Cold defense mechanisms in vagotomized rats

1997 ◽  
Vol 273 (2) ◽  
pp. R784-R789 ◽  
Author(s):  
A. A. Romanovsky ◽  
V. A. Kulchitsky ◽  
C. T. Simons ◽  
N. Sugimoto ◽  
M. Szekely
Keyword(s):  
Defense Mechanisms ◽  
Low Dose ◽  
Jugular Vein ◽  
High Dose ◽  
Febrile Response ◽  
Sharp Rise ◽  
Tail Pinch ◽  
External Cooling ◽  
Brown Adipose ◽  
The Common

Subdiaphragmatically vagotomized rats cannot mount a febrile response to pyrogens and are believed to have severe thermoregulatory deficiencies. We addressed the issue of thermoeffector competence of vagotomized rats by asking three questions. In Expt. 1 we asked, can vagotomized rats readily recruit tail skin vasoconstriction in the course of a moderate cold exposure? In Expt. 2 the question was, can brown adipose tissue (BAT) thermogenesis readily be activated in vagotomized rats (e.g., in response to a tail pinch)? In Expt. 3, we investigated the question: can vagotomized rats elevate their body temperature in response to ephedrine (a drug of high hyperthermizing potential) to the same extent as sham-operated controls? Rats were vagotomized or sham operated and implanted with a catheter into the jugular vein and a thermocouple into the interscapular BAT. To prevent the common complications of vagotomy, special perioperative care was given. During experiments, colonic, tail skin, and BAT temperatures (Tc, Tsk, and TBAT, respectively) were measured. The vagotomized animals were well nourished and had a body mass (325 +/- 6 g) similar to that of the controls (338 +/- 6 g). In Expt. 1, in response to external cooling (15 degrees C, 1 h), the vagotomized (n = 30) and sham-operated (n = 31) rats recruited tail skin vasoconstriction at close values of both Tc (37.84 +/- 0.08 and 37.97 +/- 0.07 degrees C) and Tsk (33.16 +/- 0.17 and 33.18 +/- 0.18 degrees C, respectively). In Expt. 2, tail pinch-associated stress in vagotomized rats resulted in a sharp rise in the TBAT-Tc gradient by 0.3-1.0 degree C. In Expt. 3, ephedrine administered intravenously (whether in a 5 or 35 mg/kg dose) evoked similar hyperthermic responses in the vagotomized and sham-operated rats: a moderate (approximately 2.5 degrees C) Tc rise in the low dose and a "supramaximal" (approximately 5.0 degrees C) rise in the high dose. In sum, the answer to all three questions asked is yes. Vagotomized rats, at least when well nourished, exhibit no signs of thermoeffector deficiency. It is, therefore, not effector incompetence but rather vagal deafferentation per se that can explain the febrile irresponsiveness of vagotomized rats.

scholarly journals Chronic fluoxetine treatment induces lipid accumulation but does not alter the expression of Pref-1 in rat adipose tissue

2018 ◽  
Vol 68 (1) ◽  
pp. 109-115 ◽  
Author(s):  
László-István Bába ◽  
Zsolt Gáll ◽  
István Lóránt Bíró ◽  
Tibor Mezei ◽  
Imre Zoltán Kun ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Low Dose ◽  
Immunohistochemical Method ◽  
High Dose ◽  
Adipose Tissues ◽  
Fluoxetine Treatment ◽  
Brown Adipose ◽  
Chronic Fluoxetine ◽  
Rat Adipose Tissue ◽  
Different Doses

Abstract This study aims to investigate the effects of chronic fluoxetine (FLX) treatment on preadipocyte factor-1 (Pref-1) expression in subcutaneous, visceral and brown adipose tissues, and on the size of vacuoles in a dipocytes obtained from the perirenal regions in rats. Twenty-eight Wistar rats were treated with FLX at two different doses and fourteen animals received vehicle. After 40 days of treatment, the subcutaneous, perirenal and interscapular adipose tissues were collected. Pref-1 expression was examined using an immunohistochemical method and the vacuolar area was measured in stained sections. In the low dose FLX group, the size of vacuoles increased both in male and female animals. The high dose of FLX also induced a significant increase of vacuole size, but only in male animals. Neither of the two doses of FLX has significantly affected the Pref-1 expression in any type of adipose tissue.

