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PubMed1980

Defined medium for Aquaspirillum serpens VHL effective in batch and continuous culture.

A defined medium for Aquaspirillum serpens VHL allows the replacement of the complex media now in use. It was developed by batch culture methods but supports growth in continuous culture. A basal salts medium supplemented with L-aspartic acid, L-alanine, and L-glutamic acid provided the best growth (turbidity), as long as ammonium chloride was omitted. Ammonium chloride caused either a lag or a reduction or a complete inhibition of the growth of A. serpens VHL on the above amino acids and other organic supplements depending on the combination used. Ammonium sulfate and ammonium hydroxide with L-glutamic acid allowed growth, but the lag period was increased in shake flask cultures. Vitamins, cysteine hydrochloride, and carbon dioxide had no effect on the growth rate. Viability (less than 50%) was inadequate to maintain continuous culture with L-glutamic acid as the sole source of carbon and nitrogen. Combinations of amino and carboxylic acids were then tested and, of these, L-glutamic acid (1 g/liter) and L-histidine (75 mg/liter) without ammonium chloride in the basal salts medium supported growth in batch and continuous culture. L-Glutamic acid was the limiting substrate for growth.

Alanine↗

PubMed1963

Adverse effect of ammonium salts on the antibacterial activity of paraformaldehyde solutions.

The antibacterial activity of aqueous solutions of paraformaldehyde in concentrations from 0.1 to 0.4% (w/v) is bacteriostatic rather than bactericidal in the presence or absence of ammonium chloride. The presence of ammonium chloride significantly lengthened the time of exposure to paraformaldehyde necessary for inhibition of growth of the test organism (Staphylococcus aureus FDA 209) when unbuffered solutions were used. Elevation of the pH of the reacting mixture of paraformaldehyde and ammonium chloride by partial buffering lengthened the time of exposure necessary for inhibition of growth of the test organism. Decrease of antibacterial activity was concomitant with the disappearance of paraformaldehyde from the reacting mixture. The reaction of paraformaldehyde with ammonium chloride was rapid at room temperature (25 C) and at pH levels near neutrality. The fate of the reacting paraformaldehyde, including the possibility of the formation of hexamethylenetetramine or methylenimine, is discussed with particular reference to loss of antibacterial activity.

Ammonium Chloride↗

PubMed1984

Asparagine and glutamine metabolism in chicks.

In a series of four experiments, asparaginase and glutaminase activity was measured in liver and kidney tissue of 7- to 19-day-old male broiler chicks. In Experiment 1, chicks were fed purified amino acid diets with 14.8 and 44.6% protein equivalents (PE) with 1, 3, or 5% added sodium bicarbonate. In Experiments 2, 3, and 4 the chicks were fed a 23% protein basal control diet, basal diet containing 5% ammonium chloride, and basal diet containing 5% ammonium chloride with 5 or 10% sodium bicarbonate, asparagine, or glutamine. In Experiments 2 and 4 the chicks were also fed 25, 50, or 75% protein-isolated soy-purified diets. The 44.6% PE diet increased liver and kidney asparaginase activity in chicks as compared to chicks fed a 14.8% PE diet. The addition of sodium bicarbonate to the 44.6% PE amino acid diet decreased the kidney asparaginase activity equivalent to kidney asparaginase activity of chicks fed the 14.8% PE diet. Asparaginase activity increased 4-fold in the kidneys of chicks fed the 23% protein basal diet containing 5% ammonium chloride and the pH of the urine from the chicks was 4.9. Chicks fed basal diets with 5% ammonium chloride plus 10% sodium bicarbonate or asparagine had the same kidney asparaginase activity and urine pH as chicks fed the 23% protein basal control diet. Glutamine added to chick diets containing 5% ammonium chloride did not decrease the kidney asparaginase activity or the urine acidity. Liver asparaginase activity was not increased in acidotic chicks fed diets with 5% ammonium chloride. The asparaginase activity of liver and kidney tissue were both significantly increased in chicks fed 75% protein-isolated soy purified diets and the pH of their urine was 5.6. The increase in liver asparaginase of chicks fed 75% protein or 44.5% PE diets was probably due to an endocrine gluconeogenic response producing increased catabolism of the majority of amino acids. The increase in kidney asparaginase of chicks fed 75% protein, 44.5% PE diets, and 23% protein basal diets with 5% ammonium chloride was primarily related to metabolic acidosis. Phosphate-dependent glutaminase (PDG) activity was localized in chick kidney mitochondria and was heat sensitive (55 C for 30 sec). The phosphate-independent glutaminase (PIG) activity was primarily localized in chick kidney mitochondria but was stable to a temperature of 55 C for 30 sec.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗

PubMed1994

Renal tubular cell protein breakdown in uninephrectomized and ammonium chloride-loaded rats.

Kidney enlargement after unilateral nephrectomy or the induction of a systemic acidosis with ammonium chloride is associated with an increase in kidney protein content. This reflects an imbalance between protein breakdown and protein synthesis. Because it has been shown in diabetic nephromegaly that depressed protein breakdown contributes to the increase in kidney protein content, this study examined whether altered protein breakdown is common to all forms of renal hypertrophy. Accordingly, protein turnover was measured in isolated proximal tubules from kidney in rats undergoing renal enlargement after uninephrectomy or chronic ammonium chloride-induced acidosis. In both conditions, kidney protein content and protein synthesis ([14C]valine incorporation) increased significantly. Fractional protein degradation was depressed in renal tubules isolated from the acidotic rats and was accompanied by a decrease in proximal tubule cathepsin B and combined B and L activities. These changes are comparable to earlier observations with the diabetic kidney. In contrast, after unilateral nephrectomy, protein breakdown is not reduced, and it can reasonably be concluded that, in this condition, protein gain reflects increased protein synthesis alone. It was concluded that the pattern of protein turnover leading to protein accretion in renal hypertrophy varies according to the initial stimulus for renal growth.

Adaptation, Physiological↗

PubMed2002

Development of viral disinfectant assays for duck hepatitis B virus using cell culture/PCR.

Human hepatitis B virus (HBV) is a worldwide public health problem with chronic carriers at risk for developing cirrhosis and hepatocellular carcinoma. Accidental nosocomial infections from inadequately disinfected equipment or exposure to blood and body fluids from patients are major routes. To solve such problems, disinfectants to inactivate HBV must be validated. Duck hepatitis B virus (DHBV) is accepted as a surrogate for HBV, due to their similar sensitivities to disinfectants and its safety. Ducklings are used for disinfectant efficacy assays; however, the same virus titer is obtained using duck embryonic hepatocytes. Viral titration in disinfectant efficacy assay is conducted using Southern hybridization of infected duck serum. However, this test requires radioisotopes. Therefore, disinfectant assessment protocols were developed using duck embryonic hepatocytes with polymerase chain reaction (PCR) or nested PCR. The ease of handling, lowered cost and enhanced sensitivity make PCR desirable. Chicken embryonic hepatocytes were applied to DHBV disinfectant efficacy assay. Results were consistent and could be used under certain conditions. The virucidal activities of two quaternary ammonium chloride disinfectants, n-alkyl dimethyl benzyl ammonium chloride and alkyl dimethyl benzyl ammonium chloride (10C-12C) were compared and effective concentrations were 1200 and 1800 ppm, respectively. Efficacies of these disinfectants were validated using real-time quantitative PCR. Results confirmed that the efficacy of n-alkyl dimethyl benzyl ammonium chloride was higher than alkyl dimethyl benzyl ammonium chloride (10C-12C). This assay was useful for rapid discrimination of killing potentials of disinfectants. In conclusion, these assays can be applied to other viruses that are unable to cause CPE in cell cultures and broadened the utility of DHBV as animal model for HBV.

Animals↗

PubMed2004

Cytoprotective effect of estrogen on ammonium chloride-treated C6-glioma cells.

