scholarly journals Plasma amino acids and tissue methionine levels in fruit bats (Rousettus aegyptiacus) with nitrous oxide-induced vitamin B12 deficiency

1985 ◽  
Vol 53 (3) ◽  
pp. 657-662 ◽  
Author(s):  
Justin Van Der Westhuyzen ◽  
Suasn V. Van Tonder ◽  
Jayne E. Gibson ◽  
Terence A. Kilroe-smith ◽  
Jack Metz
Keyword(s):  
Nitrous Oxide ◽  
Vitamin B12 Deficiency ◽  
Dietary Supplementation ◽  
Basal Diet ◽  
Neurological Impairment ◽  
Vitamin B ◽  
Muscular Weakness ◽  
Fruit Bats ◽  
B12 Deficiency ◽  
Methionine Synthesis

1. The effect of methylcobalamin inactivation by the gas nitrous oxide on plasma amino acid and tissue methionine levels in fruit bats (Rousettus aegyptiacus) was examined.2. Animals exposed to N2O-oxygen (1:1, v/v) for 90 min daily received a fruit diet with or without methionine or betaine supplements. Exposure and diets were continued for up to 17 weeks or until neurological impairment and muscular weakness was established.3. All the groups exposed to N2O had significantly lower liver, brain and plasma methionine concentrations except the methionine-supplemented animals which showed significantly raised levels. Plasma homocysteine, which was absent in controls, was present in all the N2O-exposed groups.4. Betaine supplementation resulted in reduced accumulation of homocysteine in plasma. However, plasma and liver methionine levels were only slightly increased compared with animals on the basal diet, and brain methionine levels were the lowest of all the groups studied.5. These results support the hypothesis that reduced methionine synthesis is an important contributor to the development of neurological impairment in this species and suggest that dietary supplementation with the methionine precursor betaine cannot replace the loss of vitamin B12-dependent methionine synthesis.

scholarly journals One month of nitrous oxide abuse causing acute vitamin B12 deficiency with severe neuropsychiatric symptoms

2019 ◽  
Vol 12 (2) ◽  
pp. bcr-2018-228001 ◽  
Author(s):  
Michael S Lundin ◽  
John Cherian ◽  
Michael Nyika Andrew ◽  
Richa Tikaria
Keyword(s):  
Nitrous Oxide ◽  
Neuropsychiatric Symptoms ◽  
Vitamin B12 Deficiency ◽  
Vitamin B ◽  
Lower Extremity Weakness ◽  
Studying Abroad ◽  
The Usa ◽  
B12 Deficiency ◽  
Whipped Cream ◽  
Brain And Spinal Cord

A 21-year-old university student studying abroad in the USA presented to the emergency department with double vision, lower extremity weakness with difficulty ambulating and other neuropsychiatric symptoms. MRI of the brain and spinal cord were normal. Vitamin B12 was 78 pg/mL (58 pmol/L, reference 211–911 pg/mL). The patient had been using nitrous oxide capsules used for whipped cream recharging, which she obtained from other students, a few times daily for a month for the purpose of anxiety relief. The patient was not a vegan or vegetarian. The patient was treated with intramuscular vitamin B12 repletion with partial resolution of neurologic symptoms and discharged on vitamin B12 supplementation.

scholarly journals Encephalitis secondary to nitrous oxide and vitamin B12 deficiency

2019 ◽  
Vol 12 (12) ◽  
pp. e229380
Author(s):  
Gareth Hughes ◽  
Ed Moran ◽  
Martin J Dedicoat
Keyword(s):  
Cerebrospinal Fluid ◽  
Nitrous Oxide ◽  
Peripheral Neuropathy ◽  
Vitamin B12 ◽  
Tuberculous Meningitis ◽  
Vitamin B12 Deficiency ◽  
Vitamin B ◽  
Severe Vitamin ◽  
Elevated Protein ◽  
B12 Deficiency

A 27-year-old woman presented with confusion, agitation and fever. Having initially been treated as an infective encephalitis case her initial and subsequent lumbar punctures revealed cerebrospinal fluid with a worsening pleocytosis and elevated protein. It was initially felt she had been suffering from tuberculous meningitis and started on treatment it later became apparent that she had a severe vitamin B12 deficiency related to recreational nitrous oxide use. She also was noted to have a peripheral neuropathy. After replacing her vitamin B12 and later stopping her tuberculous medication once cultures were negative her cognition and peripheral neuropathy continued to improve.