Defect Structure at Buried Silicon Nitride Layers

1985 ◽  
Vol 45 ◽  
Author(s):  
E.H. Te Kaat ◽  
J. Belz
Keyword(s):  
Silicon Nitride ◽  
Low Dose ◽  
Electronic Devices ◽  
High Dose ◽  
Local Defect ◽  
Defect Structures ◽  
Rectangular Profile ◽  
The Common ◽  
Nitride Layers ◽  
Spherulitic Structure

ABSTRACTBuried insulating silicon nitride layers are formed by a 400°C N+-implantation at 150 keV with fluences from 0.35 to 1×1018 N+/cm2 and subsequent anneal at 1200°C in dry nitrogen. TEM and AES measurements on bevelled samples yield a correlation of ion and damage profiles to local defect structures. Low dose implantation results in polycrystalline precipitates of scaled spherulitic structure. High dose continuous polycrystalline nitride layers have good insulation properties following a 5 hour anneal. During anneal, the common asymmetrical ion depth profile transforms to a nearly rectangular profile. The silicon surface layer contains 106 to 108 dislocations/cm2, which seem to be passivated, since detrimental effects on electronic devices have not been measured.

scholarly journals Immunoprotective effects of oral intake of heat-killed Lactobacillus pentosus strain b240 in elderly adults: a randomised, double-blind, placebo-controlled trial

2012 ◽  
Vol 109 (10) ◽  
pp. 1856-1865 ◽  
Author(s):  
Shoji Shinkai ◽  
Masamichi Toba ◽  
Takao Saito ◽  
Ikutaro Sato ◽  
Mina Tsubouchi ◽  
...  
Keyword(s):  
Common Cold ◽  
Low Dose ◽  
Controlled Trial ◽  
Oral Intake ◽  
High Dose ◽  
Elderly Adults ◽  
Double Blind ◽  
Lactobacillus Pentosus ◽  
Sf 36 ◽  
The Common

Oral intake of Lactobacillus pentosus strain b240 (b240) has been shown to enhance the secretion of salivary secretory IgA in elderly adults. However, its clinical benefits remain to be determined. We tested the hypothesis that b240 exerts a protective effect against the common cold in elderly adults. The design of the present study was a randomised, double-blind, placebo-controlled trial (RCT) with parallel three-group comparison. For this purpose, 300 eligible elderly adults were randomly allocated to one of three groups, namely a placebo, low-dose or high-dose b240 group. Participants in the low-dose and high-dose b240 groups were given tablets containing 2 × 109 or 2 × 1010 cells, respectively, of heat-killed b240, while those in the placebo group were given tablets without b240. Each group consumed their respective tablets once daily for 20 weeks. The common cold was assessed on the basis of a diary. Change in quality of life was evaluated using the SF-36®. Of the total participants, 280 completed the 20-week RCT. The accumulated incidence rate of the common cold was 47·3, 34·8 and 29·0 % for the placebo, low-dose b240 and high-dose b240 groups, respectively (P for trend = 0·012). Lower incidence rates were consistently observed throughout the experimental period in the b240 groups (log-rank test, P= 0·034). General health perception, as determined by the SF-36®, dose-dependently increased in the b240 groups (P for trend = 0·016). In conclusion, oral intake of b240 significantly reduced the incidence rate of the common cold in elderly adults, indicating that b240 might be useful in improving resistance against infection through mucosal immunity.

Acetaminophen: Neonatal hepatotoxicity due to late pregnancy exposure

1987 ◽  
Vol 45 ◽  
pp. 718-719
Author(s):  
G.A. Miranda ◽  
M.A. Arroyo ◽  
C.A. Lucio ◽  
M. Mongeotti ◽  
S.S. Poolsawat
Keyword(s):  
Low Dose ◽  
Fetal Liver ◽  
Late Pregnancy ◽  
Toxic Chemicals ◽  
Control Group ◽  
High Dose ◽  
Over The Counter ◽  
Liver And Kidney ◽  
Neonatal Liver ◽  
Childbearing Women

