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Neuropathies associated with nutritional deficiencies are routinely encountered by the practicing neurologist. Although these neuropathies assume different patterns, most are length-dependent, sensory axonopathies. Cobalamin deficiency neuropathy is the exception, often presenting with a non-length-dependent sensory neuropathy. Patients with cobalamin and copper deficiency neuropathy characteristically have concomitant myelopathy, whereas vitamin E deficiency is uniquely associated with a spinocerebellar syndrome. In contrast to those nutrients for which deficiencies produce neuropathies, pyridoxine toxicity results in a non-length-dependent sensory neuronopathy. Deficiencies occur in the context of malnutrition, malabsorption, increased nutrient loss (such as with dialysis), autoimmune conditions such as pernicious anemia, and with certain drugs that inhibit nutrient absorption. When promptly identified, therapeutic nutrient supplementation may result in stabilization or improvement of these neuropathies., (© 2019 Wiley Periodicals, Inc.)

Background: Pernicious Anemia (PA), the most common cause of cobalamin deficiency anemia worldwide, is an autoimmune disease of multifactorial etiologies involving complex environmental and immunological factors. Although it was first reported by Addison in 1849 with subsequent advances in understanding of pathogenesis and molecular biology, diagnosis of PA is still challenging for clinicians because of its complexity and diverse clinical presentations., Conclusion: Herein, we provide an overview of PA, mainly focusing on its scientific and practical aspects in diagnosis. We also discuss the limitations of currently available diagnostic tools for the evaluation of cobalamin deficiency and PA., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

B 12 deficiency is the leading cause of megaloblastic anemia, and although more common in the elderly, can occur at any age. Clinical disease caused by B 12 deficiency usually connotes severe deficiency, resulting from a failure of the gastric or ileal phase of physiological B 12 absorption, best exemplified by the autoimmune disease pernicious anemia. There are many other causes of B 12 deficiency, which range from severe to mild. Mild deficiency usually results from failure to render food B 12 bioavailable or from dietary inadequacy. Although rarely resulting in megaloblastic anemia, mild deficiency may be associated with neurocognitive and other consequences. B 12 deficiency is best diagnosed using a combination of tests because none alone is completely reliable. The features of B 12 deficiency are variable and may be atypical. Timely diagnosis is important, and treatment is gratifying. Failure to diagnose B 12 deficiency can have dire consequences, usually neurological. This review is written from the perspective of a practicing hematologist., (© 2017 by The American Society of Hematology.)

Vitamin B12 deficiency may be responsible of serious hematologic and neurodevelopmental abnormalities. We report the case of an infant who was hospitalized because of recurrent infections, failure to thrive, hypotonia, and weakness. He was 8 months old and had been exclusively breastfed. Blood cell count showed pancytopenia with megaloblastic bone marrow. The serum IgG concentration was low. Vitamin B12 level was very low and associated with increased urinary methylmalonic acid. Cobalamin deficiency was caused by mother's unrecognized pernicious anemia. Vitamin B12 supply led to rapid clinical and hematologic improvement.