Important reminder: nitrous oxide (N2O) as a cause of functional vitamin B12 deficiency

2021 ◽  
Vol 14 (7) ◽  
pp. e241414
Author(s):  
Abdullahi Elsheikh Mahgoub ◽  
Smit Sunil Deliwala ◽  
Ghassan Bachuwa
Keyword(s):  
Nitrous Oxide ◽  
Vitamin B12 Deficiency ◽  
Serum Markers ◽  
Cobalamin Deficiency ◽  
Vitamin B ◽  
Sensory Level ◽  
Significant Other ◽  
Lower Extremity Weakness ◽  
Fluid Analysis ◽  
B12 Deficiency

A 32-year-old woman who misused multiple substances, including nitrous oxide (N2O), sought medical advice after she subacutely developed bilateral lower extremity weakness without a sensory level but with ataxia—her significant other developed similar symptoms with vitamin B12 deficiency due to N2O intake. Laboratory results revealed macrocytic anaemia despite normal B12 and folate levels, with serum markers pointing towards functional cobalamin deficiency. Spinal MRIs and cerebrospinal fluid analysis were unremarkable. Our patient was treated with vitamin B12 supplementation with an encouraging response.

scholarly journals Dissociation of methionine synthetase (EC 2.1.1.13) activity and impairment of DNA synthesis in fruit bats (Rousettus aegyptiacus) with nitrous oxide-induced vitamin B12 deficiency

1986 ◽  
Vol 55 (1) ◽  
pp. 187-192 ◽  
Author(s):  
Susan V. Van tonder ◽  
Angela Ruck ◽  
J. Van der Westhuzen ◽  
F. Fernandes-costa ◽  
J. Metz
Keyword(s):  
Bone Marrow ◽  
Nitrous Oxide ◽  
Dna Synthesis ◽  
Vitamin B12 Deficiency ◽  
Synthetase Activity ◽  
Fruit Bats ◽  
Fruit Bat ◽  
B12 Deficiency ◽  
Suppression Test ◽  
Homocysteine Methyltransferase

1. The effect of methylcobalamin inactivation by the anaesthetic gas nitrous oxide on the activity of the cobalamin-dependent methionine synthetase (5-methyltetrahydrofolate homocysteine methyltransferase; EC 2.1. I. 13) reaction, and on DNA synthesis, in the fruit bat Rousettus aegyptiucus, was examined.2. Methionine synthetase activity in the liver of bats exposed to N2O—oxygen (50: 50, v/v) for 90 min/d averaged 32% of that of controls after 4 d of exposure and only 5% after 12–14 weeks of exposure.3. DNA synthesis in the bone marrow, as reflected by the deoxyuridine suppression test, was unaffected by 4 d of exposure to N2O and only minimally affected after 5–10 weeks of exposure.4. These results suggest that DNA synthesis in the fruit bat is unusually resistant to inhibition of methionine synthetase and imply the existence of a non-methylated circulating folate pool in this species.

scholarly journals Assessment of vitamin B12 deficiency and B12 screening trends for patients on metformin: a retrospective cohort case review

2021 ◽  
pp. bmjnph-2020-000193
Author(s):  
Darby Martin ◽  
Jeet Thaker ◽  
Maria Shreve ◽  
Lois Lamerato ◽  
Kartazyna Budzynska
Keyword(s):  
Retrospective Cohort ◽  
Protective Factor ◽  
Vitamin B12 Deficiency ◽  
Older Age ◽  
Secondary Outcome ◽  
Vitamin B ◽  
Case Review ◽  
Large Hospital ◽  
Hospital System ◽  
B12 Deficiency

ObjectivesOur study investigated the use of vitamin B12 testing in a large cohort of patients on metformin and assesses appropriateness and benefits of screening recommendations for vitamin B12 deficiency.DesignThis retrospective cohort study included insured adult patients who had more than 1 year of metformin use between 1 January 2010 and 1 October 2016 and who filled at least two consecutive prescriptions of metformin to establish compliance. The comparison group was not exposed to metformin. Primary outcome was incidence of B12 deficiency diagnosed in patients on metformin. Secondary outcome was occurrence of B12 testing in the patient population on metformin. Records dated through 31 December 2018 were analysed.SettingLarge hospital system consisting of inpatient and outpatient data base.ParticipantsA diverse, adult, insured population of patients who had more than 1 year of metformin use between 1 January 2010 and 1 October 2016 and who filled at least two consecutive prescriptions of metformin.ResultsOf 13 489 patients on metformin, 6051 (44.9%) were tested for vitamin B12 deficiency, of which 202 (3.3%) tested positive (vs 2.2% of comparisons). Average time to test was 990 days. Average time to test positive for deficiency was 1926 days. Factors associated with testing were linked to sex (female, 47.8%), older age (62.79% in patients over 80 years old), race (48.98% white) and causes of malabsorption (7.11%). Multivariable logistic regression showed older age as the only factor associated with vitamin B12 deficiency, whereas African-American ethnicity approached significance as a protective factor.ConclusionsBased on our study’s findings of vitamin B12 deficiency in patients on metformin who are greater than 65 years old and have been using it for over 5 years, we recommend that physicians consider screening in these populations.