The potential cytoprotective effects of estrogen in the brain are of special interest in aging, neurodegenerative diseases, exposure to toxins, and trauma. Estrogen effects on neurons have been widely explored, but less is known about estrogen effects on glia. Glial cells are primary targets of ammonia toxicity, which arises from liver disease or failure (such as from cirrhosis in alcoholics), urea cycle disorders, or inborn errors of metabolism. We examined the ability of estrogen to protect glial cells from ammonium chloride toxicity using an in vitro model system. C6-glioma cells in later passage have many astrocytic characteristics and provided a convenient and well established model system for this work. When C6-glioma cells were exposed to 15 mM ammonium chloride, we observed major cell death (only 32% cell survival relative to control) within 72 h. Pretreatment with 17beta-estradiol (10 microM) significantly protected C6-glioma cells from ammonia toxicity (99% cell survival relative to control). In addition to enhancing the viability of C6-glioma cells against ammonia challenge, estrogen pretreatment was also found to protect mitochondrial function as assayed using the MTT reduction assay. Mitochondrial function was reduced to 39% of control levels in ammonia-challenged cultures and was mostly protected by estrogen (72% of control levels). The findings are potentially relevant for the development of therapeutic strategies to protect glial cells against ammonia toxicity resulting from hepatic failure or other causes.

Ammonium Chloride↗

PubMed1977

Changing meal patterns and suppression of feed intake with increasing amounts of dietary nonprotein nitrogen in ruminants.

Goats were injected intraruminally during spontaneous meals with ammonium chloride, urea, ammonium lactate, or sodium lactate arranged in a Latin square experimental design randomized for order of treatments. Urea and ammonium injections shortened meal length by 20 to 30%. Rate of eating and meal frequency were reduced. Sodium lactate injections reduced meal size. In cows, meal length and meal size also were measured. Grain concentrate, corn silage, and chopped hay were fed as complete mixed rations. In the concentrates 58+ of the nitrogen was either from soybean meal or urea. Length of the first meal after feeding was reduced from 24.3 min with soybean meal to 12.4 with urea. Meal size was reduced from 3.2 kg to 1.8 kg when urea was fed. Total feed intake was similar, 12.0 kg/day (soybean meal) and 11.6 kg/day (urea) since spontaneous meal number and size were 17 and .30 kg for soybean meal but increased to 23 and .36 kg for urea. The physiological basis for the limit on meal length with urea rations is unknown but is an important factor in successful feeding of urea when eating time is limited for cows.

Ammonium Chloride↗

PubMed1970

Renal metabolic response to acid-base changes. II. The early effects of metabolic acidosis on renal metabolism in the rat.

The early renal metabolic response was studied in rats made acidotic by oral feeding of ammonium chloride. 2 hr after feeding of ammonium chloride there was already significant acidosis. Urinary ammonia also increased after ammonium chloride ingestion and at 1(1/2) hr was significantly elevated. In vitro gluconeogenesis by renal cortical slices was increased at 2 hr and thereafter increased steadily. Ammonia production by the same slices was also increased at 2 hr, but thereafter fell and at 6 hr had decreased to levels which, although higher than those of the control, were lower than those obtained from the rats acidotic for only 2 hr. There was no correlation between in vitro gluconeogenesis and ammonia production by kidney slices from rats during the first 6 hr of acidosis, but after 48 hr of ammonium chloride feeding, these two processes were significantly correlated. The early increase in renal gluconeogenesis was demonstrable with both glutamine and succinate as substrates. The activity of the enzyme phosphoenolpyruvate carboxykinase was increased after 4-6 hr of acidosis. During this time there was a decrease in renal RNA synthesis as shown by decreased uptake of orotic acid-(5)H into RNA. Metabolic intermediates were also measured in quick-frozen kidneys at varying times after induction of acidosis. There was an immediate rise in aspartate and a fall in alpha-ketoglutarate and malate levels. There was never any difference in pyruvate or lactate levels or lactate:pyruvate ratios between control and acidotic rats. Phosphoenolpyruvate rose significantly after 6 hr of acidosis. All the data indicate that increased gluconeogenesis is an early response to metabolic acidosis and will facilitate ammonia production by utilization of glutamate which inhibits the glutaminase I enzyme. The pattern of change in metabolic intermediates can also be interpreted as showing that there is not only enhanced gluconeogenesis, but also that there may be significant increase of activity of glutaminase II as part of the very early response to metabolic acidosis.

