INVESTIGATIONS INTO THE EUGLENA METHOD FOR THE ASSAY OF THE VITAMIN B12 IN SERUM

Optic atrophy in experimental vitamin B12 deficiency in monkeys

The clinical findings and pathological changes of the visual pathway of vitamin B12 deficient monkeys have been described. The cellular morphology and counts of the peripheral blood and bone marrow remained normal during the study (nine deficient, three controls: one still alive in each group). Visual impairment was noted in all seven of the deficient animals that were evaluated by clinical observations. Ophthalmoscopic examination disclosed optic atrophy in six of the seven deficient monkeys. Degeneration of the visual pathway was demonstrated by pathological examination in eight of the deficient group of nine (one is still alive). Loss of ganglion cells was noted in the maculae of two of three deficient animals with completed studies. In the three control animals there were neither visual disturbances nor ophthalmoscopic changes and in two animals autopsies disclosed no lesions in the visual pathways. The third animal is still alive and well.

Role of porta systemic shunt and hepatocellular damage in the genesis of hepatic neuropathy

A study was undertaken to evaluate the relative role of porta-systemic shunts and hepatocellular damage in the genesis of neuropathy in chronic liver disease. Two of the 14 patients with non-alcoholic cirrhosis showed clinical evidence of neuropathy, whereas none of the patients with idiopathic portal fibrosis had evidence of neuropathy clinically. Decreased motor conduction velocities were present in some cases of idiopathic portal fibrosis as well as non-alcoholic cirrhosis. Subclinical evidence of histopathological neuropathy in the form of segmental demyelination and remyelination as well as myelin fiber loss was seen in 10 out of 11 sural nerves studied in idiopathic portal fibrosis group and in all the 10 patients in the non-alcoholic cirrhosis group. No correlation was found between histological features and various parameters studied. It is postulated that the development of clinical or subclinical neuropathy in chronic liver disease depends on two factors, being collateral shunting and hepatocellular damage or both and probably related to abnormalities of nitrogen metabolism.

Inherited lack of transcobalamin II in serum and megaloblastic anaemia: a further patient

We have studied a patient, unrelated to the patients previously described, with inherited lack of the vitamin B12 binding protein Transcobalamin II. Severe haematological abnormalities were found within a few weeks of birth and responded to treatment with both vitamin B12 and folic acid. He was maintained in partial remission with such treatment until adolescence, except for a time in early childhood when folic acid alone was given and he suffered severe neurological deterioration. A the age of 18 years he was admitted to hospital because of convulsions; the deoxyuridine suppression test showed intracellular deficiency of B12 despite a normal serum B12 and normal haemoglobin concentration. His serum failed to promote the uptake of radioactive B12 by bone marrow cells, and analysis of serum B12 binding proteins demonstrated the lack of Transcobalamin II. Treatment with injections of 1000 micrograms of B12 three times weekly corrected the abnormality shown in the deoxyuridine suppression test; following this treatment, together with changes in anticonvulsive therapy, he remains healthy without occurrence of further convulsions, and is haematologically normal.

The effect of nitrous oxide on the cell cycle in human bone marrow

The effect of 24 h exposure to nitrous oxide on the cell division cycle in human bone marrow has been studied in vivo using the technique of DNA flow microfluorimetry. All patients who received nitrous oxide showed a significant increase in the proportion of early S-phase cells with a decrease in late S, G2 and mitotic cells. These changes resemble those seen following the use of S-phase-specific cytotoxic drugs. Control patients showed no such effect. Parallel studies have suggested that interference with the function of vitamin B12 underlies this response. Nitrous oxide may provide a convenient method for studying the cell kinetic aspects of acute B12 deficiency and the possibility of using it to increase the therapeutic index of antitumour drugs is discussed.

