Hypothermia: effects of hypertonic solutions on incidence of ventricular fibrillation

1959 ◽  
Vol 196 (4) ◽  
pp. 709-710 ◽  
Author(s):  
W. Robert Beavers
Keyword(s):  
Ventricular Fibrillation ◽  
Plasma Concentrations ◽  
Plasma Calcium ◽  
Lower Body ◽  
Body Temperatures ◽  
Hypertonic Glucose ◽  
Hypertonic Solutions ◽  
Cardiac Excitability

Mongrel dogs cooled to terminus exhibited a 91% incidence of ventricular fibrillation. Animals receiving 25% glucose or 50% sucrose intravenously during cooling did not fibrillate but terminated in asystole. In untreated cooled animals, plasma concentrations decreased, and plasma calcium and sodium were unaltered. Dogs receiving hypertonic glucose or sucrose had decreased plasma calcium and sodium levels, but normal potassium concentrations at lower body temperatures. The possible mechanisms by which hypertonic fluids decrease excessive cardiac excitability are discussed.

Oral vanadyl sulfate in treatment of diabetes mellitus in rats

1989 ◽  
Vol 257 (3) ◽  
pp. H904-H911 ◽  
Author(s):  
S. Ramanadham ◽  
J. J. Mongold ◽  
R. W. Brownsey ◽  
G. H. Cros ◽  
J. H. McNeill
Keyword(s):  
Heart Function ◽  
Plasma Concentrations ◽  
Vanadyl Sulfate ◽  
Lower Body ◽  
Endogenous Insulin ◽  
Body Weights ◽  
Treatment Of Diabetes ◽  
Working Heart ◽  
Circulating Levels ◽  
Insulin Like Activity

Recent reports have suggested that vanadium in the form of vanadyl (+IV) possesses insulin-like activity. Therefore, in the present study we examined the effects of administering oral vanadyl to diabetic animals. Wistar rats made diabetic with streptozotocin and age-matched controls were maintained for 10 wk in the absence and presence of vanadyl sulfate trihydrate in the drinking water. In the presence of vanadyl, decreases in rate of growth and circulating levels of insulin were the only significant alterations recorded in control animals. In contrast, diabetic animals treated with vanadyl, despite having lower body weights and insulin levels, had normal plasma concentrations of glucose, lipid, creatinine, and thyroid hormone. In addition, abnormalities in isolated working heart function and glycerol output from adipose tissue of diabetic animals were also corrected after vanadyl treatment. These results suggest that vanadium when used in the vanadyl form is effective in diminishing the diabetic state in the rat by substituting for and replacing insulin or possibly by enhancing the effects of endogenous insulin.

The response of plasma minerals, free fatty acids and glucose to adrenaline and cortisol infusion in sheep

1986 ◽  
Vol 106 (2) ◽  
pp. 209-217 ◽  
Author(s):  
Sarah C. Bolton ◽  
T. E. C. Weekes
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Marked Decrease ◽  
Plasma Concentrations ◽  
Sodium Concentration ◽  
Plasma Calcium ◽  
Plasma Sodium ◽  
Plasma Phosphate ◽  
Plasma Sodium Concentration ◽  
Plasma Magnesium

SUMMARYAdrenaline was infused at three rates, 40, 15 or 3 μ/kg/h, in normal sheep and in sheep rendered hypercortisolaemic by infusion of cortisol at 150 μg/kg/h. In both normal and hypercortisolaemic animals, plasma concentrations of glucose and free fatty acids were increased by adrenaline treatment; plasma phosphate decreased with all treatments; plasma magnesium and potassium decreased on infusion of adrenaline at 40 or 15, but not at 3 μg/kg/h; plasma calcium decreased only on infusion of adrenaline in hypercortisolaemic animals, and plasma sodium concentration was unaffected by treatment.Induction of a degree of lipolysis likely to occur in the field was not associated with a marked decrease in plasma magnesium.

Carotid sinus depressor reflexes during hypothermia

1964 ◽  
Vol 207 (4) ◽  
pp. 777-781 ◽  
Author(s):  
J. E. Kendrick ◽  
Kenneth A. Turner
Keyword(s):  
Smooth Muscle ◽  
Carotid Sinus ◽  
Baroreceptor Reflex ◽  
The Body ◽  
Lower Body ◽  
Body Temperatures ◽  
Small Reduction ◽  
Local Cooling ◽  
Carotid Sinus Stimulation ◽  
Reflex Arc

Reducing body temperature in dogs to 24 C caused a small reduction in the size of the carotid sinus depressor response. Along with this reduction the response also became more gradual at the lower body temperatures. Systematic studies demonstrated that the more gradual nature of the response appeared to result from changes in the vascular smooth muscle. Depression of the nervous elements of the baroreceptor reflex arc during hypothermia was not evident. The response to carotid sinus stimulation in the warm, perfused hindlimb was essentially unchanged by cooling the body to 24 C. Local cooling of the perfused hindleg did not reduce the size but did result in a more gradual response.

