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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carcinus maenas and Necora puber were exposed to air for 72 h and 18 h, respectively, at 18 degreesC. Nitrogen excretion, blood and muscle ammonia content and blood urate and lactate content were recorded throughout the experimental emersion and following reimmersion (recovery period). During emersion, the rate of ammonia excretion was strongly reduced in both species, while urea and amine excretion were not enhanced. Blood and muscle ammonia content increased steadily, reaching 1.3 and 10.4 mmol l-1, respectively, after an 18 h emersion in N. puber. In contrast, in C. maenas, blood ammonia levels increased slightly during the first 12 h and then remained at this level (approximately 0.12 mmol l-1) until the end of emersion. Muscle ammonia content showed a non-significant increase at 12 h, after which values returned to control values (3.3 mmol l-1) for the next 60 h. Blood urate and lactate content increased in emersed N. puber, indicating strong internal hypoxia, but urate content did not increase in C. maenas until the third day of emersion. Upon reimmersion, both species released large amounts of ammonia within a few minutes. Two different patterns of ammonia release then were observed: ammonia excretion was enhanced for a further 3 h in N. puber, whereas raised ammonia excretion rates were observed for a further 24 h in C. maenas. These patterns, the recovery of blood and muscle ammonia levels and the calculated nitrogen balance between emersed and control crabs indicated that specific processes were used to manage the nitrogen overload induced by air exposure. Whereas N. puber shows little or no ability to limit ammonia accumulation in its body, C. maenas exhibits strong regulation of its nitrogen metabolism. The probability that amino acid synthesis is involved in this regulation and whether these species use metabolic depression as a survival strategy are discussed.
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PMID:Nitrogen metabolism of two portunid crabs, carcinus maenas and necora puber, during prolonged air exposure and subsequent recovery: a comparative study 969 86

A 4 x 4 Latin square experiment was conducted to examine abomasal passage of biogenic amines in steers fed silage and their related effects on intake, digestibility, and digestive function. Thirty percent of the dry matter (DM) in the diets consisted of alfalfa forage, which was fed as either hay or silage. The DM from alfalfa silage DM was substituted at 0, 33, 67, and 100% for DM from alfalfa hay and was fed to four ruminally and abomasally cannulated steers. The roughage component of the diet constituted 50% of the DM and consisted of 60% alfalfa silage or hay and 40% tropical corn silage. The concentrate was composed mainly of ground corn. The concentrations of putrescine and cadaverine in abomasal digesta increased as alfalfa silage in the diet increased. Abomasal recovery of biogenic amines, a product of their concentration in abomasal digesta and the passage of DM through the abomasum, was negatively correlated with intake. Abomasal recovery of most amines was 5 to 20% of intake. Abomasal recovery of cadaverine was correlated with depressed intake. Total DM intake was reduced 8.3 to 25.8% as the proportion of alfalfa silage in the diet increased. Frequency of reticular contractions, intake, ruminal DM digestibility, ruminal outflow, volatile fatty acids, and total tract DM digestibility decreased in steers fed diets that contained more alfalfa silage. Ruminal fluid pH and NH3 concentration increased in steers fed more alfalfa silage; however, mass and the DM percentage of ruminal contents decreased linearly. Postprandial insulin concentrations were quadratically related to the proportion of alfalfa hay or silage in the diet. Intraruminal metabolism of biogenic amines is extensive based on the relatively low quantities recovered in abomasal digesta; however, the amounts recovered in abomasal digesta were related to intake depression and associated physiological effects.
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PMID:Biogenic amines in silage, apparent postruminal passage, and the relationship between biogenic amines and digestive function and intake by steers. 974 85

