rats cold-acclimated in the laboratory, in which adrenal activity is lower than normal after cold acclimation.

COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: I. METABOLIC AND INSULATIVE CHANGES

1959 ◽  
Vol 37 (1) ◽  
pp. 473-478 ◽  
Author(s):  
O. Héroux ◽  
F. Depocas ◽  
J. S. Hart
Keyword(s):  
Metabolic Rate ◽  
Constant Temperature ◽  
Environmental Conditions ◽  
Resting Metabolic Rate ◽  
Thermal Acclimation ◽  
Cold Temperature ◽  
Metabolic Rates ◽  
Temperature Range ◽  
White Rats ◽  
Physiological Adjustments

Physiological adjustments to cold temperature have been compared in white rats exposed either to the outdoor fluctuating environmental conditions or to the indoor constant temperature conditions. While the metabolic adjustments such as increased peak metabolism and decreased shivering were similar in outdoor and indoor rats exposed to cold, the adjustments in insulation and thermoneutral metabolic rates were quite different. The pelage insulation increased in the rats kept outside during the winter but remained unchanged in the rats kept in a constant temperature room maintained at 6 °C. The resting metabolic rate measured at 30 °C increased in the 6 °C acclimated rats but not in the winter-exposed animals. Over the temperature range +30 °C to −15 °C, while the indoor cold-acclimated rats had a higher metabolic rate than their controls acclimated to 30 °C, the winter rats had a lower metabolism than their summer controls.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Recent Advances in Curcumin Nanocarriers for the Treatment of Different Types of Cancer with Special Emphasis on In Vitro Cytotoxicity and Cellular Uptake Studies

2020 ◽  
Vol 10 (5) ◽  
pp. 577-590
Author(s):  
Jai B. Sharma ◽  
Shailendra Bhatt ◽  
Asmita Sharma ◽  
Manish Kumar
Keyword(s):  
Cancer Cells ◽  
Cellular Uptake ◽  
Anticancer Agents ◽  
Targeted Delivery ◽  
In Vitro Cytotoxicity ◽  
Curcumin Nanoparticles ◽  
Cytotoxicity Studies ◽  
Delivery Technique ◽  
Different Types

Background: The potential use of nanocarriers is being explored rapidly for the targeted delivery of anticancer agents. Curcumin is a natural polyphenolic compound obtained from rhizomes of turmeric, belongs to family Zingiberaceae. It possesses chemopreventive and chemotherapeutic activity with low toxicity in almost all types of cancer. The low solubility and bioavailability of curcumin make it unable to use for the clinical purpose. The necessity of an effective strategy to overcome the limitations of curcumin is responsible for the development of its nanocarriers. Objective: This study is aimed to review the role of curcumin nanocarriers for the treatment of cancer with special emphasis on cellular uptake and in vitro cytotoxicity studies. In addition to this, the effect of various ligand conjugated curcumin nanoparticles on different types of cancer was also studied. Methods: A systematic review was conducted by extensively surfing the PubMed, science direct and other portals to get the latest update on recent development in nanocarriers of curcumin. Results: The current data from recent studies showed that nanocarriers of curcumin resulted in the targeted delivery, higher efficacy, enhanced bioavailability and lower toxicity. The curcumin nanoparticles showed significant inhibitory effects on cancer cells as compared to free curcumin. Conclusion: It can be concluded that bioavailability of curcumin and its cytotoxic effect to cancer cells can be enhanced by the development of curcumin based nanocarriers and it was found to be a potential drug delivery technique for the treatment of cancer.

scholarly journals Marginal Adaptation and Micropermeability of Class II Cavities Restored with Three Different Types of Resin Composites—A Comparative Ten-Month In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1660
Author(s):  
Sevda Mihailova Yantcheva
Keyword(s):  
Methylene Blue ◽  
In Vitro Study ◽  
Sem Analysis ◽  
Marginal Adaptation ◽  
Resin Composites ◽  
Polymerization Shrinkage ◽  
Gingival Margin ◽  
Different Types ◽  
Ageing Period

The development of composite materials is subject to the desire to overcome polymerization shrinkage and generated polymerization stress. An indicator characterizing the properties of restorative materials, with specific importance for preventing secondary caries, is the integrity and durability of marginal sealing. It is a reflection of the effects of polymerization shrinkage and generated stress. The present study aimed to evaluate and correlate marginal integrity and micropermeability in second-class cavities restored with three different types of composites, representing different strategies to reduce polymerization shrinkage and stress: nanocomposite, silorane, and bulk-fill composite after a ten-month ageing period. Thirty standardized class ΙΙ cavities were prepared on extracted human molars. Gingival margins were 1 mm apical to the cementoenamel junction. Cavities were randomly divided into three groups, based on the composites used: FiltekUltimate-nanocomposite; Filtek Silorane LS-silorane; SonicFill-bulk-fill composite. All specimens were subjected to thermal cycles after that, dipped in saline for 10-mounds. After ageing, samples were immersed in a 2% methylene blue. Thus prepared, they were covered directly with gold and analyzed on SEM for assessment of marginal seal. When the SEM analysis was completed, the teeth were included into epoxy blocks and cut longitudinally on three slices for each cavity. An assessment of microleakage on stereomicroscope followed. Results were statistically analyzed. For marginal seal evaluation: F.Ultimate and F.Silorane differ statistically with more excellent results than SonicFill for marginal adaptation to the gingival margin, located entirely in the dentin. For microleakage evaluation: F.Ultimate and F.Silorane differ statistically with less microleakage than SonicFill. Based on the results obtained: a strong correlation is found between excellent results for marginal adaptation to the marginal gingival ridge and micropermeability at the direction to the axial wall. We observe a more significant influence of time at the gingival margin of the cavities. There is a significant increase in the presence of marginal fissures (p = 0.001). A significant impact of time (p < 0.000) and of the material (p < 0.000) was found in the analysis of the microleakage.

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