Effects of concentration and sniff flow rate on the rat electroolfactogram

Previous reports using the electroolfactogram (EOG) to study the spatial and temporal aspects of response in the rodent olfactory epithelium had focused on high odorant concentrations that gave large responses. This investigation has used lower concentrations to test the difference between responses in the rat dorsomedial and lateral recesses with a range of nasal flow rates and a range of chemical properties. The responses to a highly polar, more hydrophilic odorant changed more steeply with flow rate than responses to a very nonpolar, hydrophobic odorant. With low flow rates there was a response delay in the lateral recess, which is consistent with the models indicating lower flow rates in that region. We observed significant volume conduction effects in which large responses in the dorsomedial region obscured smaller initial portions of the lateral responses. These effects could be removed by destroying the dorsomedial response with a high concentration of a low molecular weight ester. We caution that investigators of EOG recordings from the intact epithelium must attend to the possible presence of volume conduction, which can be assessed by attention to the selectivity of odorant response, response waveform, and response latency.     

Effects of cold dry air nasal stimulation on airway mucosal blood flow in humans

Several studies have demonstrated that nasal challenges can induce reflex responses in the respiratory system. Some authors have described bronchoconstriction and modification of the pattern of breathing following nasal challenges by irritants and cold air. We propose to determine the effect of nasal stimulation with cold dry air on airway mucosal blood flow (Qaw) in the proximal tracheal bronchial tree of healthy humans. Nine healthy subjects participated in the study. Baseline measurement Qaw, nasal airway resistance (NAR) and airway caliber by specific airways conductance (SGaw) were followed by nasal challenge with cold dry air. Qaw, NAR and Sgaw were determined after the challenge. In those subjects in which a significant decline in Qaw was recorded the protocol was repeated after pretreatment with nasal anesthesia using topical lidocaine. Cold dry air challenge produced a significant decrease in mean Qaw for the nine subjects and this response was abolished by pretreatment with nasal anesthesia using topical lidocaine. There was no significant change in Sgaw and NAR after the challenge and topical lidocaine anesthesia. Our data indicates that nasal stimulation with cold dry air leads to a reduction in Qaw and that this effect may be mediated by a nasal reflex.     

Effects of isoflurane anesthesia and pilocarpine on rat parotid saliva flow

The purpose of this study was to investigate the effects of isoflurane on unstimulated and pilocarpine-stimulated parotid saliva secretion. Ten male Sprague-Dawley rats weighing 350-400 g were randomized into two groups, and the saliva flow rate and lag phase were measured at two doses of isoflurane in a crossover study design. Increasing the isoflurane concentration from 1% to 2% was associated with a 19% decrease in saliva secretion rate, and the lag to saliva secretion was increased by 155%. To clarify whether the effect of isoflurane (1.5%) on the parotid flow varied with stimulus intensity, we measured the parotid flow induced by seven different doses of pilocarpine on sham-irradiated rats and rats irradiated with single doses of 15 Gy. A maximal pilocarpine response was obtained with 1.5 mg/kg in both irradiated and sham-irradiated rats; however, the parotid flow of the irradiated rats was 50% slower than that of the sham-irradiated rats. In conclusion, 1.5% isoflurane was found to be a good compromise between proper anesthesia and isoflurane-induced inhibition of saliva secretion. Pilocarpine induces saliva secretion in a dose-dependent matter, with supra-maximal stimulation achieved using 1.5 mg/kg.     

模拟空气潜水对大鼠脾组织氧自由基生成的影响

目的:观察模拟空气潜水对大鼠脾组织氧自由基(OFR)生成的影响。方法:腹腔注射自旋捕捉剂,高气压处理后检测大鼠脾组织生成的OFR。结果:模拟空气潜水后大鼠脾组织OFR生成增多,并检测到了.OH信号。结论:空气模拟潜水时呼吸气中高分压氧可促进脾组织OFR生成,主要类型可能为羟自由基。     

Effects of curved inlet tubes on air flow and particle deposition in bifurcating lung models

In vivo bifurcating airways are complex and the airway segments leading to the bifurcations are not always straight, but curved to various degrees. How do such curved inlet tubes influence the motion as well as local deposition and hence the biological responses of inhaled particulate matter in lung airways? In this paper steady laminar dilute suspension flows of micron-particles are simulated in realistic double bifurcations with curved inlet tubes, i.e., 0 degrees < or =theta< or =90 degrees, using a commercial finite-volume code with user-enhanced programs. The resulting air-flow patterns as well as particle transport and wall depositions were analyzed for different flow inlet conditions, i.e., uniform and parabolic velocity profiles, and geometric configurations. The curved inlet segments have quite pronounced effects on air-flow, particle motion and wall deposition in the downstream bifurcating airways. In contrast to straight double bifurcations, those with bent parent tubes also exhibit irregular variations in particle deposition efficiencies as a function of Stokes number and Reynolds number. There are fewer particles deposited at mildly curved inlet segments, but the particle deposition efficiencies at the downstream sequential bifurcations vary much when compared to those with straight inlets. Under certain flow conditions in sharply curved lung airways, relatively high, localized particle depositions may take place. The findings provide necessary information for toxicologic or therapeutic impact assessments and for global lung dosimetry models of inhaled particulate matter.     