The prevalence and nature of anemia among apparently normal subjects in Fiji

A total of 4939 apparently healthy Fijian and Indian subjects living in Fiji were tested for anaemia by determination of the microhaematocrit of a sample of capillary blood. The prevalence of anaemia during childhood varied with age but was similar for Fijians and Indians of either sex. The overall prevalences were: 0-4 years, 20.3%; 5-9 years, 3.7%; 10-14 years, 23.5%. The prevalence of anaemia among Indian women (33.3%) was substantially higher than that for Indian men (6.9%), Fijian women (8.1%) or Fijian men (6.8%). Iron deficiency was the most common cause of anaemia and was established by laboratory studies in 203 (68%) of 298 anaemic subjects who were followed up. Iron deficiency was an important aetiological factor in 91 (93%) of 98 subjects with moderate or severe anaemia. Folate deficiency was found, usually in combination with iron deficiency, in 44 or 141 anaemic indian adults were followed up. Folate deficiency was uncommon in Fijian adults and among children of either race. Two cases of nutritional vitamin B12 deficiency, one case of pernicious anaemia, 6 cases of heterozygous thalassaemia and one case of heterozygous haemoglobin E were found among the anaemic Indian subjects. No cases of vitamin B12 deficiency anaemia, thalassaemia or haemoglobinopathy were detected among the Fijians. In 5 Indians and 7 Fijians the anaemia was associated with an underlying chronic disorder. This study emphasizes that in Fiji, as in other developing countries, nutritional anaemia is prevalent among asymptomatic subjects. Iron deficiency is by far the most common cause.

Sickle cell anemia and trait in southern India: further studies

Population surveys and family studies among 568 members of nine ethnic groups in southern India identified 15 homozygotes for sickle hemoglobin (HbS)who had mild clinical and hematological manifestations with high levels of fetal hemoglobin (mean=20%, range 8-36%) in a heterogeneous red cell distribution. In one family, the heterozygous mother had a hemoglobin pattern consistent with a form of the heterocellular hereditary persistence of fetal hemoglobin. Sickle cell trait was found in 153(27%) of those studied. Chromatographic quantitation of the hemoglobin fractions in these heterozygotes showed a trimodal distribution of the proportion of HB Sexplicable by a genetic model postulating the presence of genotypes with two (-alpha/-alpha), three (-alpha/alpha alpha) and four (alpha alpha/alpha alpha) active alpha-globin genes. Globin synthesis studies in four heterozygotes believed to have two active alpha-globin genes demonstrated an alpha/non-alpha total activity ratio (0.57) consistent with this model.

Effects of low cobalamin diet and chronic cyanide toxicity in baboons

The effects of a low cobalamin (Cbl) diet, together with chronic cyanide or thiocyanate administration in some animals have been investigated in baboons over a period of 42 months. All animals remained healthy throughout the study and gained weight at a similar rate. None became anaemic or showed major haematological changes and there were no major neurological changes. Plasma total Cbl in the animals on the low Cbl diet fell within 9 months to values below the lower limit in man and were lowest at 24 months in baboons not receiving cyanide or thiocyanate. A striking feature in all animals, however, was an apparently seasonal increase in the plasma total Cbl each autumn with a corresponding decrease the following spring. This fluctuation was detected by radioisotopic assay but not by Euglena. Methylmalonic (MMA) excretion after oral valine ranged from 0.1--8.4 mg/24 h and was greatest in animals on the low Cbl diet and not receiving cyanide or thiocyanate. The results suggested an inverse relationship between MMA excretion and plasma total Cbl. Plasma thiocyanate was consistently higher in animals receiving cyanide or thiocyanate and at the end of the study plasma cyanide was highest in animals on the low Cbl diet receiving cyanide. The results support the suggestions that cyanide affects bodily handling of Cbl and that hydroxo-cobalamin plays a part in detoxication of cyanide.