Exposure to drugs and toxic chemicals, during late pregnancy, is a common occurrence in childbearing women. Some studies have reported that more than 90% of pregnant women use at least 1 prescription; of this, 60% used more than one. Another study indicated that 80% of the consumed drugs were not prescribed, and of this figure, 95% were “over-the-counter” drugs. Acetaminophen, the safest of all over-the-counter drugs, has been reported to induce fetal liver necrosis in man and animals and to have abortifacient and embryocidal action in mice. This study examines the degree to which acetaminophen affects the neonatal liver and kidney, when a fatty diet is simultaneously fed to the mother during late pregnancy.Timed Swiss Webster female mice were gavaged during late pregnancy (days 16-19) with fat suspended acetaminophen at a high dose, HD = 84.50 mg/kg, and a low dose, LD = 42.25 mg/kg; a control group received fat alone.

Evaluation of hippocampus in rhesus monkeys after chronic (1-year) inhalation exposure to marijuana: I. Electron microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 398-399
Author(s):  
A.M. Andrews ◽  
S.W. Wilson ◽  
A.C. Scallet ◽  
S.F. Ali ◽  
J. Bailey ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Rhesus Monkeys ◽  
Low Dose ◽  
Inhalation Exposure ◽  
Synaptic Cleft ◽  
High Dose ◽  
Withdrawal Time ◽  
Treatment Groups ◽  
Ultrastructural Evidence ◽  
Male Rhesus

Exposure of rhesus monkeys (Macaca mulatta) to marijuana via inhalation or to intravenous delta-9-tetrahydrocannabinol (THC), reportedly caused ultrastructural evidence of increased synaptic width. Chronic marijuana smoke in a single rhesus monkey examined after a six month withdrawal time caused ultrastructure changes in the septal, hippocampal and amygdala regions; the synaptic cleft was widened, electron opaque material was found in the cleft and in the pre- and postsynaptic regions, with some clumping of the synaptic vesicles. The objective of our study was to assess neuropathological alterations produced by chronic inhalation of marijuana smoke.Nineteen male rhesus monkeys, 3-5 years of age and weighing 3-8 kg, were divided into four treatment groups: a) sham control, b) placebo smoke (7 days/ week) c) low dose marijuana (2 times/week with 5 days/week sham) and d) high dose marijuana (7 times/week). A smoke exposure consisted of smoke from one cigarette (2.6% THC) burned down to 10 mm butt length. Smoke was administered via smoke generator (ADL II, Arthur D. Little, Inc. Cambridge, MA) and nose-mouth only masks (local production) equipped with one-way valves.

Benefit/Risk Profile of Combined Antiplatelet Therapy with Ticlopidine and Aspirin

1991 ◽  
Vol 65 (05) ◽  
pp. 504-510 ◽  
Author(s):  
Raffaele De Caterina ◽  
Rosa Sicari ◽  
Walter Bernini ◽  
Guido Lazzerini ◽  
Giuliana Buti Strata ◽  
...  
Keyword(s):  
Platelet Function ◽  
Low Dose ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Stable Coronary Artery Disease ◽  
High Dose ◽  
Single Drug ◽  
Before And After ◽  
Serum Thromboxane ◽  
Artery Disease