Acidosis↗

PubMed1995

NTP Toxicology and Carcinogenesis Studies of Benzethonium Chloride (CAS No. 121-54-0) in F344/N Rats and B6C3F1 Mice (Dermal Studies).

Benzethonium chloride is used primarily in cosmetics for its antimicrobial and cationic surfactant properties. Benzethonium chloride was nominated by the National Cancer Institute to the NTP for study from a class study of chemicals used as biocides. The chemical was selected based on a suspicion of carcinogenicity and its known widespread human exposure. Male and female F344/N rats and B6C3F1 mice were topically administered benzethonium chloride (greater than 98% pure) for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium and cultured Chinese hamster ovary cells. 16-DAY STUDY IN RATS: Groups of five male and five female F344/N rats were topically administered 0, 6.3, 12.5, 25, 50, or 100 mg benzethonium chloride/kg body weight. Rats were administered a total of 12 doses in a fixed volume of 250 &mgr;L ethanol. All rats survived to the end of the study. The final mean body weights and body weight gains of rats administered 50 or 100 mg benzethonium chloride/kg body weight were significantly less than those of the controls. Clinical findings at necropsy included thickening or hardening of the skin at the site of application in all rats administered 50 or 100 mg/kg and in 25 mg/kg males. Lesions at the site of application appeared crusty or red-grey in color. Epithelial hyperplasia with or without inflammation occurred at the site of application in all groups of males and females administered benzethonium chloride. 16-DAY STUDY IN MICE: Groups of five male and five female B6C3F1 mice were topically administered 0, 6.3, 12.5, 25, 50, or 100 mg benzethonium chloride/kg body weight. Mice were administered a total of 12 doses in a fixed volume of 100 &mgr;L ethanol. One 100 mg/kg male mouse died on day 4 of the study. Final mean body weights of all groups of males and females were similar to those of the controls. Clinical findings included mild irritation at the site of application in 50 and 100 mg/kg males and females and in 25 mg/kg males. Epithelial hyperplasia with or without inflammation occurred at the site of application in all groups of males and females administered benzethonium chloride. 13-WEEK STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were topically administered 0, 1.56, 3.13, 6.25, 12.5, or 25 mg benzethonium chloride/kg body weight, 5 days per week for 13 weeks. Doses were administered in ethanol at a volume not exceeding 300 &mgr;L. All rats survived to the end of the study. The final mean body weight and body weight gain of 25 mg/kg males were significantly lower than those of the controls. The final mean body weights of all other groups of males and of all groups of females were similar to those of the controls. Clinical findings included irritation at the site of application in groups administered 3.13 mg/kg or greater. There were no differences in absolute or relative organ weights considered to be related to chemical administration. Epithelial hyperplasia was observed at the site of application in all groups of males and females administered benzethonium chloride. Additionally, inflammation and ulceration were observed at the site of application in males and females administered 3.13 mg/kg or greater. Based on the lesions observed in the 13-week study, benzethonium chloride dose levels selected for the 2-year dermal study in male and female rats were 0.15, 0.5, and 1.5 mg/kg. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were topically administered 0, 1.56, 3.13, 6.25, 12.5, or 25 mg benzethonium chloride/kg body weight, 5 days per week for 13 weeks. Doses were administered in ethanol at a volume not exceeding 100 &mgr;L. All mice survived to the end of the study. The final mean body weights of all dosed groups of males and females were similar to those of the controls; the mean body weight gain of 25 mg/kg males was significantly less than that of the controls. Males administered 6.25, 12.5, or 25 mg/kg developed irritation, thickening of the skin, scales, and/or discoloration at