Megaloblastic haemopoiesis in patients receiving nitrous oxide

In a prospective study the incidence of megaloblastic change after ventilation with nitrous oxide for periods of up to 24 h has been determined and the cause of the altered D.N.A. synthesis studied with the deoxyuridine (dU) suppression test in 22 patients undergoing cardiac bypass surgery. 8 patients who received nitrous oxide and oxygen for 24 h had megaloblastic bone-marrow aspirates and abnormal dU suppression tests at the end of ventilation. 5 patients who received no nitrous oxide had normoblastic aspirates and normal dU suppression test. Of the remaining 9 patients, who received nitrous oxide during the operation only, 3 had abnormal dU suppression tests at 24 h. The abnormality revealed by the dU suppression tests was identical with that found in vitamin-B12 deficiency, but the patients' serum-B12 concentrations were normal. These results suggest that nitrous oxide interferes with the function of vitamin B12. Nitrous oxide oxidises vitamin B12 in vitro, and probably also in vivo when premixed 50% nitrous oxide and 50% oxygen mixture ('Entonox') is given.

Measurement of ferritin in serum by radioimmunoassay

A method for the measurement of circulating ferritin concentrations by direct radioimmunoassay is presented. The method described is simple to operate, precise, and sensitive and is suitable for the routine diagnostic measurement of ferritin in either plasma or serum.

Deoxyuridine suppression studies in bone marrow in primary refractory sideroblastic anemia

Because unexplained megaloblastic erythroid maturation occurs in patients with primary refractory sideroblastic anemia (PRSA), deoxyuridine (dU) suppression tests using 125I-UdR were performed on bone marrow from five patients with PRSA. All patients had megaloblastic alterations in the marrow erythroid precursors (with normal serum folate and B12 levels) and numerous ringed sideroblasts, and most had marrow iron overload. Results of the dU suppression tests were normal in all five, both with and without incubation with pharmacologic amounts of folate, B12, and pyridoxal phosphate with or without 1-serine. Despite occasional hematologic improvement subsequent to folate, pyridoxine, or pyridoxal phosphate (PLP) administration in some patients with PRSA, normal dU suppression implies that in our group the availability of B12 and folate (and possibly PLP) was not limiting in the utilization of folate for DNA-thymine synthesis. The marrow erythroid maturation defect remains unexplained.

Sickle cell anemia and trait in a population of southern India

In an ethnic group in southern India, the Irula, seven individuals with sickle cell anemia were found to manifest only mild illness. Although a relatively high level of fetal hemoglobin was present in one, none of the factors thought to ameliorate the course of sickling disorders could be identified in the remaining six. In a random population survey, sickle hemoglobin was found in 90 of 292 Irula (31%). In those with sickle cell trait, the proportion of sickle hemoglobin in hemolysates (mean = 26%, range 19-32%) was substantially lower than that reported for any other population.

Blast crisis of chronic myeloid leukaemia (CML). I. Presentation simulating acute lymphoid leukaemia (ALL)

Seven patients presenting as an acute leukaemia caused difficulty in diagnosis. The lymphoid appearance of the balst cells either initially or during treatment suggested acute lymphoid leukaemia (ALL). In each case the Philadelphia chromosome was shown to be present thus suggesting that these cases were examples of chronic myeloid leukaemia (CML) presenting in blast crisis without a detectable chronic phase. The implications of these findings are discussed and the difficulty in achieving a precise diagnosis in the acute leukaemias is emphasised. Cytogenetic analysis should be carried out whenever the type of acute leukaemia present is of critical importance.

Cotrimoxazole and folate metabolism

Cotrimoxazole 4 tablets daily (1 tablet = trimethoprim 80 mg and sulphamethoxzole 400 mg) was given for a period of six to fourteen days to 13 inpatients, and serum-folate levels were measured before and one day after the course of treatment. The results were compared with those from 8 patients not receiving antibacterial therapy, tested on admission and one week later. Two assay techniques were used, one employing Lactobacillus casei and the other 125I-labelled folate isotope dilution. The microbiological technique showed a significant decline in folic-acid levels in the serum after cotrimoxazole, and this decline was not seen in controls. By contrast, the radioisotope technique showed no significant alteration in serum-folate levels compared with controls. This suggests that cotrimoxazole does not depress true serum-folate and that many low microbiological results obtained during cotrimoxazole therapy reflect interference with the assay organism. There is insufficient evidence to incriminate cotrimoxazole as a significant cause of blood dyscrasias in excess of those which might occur on sulphonamide alone or even with other antibacterials.

