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PubMed1983

Subchronic and reproductive toxicology studies on acrylic acid in the drinking water of the rat.

In the subchronic study acrylic acid was incorporated in the drinking water of Fischer 344 rats (15 per group) for three months at dosage levels of 0.75, 0.25, 0.083 or 0 g/kg/day. No deaths occurred during the study but several treatment-related effects were observed. At 0.75 g/kg/day dosage level, body weight gain was reduced as were food and water consumption. Changes in organ weights and clinical chemistry parameters were observed along with increases in urine specific gravity and protein concentration. Similar, though less profound, changes occurred at 0.25 g/kg/day. At 0.083 g/kg/day, the only effect was a reduction of water consumption by male rats. There were no significant treatment-related histopathologic changes. Many of the effects observed may have been the result of decreased water and food consumption rather than specific toxic effects of acrylic acid. In the reproduction study, the same dosages of acrylic acid were given to groups of 10 males and 20 females for 90 days after which the animals were mated. Treatment was continued throughout gestation and lactation. Treatment-related effects included decreased body weight gain, and reduced food and water consumption in F0 rats at the 2 highest dosage levels. Organ weight changes occurred in both F0 and F1 animals and reduced body weight gain was seen in the F1 pups at the highest level. No statistically significant changes in reproductive indices were observed, perhaps because of an atypical control group.

Acrylates↗

PubMed1981

Effect of dietary zearalenone on reproduction of chickens.

Variable quantities of zearalenone (0, 10, 25, 50, 100, 200, 400, or 800 mg/kg diet) were incorporated into a practical laying hen diet and fed to 30-week-old White Leghorn females in egg production. During the 3 week pretest and 8 week experimental periods hens were inseminated weekly with .05 ml of pooled semen from males fed normal diets. Zearalenone was without effect on egg production, egg size, feed consumption, change in body weight, fertility, hatchability of fertile eggs, growth of progeny to 3 weeks of age, comb, weight, oviduct weight, heart weight, liver weight, spleen weight, egg shell thickness, Haugh units, blood hematology, serum calcium, serum inorganic phosphorus, and serum alkaline phosphatase. Zearalenone above 50 mg/kg of diet caused reduced serum cholesterol. In a reciprocal study, adult male New Hampshire chickens were fed diets containing 0, 100, or 800 mg/kg zearalenone for an 8 week period. Semen was collected and inseminated into White Leghorn females fed normal diets. Zearalenone was without effect on fertility or hatch of fertile eggs resulting from matings of these males. Zearalenone resulted in reduced serum inorganic phosphorus, serum cholesterol, and serum alkaline phosphatase in males. Histological examination of a number of tissues in both males and females revealed no changes due to zearalenone feeding. It is concluded that zearalenone up to 800 mg/kg of diet is without effect on reproductive performance of mature chickens.

Animal Feed↗

PubMed1975

[Artificial hyperventilation in head injury. I. Spontaneous hyperventilation and assisted ventilation (author's transl)].

The present study was desined to clarify the roles of artificial hyperventilation in management of the patients with cerebral injury. Here reported is the first part of the serial studies and concerned with general informations about hyperventilation. The measurements of PaCO2, minute ventilation volume (VE), dead space (VD), tidal volume (VT), cardiac output (by dye dilution method), oxygen consumption (by Fick' principle) and oxygen equilibrium were performed in the patients suffering from acute, severe head injury. And the effect of assisted ventilation on them were investigated (using pressure-limited respirator). 1. There was a common finding that marked and sustained increase in VE, VA (alveolar ventilation), and decrease in PaCO2 existed during the first week of injury. 97% of both VE and VA were above normal and mean value of PaCO2 was 29-33 mmHg. The syndrome of spontaneous hyperventilation was evidently more prominent in the nonsurvived group of patients. It was noteworthy that increased VE (or VA) was dependent neither on VD or pulmonary dysfunction nor on metabolic acidosis of arterial blood. The relation of VA to base excess in head injury was well contrasted to that of acute CO poisoning. 2. Assisted ventilation resulted in increased VT and decreased respiratory rate, and little change in VE. Consequently, PaCO2 changed only from 33.0 to 29.4 mmHg as a mean of entire series of patients. But when the influence affected by hypoxemic drive was subsided, a significant reduction of PaCO2 was disclosed following assisted ventilation. The assisted ventilation with pure oxygen was also associated with reduced cardiac output (from 6.0l/min to 5.3l/min), though the oxygen consumption changed variedly among the patients. 3. The fact was confirmed that both hypocapnea and alkalosis produced the left-sised shift of oxygen dissociation curve, decrease in P50 (P02 at 50% saturation of oxygen), and in addition, narrowed arterio-mixed venous oxygen difference. The changes of artero-mixed venous oxygen saturation difference which were calculated at 100 mmHg of PaO2 and 40mmHg of mixed venous PO2 were in a linear fashion with those of P50. Apart from the problems on injured brain, the beneficial and non-beneficial effects of hyperventilation were further discussed. The availability and inidcation of artificial hyperventilation should be precisely evaluated later, in a comprehensive manner with the subsequent studies (Part 2 and 3) on cerebral metabolism and intracranial pressure.