the site of application, as did femaleale mice administered 12.5 or 25 mg/kg. Increased incidences of epithelial hyperplasia and inflammation were observed at the site of application in all groups of males and females administered benzethonium chloride. Based on the lesions observed in the 13-week study, benzethonium chloride dose levels selected for the 2-year dermal study in mice were 0.15, 0.5, and 1.5 mg/kg. 2-YEAR STUDY IN RATS: Groups of 60 male and 60 female F344/N rats were topically administered 0, 0.15, 0.5, or 1.5 mg benzethonium chloride/kg body weight 5 days per week for 103 weeks. Doses were administered in ethanol, and dose volumes were adjusted weekly according to the average body weights of the groups. As many as nine rats per group were evaluated after 15 months of chemical administration. Survival, Body Weights, and Clinical Findings: Survival of dosed rats was similar to that of the controls throughout the study. Mean body weights of all dosed groups of males and females were similar to those of the controls throughout the study. Reddening of the skin was observed at the site of application in all dosed groups of males and females. There were no other clinical findings considered to be related to chemical administration. Pathology Findings: There were no increased incidences of neoplasms in dosed male or female rats that were attributed directly to the administration of benzethonium chloride. Increased incidences of epithelial hyperplasia, sebaceous gland hyperplasia, and ulcers were observed at the site of application in dosed females. The incidence of epithelial hyperplasia was increased in 0.5 and 1.5 mg/kg males. 2-YEAR STUDY IN MICE: Groups of 60 male and 60 female B6C3F1 mice were topically administered 0, 0.15, 0.5, or 1.5 mg benzethonium chloride/kg body weight 5 days per week for 103 weeks. Doses were administered in ethanol, and dose volumes were adjusted weekly according to the average body weights of the groups. As many as 10 mice per group were evaluated after 15 months of chemical administration. Survival, Body Weights, and Clinical Findings: Survival of dosed mice was similar to that of the controls throughout the study. Mean body weights of all dosed groups of males and females were similar to those of the controls throughout the study. Reddening of the skin was observed at the site of application in all dosed groups of males and in 0.15 mg/kg females. There were no other clinical findings attributed to chemical administration. Pathology Findings: There were no increased incidences of neoplasms in dosed males or females that were related to administration of benzethonium chloride. Increased incidences of epithelial hyperplasia were observed at the site of application in dosed males and females. GENETIC TOXICOLOGY: Benzethonium chloride was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 and did not induce sister chromatid exchanges or chromosomal aberrations in cultured Chinese hamster ovary cells. All tests were conducted with and without S9 metabolic activation enzymes. CONCLUSIONS: Under the conditions of these 2-year dermal studies, there was no evidence of carcinogenic activity of benzethonium chloride in male or female F344/N rats receiving 0.15, 0.5, or 1.5 mg/kg. There was no evidence of carcinogenic activity in male or female B6C3F1 mice receiving 0.15, 0.5, or 1.5 mg/kg. Exposure of rats and mice to benzethonium chloride by dermal application in ethanol for 2 years resulted in epithelial hyperplasia in male and female rats and mice and sebaceous gland hyperplasia and ulcers in female rats at the site of application. Synonyms: Benzyldimethyl- p -(1,1,3,3-tetramethylbutyl) phenoxyethoxy-ethylammonium chloride; diisobutylphenoxyethoxyethyldimethyl benzyl ammonium chloride; p -tert-octylphenoxyethoxyethyldimethylbenzyl ammonium chloride Trade names: Anti-germ 77, Antiseptol, BZT, Diapp, Disilyn, Hyamine, Hyamine 1622, Phemeride, Phemithyn, Polymine D, Quatrachlor, Solamine

Journal Article↗

PubMed1999

Effect of electrolyte and solvent composition on capillary electrophoretic separation of some pharmaceuticals in non-aqueous media.

