The relationship of serum cobalamin to methylmalonic acid concentrations and clinical variables in cats.

BACKGROUND: Serum cobalamin concentration [CBL] suggests CBL deficiency in cats but serum methylmalonic acid concentration [MMA] more accurately indicates CBL deficiency. OBJECTIVE: To examine the ability of [CBL] to predict CBL deficiency defined by increased [MMA], and relationships of [CBL] and [MMA] with select clinical and clinicopathological variables. ANIMALS: One hundred sixty-three client-owned cats with [CBL] measurements, 114 cats with simultaneous [MMA] measurements; 88 cats with medical information. METHODS: Prospectively collected [CBL] and [MMA] were compared using scatter plots, receiver operating characteristic and correlative analyses with historical [CBL] thresholds and those identified in the study. [CBL] and [MMA] were compared retrospectively to specific clinical and clinicopathological variables. RESULTS: [CBL] correlated negatively with [MMA] (τ = -0.334, P < .0001). [MMA] ≥ 1,343 nmol/L identified CBL deficiency. [CBL] = 209 pg/mL optimized sensitivity (0.51), specificity (0.96), PPV (0.89), and NPV (0.74) for detecting [MMA] ≥ 1,343 nmol/L. Prevalence of CBL deficiency was 42% (48/114) when defined by [MMA] ≥ 1,343 nmol/L versus 23% (27/114) by [CBL] ≤ 209 pg/mL. Unexpectedly, 23 and 45% of 48 cats with [MMA] ≥ 1,343 nmol/L had [CBL] > 900 pg/mL and 290 pg/mL (historical thresholds). [CBL] correlated with mean corpuscular volume (τ = -0.199, P = .013) and [MMA] with hematocrit (τ = -0.28, P = .006). CONCLUSIONS AND CLINICAL IMPORTANCE: Cobalamin deficiency ([MMA] ≥ 1,343 nmol/L) occurred in 42% of cats and is predicted with high specificity by [CBL] ≤ 209 pg/mL. CBL status correlates with microcytosis and anemia. Discordance between [CBL] and [MMA] cautions against relying on any single marker for determining CBL status.

Pilot project and evaluation of delivering diabetes work-based education using video conferencing.

CONTEXT: Diabetes is a chronic long-term disease with an increasing incidence. There is a need to increase access to effective care and to ensure such care is delivered as locally as possible. The geographical spread of NHS Highland Scotland presents additional challenges to ensuring a skilled workforce given education is normally work-based tuition and assessment. The aim of this pilot project was to deliver teleconferenced diabetes training to healthcare and allied healthcare professionals who provide basic level care for, and management of, people with diabetes and to evaluate this training. ISSUE: Work-based diabetes education was designed to be delivered by a diabetes educator through videoconferencing or face to face (F2F) for healthcare professionals in peripheral settings in the Scottish Highlands region over two half-days. The education covered theoretical and practical training in diabetes. The evaluation of the project was through post-course questionnaires and assessment instruments to capture views of the content and delivery mode, as well as student performance. LESSONS LEARNED: Feedback from participants indicated that the educational content was relevant and that the use of videoconferencing (VC) could provide accessibility to training where distance, cost and other issues may make access difficult. Student performance on the assessment instruments did not differ between those who received the training through video conferencing and those who received the training through F2F delivery. Video conferencing can counteract the difficulties of accessing training for clinical peripherally based professionals. Training through VC did not compromise student acquisition of learning outcomes. Feedback indicates that VC can reduce the interactive nature of the learning and teaching experience.

Association between granulomatous colitis in French Bulldogs and invasive Escherichia coli and response to fluoroquinolone antimicrobials.