Background: Vitamin B12 deficiency may result in pernicious anemia (PA). This study evaluated whether all the patients with vitamin B12 deficiency had PA., Methods: The blood hemoglobin (Hb), iron, vitamin B12, folic acid, and homocysteine concentrations and mean corpuscular volume (MCV) in 90 vitamin B12-deficient patients were measured and compared with the corresponding data in 180 age- and sex-matched healthy control subjects. PA was defined by World Health Organization (WHO) as having an Hb concentration <13 g/dl for men and <12 g/dl for women, an MCV ≧ 100 fl, a serum vitamin B12 level <200 pg/ml, and serum gastric parietal cell antibody (GPCA) positivity., Results: We found that 35 (38.9%) and 20 (22.2%) patients with vitamin B12 deficiency had deficiencies of Hb (men <13 g/dl, women <12 g/dl) and iron (<60 μg/dl), respectively. Moreover, 65 (72.2%) and 37 (41.1%) patients with vitamin B12 deficiency had abnormally high blood homocysteine level (>12.7 μM) and high MCV (≧100 fl), respectively. In addition, 43 (47.8%) vitamin B12-deficient patients with had GPCA positivity. Patients with vitamin B12 deficiency had a significantly higher frequency of Hb or iron deficiency, of abnormally elevated blood homocysteine level or high MCV, and of GPCA positivity than healthy control subjects (all P-values < 0.001). However, only 17 (18.9%) of 90 vitamin B12-deficient patients were diagnosed as having PA by the WHO definition., Conclusion: Only 18.9% of patients with vitamin B12 deficiency are discovered to have PA by the WHO definition., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Several genome-wide association studies (GWAS) have identified a strong association between serum vitamin B12 and fucosyltransferase 2 (FUT2), a gene associated with susceptibility to Helicobacter pylori infection. Hazra et al. conducted a meta-analysis of three GWAS and found three additional loci in MUT, CUBN and TCN1. Other GWAS conducted in Italy and China confirmed the association for FUT2 gene. Alpha-2-fucosyltransferase (FUT2) catalyzes fucose addition to form H-type antigens in exocrine secretions. FUT2 non-secretor variant produces no secretion of H-type antigens and is associated with high-plasma vitamin B12 levels. This association was explained by the influence of FUT2 on H. pylori, which is a risk factor of gastritis, a main cause of vitamin B12 impaired absorption. However, we recently showed that H. pylori serology had no influence on FUT2 association with vitamin B12, in a large sample population, suggesting the involvement of an alternative mechanism. GIF is another gene associated with plasma levels of vitamin B12 and gastric intrinsic factor (GIF) is a fucosylated protein needed for B12 absorption. Inherited GIF deficiency produces B12 deficiency unrelated with gastritis. We report 2 families with heterozygous GIF mutation, 290T>C, M97T, with decreased binding affinity of GIF for vitamin B12 and one family with heterozygous GIF mutation 435&#95;437delGAA, K145&#95;N146delinsN and no B12 binding activity of mutated GIF. All cases with vitamin B12 deficit carried the FUT2 rs601338 secretor variant. Ulex europeus binding to GIF was influenced by FUT2 genotypes and GIF concentration was lower, in gastric juice from control subjects with the secretor genotype. GIF290C allele was reported in 5 European cases and no Africans among 1282 ambulatory subjects and was associated with low plasma vitamin B12 and anaemia in the single case bearing the FUT2 secretor variant. We concluded that FUT2 secretor variant worsens B12 status in cases with heterozygous GIF mutations by impairing GIF secretion, independently from H. pylori-related gastritis., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Vitamin B12 deficiency is an important nutritional disorder causing neurological manifestations of myelopathy, neuropathy and dementia. Sub-acute combined degeneration (SCD) with involvement of the posterior columns in the cervical and thoracic cord is a common presentation of this disorder. In this case report, we describe a 43 year old woman with pernicious anemia and myelopathy with atypical clinical features. The patient presented with motor symptoms, a sensory level and bladder dysfunction. She had severe autonomic disturbances including an episode of unexplained bronchospasm, which has not been previously reported as a manifestation of vitamin B12 deficiency. We review the literature regarding these rarely reported features of vitamin B12 deficiency, and discuss aspects of management of this reversible condition. We emphasize the importance of awareness of autonomic disturbances in B12 deficient individuals.

Despite advances in surgical reconstruction, total gastrectomy still is accompanied by various complications, especially chronic ones, such as pernicious anemia, resulting in refractory malnutrition. As an alternative approach, we have proposed a tissue-engineered stomach as a replacement of the native stomach. This study aimed to assess the secretory functions of a tissue-engineered stomach in a rat model and the nutritional status of the recipients over an extended time period. Stomach epithelial organoid units were isolated from neonatal rats and seeded onto biodegradable polymers. These constructs were implanted into the omenta of adult recipient rats. After 3 weeks, cyst-like structures had formed, henceforth referred to as tissue-engineered stomachs. The recipient stomachs were resected and replaced by their tissue-engineered counterparts. At 24 weeks after implantation, the secretory function of the tissue-engineered stomach was evaluated using immunohistochemical staining. The hemoglobin levels and nutritional status of the recipients were compared with a control group that had undergone a simple Roux-en-Y reconstruction following total gastrectomy. Recipient rats tolerated the tissue-engineered stomachs well. X-ray examination using barium as contrast showed no bowel stenosis. Staining for proton pump alpha-subunit and gastrin demonstrated the existence of parietal cells and G-cells in the neogastric mucosa, respectively, suggesting secretory functions. The treatment group showed significantly higher hemoglobin levels than the control group, although no differences in the body weight change, total protein, or cholesterol levels were observed between the two groups. A tissue-engineered stomach has the potential to function as a food reservoir following total gastrectomy. It is conjectured that replacement with a tissue-engineered stomach might restore the proton pump parietal cells and G-cells, and thereby improve anemia after a total gastrectomy in a rat model.

