The effect of temperature, age and density of gametocytes, and changes in gas composition on exflagellation of Leucocytozoon simondi

1973 ◽  
Vol 51 (6) ◽  
pp. 577-587 ◽  
Author(s):  
N. R. Roller ◽  
S. S. Desser
Keyword(s):  
Inverse Relationship ◽  
The Body ◽  
Effect Of Temperature ◽  
Gas Composition ◽  
Fresh Blood ◽  
Infected Blood ◽  
Per Se ◽  
Time Required ◽  
Made In

The rate of initiation of exflagellation of microgametocytes of Leucocytozoon simondi was studied in relation to temperature, age and density of gametocytes, and changes in gas composition. Observations were made in vitro through examination of fresh blood, and thin blood films were prepared at appropriate intervals. An inverse relationship between temperature and the time required for initiation of ex-flagellation was demonstrated. There was a decrease in the time required for initiation of exflagellation as the temperature increased from 15 to 26C. Between 26 and 40C exflagellation usually occurred in 1–1½ min. Exflagellation at 40C, which approximates the body temperature of the host, indicates that a drop in temperature per se is not necessary for the initiation of exflagellation. Gametocytes appear to be capable of exflagellation for about 5 days postmaturity. Differences in density of parasitemia do not affect the time for initiation of exflagellation. The presence of O2 and a decrease in CO2 are important stimuli for exflagellation. The effect of the above factors on the initiation of exflagellation is discussed in relation to the uptake of infected blood by the simuliid vector of the parasite, and compared with the situation in related Haemosporina

Beautiful Bodies and Shameful Embodiment in Plotinus’s Enneads

2017 ◽  
Author(s):  
Lesley-Anne Dyer Williams
Keyword(s):  
The Body ◽  
Per Se ◽  
The One ◽  
Human Embodiment ◽  
Made In

This chapter explains why it is possible for Plotinus to appreciate the beauty of bodies, including human bodies, even while he was personally ashamed of his own embodiment. It accomplishes this task first by introducing distinctions between body, matter, form, soul, and entelechy that are made in Plotinus’ arguments with the philosophies of materialism, simple hylomorphism, and Gnosticism. For Plotinus, body is distinguished from matter because a body is formed matter. Since form is inherently good in his philosophy, bodies—as formed matter—cannot be evil. Plotinus’ writings seek to harmonize Platonic and Aristotelian accounts of form as found in bodies. Aristotelianism is especially important for him when it comes to his account of the soul as an immanent form in the body, but he follows Plato in having an account of soul in body that is not restricted to this immanent form. He also follows Plato in believing that the beauty of form in bodies can potentially turn the soul towards the Good while simultaneously acknowledging that human embodiment in particular can distract a soul from contemplating the One. These distinctions found in Plotinus’s treatises are then used in the last part of the chapter in order to interpret Porphyry’s stories concerning his teacher’s disconcerted preoccupation with embodiment. It is argued that Plotinus refused to sit for a portrait not because he objected to the imitation of bodily things for their own sake, not because he repudiated art or even bodies per se.

Alteration of activation energy of reaction in the catalase of human erythrocyte by cimetidine, an in vitro thermokinetics study

2020 ◽  
Vol 09 ◽  
Author(s):  
Dariush Minai-Tehrani
Keyword(s):  
Activation Energy ◽  
Human Erythrocyte ◽  
Cell Injury ◽  
Gastrointestinal Diseases ◽  
Maximum Activity ◽  
The Body ◽  
Effect Of Temperature ◽  
Histamine H2 Receptor ◽  
In Cells

Background: Hydrogen peroxide is normally formed during the metabolic pathway of the body. It is a toxic compound for vital cells, which can oxidize many macromolecules and cause damage in cells. Catalase can degrade H2O2 in cells and prevent cell injury. Cimetidine is a histamine H2 receptor blocker which decreases the release of stomach acid and is used for gastrointestinal diseases. Cimetidine inhibited catalase by mixed inhibition. Objective: In this study, effect of temperature on the binding of cimetidine to human erythrocyte catalase was investigated and kinetic factors of the binding were determined. Results: Dixon plot confirmed the mixed type of inhibition and determined the Ki of the drug. Maximum activity of the enzyme was observed at 30oC. Arrhenius plot demonstrated that the activation energy of the enzyme reaction in the absence and presence of cimetidine was about 4.7 and 8.13 kJ/mol, respectively. Temperature coefficient (Q30-40) was determined as about 1.11 and 1.09 in the absence and presence of cimetidine. Conclusion: Cimetidine was able to increase the activation energy of the reaction of catalase, which confirmed the inhibition of the enzyme based on the kinetic results.

