Preservation of Blood Ammonia by Rapid Freezing-A Method for Delayed Determinations

1964 ◽  
Vol 10 (11) ◽  
pp. 991-1001 ◽  
Author(s):  
Marshall J Orloff ◽  
Clarence O Stevens
Keyword(s):  
Chemical Method ◽  
Ammonia Concentration ◽  
Rapid Freezing ◽  
Blood Ammonia ◽  
Ammonia Content ◽  
Dry Ice ◽  
Dog Blood ◽  
Delayed Measurements ◽  
Frozen State ◽  
And Storage

Abstract A method is described for preservation of blood for delayed determinations of ammonia by rapid freezing of the samples in a dry ice and acetone solution followed by storage of the specimens in the frozen state. The method was evaluated by first establishing the reproducibility of the chemical method used for blood ammonia analysis in 714 consecutive samples of dog blood which were analyzed in duplicate, and then determining whether freezing caused greater changes in ammonia concentration than one would expect knowing the reproducibility of the chemical method. Studies in 200 samples of dog blood with ammonia levels of 16 to 2904 µg./100 ml., each of which was analyzed immediately and after 24 hr. of freezing, showed that freezing and storage for 24 hr. did not significantly affect the blood ammonia content. Studies of 22 samples of frozen dog blood with ammonia levels of 11 to 2624 µg/100 ml., parts of each of which were analyzed daily for 5 consecutive days, showed that storage in the frozen state for up to 72 hr. had no significant effect on the ammonia concentration, but that storage for 96 hr. or longer resulted in increases in blood ammonia beyond acceptable limits. It is concluded that accurate delayed measurements of blood ammonia may be accomplished by rapid freezing of the blood immediately after shedding, and storage of the frozen samples for up to 72 hr.

Changes in Ammonia Values of Protein-free Filtrates of Blood During Storage in the Frozen State

1962 ◽  
Vol 8 (6) ◽  
pp. 593-597 ◽  
Author(s):  
Charles E Wilder
Keyword(s):  
Frozen Storage ◽  
Ammonia Concentration ◽  
Ammonia Level ◽  
Blood Ammonia ◽  
Trichloracetic Acid ◽  
Frozen State ◽  
Significant Change

Abstract Protein-free filtrates of blood treated with trichloracetic acid were divided into two or three parts. The ammonia concentration of one of these was determined immediately by the ninhydrin method described by Nathan and Rodkey (1). The others were kept frozen for periods of 1-8 days and then thawed and analyzed. The blood ammonia concentrations calculated from these filtrate values were compared. A significant change in ammonia level during frozen storage was demonstrated.

Respiratory Ammonia Output and Blood Ammonia Concentration During Incremental Exercise

1999 ◽  
Vol 20 (02) ◽  
pp. 71-77
Author(s):  
W. Ament ◽  
J. Huizenga ◽  
E. Kort ◽  
T. Mark ◽  
R. Grevink ◽  
...  
Keyword(s):  
Ammonia Concentration ◽  
Incremental Exercise ◽  
Blood Ammonia

Dry Ice Self-Pressurised Rapid Freezing (DryIce SPRF): all you need to cool for cryofixation of nematodes is dry ice

Nematology ◽  
2021 ◽  
pp. 1-17
Author(s):  
Myriam Claeys ◽  
Vladimir V. Yushin ◽  
Wim Bert
Keyword(s):  
Crystalline State ◽  
Medium Composition ◽  
Ice Crystals ◽  
Rapid Freezing ◽  
High Pressure Freezing ◽  
Dry Ice ◽  
Transmission Electron ◽  
State Of Water ◽  
Pressure Medium ◽  
Excellent Preservation