Brain Injuries↗

PubMedDate not supplied

[Neutral peptide hydrolases in the blood serum and lungs in hypoxia].

In rats exposed to hypoxia (breathing 11% O2-N2 for 15 min), activity of neutral peptide hydrolases in lungs and serum was measured before and after altitude chamber training. When exposed to normal air breathing, activity of lung neutral peptide hydrolases was markedly higher in Group 1 rats, i.e. those in whom O2 consumption changed insignificantly in response to the hypoxic test, than in Group 2 rats, i.e. those in whom O2 consumption increased in response to the hypoxic test. After altitude chamber training activity of lung and serum neutral peptide hydrolases decreased in Group 1 rats and increased in Group 2 rats. The potential correlation between lung and blood neutral proteolysis is discussed. Its contribution to the biochemical control of oxygen transport via blood rheological properties and vascular tone is considered.

Animals↗

PubMed1989

Decreased oxygen consumption as a toxic manifestation of protamine sulfate reversal of heparin anticoagulation.

Protamine sulfate has been observed to interfere with the control of isolated mitochondrial respiration in vitro. This study was designed to determine if oxygen consumption changes in intact animals occur in vivo during protamine administration. Oxygen consumption was assessed in seven dogs anticoagulated with heparin (150 IU/kg) and reversed 30 minutes later with protamine sulfate (1.5 mg/kg). Oxygen saturations measured included arterial (SaO2 arterial), mixed venous (SvO2 systemic), jugular (SvO2 jugular), portal (SvO2 portal), and coronary (SvO2 coronary). Cardiac output (CO) and carotid artery flow determinations allowed calculation of systemic oxygen consumption (VO2 systemic) and cerebral oxygen consumption VO2 cerebral. Hemodynamic measurements included arterial blood pressure (BP), pulmonary artery systolic and diastolic pressures (PAS, PAD), and heart rate (HR). Protamine sulfate administration resulted in hypotension (delta BP -64 mm Hg), pulmonary hypertension (delta PAS + 13 mm Hg, delta PAD + 11 mm Hg), and bradycardia (delta HR -30). Shortly after protamine administration, CO fell 54% and carotid artery flow fell more than 50%, yet declines in SvO2 systemic and SvO2 jugular were not observed. In fact these parameters increased 3% and 2%, respectively. VO2 systemic fell 55% and VO2 cerebral fell 57%. Similarly, SvO2 portal and SvO2 coronary increased 6% and 9%, respectively. Significant correlations existed between changes in VO2 systemic and BP (r = 0.05, p less than 0.001), HR (r = 0.3, p less than 0.01, PAD (r = -0.3, p less than 0.05, and CO (r = 0.8, p less than 0.001). Impaired oxygen utilization was most evident during the first 5 minutes after protamine administration. This investigation, for the first time, establishes that protamine sulfate decreases in vivo oxygen consumption, a finding that may account for certain of the drug's adverse side effects.

Animals↗

PubMedDate not supplied

Influences on children's attitudes toward alcohol consumption.

PURPOSE OF THE STUDY: To determine whether children's attitudes toward alcohol consumption changed as they grew older and to what extent peers might influence the decision to drink alcoholic beverages. METHOD: A cross-sectional descriptive study of 500 children ages 8-15 years was performed using a questionnaire. Data analysis included descriptive statistics and contingency analysis. RESULTS: Age was the only variable significantly related to decision making. Attitudes toward alcohol were more favorable in older children. Peer influence did not appear to affect drinking behavior. CONCLUSION: Older children (ages 14-15) are more favorably disposed to drinking than younger children. Children may be more influenced by parents than is realized. Parental guidance just prior to age 14 may be an effective intervention.