Although valproic acid has gradually gained its popularity in the treatment of various seizure disorders, overdose of valproate is not common. An 18-y-old man with a history of epilepsy controlled by sodium valproate and clonazepam attempted suicide with an ingestion of 45 g sodium valproate. He presented to our service with drowsiness and irritability. Extremely high serum ammonia (623 ug/dL) and elevated serum valproate concentration (575 ug/mL) were found on admission. Several metabolic abnormalities, including hypernatremia, hypocalcemia and metabolic acidosis, as well as, increased serum transaminase levels were also recorded. With supportive measures, he became clear 24 h later and was discharged 6 d after ingestion. Serial follow-up of his serum valproate and ammonia levels disclosed a close relationship between these 2 measurables. After acute overdose of valproic acid, patients usually present with mild and generally reversible depression of the central nervous system. However, impairment of liver function, hyperammonemia, fluid-electrolyte disturbances, coma, seizures, hypotension and even death may occur following valproate overdose. Symptomatic and supportive measures are the mainstay in the treatment of valproic acid overdose. With prompt diagnosis and early institution of treatment, a complete recovery should be anticipated.
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PMID:A case of severe hyperammonemia and unconsciousness following sodium valproate intoxication. 983 Jun 96

In forty-five Holstein Frisian dairy cows (1-6 weeks post partum; mean age: 5.1 +/- 1.2 years) the serum total bile acid concentrations (SBA) were measured enzymatically. In all cows a left sided abomasal displacement was corrected surgically by right side laparotomy and omentopexy three days before investigation. The liver fat content was determined in all cows histologically. Liver failure was assumed if typical clinical signs (ataxia, general depression, recumbency or coma), an increased venous plasma ammonia level (> 35 mumol/l) and a decreased plasma amino acid index (< 4.0) were found. Cows without liver failure (N = 29) were grouped according to the liver fat content as cows with mild (N = 5), moderate (N = 19) or severe hepatosteatosis (N = 5). Histological examination of liver biopsies in cows with liver failure (N = 16) revealed in twelve cases a severe fatty liver and in four cases a hydropic degeneration of the liver tissue. Although in cows without liver failure mean SBA concentrations were higher in the group with moderate (47.3 +/- 30.9 mumol/l) or severe fatty liver (32.9 +/- 21.7 mumol/l) than in that with mild lipidosis (18.0 (16.8 mumol/l), differences were not significant. The mean SBA concentration in cows with liver failure (70.5 +/- 49.5 mumol/l) was only significantly (p < 0.05) increased compared to cows with uncomplicated mild hepatic lipidosis. In conclusion, the determination of SBA concentrations is of little value in the recognition of fatty liver or even liver failure due to the considerable variance of SBA concentrations in dairy cows.
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PMID:Total serum bile acid concentrations in dairy cows with fatty liver and liver failure. 1002 57

The ammonia and GABAergic neurotransmission hypotheses of the pathogenesis of hepatic encephalopathy (HE) have appeared to be unrelated and perhaps mutually exclusive. Observations in animal models of fulminant hepatic failure, that are consistent with increased GABAergic inhibitory neurotransmission contributing to the manifestations of HE, include: (i) abnormal visual evoked potential waveforms that resemble those induced by GABA(A)/benzodiazepine (BZ) receptor complex agonists; (ii) GABA(A)/BZ receptor complex antagonist-induced ameliorations of encephalopathy; (iii) increased resistance to drugs which decrease GABAergic tone; and (iv) hypersensitivity of CNS neurons to depression by GABA(A)/BZ receptor complex agonists. Mechanisms of increased GABAergic tone in HE may include the following: (i) increased brain concentrations of natural BZs; and (ii) increased GABA concentrations in synaptic clefts, possibly due to increased blood-brain-barrier permeability to GABA and a decrease in GABA(B) receptor density. Both neuroelectrophysiological and behavioral data indicate that ammonia concentrations in the range 0.75-2 mM induce increased excitatory neurotransmission. In contrast, recently, ammonia concentrations in the range 0.15-0.75 mM, i.e. concentrations that commonly occur in plasma in precoma HE, have been shown: (i) to increase GABA-induced chloride current in cultured neurons; and (ii) to enhance synergistically the binding of GABA(A)/BZ receptor agonists. In addition, increased ammonia concentrations enhance synthesis of neurosteroids in astrocytes, and some neurosteroids potently augment GABAergic neurotransmission. Thus, the modestly elevated concentrations of ammonia, that commonly occur in liver failure, may contribute to the manifestations of HE by enhancing GABAergic inhibitory neurotransmission. This concept appears to unify the ammonia and GABAergic neurotransmission hypotheses.
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PMID:Does ammonia contribute to increased GABA-ergic neurotransmission in liver failure? 1020 26