Background: Mitochondrial dysfunction is one of the most characteristic properties of the cancer cell. However, it is not known whether oxidative energy metabolism has already become altered in conditions of atrophic gastritis, a precancerous state of gastric disease. The purpose of our study was to comparatively characterize oxidative phosphorylation (OXPHOS) in the atrophic and nonatrophic gastric corpus mucosa., Methods: Mucosal biopsies were taken from 12 patients with corpus dominant atrophic gastritis and from 12 patients with nonatrophic mucosa (controls). One part of the tissue samples was permeabilized with saponin for analysis of the function of the respiratory chain using high-resolution respirometry, and another part was used for histopathological examination. The serum level of pepsinogen I (S-PGI) was determined with a specific enzyme immunoassay (EIA)., Results: Compared to the control group, the maximal capacity of OXPHOS in the atrophy group was almost twofold lower, the respiratory chain complex I-dependent respiration, normalized to complex II-dependent respiration, was reduced, and respiratory control by ADP in the presence of succinate was increased in the atrophic corpus mucosa. In the whole cohort of the patients studied, serum S-PGI level correlated positively with complex I-dependent respiration or complex I-dependent to complex II-dependent respiration ratio., Conclusions: Corpus dominant atrophic gastritis is characterized by decreased respiratory capacity and relative deficiency of the respiratory complex I of mitochondria in the mucosa, the latter defect probably limiting mitochondrial ATP production and energetic support of the secretory function of the zymogenic mucosal cells.

Cobalamin-deficient (Cbl-D) central neuropathy in the rat is associated with a locally increased expression of neurotoxic tumour necrosis factor-alpha (TNF-alpha) and a locally decreased expression of neurotrophic epidermal growth factor (EGF). These recent findings suggest that cobalamin oppositely regulates the expression of TNF-alpha and EGF, and raise the possibility that these effects might be independent of its coenzyme function. Furthermore, adult Cbl-D patients have high levels of TNF-alpha and low levels of EGF in the serum and cerebrospinal fluid. Serum levels of TNF-alpha and EGF of cobalamin-treated patients normalize concomitantly with haematological disease remission. These observations suggest that cobalamin deficiency induces an imbalance in TNF-alpha and EGF levels in biological fluids that might have a role in the pathogenesis of the damage caused by pernicious anaemia.

Background: Cobalamin attached to transcobalamin II (TC II), known as holo-TC II, is the active cobalamin fraction taken up by tissues. Holo-TC II is also the form in which absorbed cobalamin enters the circulation from the ileum. Therefore, holo-TC II has been proposed variously as a marker of cobalamin adequacy, cobalamin absorption, or both, including even its advocacy as a surrogate Schilling test. Such claims carry conflicting diagnostic implications because metabolic adequacy and absorption are not identical., Objective: The objective was to examine metabolic and absorptive influences on holo-TC II., Design: Treated patients with pernicious anemia (PA), who have abnormal absorption but a normal metabolic status, were chosen as the model to differentiate between the effects of the 2 cobalamin-related characteristics. Serum holo-TC II and indexes of cobalamin metabolism in 23 treated patients were compared with those of 6 untreated PA patients (abnormal absorption and metabolic status) and 33 control subjects (normal absorption and metabolic status)., Results: Holo-TC II, which correlated directly with cobalamin and inversely with homocysteine, was significantly higher in treated PA patients in metabolic remission than in untreated PA patients (74 +/- 59 compared with 9 +/- 6 pmol/L) and was significantly lower than in control subjects (105 +/- 58 pmol/L), although the latter difference was small and the values overlapped greatly., Conclusions: Metabolic cobalamin status is a major determinant of serum holo-TC II. Absorption status may have mild influence as well, although other explanations remain possible. Serum holo-TC II cannot be used clinically to diagnose cobalamin malabsorption because of overlap with normal values. The influences on holo-TC II are complex and require careful analysis.

Decreased bone mineral density is a frequent finding in gastrointestinal disease. Factors contributing to this are (1) malabsorption of vitamin D, calcium and possibly vitamin K and other nutrients; (2) treatment with glucocorticoids; (3) inflammatory cytokines in inflammatory bowel disease; and (4) hypogonadism induced by gastrointestinal disease. A low bone mineral density has been reported in (1) patients who have undergone gastrectomy (27-44% with Z-scores of < -1); (2) pernicious anaemia; (3) coeliac disease (8-22% with Z-scores of < -2); (4) Crohn's disease (mean 32-38% with Z-scores of < -1); and (5) ulcerative colitis (mean 23-25% with Z-scores of < -1). Reduced bone mineral density is thus prevalent in these individuals and is compounded by age related bone loss, leading to the development of severe bone disease in some patients.