Adolescent↗

PubMed1989

[The lacto-tampon concept. Determination and prevention of an increased risk for caries].

The lactobacillus count and buffer capacity (final pH) of whole stimulated saliva was assessed and related to the caries increment over the next 12 months in 327 teenagers. The caries increment was 3-4.5 times higher in children having a high lactobacillus count combined with a low buffer capacity, compared with other lacto-buffer combinations (P less than, 01-,001). The protective influence of a high buffer capacity seems to be stronger than the caries-promoting influence of high sugar consumption, indicated by a high lactobacillus count. On the one hand a low sugar consumption seems to have a decisive determining preventive effect even in children having impaired buffer systems. On the other hand a high sugar consumption strongly promotes caries when the buffer capacity is low. It is also demonstrated that consumption changes during a longitudinal study may impair the relationships between the salivary parameters, assessed at baseline, and the caries increment during the study.

Adolescent↗

PubMed1988

[Neurogenic control of oxidative metabolism in the liver].

In acute experiments on dogs, stimulation of the hypothalamic ventromedial nucleus induced changes of hepatic circulation and increased the rate of O2 consumption by the liver. In stimulation of supraoptic and lateral hypothalamic nuclei the hepatic O2 consumption changed insignificantly. The hypothalamic effects on the liver tissue respiration was blocked by obsidan (propranolol) but not by atropine. A correlation exists between shifts of the O2 consumption rate and those of temperature in the liver. The data suggest that hypothalamus can modify the liver oxidative metabolism through the sympathetic nervous system and beta-adrenergic receptors of the hepatocytes and redistribute the energy of this metabolism between processes of thermogenesis and endothermic reactions in the liver.

Animals↗

PubMed1987

Comparison of the effects of lateral and ventro-posterior hypothalamic damage on the predatory behavior of cats.

Two groups of seven cats estimated preoperatively as good mice-killers were subjected to the damage of either the lateral hypothalamus (LH) or the ventro-posterior hypothalamus (VPH). The LH damage produced global impairment of the predatory behavior, such as interest in, catching, killing, or consuming the mouse, whereas VPH damage left intact most components of the predatory act, except for mouse consumption. Changes in food preference, i.e. the choice between mice and meat, were found in both groups of cats. Instead of the preoperative preference of mouse over meat, postoperative preference of meat was found in both groups. Postoperative restoration of the predatory behavior, observed in both groups, proceeded faster in the VPH cats than in the LH cats, for which the impairment lasted for several months.

Animals↗

PubMed1987

Objective and useful mobility assessment of patients with arthropathy of the hip and knee.

Walking ability was objectively assessed by measurements of endurance, oxygen consumption, and pulse rate response. Twenty-four control subjects and 38 patients with arthropathy of the hip or knee were asked to walk on a treadmill, initially at 1 km/hour, for four minutes. The speed was increased by 1 km/hour every four minutes, until the subjects has walked for four minutes at 7 km/hour, or until they could not continue. Oxygen consumption, heart rate, cadence, and step length were measured. The controls could all walk for 1400 m, reaching a walking speed of 6 km/hour, and showed a consistent relation between heart rate, oxygen consumption, and speed of walking. The majority of arthritic patients failed to reach either this distance or speed. They had a significantly increased metabolic cost, and there was a good correlation (r = 0.65 to 0.99) between the changes in pulse rate and oxygen consumption in each individual patient. The endurance, heart rate response, and oxygen consumption changes shown by patients proved to be reproducible characteristics in patients whose disease was static.

Adult↗

PubMed1984

Effect of decreased O2 affinity of hemoglobin on work performance during exercise in healthy humans.