Non-aqueous capillary electrophoresis was used to study the separation selectivity of positively charged drug substances and negatively charged diuretics. Study was made of the effects of organic solvent composition and the background electrolyte on the separation. The separation selectivity could be altered considerably by varying the methanol/acetonitrile composition. In addition, the migration order and the resolution of the pharmaceuticals could be altered merely by changing the electrolyte cation or the anion. The electrolytes tested were alkali metal acetates, ammonium acetate, ammonium chloride and ammonium bromide. As with aqueous background electrolyte solutions, the electroosmotic flow was decreased with increasing size of the alkali metal cation of the electrolyte in methanol/acetonitrile 50:50 (v/v).

Acetates↗

PubMed1984

Effect of ruminal ammonia-nitrogen concentration on protein degradation in situ.

Two experiments were conducted to determine the effect of ruminal ammonia-nitrogen concentration on rate of ruminal protein degradation. In Experiment 1, four Holstein steers were fed a basal diet of corn grain and corn silage at hourly intervals. Continuous intraruminal infusions of solutions containing sodium bicarbonate and either sodium chloride or ammonium chloride resulted in ruminal ammonia-nitrogen concentrations that averaged 4.8 and 17.3 mg/dl. Ruminal fluid pH, fluid volume, and turnover rate of fluid and molar percentage of acetate, propionate, and butyrate were similar across treatments, reflecting steady state conditions. Rates of nitrogen and dry matter disappearance from polyester bags containing soybean protein supplements with 10.2 or 50.1% soluble nitrogen were not affected by increase of ruminal ammonia-nitrogen concentrations from 4.8 to 17.3 mg/dl. In Experiment 2, Holstein steers were fed twice daily a basal diet of urea-supplemented corn grain and corn silage. Polyester bags containing soybean protein supplements were placed in the rumen at -4, 0, or 4 h with reference to feeding and incubated from 1 to 12 h. Peak ruminal ammonia-nitrogen concentrations occurred during different periods of incubation for each treatment. Ruminal ammonia-nitrogen concentrations ranged from 3 mg/dl at 6 h postfeeding to 46 mg/dl at 1 h postfeeding. Nitrogen and dry matter disappearance rates during 0 to 1 and 1 to 12 h of incubation did not differ among treatments.

Ammonia↗

PubMed1985

Cardiorespiratory changes following chemical applications to gut serosa.

Application of 0.2-0.3 ml of 1 M ammonium chloride, 100 mM citric acid, 100 mM hydrochloric acid, 1% potassium chloride, 1% ammonium oxalate, 1% oxalic acid, 0.5% sodium hydroxide, 200 micrograms% bradykinin or 20 mg% capsaicin to gastrointestinal serosa produced a fall in blood pressure and inhibition of respiration in hypertensive as well as normotensive rats. In 6 (8%) of the animals studied, a fall in heart rate was also seen which was blocked by atropine. The blood pressure changes were independent of changes in heart rate. After acute abdominal vagotomy, while the respiratory inhibition following chemical application on gut serosa was enhanced, the cardiovascular responses were the same as before. In animals subjected to sympathetic denervation by spinal section at T5, celiac ganglionectomy or splanchnicotomy, a similar application produced an augmented respiratory response while the cardiovascular parameters were unaffected. These results show that the above inhibitions were mediated through the sympathetic afferents and a minor stimulation of respiration, via vagal afferents. The efferent pathway for the cardiac changes seems to be via vagus and the vascular changes via the sympathetics. In chronic vagotomized animals, the same stimulation produced a response similar to that seen in animals with intact vagus. An adaptive response may be operating in chronic animals reverting the status back to normal.

Ammonium Chloride↗

PubMed1997

Effect of ammonia on motor function in adult rats.