Effects of tin-protoporphyrin IX on blood flow in a rat tumor model

Carbon monoxide (CO), one of the products of heme oxygenase (HO) catalyzed heme degradation, is a vasodilator. The aim of the present study was to clarify the role of HO in blood flow maintenance in tumors. Male BD9 rats bearing subcutaneous transplants of the P22 carcinosarcoma tumor were treated intraperitoneally (i.p.) with either tin-protoporphyrin IX (SnPP; 45 micromol/kg), a selective inhibitor of HO or copper-protoporphyrin IX (CuPP; 45 micromol/kg), used as a negative control. The extent of HO activity inhibition was measured using a spectrophotometric assay of bilirubin production and blood flow rates to the tumor and a range of normal tissues were assessed using the uptake of the radiolabelled tracer, iodo-antipyrine ((125)I-IAP). The animals were cannulated under fentanyl citrate/fluanisone (Hypnorm)/midazolam anesthesia. In the P22 tumor, SnPP, but not CuPP, caused a complete inhibition of HO activity 15 min post-treatment. Administration of SnPP 15 min before blood flow measurements reduced tumor blood flow by 17%, with no effects in any of the normal tissues studied. However, CuPP induced a greater reduction in tumor blood flow than SnPP (45% decrease). Furthermore, CuPP caused a reduction in blood flow to the skin and small intestine but a significant increase to skeletal muscle. The current findings conclusively establish only a minor role played by the HO/CO system in the maintenance of blood flow in this tumor system, despite relatively high levels of HO-1 protein and HO activity. The results also highlight the potential usefulness of CuPP as a tumor blood flow modifier.     

Effects of calcitonin gene-related peptide on renal blood flow in the rat

The effects of alpha-rat calcitonin gene-related peptide (alpha-rCGRP) on systemic and renal hemodynamics and on renal electrolyte excretion were examined in normal anesthetized rats. In one group of rats (n = 7), infusions of alpha-rCGRP at doses of 10, 50, 100, and 500 ng/kg/min for 15 min each produced dose-related and significant decreases in mean arterial pressure from a control of 130 +/- 3 mm Hg to a maximal depressor response of 91 +/- 2 mm Hg. During the first three doses of alpha-rCGRP, renal blood flow progressively and significantly increased from a control of 5.0 +/- 0.3 ml/min to a peak level of 6.3 +/- 0.3 ml/min achieved during the 100 ng/kg/min infusion. With the highest infusion rate of 500 ng/kg/min, renal blood flow fell below the control level to 4.5 +/- 0.2 ml/min (P less than 0.05). The responses in renal blood flow and mean arterial pressure were associated with reductions in renal vascular resistance. After cessation of alpha-rCGRP infusions, arterial pressure, renal blood flow, and renal vascular resistance gradually returned toward the baseline values. In another group of rats (n = 9), infusion of alpha-rCGRP for 30 min at 100 ng/kg/min produced a significant reduction in urinary sodium excretion from 0.28 +/- 0.06 to 0.14 +/- 0.5 muEq/min (P less than 0.05). Urine flow and urinary potassium excretion also appeared to decrease, but the changes were not significantly different (P greater than 0.05) from their respective baselines. These results demonstrate that alpha-rCGRP is a potent and reversible hypotensive and renal vasodilatory agent in the anesthetized rat. The data also suggest that alpha-rCGRP may have significant effects on the excretory function of the kidney.     

Effects of nicotine on oviducal blood flow and embryo development in the rat

Nicotine (5.0 mg/kg) was injected (s.c.) twice daily on Day 1 or Days 1-4 or 1-5 of pregnancy. Cumulative doses of nicotine retarded embryo cell cleavage and substantially reduced embryo cell number (saline vs nicotine: 42.5 +/- 1.7 vs 22.1 +/- 1.9 nuclei/embryo, at 12:00 h on Day 5; P less than 0.05). However, treatment for even 1 day (Day 1) significantly reduced cell number (saline vs nicotine: 42.5 +/- 1.7 vs 30.5 +/- 0.9, at 12:00 h day on Day 5; P less than 0.01). Nicotine injection also resulted in a marked and prolonged reduction in oviduct blood flow (pretreatment vs 90 min after nicotine: 0.61 +/- 0.06 vs 0.37 +/- 0.10 ml/min . g-1; P less than 0.005). The results indicate that, in the rat, even a brief exposure to nicotine, the chief alkaloid of tobacco, reduces oviducal blood flow and the rate of embryo cell proliferation. The embryo is therefore susceptible to the effects of nicotine before implantation.     