A reduction in O2 affinity of hemoglobin should increase tissue oxygenation or maintain tissue oxygenation and at the same time spare cardiac work. Large, sustained reductions in O2 affinity of hemoglobin are induced best by primary (non-Bohr effect) stimulation of red blood cell 2,3-diphosphoglycerate (DPG) caused by a dual, cumulative effect on O2 affinity for hemoglobin, direct, from DPG itself, and indirect, from DPG-induced red blood cell acidosis. In an attempt to induce significant, sustained reductions in O2 affinity of hemoglobin by primary DPG stimulation, six normal humans were given a diphosphonate (etidronate disodium [Didronel] 20 mg/kg/day p.o.) followed by infusion of 10% fructose (0.5 L/hr for 3 hours) with added phosphate (0.28 mmol/kg/hr) and, subsequently, fructose-phosphate by itself. Participants underwent exercise testing (bicycle ergometer) and cardiopulmonary parameters were measured before and after administration of Didronel plus fructose-phosphate infusion, as well as before and after fructose-phosphate infusion alone. The sum of DPG and adenosine triphosphate as well as the P50 increased significantly after infusion of fructose-phosphate with and without prior administration of Didronel. DPG-ATP correlated closely with P50. When P50 was elevated, the cardiac index at high work load was lower than when P50 was normal (with comparable O2 consumption); changes in P50 correlated inversely with changes in cardiac index. Thus, with reduced O2 affinity of hemoglobin, participants could perform at comparable work loads and utilize the same amount of O2 with less cardiac work. Future studies should include adapting these findings to states of O2 deficit.

2,3-Diphosphoglycerate↗

PubMed1984

[Toxic effects of endotoxin perfusion on isolated rat bowel].

The isolated small bowel from duodenojejunal junction to ileocecal junction with intact SMA and SMV was perfused with Krebs-Ringer solution intraluminally in rat. After all the branches from aorta and portal vein other than SMA and SMV were ligated, aorta and portal vein were cannulated and perfused with Krebs-Dextran solution. The isolated perfused bowel was transferred immediately to the chamber equipped with constant temperature and humidity. For the purpose of studying the direct toxicity to the bowel tissue, B4 endotoxin (Difco) was added to intravascular perfusate. Significant physiological and chemical changes listed below were observed as compared with those of the control group which was perfused with endotoxin free perfusate. Active transport of D-glucose was decreased. Net entry of water into the gut lumen was decreased. pH in intravascular fluid was significantly decreased. Lactic acid level in intravascular fluid was significantly high, which was well correlated with pH change. O2 consumption change was not marked, but CO2 accumulation in intravascular perfusate was significant. These were the results of the toxic effects of endotoxin on the rat bowel.

Animals↗

PubMedDate not supplied

[Oxygen consumption as an indicator of the adaptation of animals to altitude hypoxia].

Altitude chamber experiments have shown that the quantity of oxygen consumption in the posthypoxic period as an index of adaptation to hypoxia is of a low informative value: during the normal course of adaptation, oxygen consumption changes insignificantly or decreases slightly; it increases somewhat if the hypoxic atmosphere contains CO2 (pCO2 = 19 - 27 mm Hg) and declines significantly (by 22.6%) only if adaptation is disordered. At the same time oxygen consumption can be a highly informative index, characterizing the efficiency of adaptation to hypoxia only if it is measured immediately after exposure to acute hypoxia. In this experimental design the magnitude of oxygen consumption increases with increasing oxygen debt which, as follows from our experiments, shows the degree of conditioning to altitude hypoxia.

Adaptation, Physiological↗

PubMed1983

[Blood flow and oxygen tension and consumption in skeletal muscles after hypothalamic stimulation].

In acute experiments on dogs under nembutal anesthesia, stimulation of different parts of the hypothalamus increased the muscle blood flow and O2 consumption and decreased vascular resistance. PO2 in m. gastrocnemius altered in both directions as a function of blood flow and O2 consumption changes. There was a good correlation between the initial level of PO2 and its shifts caused by hypothalamic stimulation. In most cases flow reactions were blocked with atropine. The stimulation of the hypothalamus seems to evoke cholinergic vasodilatation in skeletal muscles. The data suggest that initial level of muscle PO2 determines the redistribution of the increased blood flow between nutritional and non-nutritional vessels within the skeletal muscles and thus affects transcapillary exchange and O2 consumption during cholinergic vasodilatation.

Animals↗

PubMed1981

Oxygen transport and tissue oxygenation under moderate and extreme hemodilution during coronary bypass surgery.