Selective vitamin B(12) malabsorption or Gräsbeck-Imerslund disease (megaloblastic anemia 1) is frequently accompanied by proteinuria. The malabsorption-proteinuric syndrome of Finnish patients is caused by a defect in the multiligand receptor cubilin. We studied the urinary proteins of control subjects and 13 adult patients with three defined cubilin mutations (FM1, FM2, FM3), all diagnosed during childhood and subsequently observed. The overall kidney function was unimpaired and did not deteriorate with time. The excretion of total protein and albumin, and to lesser extent of transferrin, immunoglobulin light chains, and alpha(1)- and beta(2)-microglobulins, was clearly elevated in 3 patients, mildly elevated in 3, and hardly or not at all increased in the rest. The urinary cobalamin-intrinsic factor receptor was low in 5 patients studied and lowest in the group with clear-cut proteinuria. The proteinuria was not of the classical glomerular or tubular type, but apparently due to the lack of cubilin function needed for tubular reabsorption of some, but not all, proteins of the primary urine.

The unknown biochemical basis for neurologic dysfunction in cobalamin deficiency and the frequent divergence between neurologic and hematologic manifestations led us to study homocysteine metabolism in 22 patients with pernicious anemia. Serum levels of total homocysteine (tHcy), methionine, S-adenosylmethionine (AdoMet), cysteine, cysteinylglycine (cys-gly), and glutathione (GSH) were measured. Only levels of tHcy and cysteine were increased and only GSH was decreased in cobalamin deficiency as a whole, compared with 17 control subjects. AdoMet correlated only with methionine levels (P =.015) and cysteine only with cys-gly (P =.007) in healthy subjects, but in cobalamin-deficient patients AdoMet correlated instead with cysteine, cys-gly, and folate levels only (P =.008, P =.03, and P =.03, respectively). Significant differences appeared in clinically subgrouped cobalamin-deficient patients. The 11 patients with neurologic defects had higher mean levels of folate (27.9 versus 15.4 nM), AdoMet (117.2 versus 78.6 nM), cysteine (462 versus 325 microM), and cys-gly (85.0 versus 54.7 microM) than the 11 neurologically unaffected patients. Cobalamin therapy restored all metabolic changes to normal. The results indicate that changes in several metabolic pathways differ in patients with and without neurologic dysfunction. Cysteine levels were the most significant predictors of neurologic dysfunction, but it is unclear if they are direct or indirect indicators of neurotoxicity. The higher AdoMet levels in neurologically affected patients may result from inhibition of glycine N-methyltransferase by those patients' higher folate levels. The origin of the folate differences is unclear and possibly varied. Low AdoMet and GSH levels were independent predictors of anemia.

Low cobalamin concentrations are common in the elderly. Although only a minority of such persons display clinically obvious symptoms or signs, metabolic data clearly show cellular deficiency of cobalamin in most cases. The evidence suggests that this is not a normal physiologic expression of the aging process. Rather, the elderly seem at increased risk for mild, preclinical cobalamin deficiency. Classical disorders such as pernicious anemia are the cause of this deficiency in only a small proportion of the elderly. A more frequent problem is food-cobalamin malabsorption, which usually arises from atrophic gastritis and hypochlorhydria but other mechanisms seem to be involved in some patients. The diminished absorption should not be viewed as a natural consequence of aging. The partial nature of this form of malabsorption produces a more slowly progressive depletion of cobalamin than does the more complete malabsorption engendered by disruption of intrinsic factor-mediated absorption. The slower progression of depletion probably explains why mild, preclinical deficiency is associated with food-cobalamin malabsorption more often than with pernicious anemia. Decisions about the optimal management of the very common problem of mild, preclinical cobalamin deficiency in the elderly await further clarification of the processes and the complex issues involved, including the possibility that routine nitrous oxide use during surgery, proposed dietary changes, and other practices may further stress the marginal cobalamin status of many elderly people.

Background & Aims: The gastrin precursor progastrin produces multiple alternative active products, but the pathways of posttranslational processing in human antral mucosa have not yet been studied directly. The aim of this study was to investigate the biosynthetic relationships and release kinetics of newly synthesized progastrin-derived peptides in the antrum of patients with pernicious anemia., Methods: Antral mucosal explants were incubated with [35S]sulfate and [3H]tyrosine to label progastrin and its derivatives, which were detected by online scintillation counting after immunoprecipitation and high-performance liquid chromatography., Results: [35S]- and [3H]progastrin were detected within 2.5 hours, and labeled G34Gly and G34 were readily detected after 5-hour incubation. Pulse-chase studies indicated conversion of progastrin to G17 via G34Gly and G34. Secretion of newly synthesized G34, but not G34Gly, was routinely detected; G17Gly was present only in trace quantities in cell extracts and media. In control samples, progastrin synthesis was about 10 times lower than in pernicious anemia samples, although the proportions of different labeled amidated gastrins after 5-hour incubation were similar., Conclusions: In the antrum of patients with pernicious anemia, Gly-gastrins, particularly G34Gly, are biosynthetic intermediates and not major secretory products. Some G34 is secreted preferentially under basal conditions.