Stomach infection with pathogenic strains of Helicobacter pylori causes in some patients severe gastroduodenal diseases. These bacteria produce various virulence factors and, here, we review the recent acquisition on the biochemical mode of action of three major factors. We discuss the role of urease both as buffer of the stomach pH and as source of ammonia. The vacuolating toxin alters the endocytic pathway of non-polarized cells, inducing the release of acid hydrolases, the depression of extracellular ligand degradation and of antigen processing and, in the presence of ammonia, swelling of late-prelysosomal compartments. In polarized epithelial monolayers, vacuolating toxin induces an increase of the paracellular permeability, independent of vacuolation. The neutrophil activating protein induces the production of oxygen radicals in human neutrophils and could contribute to the damage of the stomach mucosa. The activities of these factors are discussed in terms of the need of the bacterium of increasing the supply of nutrients from the stomach lumen and from the mucosa.
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PMID:Molecular and cellular activities of Helicobacter pylori pathogenic factors. 1037 70

In 3 mature female horses of varying breeds, episodes of colic and depression for 14 days preceded an encephalopathic disorder with maniacal behaviour, anxiety, profuse sweating and, in one case, terminal opisthotonus. Blood ammonia levels were elevated approximately 10-fold. At necropsy, there were gastrointestinal serosal and mesenteric haemorrhages. Histologically, all 3 cases revealed diffuse Alzheimer type II astrocytes in the cerebral grey matter. Alzheimer type II astrocytes were glial fibrillary acidic protein (GFAP) negative or only weakly positive, weakly S-100 positive, and vimentin negative. In the absence of primary hepatic and/or renal lesions, an increase in intestinal ammonia absorption due to ileus or increased ammonia production by colonic bacteria is hypothesised.
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PMID:Encephalopathy with idiopathic hyperammonaemia and Alzheimer type II astrocytes in equidae. 1059 28

The ruminally fistulated sheep was used as a model to study the effects of fat supplementation (Ca-soaps and free long chain fatty acids from palm oil) on rumen physiology and digestibility of the nutrients. The animals were fed with a typical ration of hay and concentrate supplying nutrients according to maintenance levels. The following results should be pointed out: The addition of free fatty acids and their Ca-soaps induced a retarded recovery of postprandially decreased pH-values in ruminal fluid. This retardation was more pronounced after addition of free long chain fatty acids than with their Ca-soap-analogous acids. Compared to the control, the concentration of short chain fatty acids was depressed by fat addition in the period 2 hours after feed intake. The release of ammonia in the first period after feed intake was reduced by fat addition. A lack of synchronity could be observed in this post-prandial period in ruminal fluid between concentration of short chain fatty acids and ammonia. This effect was most obvious with supplementation of unprotected fatty acids. This might be one reason for the better tolerance of Ca soaps from palm oil fatty acids. Formation of hydrides, branched chains and transforms proceeds more effectively with free fatty acids than with their analogous forms of Ca-soaps. The well-known effect of depression of digestibility of nutrients due to fat supplementation was--under present conditions--quite low. This might be different in lactating dairy cows with higher levels of feed intake. With high feed intake, passage time is reduced. This will affect digestibility and interactions with fat supplementation.
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PMID:[Rumen fermentation and digestibility of nutrients studied by the addition of Ca soaps of palm oil fatty acids and their analogous fatty acids in the sheep model]. 1063 33