Changes in motor function were assessed in male rats after injecting graded doses (100, 200, 400, and 800 mg/kg, IP) of ammonium chloride and ammonium acetate. The effects were correlated with the concentrations of ammonia and glucose in the brain and blood. Spontaneous motor activity and motor coordination were inhibited after injecting 100 and 200 mg/kg, whereas with 400 and 800 mg/kg the animals exhibited convulsive movements. A dose-dependent increase was found in the concentrations of ammonia and glucose in both blood and brain. These were restored, 25 min after treatment, to control levels in the blood and not in the brain. A correlation was found between the time courses of inhibitory motor events and a rise in brain ammonia levels. Convulsant action of ammonium salts was accompanied by a marked elevation of ammonia and glucose concentration in the brain. The findings suggest that detoxication of diffused ammonia is a rate-limiting process in the brain and that ammonia, at toxic concentrations, decreases glucose utilization in the brain, resulting in an inhibition of motor function. A very high concentration of ammonia in the brain, although inhibiting glucose utilization, produces clonic convulsions probably by activating directly the motor neurons.

Acetates↗

PubMed1991

Effect of urease on HeLa cell vacuolation induced by Helicobacter pylori cytotoxin.

Concentrated broth culture supernatants from 50 to 60% of Helicobacter pylori strains induce eukaryotic cell vacuolation in vitro. A quantitative assay for cell vacuolation was developed on the basis of the rapid uptake of visibly vacuolated HeLa cells was significantly greater than that of nonvacuolated cells. By using the rapid NRU assay, we sought to determine the roles of H. pylori cytotoxin, urease, and ammonia in the vacuolation of HeLa cells. The NRU of HeLa cells incubated in medium containing ammonium chloride or ammonium sulfate was significantly greater than that of cells incubated in medium alone. In addition, ammonium salts augmented the NRU induced by H. pylori supernatants. The NRU induced by jack bean urease was augmented by the addition of urea to cell culture medium; this suggests that urease-mediated NRU occurs via the generation of ammonia. Acetohydroxamic acid blocked the NRU induced by jack bean urease and urea but failed to block the uptake induced by H. pylori supernatants. Supernatant from a non-urease-producing H. pylori mutant strain induced NRU identical to that of the urease-positive parental strain. These observations indicate that the vacuolating activity in H. pylori supernatants is not mediated solely by urease activity but that it may be potentiated by urease-mediated ammonia production.

Ammonium Chloride↗

PubMed1987

A possible synergism of dietary phosphate and urine-acidifying salts in preventing silica urolithiasis in a rat model.

Using an animal model involving rats fed tetraethylorthosilicate, the minimal effective dietary concentration of ammonium chloride for reduction of silica urolithiasis was determined to be approximately 0.10 equivalents/kg diet. Ammonium sulfate appeared to be only slightly less effective. The lower incidences of urolithiasis were associated with urinary pH less than 7. A subprophylactic concentration (0.067 equivalents/kg diet) of ammonium chloride was factored with three levels of supplemental phosphorus (0, 0.15 and 0.30%) from Na2HPO4 to determine whether the antiurolithic effects of dietary phosphate and urinary-acidifying salts are synergistic. Phosphate had no effect on urinary pH. A 50% urolith incidence occurred in controls; the incidence was 25% (P = 0.08) with 0.15 and 10% (P less than 0.01) with 0.30% phosphorus. Urinary pH was 7.5 in controls compared with approximately 7.2 in rats given the subprophylactic level of ammonium chloride, but ammonium chloride alone had no effect on urolithiasis. However, complete protection from urolithiasis was provided by each of the two levels of phosphorus in combination with ammonium chloride. It is concluded that supplemental dietary phosphorus is most effective for protection against silica urolithiasis under conditions contributing toward urinary acidification due to a possible synergism between dietary phosphorus and urinary acidifying salts.

Ammonium Chloride↗

PubMed2003

Preparation and modification of N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride nanoparticle as a protein carrier.