A familial abnormality of circulating vitamin B12 binding proteins: occurrence in a family of high serum concentrations of transcobalamin II

A family is described in which two members (a father and a daughter), both with quiescent ulcerative colitis, had abnormally high serum concentrations of a vitamin B12 binding protein. This protein had the molecular weight of transcobalamin II on gel filtration, and behaved like transcobalamin II with respect to its elution from DE-23 cellulose, its inhibition at acid pH, its absorption by uncoated charcoal, its binding by anti-TC II antibodies, and its ability to transfer vitamin B12 to transformed lymphocytes. Its plasma clearance and tissue distribution when injected into rabbits was indistinguishable from that of transcobalamin II from normal subjects. It migrated on electrophoresis in the beta, gamma region. This is the first case report of related subjects in whom high serum concentrations of transcobalamin II have been observed.

Nutrition in cryptogenic cirrhosis and chronic aggressive hepatitis

The nutritional status of 80 patients with non-alcoholic chronic liver disease was assessed by determination of various nutritional parameters in body fluids. With the exception of vitamin C there was a higher incidence (40%) of fat soluble vitamin deficiency (vitamins A, E, and carotene) than of the water soluble vitamins. Less than 10% of patients showed evidence of vitamin B12, nicotinic acid, thiamin, or riboflavin deficiency, and 17% had evidence of folic acid deficiency. The presence of deficiency was not related to age of the patient or fat absorption, and an inadequate dietary intake was not a major cause of deficiency. The incidence of nutritional deficiency is less frequent in non-alcoholic as compared with alcoholic liver disease.

A column radioassay for the quantification of vitamin B-12

A rapid and convenient column radioassay for the quantification of vitamin B-12 in clinical specimens has been developed. A mixture of the specimen and radiolabeled B-12 was applied to a column containing immobilized intrinsic factor and allowed to incubate for two hours. A buffer wash then separated bound and free B-12. The average intra- and inter-assay coefficients of variation over the range of interest was about 30 pg/ml in the sample and recovery and parallelism studies gave satisfactory results. The values obtained for clinical specimens by the column procedure correlated well with those obtained by reference method.

Vitamin B12 absorption after resection of ileum in childhood

Impaired absorption of vitamin B₁₂ has been shown by a whole body counter technique in 7 of 10 infants and children who had resection of over 45 cm of ileum. Absorption was normal in 2 patients who had 15 cm or more terminal ileum remaining. If absorption was abnormal the serum level of vitamin B₁₂ did not fall below the lower limit of the normal range for several years, puberty being a particularly vulnerable time. Though the site and length of the resection often suggested whether vitamin B₁₂ deficiency was likely to occur, an absorption test was necessary for accurate prediction and to allow treatment to be given rationally before complications occurred. The whole body counter technique was particularly suitable for children as it did not involve collection of urine or faeces, injections, or admission to hospital.

Indices of granulocyte activity in inflammatory bowel disease

In conditions with increased neutrophil production, the serum total vitamin B(12)-binding capacity (TBBC) is considered to correlate with the blood pool size of neutrophil granulocytes. The serum lysozyme, on the other hand, is a measure of neutrophil (and monocyte) turnover. The mean serum TBBC was significantly raised in patients with ulcerative colitis (range 1.23-5.51 ng/ml; mean 2.64 ng/ml) and patients with Crohn's disease (range 1.58-9.29 ng/ml; mean 2.93 ng/ml). The elevated values were shown to be due to rises in the granulocyte-secreted binding proteins, transcobalamins I and III. The TBBC was shown to rise with increasing activity of disease and to correlate roughly with the blood neutrophil granulocyte count. Patients with inflammatory bowel disease also had a significantly raised mean level of serum lysozyme (range 3.1 to 10.4 mug/ml; mean 6.8 mug/ml), but there was no correlation in individual patients between serum lysozyme and total B(12)-binding capacity. These results are taken to indicate an enlarged granulocyte pool and increased granulocyte turnover in inflammatory bowel disease.