Calcium content of frog sciatic nerve during chronic hypocalcemia and hypercalcemia

1987 ◽  
Vol 253 (4) ◽  
pp. R655-R660
Author(s):  
K. C. Wadhwani ◽  
H. Levitan ◽  
S. I. Rapoport
Keyword(s):  
Plasma Concentration ◽  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Plasma Concentrations ◽  
Calcium Regulation ◽  
Calcium Content ◽  
Plasma Calcium ◽  
Ionized Calcium ◽  
Steady State Plasma Concentration ◽  
Perineurial Sheath

We examined the calcium contents of desheathed peripheral nerve, perineurial sheath, and whole sciatic nerve in the frog as a function of the steady-state plasma concentration of ionized calcium. Chronic hypocalcemia was induced by parathyroidectomy and by bathing frogs in a phosphate medium. Chronic hypercalcemia was induced by administering vitamin D3 and by bathing frogs for up to 2 wk in medium containing 50 mM CaCl2. Calcium was measured with a calcium-sensitive electrode and by atomic absorption spectroscopy. The calcium contents (mmol/kg wet wt) in whole nerve, desheathed nerve, and the perineurial sheath varied linearly with slopes of 0.72, 0.71, and 1.72, respectively, with plasma concentration (mM) of ionized calcium, which ranged from 0.3 to 8.0 mM. In the same animals the calcium content in the cerebrum was independent of plasma calcium between 0.5 and 1.5 mM but rose at higher plasma concentrations. Our results indicate that net calcium concentration in the frog peripheral nerve is not regulated during chronic hypocalcemia and hypercalcemia, whereas brain calcium is regulated at plasma calcium concentrations less than 1.5 mM. The lack of calcium regulation in the nerve is attributed to the lack of calcium regulation in the endoneurial compartment.

Cold and hyperosmolar fluids in canine trachea: vascular and smooth muscle tone and albumin flux

1989 ◽  
Vol 66 (3) ◽  
pp. 1309-1315 ◽  
Author(s):  
M. E. Deffebach ◽  
R. O. Salonen ◽  
S. E. Webber ◽  
J. G. Widdicombe
Keyword(s):  
Smooth Muscle ◽  
Muscle Tone ◽  
Control Period ◽  
Smooth Muscle Contraction ◽  
Hypertonic Solution ◽  
Tracheal Lumen ◽  
Smooth Muscle Tone ◽  
Hypertonic Glucose ◽  
Hypertonic Solutions ◽  
Cervical Trachea

We have studied the effects of liquids of various osmolalities and temperatures on the tracheal vasculature, smooth muscle tone, and transepithelial albumin flux. In 10 anesthetized dogs a 10- to 13-cm length of cervical trachea was cannulated to allow instillation of fluids into its lumen. The cranial tracheal arteries were perfused at constant flow, with monitoring of the perfusion pressures (Ptr) and the external tracheal diameter (Dtr). Control fluid was Krebs-Henseleit solution (KH) with NaCl added to result in a 325-mosM solution (isotonic). Hypertonic solutions were KH with NaCl (warm hypertonic) or glucose (hypertonic glucose) added to result in a 800-mosM solution. All solutions were at 38 degrees C, with isotonic and the hypertonic NaCl solutions also given at 18 degrees C (cold isotonic and cold hypertonic). Fluorescent labeled albumin was given intravenously, and the change in fluorescence in the fluid was measured during each 15-min period. Changing from warm isotonic to cold isotonic decreased Dtr and Ptr. Changing from warm isotonic to warm hypertonic or hypertonic glucose decreased Ptr with no change in Dtr. The cold hypertonic responses were not different from cold isotonic responses. Warm hypertonic solution increased albumin flux into the tracheal lumen over a 15-min period to three times that of the control period, persisting for 15 min after replacement with warm isotonic solution. Cooling induces a vasodilation and smooth muscle contraction of the trachea, whereas hypertonic solutions result in vasodilation and, if osmolality is increased with NaCl, an increase in albumin flux into the tracheal lumen.

Thirst and vasopressin release in the dog: an osmoreceptor or sodium receptor mechanism?

1980 ◽  
Vol 238 (5) ◽  
pp. R333-R339 ◽  
Author(s):  
T. N. Thrasher ◽  
C. J. Brown ◽  
L. C. Keil ◽  
D. J. Ramsay
Keyword(s):  
Plasma Osmolality ◽  
Sodium Concentration ◽  
Plasma Sodium ◽  
Nacl Solution ◽  
Elevated Plasma ◽  
Vasopressin Release ◽  
Hypertonic Glucose ◽  
Hypertonic Solutions ◽  
Vasopressin Secretion ◽  
Plasma Arginine

The effects of intravenous infusion of hypertonic NaCl, sucrose, glucose, urea, or isotonic NaCl solution on thirst and plasma arginine vasopressin concentration (AVP) were studied in five conscious dogs. The changes in osmolality and sodium concentration of plasma and cerebrospinal fluid (CSF) were measured at the threshold of drinking, or after 45 min if no drinking occurred. Hypertonic NaCl and sucrose stimulated drinking in all dogs and significantly elevated plasma AVP. Equally hypertonic glucose, urea, or isotonic NaCl failed to stimulate any drinking or vasopressin secretion. All hypertonic solutions caused significant and similar increases in the osmolality and sodium concentration of CSF. Plasma osmolality was increased by the hypertonic solutions. Plasma sodium was increased by hypertonic NaCl, decreased by sucrose and glucose, and not changed by urea. Isotonic NaCl had no effect on either plasma or CSF composition. These data are not consistent with either a sodium or an osmoreceptor mechanism located within the blood-brain barrier (BBB) or with a peripheral sodium receptor mechanism. An intracranial osmoreceptor located on the blood side of the BBB is proposed to explain these results.