Temperature dependence of in vitro androgen production in testes from hibernating ground squirrels, Spermophilus lateralis

1987 ◽  
Vol 65 (12) ◽  
pp. 3020-3023 ◽  
Author(s):  
Brian M. Barnes ◽  
Paul Licht ◽  
Irving Zucker
Keyword(s):  
Ground Squirrel ◽  
Temperature Compensation ◽  
Laboratory Mouse ◽  
Ground Squirrels ◽  
The Body ◽  
Effect Of Temperature ◽  
Dependent Manner ◽  
Spermophilus Lateralis ◽  
Dose Dependent

The effect of temperature on the in vitro androgen secretion of testes from hibernating ground squirrels was measured in response to stimulation by luteinizing hormone (LH). We wished to determine whether hibernating ground squirrels can maintain responsiveness of gonads while at the low body temperatures of torpor. In gonads incubated at 32 °C, secretion of testosterone increased in a dose-dependent manner in response to ovine-LH or ground squirrel pituitary homogenate. This responsiveness was reduced at 20 and 9 °C and absent at 5 °C, the temperature that most closely approximates the body temperature of torpid ground squirrels. This temperature sensitivity was similar to that in the nonhibernating laboratory mouse. Superfusion of ground squirrel testes revealed a lag of testosterone secretion in response to LH and, additionally, an ability of testes to secrete testosterone after being only briefly exposed to ovine-LH while at 5 °C. These results provide evidence against a hypothesis of temperature compensation that would allow continued testis function during torpor, and support a previous study which indicated that gonadal growth is restricted to intervals of normothermy during and after the hibernation season.

scholarly journals THE FATE OF TYPHOID BACILLI WHEN INJECTED INTRAVENOUSLY INTO NORMAL RABBITS

1915 ◽  
Vol 22 (4) ◽  
pp. 475-483 ◽  
Author(s):  
Carroll G. Bull
Keyword(s):  
Typhoid Fever ◽  
Blood Serum ◽  
Whole Blood ◽  
Blood Stream ◽  
The Body ◽  
Polymorphonuclear Leucocytes ◽  
Fresh Blood ◽  
Shed Blood ◽  
Destructive Processes

Typhoid bacilli are agglutinated promptly in the circulating blood of normal rabbits and quickly removed from the blood stream. The clumped bacilli accumulate in the organs and are taken up by assembled polymorphonuclear leucocytes in the liver, spleen, and possibly other organs. The phagocyted clumps of bacilli are digested and destroyed by the phagocytes. Hence, destruction of typhoid bacilli intra vitam is brought about by an entirely different process than is the destruction by serum and whole blood in vitro. While the latter is caused by bacteriolysis, the former results from agglutination and intraphagocytic digestion. Lysis by fresh blood serum is not appreciably affected by spleen or kidney pulp, but it is inhibited by liver pulp. The action of the liver is referable to its biliary constituents, which exert anticomplementary action. Probably in certain examples of typhoid fever in man the typhoid bacilli in the circulating blood being inagglutinable cannot be removed by the organs and hence are not phagocyted and destroyed. The observed disparity between the ready destruction of typhoid bacilli by serum and shed blood and the resistance sometimes offered by the bacilli in the infected body is explained by the essential differences in the destructive processes in operation within and without the body.

scholarly journals The temperature dependence of the adrenergic Na+/H+ exchanger of trout erythrocytes

1990 ◽  
Vol 148 (1) ◽  
pp. 303-312 ◽  
Author(s):  
A. R. Cossins ◽  
R. V. Kilbey
Keyword(s):  
Steady State ◽  
Rainbow Trout ◽  
Temperature Dependence ◽  
Effect Of Temperature ◽  
Transport Mechanisms ◽  
Adrenergic Stimulation ◽  
Temperature Dependent ◽  
Effects Of Temperature ◽  
Time Required

The effects of temperature upon the adrenergic Na+/H+ exchange of rainbow trout erythrocytes have been studied in vitro. The initial rates of H+ ejection and of increase of intracellular Na+ [(Na+]i) in adrenergically stimulated cells were highly temperature-dependent, with apparent Arrhenius activation energies of 112.8 +/− 10.0 (mean +/− S.D., N = 4) and 84.1 +/− 3.0 kJ mol-1 (N = 3), respectively. The steady-state [Na+]i following stimulation decreased progressively with cooling, whilst the time required for [Na+]i to return to control values after removal of agonist was greatly increased. The change in intracellular pH resulting from adrenergic stimulation was reduced by cooling, such that at 4 degrees C adrenergic responses were barely measurable. The effect of temperature upon the steady-state [Na+]i and pHi was probably caused by a disparity in the temperature dependence of the transport mechanisms that contribute to the respective steady states.