Acquired kidney and liver diseases are relatively common diseases that can raise the potential for nutrient intoxication. For example, high-protein diets increase glomerular blood flow and the blood pressure gradient across the glomerular capillary wall in the kidney, which can result in injury to membranes. Likewise, the liver can increase nutrient intoxication because it is involved in the intermediary metabolism of many nutrients, serves as the storage organ for many nutrients, and is important in the biotransformation and excretion of nutrients. In this paper, vitamin A serves as an example to illustrate how kidney disease and liver disease can increase a single nutrient's toxicity.

Somatostatin is involved in the regulation of gastrin by intragastric pH in animal models. To investigate whether this is so in man, we measured gastrin and somatostatin mRNA in endoscopic biopsies from six patients with hypergastrinemia and achlorhydria due to pernicious anemia and 12 age- and sex-matched controls. The pernicious anemia patients had significantly higher fasting plasma gastrin concentrations with a median (range) of 640 (420-3500) pmol/liter compared with 5 (2-58) pmol/liter, P < 0.001. The median gastrin mRNA/rRNA ratio was 10.4 (3.7-38.0) in the pernicious anemia patients compared with 1.7 (0.7-8.3) in the controls (P < 0.02), and it correlated strongly with the plasma gastrin concentration, r = 0.93, P < 0.0001. In contrast, the median somatostatin mRNA/rRNA ratio was lower in the pernicious anemia patients 0.84 (0.58-2.32) versus 2.04 (0.05-6.47) in the controls, P < 0.05. These findings suggest that in pernicious anemia gastric neutralization leads to hypergastrinemia through the modulation of antral gastrin synthesis by somatostatin.

Objective: We discuss the pathophysiologic mechanisms, clinical features, diagnosis, and treatment of pernicious anemia (PA)., Design: A review of the clinical applications of the diagnostic and therapeutic progress of PA is presented., Material and Methods: A patient with PA may have a wide range of initial complaints that affect various organ systems or may be entirely asymptomatic. Hematologic variables may be normal in patients with cobalamin (Cbl) deficiency. Because of the difficulties in diagnosing Cbl deficiency, alternatives to measuring Cbl have been sought. Determining the urinary methylmalonic acid level is a less invasive, more practical, and, possibly, more sensitive method. The Schilling test is performed for assessment of the absorption of orally ingested radiolabeled crystalline cyano-Cbl; results should be interpreted cautiously., Results: Vitamin B12 therapy should be lifelong. It is customarily administered intramuscularly. Other routes of administration have been studied., Conclusion: PA is one of the most treatable hematologic disorders.

The levels of serum pepsinogen I (PG I) and pepsinogen II (PG II) were determined by IRMA (immunoradiometric assay) and the ratio of PG I/II calculated in 37 patients with type A gastritis and concomitant pernicious anemia (PA) and in 97 with chronic gastritis (type B gastritis) among Japanese. In several patients from each group, PG I and PG II in the gastric mucosa were stained by an enzyme antibody assay to compare the percentage of positively stained cells with levels of serum PG I and PG II. The levels of serum PG I and PG II in chronic gastritis decreased as the degree of atrophy increased. Serum PG I and PG II levels in PA were lower than those of patients with severe atrophy. Most of serum PG I levels in PA were less than 10 ng/ml. The PG I/II ratio also decreased as the severity of atrophy increased, distinctly showing that in PA, the ratio were quite low and most of them are less than 1.0. Gastric mucosal pepsinogen showed a tendency similar to that of serum levels and also refrected the degree of atrophy. Therefore, by measuring these parameters it should be easier to determine the extent of atrophy, and to establish a serological diagnosis of type A gastritis associated with PA.