Is obesity associated with lower body temperatures? Core temperature: a forgotten variable in energy balance

Metabolism ◽  
2009 ◽  
Vol 58 (6) ◽  
pp. 871-876 ◽  
Author(s):  
Lewis Landsberg ◽  
James B. Young ◽  
William R. Leonard ◽  
Robert A. Linsenmeier ◽  
Fred W. Turek
Keyword(s):  
Energy Balance ◽  
Core Temperature ◽  
Lower Body ◽  
Body Temperatures

Effects of Lowered Temperature on Time Estimation

1975 ◽  
Vol 27 (4) ◽  
pp. 531-538 ◽  
Author(s):  
C. R. Bell
Keyword(s):  
Time Estimation ◽  
Lower Body ◽  
Body Temperatures ◽  
Cast Doubt ◽  
The Brain

Body (ear) temperature of 14 subjects was lowered in order to examine its effect upon performance of a task requiring estimation of an interval of 60 s. Although there was some evidence that subjects counted more slowly at lower body temperatures, the inconsistency of the effect was such as to cast doubt on the hypothesis of a “biochemical clock” or “metabolic pacemaker” in the brain said to subserve human time estimation of brief intervals.

scholarly journals Endocrine control of calcium and magnesium metabolism in ruminants

1969 ◽  
Vol 28 (02) ◽  
pp. 183-189
Author(s):  
A. D. Care
Keyword(s):  
Hormone Secretion ◽  
Plasma Concentrations ◽  
Plasma Calcium ◽  
Magnesium Concentration ◽  
Endocrine Control ◽  
Blood Calcium ◽  
Hormone Effects ◽  
Endocrine Factors ◽  
Calcium And Magnesium ◽  
Calcitonin Secretion

Although the importance of calcium and magnesium homoeostasis has been recognized for many years the precise mechanisms by which this is achieved are still not clearly understood. Over recent years interest in blood calcium regulation has been stimulated by the discovery, isolation and synthesis of calcitonin. Its significance in normal adults, however, remains in some doubt (vide infra). In this paper is outlined our present knowledge of the endocrine factors which help to regulate the control of plasma calcium and magnesium concentration in ruminants through the operation of negative feedback mechanisms. Mention will also be made of those hormones which, although capable of altering the plasma concentrations of either calcium or magnesium, are secreted independently of these concentrations. It will be seen that in many instances the chemical similarity between calcium and magnesium is reflected in hormone effects or in hormone secretion rates. However, this is not always found to be so, e.g. the control of calcitonin secretion appears to be affected in different directions by plasma calcium and magnesium concentrations.

A STUDY OF BLOOD PRESSURE RESPONSES DURING HYPOTHERMIA IN HYPOPHYSECTOMIZED RATS

1964 ◽  
Vol 42 (2) ◽  
pp. 209-215 ◽  
Author(s):  
J. Hunter ◽  
R. E. Haist
Keyword(s):  
Blood Pressure ◽  
Body Temperature ◽  
The Body ◽  
Lower Body ◽  
Body Temperatures ◽  
Renal Vessels ◽  
Hypophysectomized Rats ◽  
Blood Pressure Responses ◽  
Cooling Procedure ◽  
Intact Rats

When intact rats are cooled, the blood pressure is well maintained down to a body temperature of 22 °C, below which it rapidly falls. When hypophysectomized rats are cooled the reduction in blood pressure bears a linear relation to the body temperature. The infusion of Pitressin into hypophysectomized animals during the cooling procedure restores the blood pressure – body temperature relationship to that seen in intact rats. This occurs whether or not the renal vessels are ligated and hence appears to be independent of renal factors. However, when the kidneys are exteriorized and warmed and, at the same time, Pitressin is infused into the hypophysectomized cooled rats, there is an excellent maintenance of blood pressure at the lower body temperatures, the blood pressure being 110 mm Hg when the body temperature is 12 °C. Infusions of angiotensin II and of renin also are effective in maintaining blood pressure in hypothermic hypophysectomized animals. This effect of renin is not influenced by exteriorizing and warming the kidneys, hence the enhancement of the effect of Pitressin by this procedure is not a consequence of the warming alone. Warming the exteriorized kidneys may release some factor or cause some change which, in the presence of Pitressin, effectively maintains blood pressure at low body temperatures.

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