Summary Cryofixation immediately arrests all biochemical, physiological and dynamic processes underway in the sample in their present state, resulting in both excellent preservation of the specimen’s ultrastructure and its antigenicity. Cryofixation involves extremely rapid cooling of specimens, creating an amorphous, or ‘non-crystalline’, state of water containing no detectable ice crystals, a process dependent on pressure, medium composition and temperature. Self-Pressurised Rapid Freezing (SPRF) employs plunge freezing of specimens in a sealed copper tube into a cryogen such as nitrogen slush (−210°C), liquid nitrogen (−196°C), ethane (−183°C) or propane (−120°C). In this study we have explored the use of SPRF with cooled acetone on dry ice (−80°C) as the cryogen, a method named DryIce SPRF. Although with this relatively high temperature amorphous water cannot be formed, we have demonstrated that the ultrastructural and antigenicity results after DryIce SPRF on Caenorhabditis elegans are perfectly comparable with those achieved using High Pressure Freezing and SPRF. Thus, with sufficient pressure optimal results, with ice crystals below the resolution of transmission electron microscopy, can be achieved even at −78°C. Furthermore, a huge advantage of DryIce SPRF over other techniques is its use of affordable, easily available and safe products.

Effects of Dry Ice and Superchilling on Quality and Shelf Life of Arctic Charr (Salvelinus alpinus) Fillets

2007 ◽  
Vol 3 (3) ◽  
Author(s):  
Huynh Nguyen Duy Bao ◽  
Sigurjón Arason ◽  
Kristín Anna Þórarinsdóttir
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Negative Effects ◽  
Dry Ice ◽  
Fish Flesh ◽  
Microbial Analysis ◽  
And Storage

The influence of different cooling techniques (dry ice/ice packs) and storage temperature (-2°C/3°C) to prolong the shelf life of Arctic charr (Salvelinus alpinus) fillets were evaluated by sensory analysis, physical methods, chemical and microbial analysis. The effects of storage temperature were stronger than of different cooling agents. Superchilling (-2°C) of fillets packed with dry ice resulted in 6 days extension of shelf life compared to chilling (3°C). The use of dry ice parallel to superchilling prolonged shelf life for 1 day compared to fillets stored with ice packs. No negative effects on quality of the fillets where detected that could be linked to cell destruction caused by partial freezing or to sour taste, caused by absorption of CO2 gas in fish flesh.

Comparison of the effect of various amino acids upon the blood ammonia concentration of patients with liver disease

1973 ◽  
Vol 26 (9) ◽  
pp. 916-925 ◽  
Author(s):  
Daniel Rudman ◽  
John T. Galambos ◽  
Robert B. Smith ◽  
Atef A. Salam ◽  
W. Dean Warren
Keyword(s):  
Amino Acids ◽  
Liver Disease ◽  
Ammonia Concentration ◽  
Blood Ammonia

Transient hyperammonaemia following epileptic seizures in cats

2020 ◽  
pp. 1098612X2096274
Author(s):  
Charlotta H Nilsson ◽  
Mikael BT Svensson ◽  
Susanne JM Säve ◽  
Sofie AE Van Meervenne
Keyword(s):  
Epileptic Seizure ◽  
Specific Treatment ◽  
Epileptic Seizures ◽  
Reference Interval ◽  
Ammonia Concentration ◽  
Blood Ammonia ◽  
Initial Testing ◽  
Close Proximity ◽  
Veterinary Hospital

Objectives The aim of this study was to determine whether transient postictal hyperammonaemia exists in cats. Methods The medical records of all feline patients that presented at a Swedish veterinary hospital between 2008 and 2018 were retrospectively reviewed to find those that had a recent or ongoing epileptic seizure. To qualify for inclusion, the medical record had to include information on at least one ammonia value taken in close proximity to, or during, an active seizure, the cat must have exceeded the normal upper limit of blood ammonia concentration on initial testing (reference interval 0–95 μmol/l), and there needed to be a follow-up ammonia value available within a maximum of 3 days. Results Five cats were included in the study, and they had blood ammonia concentrations on initial testing ranging from 146 to 195 µmol/l. They were all retested within a period of 2 h to 3 days of the original reading. All five cats had a spontaneous decrease in ammonia levels without any specific treatment for hyperammonaemia. Conclusions and relevance Pursuant to the findings of this retrospective study, transient hyperammonaemia may be noted after epileptic seizure in cats. Consequently, a differential diagnostic list in feline patients with hyperammonaemia could, depending on the context, include non-hepatic-related pathologies, such as epileptic seizures.