Vitamin B12 deficiency is the dominant nutritional cause of hyperhomocysteinemia in a folic acid-fortified population

2005 ◽  
Vol 43 (10) ◽  
Author(s):  
Ralph Green ◽  
Joshua W. Miller
Keyword(s):  
United States ◽  
Folic Acid ◽  
Vitamin B12 Deficiency ◽  
The United States ◽  
Community Dwelling ◽  
Vitamin B ◽  
Prevalence Rates ◽  
Total Vitamin ◽  
Folic Acid Fortification ◽  
B12 Deficiency

AbstractPrevalence rates for folate deficiency and hyperhomocysteinemia have been markedly reduced following the introduction of folic acid fortification in the United States. We report the prevalence of hyperhomocysteinemia in a population of community-dwelling elderly Latinos in the post-folic acid fortification era. We measured homocysteine, total vitamin B

Ileocaecal tuberculosis: an under-recognised cause of vitamin B12 deficiency

2018 ◽  
Vol 49 (2) ◽  
pp. 143-144
Author(s):  
Ashok Kumar Pannu ◽  
Dinesh Raja Palanisamy
Keyword(s):  
Terminal Ileum ◽  
Vitamin B12 Deficiency ◽  
Abdominal Tuberculosis ◽  
Megaloblastic Anaemia ◽  
Vitamin B ◽  
Lower Quadrant ◽  
Abdominal Tenderness ◽  
B12 Deficiency ◽  
Clinical Triad ◽  
Right Lower Quadrant

A combination of anaemia and knuckle pigmentation should always raise concern for megaloblastic anaemia. As the terminal ileum is the site of vitamin B12 absorption and also the commonest site of abdominal tuberculosis, a clinical triad of prolonged fever, knuckle pigmentation and right lower quadrant abdominal tenderness should suggest ileocaecal tuberculosis in endemic areas.

scholarly journals Improved testing for vitamin B12 deficiency: correcting MMA for eGFR reduces the number of patients classified as vitamin B12 deficient

2018 ◽  
Vol 55 (6) ◽  
pp. 685-692 ◽  
Author(s):  
Saskia LM van Loon ◽  
Anna M Wilbik ◽  
Uzay Kaymak ◽  
Edwin R van den Heuvel ◽  
Volkher Scharnhorst ◽  
...  
Keyword(s):  
Data Mining ◽  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Vitamin B12 Deficiency ◽  
The Elderly ◽  
Vitamin B ◽  
Data Mining Approach ◽  
Number Of Patients ◽  
B12 Deficiency ◽  
The Relationship

Background Methylmalonic acid (MMA) can detect functional vitamin B12 deficiencies as it accumulates early when intracellular deficits arise. However, impaired clearance of MMA from blood due to decreased glomerular filtration rate (eGFR) also results in elevated plasma MMA concentrations. Alternative to clinical trials, a data mining approach was chosen to quantify and compensate for the effect of decreased eGFR on MMA concentration. Methods Comprehensive data on patient’s vitamin B12, eGFR and MMA concentrations were collected ( n = 2906). The relationship between vitamin B12, renal function (eGFR) and MMA was modelled using weighted multiple linear regression. The obtained model was used to estimate the influence of decreased eGFR on MMA. Clinical impact was examined by comparing the number of patients labelled vitamin B12 deficient with and without adjustment in MMA. Results Adjusting measured MMA concentrations for eGFR in the group of patients with low-normal vitamin B12 concentrations (90–300 pmol/L) showed that the use of unadjusted MMA concentrations overestimates vitamin B12 deficiency by 40%. Conclusions Through a data mining approach, the influence of eGFR on the relation between MMA and vitamin B12 can be quantified and used to correct the measured MMA concentration for decreased eGFR. Especially in the elderly, eGFR-based correction of MMA may prevent over-diagnosis of vitamin B12 deficiency and corresponding treatment.

scholarly journals Homocystinuria masquerading as vitamin B12 deficiency

2012 ◽  
Vol 4 (2) ◽  
pp. 326-328
Author(s):  
M Wadhwani ◽  
S Beri ◽  
A Saili ◽  
S Garg
Keyword(s):  
Vitamin B12 ◽  
Megaloblastic Anemia ◽  
Vitamin B12 Deficiency ◽  
Interesting Case ◽  
Vitamin B ◽  
Ophthalmological Examination ◽  
Ophthalmic Manifestations ◽  
History Of ◽  
B12 Deficiency ◽  
Vitamin B 12

Background: Homocystinuria is a rare metabolic disorder charcterised by excess homocysteine in the urine. Vitamin B12 deficiency has diverse cutaneous, nervous and ophthalmic manifestations. Objective: To report a case of homocystinuria masquerading as vitamin B 12 deficiency. Case: We hereby are presenting an interesting case of a 4 year old boy who was being treated for Vitamin B 12 deficiency on the basis of history of delayed milestone, abdominal pain and hyperpigmentation of skin which was diagnosed as homocystinuria. Conclusion: It is important to carry out ophthalmological examination in every case of megaloblastic anemia if associated with blurring of vision and mental retardation.DOI: http://dx.doi.org/10.3126/nepjoph.v4i2.6554 Nepal J Ophthalmol 2012; 4 (8): 326-328

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