Antisera were raised against fragment 38-54 of human progastrin. All of eight immunized rabbits responded, but only one (No. 2145) produced high-titer (3.2 x 10(4)) and high-avidity (Keff degrees = 1.2 x 10(12) l/mol) antibodies. A radioimmunoassay based on antiserum 2145 and monoiodinated gastrin-34 was specific for the N-terminal sequence of human gastrin-34. It measured concentrations of 9.7 +/- 1, 18.4 +/- 2 pmol/l (mean +/- SEM) and 1.553 (0.7-476) nmol/l (median (range], respectively, in sera from normal subjects (n = 20), patients with duodenal ulcer (n = 19), and Zollinger-Ellison patients (n = 8). Conventionally measured concentrations of carboxyamidated gastrins in the same sera were 21.4 +/- 1, 23.8 +/- 3 pmol/l (mean +/- SEM) and 0.833 (0.4-214) nmol/l (median (range)), respectively. The results show that radioimmunoassays specific for the N-terminus of human gastrin-34 discriminate between healthy subjects and patients with duodenal ulcer. The improved diagnostic specificity is due to co-measurement of unprocessed and partly processed progastrins that occur in plasma of patients with duodenal ulcer disease and gastrinomas. We suggest that conventional gastrin assays are supplemented with assays specific for the N-terminus of gastrin-34 in studies of duodenal ulcer disease.

The meaning of a low serum cobalamin level when the classic findings of pernicious anemia are lacking is undergoing reevaluation. We therefore studied the neurologic status of 11 patients who had low cobalamin levels without definite hematologic evidence of deficiency. Neurologic evaluation included pattern-shift visual and median and posterior tibial nerve somatosensory evoked potentials. None of the patients had megaloblastic changes in the blood or bone marrow, although 7 of the 11 had subtle cellular cobalamin disturbances demonstrated by an abnormal deoxyuridine suppression test result. Seven patients had normal Schilling test results and 2 had borderline results; however, 2 of the 5 patients tested further had food-cobalamin malabsorption, while a third had prepernicious anemia. The patients displayed a variety of neurologic problems, including dementia, depression, myelopathy, neuropathy, and seizure disorder; 1 patient was neurologically normal by clinical criteria. Evoked potential abnormalities were demonstrable in 8 of the 9 patients with subtle cobalamin deficiency, and in at least 5 cases the disturbance was central. In contrast, both patients whose low serum cobalamin levels were found on evaluation to be spurious had normal evoked potentials. Evoked potential abnormalities improved in the one patient retested after cobalamin therapy. These findings demonstrate that neurologic deficits occur not only in classic cobalamin deficiency but also in subtle or atypical cobalamin deficiency states in which anemia is absent and Schilling test results are normal. Electrophysiologic evidence of neurologic impairment is often present, even in patients without obvious clinical neurologic abnormalities.

Patients may fail to absorb cobalamin (vitamin B12) bound to food even when they have adequate intrinsic factor to absorb free cobalamin normally. We studied cobalamin transfer from egg yolk cobalamin-binding protein to human saliva and gastric juice as a model of this important first step in cobalamin assimilation. The cobalamin-binding protein of egg yolk eluted with human R binder on Sephadex gel chromatography and bound cobalamin with a comparable affinity, but it did not cross-react with R binder immunologically. Transfer of cobalamin from egg yolk to saliva or gastric juice R binder did not occur at neutral pH. Slight transfer (8%-12% of the 57Co-cobalamin bound to egg yolk) occurred when the saliva was acidified to pH 1.5. This minor transfer by acid was not inhibited by pepstatin A, a pepsin inhibitor. Acidification caused variable transfer to gastric juice R binder (12%-40%) that appeared to be partially due to residual gastric pepsin activity. Adding 1200 U of pepsin per milliliter enhanced cobalamin transfer to saliva or gastric juice R binders (39%-58% transfer). At no time was cobalamin transferred directly to intrinsic factor; R binder-deficient gastric juice failed to accept cobalamin from egg yolk. The transfer of cobalamin from egg yolk to human R binder requires both an acid pH and pepsin activity. While as little as 30 U of pepsin added per milliliter of saliva promoted transfer of cobalamin, the requirement for an acid pH was very strict. Virtually no transfer occurred when pH exceeded 2.0, regardless of the amount of pepsin present. Acid provided an optimal pH for pepsin activity and, to a lesser extent, affected transfer by a mechanism unrelated to pepsin. Our data suggest that compromised pepsin secretion and, probably even more importantly, compromised acid secretion interfere with transfer of food cobalamin to R binder.