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) is water-soluble derivative of chitosan (CS), synthesized by the reaction between glycidyl-trimethyl-ammonium chloride and CS. HTCC nanoparticles have been formed based on ionic gelation process of HTCC and sodium tripolyphosphate (TPP). Bovine serum albumin (BSA), as a model protein drug, was incorporated into the HTCC nanoparticles. HTCC nanoparticles were 110-180 nm in size, and their encapsulation efficiency was up to 90%. In vitro release studies showed a burst effect and a slow and continuous release followed. Encapsulation efficiency was obviously increased with increase of initial BSA concentration. Increasing TPP concentration from 0.5 to 0.7 mg/ml promoted encapsulation efficiency from 46.7% to 90%, and delayed release. As for modified HTCC nanoparticles, adding polyethylene glycol (PEG) or sodium alginate obviously decreased the burst effect of BSA from 42% to 18%. Encapsulation efficiency was significantly reduced from 47.6% to 2% with increase of PEG from 1.0 to 20.0 mg/ml. Encapsulation efficiency was increased from 14.5% to 25.4% with increase of alginate from 0.3 to 1.0 mg/ml.

Adsorption↗

PubMed2003

Enhanced loading of water-soluble actives into bicontinuous cubic phase liquid crystals using cationic surfactants.

Over the past few years, bicontinuous cubic phase liquid crystals have been investigated for their applicability to controlled delivery of active ingredients. These liquid crystals have a unique structure of interpenetrating channels of water and lipid that provides compatibility with water-soluble, lipid-soluble, and amphiphilic active ingredients. Actives tend to be stable in the matrix and the structure provides control over their release. However, loading of water-soluble actives is difficult. It is especially problematic for cubic phase liquid crystal dispersions (cubosomes) given the large fraction of bulk water present. The inherent problem reflects the preference of the water-soluble actives to associate with water rather than with the liquid crystals. Ideally, the properties of the liquid crystal can be tailored to enhance the association of the liquid crystal with the active, thereby increasing loading. It is found that the inclusion of surfactant into the liquid crystal can provide this function. This work illustrates the enhanced loading of negatively charged, water-soluble active ketoprofen by the inclusion of positively charged surfactants into the liquid crystal. Loading differences resulting from the inclusion of dioctadecyl dimethyl ammonium chloride (DODMAC) and dioctadecyl ammonium chloride (DOAC) into the liquid crystal demonstrate that the magnitude of the enhancement is dependent on the surfactant concentration and the steric nature of its head group. The upper limit of the enhancement is explored by the inclusion of di(canola ethyl ester) dimethyl ammonium chloride (DEEDAC) formulated to greater than 20 wt% and demonstrates an order-of-magnitude enhancement over previous reports. This work provides a practical demonstration of functionalizing cubic phase liquid crystals and lays the framework for future work.

Journal Article↗

PubMed2005

[Influence of nitrogen source NH4 Cl concentration on curdlan production in Alcaligenes faecalis].

The effect of initial ammonium chloride level on production of curdlan in Alcaligenesfaecalis was investigated. It was found that ammonium chloride was the limiting substrate for cell growth during the batch fermentation process. However, the cell growth and curdlan production could not be enhanced by solely increasing the initial ammonium chloride level. The pH drop in the broth due to the consumption of ammonium chloride also effected the cell growth and curdlan production. By simultaneously increasing the initial ammonium chloride concentration and implementing an optimal pH control strategy, which is to control pH at 7.0 in the growth phase, and then shift to 5.6 in the production phase, the biomass and curdlan production in batch fermentation were increased markedly. If the initial ammonium chloride concentration was increased from 1.1 g/L to 3.6 g/L, biomass concentration of 7.2 g/L was obtained, and the final curdlan concentration reached 30.5 g/L, which was 51.7% higher than that of the former case. As the cell growth was improved due to the increase of the initial ammonium chloride concentration, the agitation speed and aeration rates must be enhanced to suit the higher oxygen uptake requirement. However, as curdlan molecules is subject to the structural breakage due to the high shear stress at higher agitation speed, an overall optimal condition for both productivity and quality of curdlan should be considered comprehensively.

Alcaligenes faecalis↗