Oxygen transport and tissue oxygenation were investigated in twelve patients undergoing coronary bypass surgery under normovolemic moderate and extreme hemodilution. Moderate hemodilution, that was carried out after induction of anesthesia, decreased the mean hematocrit from 0.43 to 0.33. Concurrently, the cardiac index and the left ventricular filling pressure increased slightly whereas the systemic oxygen transport declined by 20%. This was associated with elevated oxygen extraction. The subcutaneous tissue oxygen tension underwent a transient increase during moderate hemodilution. During cardiopulmonary bypass and extreme hemodilution the mean hematocrit declined to 0.16. Simultaneously, the tissue PO2 decreased clearly reaching its minimum at the deepest hypothermia. After coming off bypass and reinfusion of the autologous blood the tissue PO2 approached the preoperative levels. In general, total body oxygen consumption changed parallelly with the tissue oxygen tension. Lactate concentration in the mixed venous blood increased in the beginning of the extracorporeal circulation and remained rather stationary thereafter. All patients recovered normally without any perioperative myocardial infarctions.

Adult↗

PubMed1982

[Blood supply and oxygen consumption in cat musculus gastrocnemius during isometric tetanus and intra-arterial infusion of norepinephrine].

In anesthetized cats with maximal isometric tetanus induced by the n. ischiadicus stimulation, the initial oxygen consumption depended on the 2--fold reduction of initial blood flow, the anaerobic metabolism index remaining the same, at that. Stimulation of the nerve induces practically the same mechanical activity of the muscle in control and after i. a. administration of noradrenaline, but the working hyperemia with concomitant changes of the metabolism indices becomes weaker than in control. A correlation of muscle blood supply changes with oxygen consumption changes was revealed whereas there was no correlation between changes of these indices and changes of oxygen extraction from the blood. A possibility of effects of the primary increase in blood flow occurring in hyperemia following the mechanical factor action, on the oxygen consumption is discussed as well as effect of willed decrease in blood flow within non-hypoxic range upon the oxidated metabolism.

Animals↗

PubMed1994

Effect of cardiac filling pressures on the release of atrial natriuretic peptide during exercise in heart transplant recipients.

OBJECTIVE: To determine the influence of body posture and central hemodynamics on the plasma levels of immunoreactive atrial natriuretic peptide (irANP) during exercise in cardiac transplant patients. METHODS: Central hemodynamics, mixed expired gas and ventilatory measurements, and venous blood sampling (for irANP determination) were obtained in cardiac transplant patients at rest and during supine (n = 12) or upright (n = 12) graded cycle exercise. Cardiopulmonary and irANP responses to exercise were compared between the upright and supine postures. RESULTS: At rest (supine), irANP concentrations were similar in both groups (172 +/- 87 pg/mL supine and 182 +/- 72 pg/mL upright) and did not correlate with resting supine central hemodynamics. During exercise, central filling pressures increased in both groups but patients exercising in the supine position had a greater increase. Peak exercise right atrial pressure was 12 +/- 4 mmHg supine versus 7 +/- 5 mmHg upright (P < 0.005). Peak exercise pulmonary capillary wedge pressure was 22 +/- 6 mmHg supine versus 14 +/- 5 mmHg upright (P < 0.005). At peak exercise, irANP levels were greater in the supine than upright position (419 +/- 166 pg/mL supine versus 277 +/- 40 pg/mL upright, P < 0.05). The change in irANP from rest to peak exercise correlated (P < 0.05) with changes in pulmonary capillary wedge pressure (r = 0.67), systolic pulmonary artery pressure (r = 0.78) and right atrial pressure (r = 0.53). There was, however, no correlation between change in irANP and peak oxygen consumption, change in heart rate or change in mean arterial blood pressure. CONCLUSIONS: In cardiac transplant recipients, exercise is a stimulus for ANP secretion, and augmentation in plasma irANP levels during exercise is modulated by changes in central hemodynamics.

Adult↗

PubMed1993

[Alcohol consumption in a Danish cohort study over a period of 11 years].

A cohort living in Copenhagen County, originally consisting of 1198 persons, 577 men and 621 women, who were 40 years old in 1976, was reexamined in 1981 and again in 1987, 1052 (88%) participated in 1976, 922 (84%) in 1981, and 965 (85%) in 1987. The purpose of this study was to describe alcohol consumption changes in the cohort, with a view to identifying subgroups who significantly change their alcohol consumption behaviour. The same questionnaire was employed all three times to measure the alcohol consumption level and frequency. Alcohol consumption peaked in 1981 (45-years old) with 10.4 drinks on average a week. Men increased 8% and women 37%. There is an overall downward tendency in the consumption frequency among men whereas the opposite is the case among women. The two groups are converging toward a weekly consumption level. It seems now that the women are leading the change in the content of consumption with relatively more wine consumption. Therefore it is concluded that female consumption should be considered a target in future preventive programs.

Adult↗