The mechanism responsible for the isolated intrinsic factor deficiency in congenital pernicious anemia is unknown. A new second-antibody radioimmunoassay capable of recognizing intrinsic factor independent of the molecule's ability to bind added cobalamin was used to study six patients from three kindreds with this disorder. One of the patients was first diagnosed at age 23 because of unusual circumstances in her case; yet the other patients also demonstrated great age variability at presentation of this presumably congenital disorder, even within the same kindred. The radioimmunoassay failed to detect immunoreactive intrinsic factor in any of the six patients, suggesting that elaboration of an abnormal molecule was not the pathogenetic mechanism. An unexpected incidental finding, contrasting with this observation in congenital pernicious anemia, was immunologic evidence that a previously described patient with familial R binder deficiency clearly elaborated an abnormal R binder molecule.

The use of Co-57-labeled B12 for whole-body measurement of B12 uptake in humans has the advantage over Co-58 of easy commercial availability and lower cumulative radiation to the liver, but the disadvantage of significant attenuation. Methods devised to correct for the attenuation have used inaccurate early 100% counts. A method is described here that uses a liver phantom, containing a dissolved Co-57 B12 capsule, in a water tank. The ratios of upper to lower detector counts is related to total counts; it varies at different depths in the tank, and with the overall tank depth that is selected to accord with measured body habitus. The ratio of detector counts in the final patient count is used to read off the appropriate 100% total count. With this technique there is a clear discrimination between normal patients and those with pernicious anemia.

The effect of protein-rich food, intravenous calcitonin injections, and intragastric instillation of hydrochloric acid on serum gastrin concentrations and gastrin component pattern was studied in hypergastrinemic patients (pernicious anemia) and matched control subjects. Moreover, plasma secretin concentrations were measured during intragastric acidification. The intragastric acidification resulted in rapid fall in serum gastrin concentrations, although not below the upper limit of normal range. The small components, III (gastrin-17-like) and IV (gastrin-13-like), almost disappeared, whereas the concentrations of component I and component II (gastrin-34-like) were less affected. The increase in secretin concentrations after intragastric acidification was smaller in patients with pernicious anemia than in normal subjects, although the difference was not significant. In contrast to the results in normal control subjects, neither food nor calcitonin produced significant variations in serum gastrin concentrations and gastrin component pattern of pernicious anemia patients. The failure of food to stimulate and of calcitonin to inhibit release of gastrin in the majority of pernicious anemia patients might suggest that gastrin secretion in these patients is autonomous. However, considering the recently recognized slow metabolic clearance rate of big gastrins, the effect of intragastric acidification suggests that the mechanism for acid inhibition of the antral gastrin secretion is intact in patients with achlorhydria.

The insulin and gastrin response to oral glucose, intravenous glucose, or a protein-rich meal were measured in 44 nondiabetic patients with pernicious anemia (PA) and in 44 control subjects. 36 of the PA-patients had hypergastrinemia, while serum gastrin concentrations in the remaining eight patients were below normal. Three hypergastrinemic PA-patients were in addition studied during an oral glucose loading with synchronous intravenous infusion of gastrin-17. During both oral and intravenous glucose tests blood glucose concentrations were similar in patients and in controls. After ingestion of protein blood glucose concentrations in PA-patients with hypergastrinemia were above those of the controls (P less than 0.05). Parenteral infusion of gastrin-17 during oral glucose loading also increased blood glucose concentrations above the levels observed after glucose alone. In PA-patients with hypergastrinemia the insulin response was augmented in all tests. In patients with hypogastrinemia serum insulin concentrations were lower than normal in the fasting state and during stimulation with glucose intravenously (P less than 0.01). In hypergastrinemic patients serum gastrin concentrations decreased after oral as well as intravenous glucose administration. The decrease was larger during the oral test. In hypogastrinemia oral glucose induced, as in controls, a small initial rise followed by a slow fall in serum gastrin concentrations. No variations were seen in these patients during the intravenous glucose infusion. Gel filtration of serum from hypergastrinemic patients disclosed a decrease in the concentrations of all four main components of gastrin during the glucose loadings. Taken together with earlier studies on the effect of exogenous gastrin the results suggest that endogenous hypergastrinemia induces hyperglycemia and potentiates insulin secretion. In contrast hypogastrinemia is associated with hypoinsulinism.

Six of eight patients with Addisonian pernicious anemia were found to have diminished corticosteroid-binding globulin (CBG) concentrations, which returned within 2 weeks to normal after the im administration of cobalamin. T4-binding globulin was found to be completely normal before and after cobalamin replacement. Other estrogen-responsive proteins, i.e. ceruloplasmin, alpha 1-trypsin inhibitor, haptoglobin, transferrin, and alpha 2-macroglobulin, also did not follow CBG concentration in a parallel fashion. The immunoglobulins similarly did not follow a course parallel to that of CBG. The CBG concentration in two untreated patients had a normal increase in response to estrogen administration, similar to that described in CBG deficiency from other causes. No clue was found regarding the mechanism by which B12 influences the putative hepatic control of CBG concentration. It is speculated that at least two control points may be necessary for a normal CBG concentration. Patients with a genetic deficiency of CBG may also have to have cobalamin deficiency in order for them to reach a concentration approaching zero.