Effects of air pollutants on pollen

In vivo and in vitro pollen germination and pollen tube growth are affected by air pollutants. The stimulation and inhibition of these pollen characteristics depend on the pollen species as well as on the pollutant and its concentration, the exposure time, the relative humidity during exposure and some other factors. Mitosis, gas exchange, size and chemistry of pollen can also be influenced by air contaminants. Pollen germination and tube elongation differ in their response to air pollution stress, and both are more susceptible in vitro compared to the in vivo situation. Some possible mechanisms of action are reported in this review study. The effects of air contaminants on pollen are discussed in relation to sexual reproduction, gametophytic selection and adaptation to stress. Pollen may be used as sensitive biological indicators of pollution     

Effects of L-glutamic acid on acid secretion and mucosal blood flow in the rat stomach

The effect of intravenous administration of L-glutamic acid (L-Glu) on gastric acid secretion and gastric mucosal blood flow (GMBF) in anesthetized rats were investigated. Infusion with synthetic L-Glu alone had no effect on spontaneous acid secretion. However, L-Glu reduced histamine- (2 mg/kg/hr) or oxotremorine- (1 microg/kg/hr) stimulated acid secretion, whereas L-Glu had no effect on acid secretion induced by pentagastrin (8 microg/kg/hr). Furthermore, this inhibitory effect of L-Glu on histamine- or oxotremorine-stimulated acid secretion was blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX), a non-NMDA receptor antagonist. The effect of L-Glu on gastric mucosal microcirculation in the anesthetized rats was evaluated by using Laser Doppler Flowmetry (LDF). The results showed that L-Glu did not significantly reduce both mucosal and serosal blood flow in stomach. No significant modulatory effect on histamine- or oxotremorine-stimulated increase in GMBF was noted after infusion with L-Glu. It is concluded that L-glutamic acid is capable of the modulating of gastric acid secretion via ionotropic non-NMDA receptors, but do not affect on GMBF. However, L-glutamic acid showed no effect on acid secretion by itself.     

Effects of air flow rate, storage temperature, and harvest maturity on respiration and ripening of tomato fruits

The interactive effects of aeration rate, storage temperature, harvest maturity, and storage duration on respiration and ripening of tomato fruits (Lycopersicum esculentum var. Roma) were studied. Slow aeration rate strongly reduced the climacteric but did not affect ripening. Low temperature slowed ripening and reduced respiratory rates, but low temperature did not delay attainment of the climacteric maxima. The effect of air flow rate on the content of CO₂ in the fruits' internal atmospheres was investigated. The possibility that CO₂ is not the primary cause of respiratory inhibition under slow air flow rate is discussed.     

Effects of air ions on germination ofHelminthosporium teres

Effects of host — pathogen interactions with respect to relatively high concentrations of artificially produced air ions were studied in the laboratory. Continuous and long exposures ofHelminthosporium teres in the culture medium and under controlled conditions to positive air ions, produced a time — delay of about 6 hours on spore germination. Negative ions produced no such effect. Temporary structural abnormalities of the germ tubes were observed for two to three hours when exposed to either positive or negative air ions. Sprayed inoculum of spores on actual leaf surfaces of barley plants, exposed to positive ions, suppressed germination for a considerably longer time than those observed in the culture medium.     

Effects of acute graded reductions in testicular blood flow on testicular morphology in the adult rat

The effect of moderate reductions in testicular blood flow has not been studied systematically. The aim of this study was, therefore, to examine the effects of different degrees of blood flow reduction on testicular morphology and to determine how much flow can be reduced before damage occurs. The subcapsular testicular artery was partially ligated in the left testes of adult rats. Testicular blood flow was measured before, immediately after, and 5 h after the ligation using laser Doppler flowmetry. After 5 h of partial ligation, the testes were removed, and their morphology was examined and related to the degree of blood flow reduction. The number of in situ end-labeled- or TUNEL-positive (i.e., dying) germ cells and the volume density of intravascular polymorphonuclear (PMN) leukocytes were measured. When flow was reduced to approximately 70% or less of its pretreatment value, a dose-related increase in the number of dying spermatogonia and early spermatocytes was seen. The PMN leukocytes accumulated in testicular blood vessels after partial ligation, and the maximum number was observed in testes where flow was reduced by approximately 50% of the pretreatment value. In conclusion, early stages of spermatogenesis are sensitive to a moderate, acute reduction in blood flow. Discrete reductions in flow may, therefore, have a large impact on sperm production.     

Use of rooms with laminar air flow]

The paper deals with the problem of dependency of the reduction of microbial contamination and of dust pollution of the air mediu min the CAMERA-BOXES with a liminary flux on the aeration degree. It was shown that the degree of aeration in the camera-box constituted from 330 to 1060, with the rate of the air flux at the filter exit of from 0.2 to 0.6 m/sec. Vertical laminar flux provided release of the air from the microbes and dust. The use of the camera-box with a laminar flux for work requiring sterile conditions is recommended.