Nucleotide Degradation and Quality in Ordinary and Red Muscle of Iced and Frozen Swordfish (Xiphias gladius)

1966 ◽  
Vol 23 (12) ◽  
pp. 1821-1833 ◽  
Author(s):  
W. J. Dyer ◽  
Doris I. Fraser ◽  
Dianne P. Lohnes
Keyword(s):  
Related Species ◽  
Frozen Storage ◽  
Enzymic Activity ◽  
Slow Freezing ◽  
Rapid Freezing ◽  
Quality Test ◽  
Red Muscle ◽  
Nucleotide Degradation ◽  
And Storage ◽  
Iced Storage

In iced dressed swordfish, inosine monophosphate, initially the predominant nucleotide (5.2 μmole/g), was dephosphorylated to inosine during 19 days storage. Hypoxanthine increased very slowly to about 1 μmole/g while quality (taste panel) showed no significant decrease to 15 days but was near borderline at 19 days. These changes occurred more slowly than in cod and related species. The sequence of nucleotide changes occurred much earlier in the red muscle. Rapid freezing and storage at −26 C for 4–5 months inhibited nucleotide enzymic activity, and quality remained unchanged. Slow freezing and storage for 1 week at −4 C significantly reduced quality to borderline or unacceptable levels, but only slightly affected the nucleotide degradation, indicating that other factors were responsible for the loss in quality. Dephosphorylation and hypoxanthine accumulation continued during further storage at −4 C. The levels of hypoxanthine reached during 19 days iced storage or 4–5 months frozen storage were not sufficiently high to impart bitter flavors, except possibly in the red muscle. A simple measure of inosine (+ hypoxanthine) may be useful as a quality test; a supplementary hypoxanthine test could be used to confirm spoilage.

scholarly journals Dependence of in vivo glutamine synthetase activity on ammonia concentration in rat brain studied by 1H - 15N heteronuclear multiple-quantum coherence-transfer NMR

1995 ◽  
Vol 311 (2) ◽  
pp. 681-688 ◽  
Author(s):  
K Kanamori ◽  
B D Ross ◽  
E L Kuo
Keyword(s):  
Quantum Coherence ◽  
Ammonia Concentration ◽  
Multiple Quantum ◽  
Blood Ammonia ◽  
Coherence Transfer ◽  
Heteronuclear Multiple Quantum Coherence ◽  
Glutamine Synthesis ◽  
Gaba Synthesis ◽  
Multiple Quantum Coherence

The dependence of the in vivo rate of glutamine synthesis on the substrate ammonia concentration was studied in rat brain by 1H-15N heteronuclear multiple-quantum coherence-transfer NMR in combination with biochemical techniques. In vivo rates were measured at various steady-state blood and brain ammonia concentrations within the ranges 0.4-0.55 mumol/g and 0.86-0.98 mumol/g respectively, after low-rate intravenous 15NH4+ infusion (isotope chase). The rate of glutamine synthesis at steady state was determined from the change in brain [5-15N]glutamine levels during isotope chase, observed selectively through the amide proton by NMR, and 15N enrichments of brain glutamine and of blood and brain ammonia measured byN gas chromatography-MS. The in vivo rate (v) was 3.3-4.5 mumol/h per g of brain at blood ammonia concentrations (s) of 0.40-0.55 mumol/g. A linear increase of 1/v with 1/s permitted estimation of the in vivo glutamine synthetase (GS) activity at a physiological blood ammonia concentration to be 0.4-2.1 mumol/h per g. The observed ammonia-dependence strongly suggests that, under physiological conditions, in vivo GS activity is kinetically limited by sub-optimal in situ concentrations of ammonia as well as glutamate and ATP. Comparison of the observed in vivo GS activity with the reported in vivo rates of glutaminase and of gamma-aminobutyrate (GABA) synthesis suggests that, under mildly hyperammonaemic conditions, glutamine is synthesized at a sufficiently high rate to serve as a precursor of GABA, but glutaminase-catalysed hydrolysis of glutamine is too slow to be the sole provider of glutamate used for GABA synthesis.

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