Normal red cells in man were found to contain predominantly folate pentaglutamates with smaller amounts of tetra- and hexapolyglutamates. There was no change in the type of polyglutamate present in red cells from patients with vitamin B12 deficiency and primary folate deficiency. In contrast to the fall in red cell polyglutamate concentration in vitamin B12 deficiency, there was a marked fall in short-chain folates in early folate deficiency (treated non-anaemic epileptics) and a fall in both short chain and long chain polyglutamates in patients with severe folate deficiency and megaloblastic anaemia. These differences in folate distribution within cells exclude a primary failure to transport methylfolate into cells as the lesion in vitamin B12 deficiency. The failure of folate polyglutamate synthesis in ivtamin B12 deficiency arises either from a failure to provide the proper substrate for polyglutamate synthesis or to a direct requirement for vitamin B12 for polyglutamate synthesis.

Sessile polyps in the antrum were found in 12 of 51 patients with pernicious anaemia. During gastroscopy, mucosal biopsies for gastrin determination were taken from the antrum and fundus and from the polyps. Patients with high gastrin concentration in the antral mucosa showed high serum gastrin concentrations, while most patients with low antral gastrin concentrations also had low serum gastrin values. On an average, the gastrin concentrations in the antrum were approximately 10 times, and those in the fundus approximately 100 times, higher than the corresponding values obtained in a reference group. The gastrin content in the polyps was not different from that in the surrounding antral mucosa. This study suggests that the polyps are not due to a functional hypertrophy of the antral mucosa caused by locally increased production of gastrin.

138 Indian patients with megaloblastic haemopoiesis were studied. All were lifelong vegetarians. The diagnosis was nutritional cobalamin deficiency in 95 and pernicious anaemia in 20; only 4 patients had folate deficiency. A third had intestinal malabsorption, 20 had features of osteomalacia, and 87 were iron deficient. Tuberculosis was diagnosed in 17. Cobalamin deficiency may have contributed to these complications via intestinal malabsorption and impaired bacterial killing of phagocytosed bacilli by cobalamin-deficient macrophages. The frequency of pernicious anaemia was the same in Indian subjects as in Caucasians.

The widely held view that the neurological and haematological complications of vitamin-B12 deficiency have different metabolic mechanisms appears unsound. It is suggested that the metabolic mechanisms involved are similar and that the neurological manifestations are the result of a secondary disturbance in folate metabolism as has already been postulated for the megaloblastosis.

The intrinsic factor activity of powdered hog duodenal mucosa was confirmed by measurements of the absorption of labelled vitamin B 12 (Schilling-test) in 7 cases of Addisonian pernicious anaemia. In view of the fact that, according to earlier studies of the authors based on a bacteriological test, human duodenal juice also exhibits an intrinsic factor activity, it is suggested that the duodenal intrinsic factor may be involved in the pathogenesis of pernicious anaemia. The results of the Schilling-test are critically reviewed in the light of recent published evidence.

Two children from different families with pernicious anemia are described. The defect appears to be the lack of intrinsic factor in the acid gastric juice. The correct diagnosis and proper therapy are essential for insuring a normal growth and development. Studies performed in other members of both families failed to reveal any hematologic disorder. The prolonged and close follow-up of the first case enabled the authors to assist in the birth of a normal offspring.

Gastric aminopyrine clearance was measured in human volunteers and dogs with untreated basal secretion, in human volunteers and dogs treated with secretory inhibitors, in dogs treated with histamine, and in patients with pernicious anaemia. When aminopyrine was given as a bolus to man or dog, aminopyrine clearance and the ratio aminopyrine concentration in gastric juice/aminopyrine concentration in plasma showed an initial peak two to three times over steady state levels. When aminopyrine was given with histamine, the peaks were even higher. No peaks occurred when an aminopyrine bolus was given to patients with pernicious anaemia or to healthy volunteers treated with secretory inhibitors. The height of the peaks paralleled the acid secretory rate. The peaks may best be explained by aminopyrine accumulation in the parietal cells and washing out of aminopyrine by volume flow. The steady state levels might reflect both parietal cell function and gastric mucosal blood flow.