SummaryTiclopidine (T) and aspirin (ASA) are two antiplatelet drugs both capable of prolonging bleeding time (BT), with a different mechanism of action. A synergism in BT prolongation has been reported and is currently considered an argument for not recommending their combination. However, a profound suppression of platelet function might be a desirable counterpart of a marked prolongation of BT, with a possible use in selected clinical situations. We therefore studied ex vivo platelet function (aggregation by ADP 0.5-1-2.5 μM; adrenaline 0.75-2.5 μM; collagen 1.5-150 μg/ml; arachidonic acid 1 mM; PAF 1 μM; adrenaline 0.17 μM + ADP 0.62 μM; serum thromboxane ([TX]B2 generation) and BT (Mielke) in 6 patients with stable coronary artery disease receiving such combination. Patients underwent sequential laboratory evaluations at baseline, after 7 days of T 250 mg b.i.d., before and after the intravenous administration of ASA 500 mg, respectively, and, finally, after a minimum of 7 days of sole ASA oral administration (50 mg/day). The experimental design, therefore, allowed a comparison of T and ASA effects (2nd and 4th evaluation), and an assessment of the combination effect (3rd evaluation). Platelet aggregation in response to all doses of ADP was depressed more by T than by ASA. Conversely, responses to adrenaline, and arachidonate were affected more by ASA than by T. For all other agents, differences were not significant. T + ASA combination was more effective (p <0.05) than either treatment alone in depressing responses to high-dose collagen (% over control, mean ± SEM: T: 95 ± 3; ASA: 96 ± 5; T + ASA: 89 ± 4). Serum TXB2 (basal, ng/ml: 380 ± 54) did not change with T (372 ± 36), dropped to <1 ng/ml on ASA injection and slightly re-increased to 9.1 ± 3.1 ng/ml on oral low-dose ASA. BT (basal 7.4 ± 0.6 min) was affected similarly by T (9.2 ± 0.8) or ASA (9.7 ± 0.9) alone, but increased to 15.0 ± 0.7 min on combination treatment (106% increase over control). Thus, the strong synergism in BT prolongation by ASA-T combination has a counterpart in the inhibition of platelet function in response to strong stimuli such as high-dose collagen, not otherwise affected significantly by single-drug treatment. This effect is a possible rationale for the clinical evaluation of T + ASA combination.

Intensive Initial Oral Anticoagulation and Shorter Heparin Treatment in Deep Vein Thrombosis

1984 ◽  
Vol 52 (03) ◽  
pp. 276-280 ◽  
Author(s):  
Sam Schulman ◽  
Dieter Lockner ◽  
Kurt Bergström ◽  
Margareta Blombäck
Keyword(s):  
Deep Vein Thrombosis ◽  
Oral Anticoagulation ◽  
Dose Group ◽  
Low Dose ◽  
Clinical Signs ◽  
Coagulation Factor ◽  
High Dose ◽  
Vein Thrombosis ◽  
Heparin Treatment ◽  
Deep Vein

SummaryIn order to investigate whether a more intensive initial oral anticoagulation still would be safe and effective, we performed a prospective randomized study in patients with deep vein thrombosis. They received either the conventional regimen of oral anticoagulation (“low-dose”) and heparin or a more intense oral anticoagulation (“high-dose”) with a shorter period of heparin treatment.In the first part of the study 129 patients were randomized. The “low-dose” group reached a stable therapeutic prothrombin complex (PT)-level after 4.3 and the “high-dose” group after 3.3 days. Heparin was discontinued after 6.0 and 5.0 days respectively. There was no difference in significant hemorrhage between the groups, and no clinical signs of progression of the thrombosis.In the second part of the study another 40 patients were randomized, followed with coagulation factor II, VII, IX and X and with repeated venograms. A stable therapeutic PT-level was achieved after 4.4 (“low-dose”) and 3.7 (“high-dose”) days, and heparin was discontinued after 5.4 and 4.4 days respectively. There were no clinical hemorrhages, the activity of the coagulation factors had dropped to the same level in both groups at the time when heparin was discontinued and no thromboembolic complications occurred.Our oral anticoagulation regimen with heparin treatment for an average of 4.4-5 days seems safe and reduces in-patient costs.

Effects of Aspirin and Sulfinpyrazone on Thromboxane and Prostacyclin Synthesis in Rabbits

1979 ◽  
Author(s):  
J McDonald ◽  
A Cerskus ◽  
M Ali
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Low Dose ◽  
High Dose ◽  
Prostacyclin Synthesis

Arachidonic acid (AA) or collagen were infused into rabbits causing intravascular platelet aggregation with thrombocytopenia, hypotension and death. Thromboxane and prostacyclin synthesis were measured by radioimmunoassay of plasma TXB2 and 6-keto-PGF1α. The effects of pretreatement with aspirin (ASA) or sulfinpyrazone(SPZ) were assessed.Death in drug-treated rabbits was always associated with elevations of plasma TXB2(1-40 ng/ml) and of 6-keto-PGF1α(1-20 ng/ml). Collagen produced only small elevations of plasma TXB2 compared to AA but protection by ASA correlated better with inhibition of TXB2 and 6-keto-PGF1α synthesis than with inhibition of aggregation. Low dose ASA produced less inhibition of prostacyclin synthesis than high dose ASA but was less effective in preventing thromboxane synthesis and death.

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