scholarly journals Dynamic Properties of Heart Fragments from Different Regions and Their Synchronization

2020 ◽  
Vol 7 (3) ◽  
pp. 81
Author(s):  
Shin Arai ◽  
Kento Lloyd ◽  
Tomonori Takahashi ◽  
Kazuki Mammoto ◽  
Takashi Miyazawa ◽  
...  
Keyword(s):  
Regenerative Medicine ◽  
Dynamic Properties ◽  
The Body ◽  
Computational Studies ◽  
Chick Embryos ◽  
Mechanical Motion ◽  
Contraction Speed ◽  
Time Required

The dynamic properties of the heart differ based on the regions that effectively circulate blood throughout the body with each heartbeat. These properties, including the inter-beat interval (IBI) of autonomous beat activity, are retained even in in vitro tissue fragments. However, details of beat dynamics have not been well analyzed, particularly at the sub-mm scale, although such dynamics of size are important for regenerative medicine and computational studies of the heart. We analyzed the beat dynamics in sub-mm tissue fragments from atria and ventricles of hearts obtained from chick embryos over a period of 40 h. The IBI and contraction speed differed by region and atrial fragments retained their values for a longer time. The major finding of this study is synchronization of these fragment pairs physically attached to each other. The probability of achieving this and the time required differ for regional pairs: atrium–atrium, ventricle–ventricle, or atrium–ventricle. Furthermore, the time required to achieve 1:1 synchronization does not depend on the proximity of initial IBI of paired fragments. Various interesting phenomena, such as 1:n synchronization and a reentrant-like beat sequence, are revealed during synchronization. Finally, our observation of fragment dynamics indicates that mechanical motion itself contributes to the synchronization of atria.

The Effect of Temperature on the Survival In Vitro of Rabbit Spermatozoa Obtained from the Vas Deferens

1930 ◽  
Vol 7 (2) ◽  
pp. 201-219
Author(s):  
ARTHUR WALTON
Keyword(s):  
Body Temperature ◽  
Sex Ratio ◽  
Vas Deferens ◽  
Liquid Paraffin ◽  
The Body ◽  
Effect Of Temperature ◽  
Gaseous Exchange ◽  
Optimum Temperature ◽  
Rabbit Spermatozoa

1. A technique is described for the investigation of in vitro problems with spermatozoa removed from the vas deferens of the rabbit. The method involves the protection of the spermatozoa by means of liquid paraffin from evaporation of rapid gaseous exchange. 2. The survival of functional integrity (fertilizing capacity) has been shown to be a function of temperature and the effect of temperature has been studied over the range from 45° C. to 0° C. Above body temperature the spermatozoa are rapidly destroyed. At body temperature (40° C.) maximal survival is about 13 hours. As the temperature is lowered survival becomes increasingly prolonged until a maximum of 7 days is reached at 15°C. The curve over the range from 15° C. to 40° C. is only approximately exponential and it is doubtful whether an analogy can be drawn between the effect of temperature on the velocity with which the spermatozoa are destroyed, and the effect of temperature on the velocity of many biological reactions which follow approximately the van't Hoff and Arrhenius questions. Below the optimum temperature (10°-15°C.) the velocity of destruction is acclerated by fall of temperature. 3. The sex-ratio of the resulting offspring is not significantly altered by keeping the spermatozoa outside the body.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum

A Simple and Inexpensive Clinical Whole Body Counter

1976 ◽  
Vol 15 (05) ◽  
pp. 248-253
Author(s):  
A. K. Basu ◽  
S. K. Guha ◽  
B. N. Tandon ◽  
M. M. Gupta ◽  
M. ML. Rehani
Keyword(s):  
The Body ◽  
Whole Body ◽  
Vitro Assay ◽  
Body Counter ◽  
Optimum Parameters ◽  
Whole Body Counter ◽  
Single Detector ◽  
Background Index ◽  
Iodide Crystal

SummaryThe conventional radioisotope scanner has been used as a whole body counter. The background index of the system is 10.9 counts per minute per ml of sodium iodide crystal. The sensitivity and derived sensitivity parameters have been evaluated and found to be suitable for clinical studies. The optimum parameters for a single detector at two positions above the lying subject have been obtained. It has been found that for the case of 131I measurement it is possible to assay a source located at any point in the body with coefficient of variation less than 5%. To add to the versatility, a fixed geometry for in-vitro counting of large samples has been obtained. The retention values obtained by the whole body counter have been found to correlate with those obtained by in-vitro assay of urine and stool after intravenous administration of 51Cr-albumin.

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