Three lamb metabolism experiments were conducted to investigate the effects of chronic administration of the novel urease inhibitor N (n-butyl) thiophosphoric triamide (NBPT) on ruminal N metabolism, fermentation, and N balance. In Exp. 1, ruminally cannulated wethers (n = 28; 45.0 +/- .9 kg) were administered one of seven doses of NBPT (0 [control], .125, .25, .5, 1, 2, or 4 g of NBPT daily) and fed a common cracked corn/cottonseed hull-based diet twice daily containing 2% urea at 2.5% of initial BW for the duration of the 15-d experiment. Overall, NBPT decreased (linear P < .0001; quadratic P < .001) ruminal urease activity, resulting in linear increases (P < .0001) in ruminal urea and decreases in ruminal NH3 N concentrations. However, the detection of an NBPT x day interaction (d 2 vs 15; P < .01) indicated that this depression in urea degradation diminished as the experiment progressed. Increasing NBPT linearly decreased (P < .01) total VFA concentrations on d 2 of the experiment, but it had no effect (P > .10) on d 15. Increasing NBPT had no effect (P > .10) on DM or ADF digestibilities, but it linearly decreased (P < .01) N digestibility. Supplementing NBPT produced a linear increase (P < .05) in urinary N excretion and a linear decrease (P < .01) in N retention. In Exp. 2, ruminally cannulated wethers (n = 30; 46.8 +/- .6 kg) were fed one of two basal diets (2.0 vs 1.1% dietary urea) at 2.5% of initial BW and dosed with either 0 (control), .25, or 2 g of NBPT daily for the duration of the 15-d experiment. There were no NBPT x dietary urea interactions (P > .10) for Exp. 2. Increasing NBPT depressed (linear and quadratic P < .0001) ruminal urease activity, producing linear (P < .0001) increases in urea N and linear decreases in NH3 N in the rumen. As in Exp. 1, an NBPT x day interaction (P < .05) was noted for urea, NH3 N, and total VFA concentrations; the maximum response to NBPT occurred on d 2 but diminished by d 15 of the experiment. Administration of NBPT did not influence (P > .10) DM, ADF, or N digestibilities in Exp. 2. In Exp. 3, wether lambs (n = 30; 26.4 +/- .7 kg) were subjected to the same treatment regimen as in Exp. 2 for a 14-d N balance experiment. Although several NBPT x dietary urea interactions (P < .05) were noted, increasing NBPT did not affect (P > .10) N digestibility. Administration of NBPT quadratically increased (P < .10) urinary N excretion, producing a linear decrease (P < .05) in N retention. These results suggest that although NBPT is capable of inhibiting ruminal urease short-term, the ruminal microflora may be capable of adapting to chronic NBPT administration, thereby limiting its practical use in improving the utilization of dietary urea.
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PMID:Influence of the novel urease inhibitor N-(n-butyl) thiophosphoric triamide on ruminant nitrogen metabolism: II. Ruminal nitrogen metabolism, diet digestibility, and nitrogen balance in lambs. 1068 21

We have studied changes in upper airway reflex sensitivity following general anaesthesia using dilute ammonia vapour as a chemical stimulant in 16 patients undergoing elective laparoscopic gynaecological surgery. We measured the threshold concentration of ammonia vapour required to elicit a transient reduction of inspiratory flow caused by glottic closure, defined as a glottic stop. Measurements of upper airway reflex sensitivity and auditory reaction time were obtained before surgery, and at 60 and 120 min after recovery. Auditory reaction time was depressed significantly at 60 min but was similar to baseline values 120 min after recovery. Upper airway reflex sensitivity remained significantly reduced at 60 and 120 min despite the return of auditory reaction time to normal. The lack of correlation between upper airway reflex sensitivity and auditory reaction time suggests that central nervous system depression alone does not explain the delayed recovery in airway reactivity.
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PMID:Upper airway reflex sensitivity following general anaesthesia for day-case surgery. 1078 Nov 24


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