Vitamin B 12 status in pregnancy among immigrants to Britain

Haemoglobin, serum vitamin B(12), and serum and red cell folate levels have been measured in 322 pregnant immigrant women in London at their first booking and in a proportion at 34 weeks of gestation and postnatally. The Indian, East-African Indian, and Pakistani and Bangladeshi patients showed significantly lower initial mean serum vitamin B(12) levels than the European group, the levels being lower in Hindu and Sikh patients than in Moslems. The patients of West Indian, Indian, and East-African Indian origin showed significantly lower initial mean haemoglobin levels than the immigrants from European countries. Though there was no overall correlation between haemoglobin and serum vitamin B(12) level the incidence of hypersegmented polymorphs and macrocytosis in the peripheral blood was highest in the Indian and East-African Indian patients, and both these features were particularly frequent in patients with subnormal serum vitamin B(12) levels. Only one patient, however, had overt megaloblastic anaemia due to vitamin B(12) deficiency. The Indian patients whose red cell folate levels were less than 200 ng/ml also had a lower mean serum vitamin B(12) level than those with red cell folate levels greater than 200 ng/ml. The Indian patients had smaller babies than the Europeans but this was not related to the differences in vitamin B(12) status between the two groups. However, out of 39 babies of the Indian group 5 (13%) showed subnormal serum vitamin B(12) levels in the first 10 days of life, the lowest level being 120 pg/ml.Though there was an overall statistically significant fall in serum vitamin B(12) between first booking and 34 weeks of pregnancy there was no significant fall in serum vitamin B(12) in those who initially had subnormal levels. Thus many Indian women are vitamin B(12) deficient in pregnancy, and this is associated with morphological blood abnormalities in many cases, but megaloblastic anaemia due to this deficiency is relatively infrequent.

Malnutrition and malabsorption in Crohn's disease with reference to the effect of surgery

Sixty-three patients with Crohn's disease showed a high incidence of nutritional deficiencies as judged by laboratory tests. Malabsorption of fat (33 per cent) and vitamin B12 (60 per cent) was not sufficiently severe to account for the malnutrition. Malnutrition was especially severe in unoperated patients with active disease, whereas malabsorption was prominent in patients with recurrent disease after resection although they had less active disease and less severe nutritional deficits. Surgery should not be withheld from a malnourished patient for fear of inducing further malnutrition; excision of toxic inflammatory disease will not only improve the immediate outlook but will also reduce the severity of further recurrences. Xylose-excretion tests give a spurious impression of malabsorption in Crohn's disease, possibly as a result of occult renal impairment, and should be abandoned.

The prevalence and significance of circulating antibodies to gastric intrinsic factor and parietal cells in gastric carcinoma

The prevalence of circulating antibodies to gastric intrinsic factor and parietal cells was examined in 60 patients with histologically proven gastric carcinoma and was found not to differ from the prevalence of these antibodies in control subjects of similar age and sex distribution.Amongst the 60 patients with gastric carcinoma seven were thought to have actual or potential pernicious anaemia. The absence of an increased prevalence of antigastric antibodies in gastric carcinoma indicates that gastritis itself, whether autoimmune or not, is the likely common denominator underlying the predisposition to gastric carcinoma in both pernicious anaemia and chronic atrophic gastritis.

