Mono-Substituted Vit. B12 Amides. I. A Microbiological Study.

Baker, Herman; Frank, Oscar; Pasher, Inez; Hutner, S. H.; Herbert, V.; Sobotka, Harry

doi:10.3181/00379727-100-24791

Cited by 20 publications

(25 citation statements)

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“…The formulation of the media generally accepted for the L. casei microbiological assay, described by several authors (Jukes, 1955;Baker et al 1959;Waters & Mollin, 1961), are almost identical in every respect, and therefore, all share the same low buffering capacity at pH 6.8. Growth of L. casei on I ng folate causes the production of enough lactic acid to produce a significant drop in pH from an initial pH 6.8 to pH 5.4 at the end of the incubation period.…”

Section: Discussionmentioning

confidence: 99%

Studies on the response ofLactobacillus caseito different folate monoglutamates

Phillips

Wright

1982

Br J Nutr

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1. The response of Lactobacillus cmei was measured for a number of the monoglutamyl forms of folate derivatives.2. At the concentrations of folate commonly used in the assay of folate vitamin in foods the response of L. cuseito folk acid, (pteroyl glutamicacid) and 5-formyl-tetrahydrofolic acid was similar, but 5-methyl-tetrahydrofolic acid gave as little as half the response of folic acid.3. present.

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Section: Discussionmentioning

confidence: 99%

Studies on the response ofLactobacillus caseito different folate monoglutamates

Phillips

Wright

1982

Br J Nutr

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“…Using the method of Baker et al (1959), we found a considerable overlap between the results in normal subjects and patients with folic acid deficiency. There was also a wide variation in results between different batches.…”

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confidence: 85%

“…There was also a wide variation in results between different batches. The diagnostic value of the method as described by Baker et al (1959) was therefore of limited value in our hands. It seemed likely that the labile folic acid material was being inadequately protected by the method as we were using it.…”

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confidence: 86%

Studies on the folic acid activity of human serum

et al. 1961

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SYNOPSIS A method for the measurement of serum folic acid activity is described, which is a modification of previous methods.The from normal subjects and patients with primary vitamin B12 deficiency. Normal subjects had serum folic acid levels from 5 9 to 210 m,ug./ml. (mean 9-9 m,ug./ml. ± 0-3 m.tg./ml. S.E.). In patients with megaloblastic anaemia requiring treatment with folic acid, other than megaloblastic anaemia of pregnancy, the levels were less than 4-0 mptg./ml. Patients with uncomplicated pernicious anaemia had levels from 6-0 to 27-0 m,tg./ml. (mean 16-6 m,ug./ml. ± 11 m,ug./ml. S.E.). The mean level in this group was higher than in normal subjects, and the highest levels of all were found in patients with subacute combined degeneration of the cord with minimal anaemia (range 14-4 to 36-8 mp,g./ml.; mean 24-8 mpg./ml. ± 2-4 mpig./ml. S.E.).The L. casei activity of the labile component is lost during autoclaving or storage at -20°C. This loss can be prevented during autoclaving by using adequate amounts of ascorbic acid in the phosphate buffer used to dilute the serum for assay and by adding ascorbic acid to serum that is to be stored. Moreover, the activity lost during the storage of serum not protected by ascorbic acid could be restored, for periods up to three months, by adding ascorbic acid to this serum before assay.The folic acid activity of blood and serum has been measured in the past by a number of workers using Streptococcus faecalis (Schweigert and Pearson, 1947; Wolff, Drouet, and Karlin, 1949;Toennies and Gallant, 1949;Girdwood, 1953;Nieweg, Faber, de Vries, and Kroese, 1954;Condit and Grob, 1958;and Cox, Meynell, Cooke, and Gaddie, 1960) and/or Lactobacillus casei (Schweigert, 1948;Simpson and Schweigert, 1949;Spray, 1952;and Spray and Witts, 1952) as test organisms. These workers were unable to demonstrate a consistent difference in the levels of folic acid activity of blood or serum in normal 'University of Queensland Travelling Scholar in Medicine.

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“…Preliminary observations showed that there was little deterioration in sera stored for six months under these conditions (Chanarin and Berry, 1964). The assay was carried out as described by Toepfer, Zook, Orr, and Richardson (1951) and Baker, Herbert, Frank, Pasher, Hutner, Wasserman, and Sobotka (1959). The serum was prepared for assay as described by Chanarin and Berry (1964).…”

Section: Methodsmentioning

confidence: 99%

Iron Deficiency and its Relation to Folic-acid Status in Pregnancy: Results of a Clinical Trial

Chanarin¹,

Rothman²,

Berry³

1965

BMJ

149

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BRITISHIsotope~~~b MEDICAL JOURNAL impression that multiple metastases are more readily shown by scanning than by pneumography or angiography. Single metastases are often revealed by these latter methods, but second or third ones are not often shown.While it is possible to predict the pathology of a certain number of lesions by studying the topography, this is by no means always so. Planiol (1963) uses an entirely different technique by means of which she is able to make a specific diagnosis in a much higher percentage of cases. Her method depends upon the change in count rate at fixed points on the skull at intervals of 2, 24, and 48 hours after an intravenous injection of radioiodinated human serum albumin. She has shown that meningiomas take up the isotope early and metastases late, while the astrocytomas take it up at an intermediate SummaryThe results of 100 brain scans are described. All the scans were made with 203Hg chlormerodrin using a standard technique. There was no selection of cases referred by neurologists and neurosurgeons, except that patients under the age of 18 were excluded.There were 53 positive scans, and all these patients appeared to have lesions, though not all these were confirmed histologically. There were 42 negative scans. Of these, 22 were probably truly negative. The remaining 20 were proved to be false-that is, these patients harboured tumours not demonstrated by the method. The causes of the false negatives are discussed and their reduced number in the future is foreshadowed.There were five equivocal scans. These showed some departure from the normal, but the appearances were not sufficiently clear-cut for definite diagnosis.Since a positive scan always denotes a lesion and the scanning process is painless and free from risk, it seems that, ideally, this investigation should be made before angiography and/or pneumography. But a negative scan in the face of positive clinical evidence of a mass always requires further investigation.The method is particularly valuable in the investigation of out-patients and of patients whose clinical picture hardly justifies submission to the more traumatic procedures which also carry some morbidity.Scanning has been a great help in the diagnosis of metastases, because the older-established neuroradiological procedures tend to show only the larger ones. The results in these cases suggest that secondary deposits in the brain are more often multiple than was previously suggested by classical neuroradiological investigation, although well known by pathologists.Location of brain turnours by modern scanning techniques is accurate. In some cases the contour and topography allow a precise pathological diagnosis to be made. Unfortunately this is by no means always so, but it is hoped that still greater accuracy will be achieved by refining the technique.Isotope encephalography has clearly earned its place alongside other neuroradiological contrast methods of investigation. , 1965, 1, 480-485 The application of newer methods to the detection of vitamin...

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Mono-Substituted Vit. B12 Amides. I. A Microbiological Study.

Cited by 20 publications

References 0 publications

Studies on the response ofLactobacillus caseito different folate monoglutamates

Studies on the response ofLactobacillus caseito different folate monoglutamates

Studies on the folic acid activity of human serum

Iron Deficiency and its Relation to Folic-acid Status in Pregnancy: Results of a Clinical Trial

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