Simple atrophic gastritis and gastric carcinoma

Gastric carcinoma was detected nine, 10, 18, and 21 years after the biopsy diagnosis of atrophic gastritis in four patients of a group of 40. The gastritis was presumed to be of the simple type. Tests of vitamin B(12) absorption in three patients gave normal results, no gastric autoantibodies were detected in the two patients tested, in all patients histological examination of the gastrectomy specimens revealed a multifocal gastritis differing from the diffuse gastritis of pernicious anaemia and in three patients the gastritis affected the antrum, which is unusual in pernicious anaemia. The 10% incidence of gastric carcinoma in 40 patients with simple atrophic gastritis followed for a mean period of 15 years is equivalent to that previously described in pernicious anaemia. However, in view of the relative incidence of atrophic gastritis with and without pernicious anaemia in the general adult population, it emerges that atrophic gastritis without pernicious anaemia is numerically the more important precursor of gastric carcinoma.

Response of low birthweight infant to treatment with folic acid

Folate deficiency, detected by measuring serum and red cell levels, was seen within a group of low birthweight infants who had been followed for a period of 9 months. A similar group treated with 14 × 100 μg folic acid by intramuscular injection over a period of 28 days during the first 5 weeks of life had significantly higher folate levels. There was no evidence of megaloblastic anaemia in the untreated group and no differences from the treated group in haemoglobin concentration or other haematological index except for a significant increase in neutrophils with 5-lobed nuclei at 3 months. We conclude that folate should be given from birth to all infants of low birthweight, but its form, and the route, dosage, and duration of treatment merit further investigation.

Activities of various cobalamins for Euglena gracilis with reference to vitamin B 12 assay with Euglena

Coenzyme B(12) and methylcobalamin in water are less active in promoting growth of Euglena gracilis Z strain than the same concentrations of cyanocobalamin and hydroxocobalamin which are equally active. When bound to human serum or human liver homogenate, however, the activities of these four cobalamins do not differ significantly with one exception. The results suggest that the Euglena assay using cyanocobalamin standards is not satisfactory for quantitation of coenzyme B(12) and methylcobalamin in water but acceptable when coenzyme B(12) and methylcobalamin are bound to serum or liver. Sulphitocobalamin in water is as active as cyanocobalamin and hydroxocobalamin but nitritocobalamin is less active. Factor B, the monocarboxylic acids of cyanocobalamin and hydroxocobalamin, and the dicarboxylic acid of cyanocobalamin in water were inactive.

Neurological disorders and adult coeliac disease

An investigation into the incidence of neurological disorder in 30 patients with adult coeliac disease has shown that three patients had severe depression, two had epileptiform convulsions, and one patient only had signs of involvement of the peripheral nervous system. Motor nerve conduction velocity was low in only one patient. When the nerve conduction velocities of the group on a gluten-free diet were compared with the group who were not on a gluten-free diet, there was no statistically significant difference. Similarly, nerve conduction velocities in patients with a low serum pyridoxal level were not significantly different from those with normal serum pyridoxal levels. Measurements of the serum level of pyridoxal in 30 patients confirmed that pyridoxine deficiency occurs in adult coeliac disease and that the restriction of gluten from the diet appeared to affect pyridoxal levels favourably.

Effect of drugs on vitamin B 12 levels obtained using the Lactobacillus leichmanii method

In 750 consecutive assays of serum vitamin B(12) levels using Lactobacillus leichmanii, 25 (3.3%) showed inhibition. A satisfactory history of drug therapy was obtained in 23 cases. Seventeen of these were receiving ampicillin at the time. Two patients showed inhibition while receiving phenoxmethyl penicillin or phenethicillin. A prospective study of 11 patients detected inhibition in seven at varying intervals during ampicillin therapy. It was shown that the vitamin B(12) as measured by the radioisotope and Euglena gracilis methods was not affected. Inhibition of L. leichmanii was reproduced in vitro with concentrations of ampicillin corresponding to those obtained in therapy. Benzylpenicillin, streptomycin, and chloramphenicol had no such effect.A prospective study of patients receiving chlorpromazine yielded negative results.Inhibition may occasionally be seen in the absence of any known intake of drugs. Measurement by other methods may be required to distinguish this from vitamin B(12) depletion.