BACKGROUND: French Bulldogs develop a form of granulomatous colitis (GC) with histopathological resemblance to GC of Boxer dogs (GCB). GCB is associated with mucosally invasive Escherichia coli whose eradication correlates with clinical remission. HYPOTHESIS/OBJECTIVES: To characterize the clinical and histopathological features, presence or absence of invasive colonic bacteria, and response to fluoroquinolones in French Bulldogs with GC. ANIMALS: A total of 6 French Bulldogs with a histological diagnosis of GC. METHODS: Retrospective study of medical records. Bacterial colonization was evaluated using 16S rRNA probes for eubacteria and E. coli. Biopsy specimens from 3 dogs were cultured for bacteria. Clinical response to fluoroquinolone antimicrobials was determined. RESULTS: All dogs were ≤1 year of age with hematochezia that was refractory to empirical therapy. Clinicopathologic and fecal analysis did not reveal abnormalities. Abdominal ultrasound revealed patchy thickening of the colon in 4/5 dogs and regional lymphadenopathy in 5/5. Colonoscopic abnormalities included irregularly thickened and ulcerated mucosa, hyperemia, and overt bleeding in 4/6 cases. Multifocal accumulations of PAS-positive macrophages and intramucosal E. coli were present in colonic biopsies of all 6 dogs. Administration of enrofloxacin (5/6) or marbofloxacin (1/6) at 4.4-10 mg/kg (median 10 mg/kg) PO q24h for 6-10 weeks was associated with clinical improvement within 5-14 days. All dogs remained in remission over a 3-30 month follow-up period. CONCLUSIONS: Granulomatous colitis in young French Bulldogs is associated with the presence of invasive E. coli and closely parallels GCB. Treatment with fluoroquinolone antimicrobials can induce lasting clinical remission.

Remission of histiocytic ulcerative colitis in Boxer dogs correlates with eradication of invasive intramucosal Escherichia coli.

BACKGROUND: Historically, histiocytic ulcerative (HUC) (or granulomatous) colitis of Boxer dogs was considered an idiopathic immune-mediated disease with a poor prognosis. Recent reports of dramatic responses to enrofloxacin and the discovery of invasive Escherichia coli within the colonic mucosa of affected Boxer dogs support an infectious etiology. HYPOTHESIS: Invasive E. coli is associated with colonic inflammation in Boxer dogs with HUC, and eradication of intramucosal E. coli correlates with clinical and histologic remission. ANIMALS: Seven Boxer dogs with HUC. METHODS: Prospective case series. Colonic biopsies were obtained at initial evaluation in 7 dogs, and in 5 dogs after treatment with enrofloxacin. Biopsies were evaluated by standardized histopathology, and fluorescence in situ hybridization (FISH) with probes to eubacteria and E. coli. RESULTS: Intramucosal E. coli was present in colonic biopsies of 7/7 Boxers with HUC. Clinical response was noted in all dogs within 2 weeks of enrofloxacin (7 + or - 3.06 mg/kg q24 h, for 9.5 + or - 3.98 weeks) and was sustained in 6 dogs (median disease-free interval to date of 47 months, range 17-62). FISH was negative for E. coli in 4/5 dogs after enrofloxacin. E. coli resistant to enrofloxacin were present in the FISH-positive dog that relapsed. CONCLUSIONS AND CLINICAL RELEVANCE: The correlation between clinical remission and the eradication of mucosally invasive E. coli during treatment with enrofloxacin supports the causal involvement of E. coli in the development of HUC in susceptible Boxer dogs. A poor response to enrofloxacin treatment might be due to colonization with enrofloxacin-resistant E. coli.

Influence of Enterococcus faecium SF68 probiotic on giardiasis in dogs.

BACKGROUND: Giardiasis is a common, potentially zoonotic disease, and dogs often harbor and shed cysts without showing clinical signs. Treatment with the probiotic Enterococcus faecium SF68 has been shown to stimulate mucosal and systemic immunity in a variety of animal models and in young dogs, and to reduce giardial cyst and antigen shedding in rodents. HYPOTHESIS: Adult dogs with chronic naturally acquired giardiasis will have decreased giardial fecal cyst and antigen shedding and increased innate and adaptive immunity after 6 weeks probiotic treatment with E. faecium SF68. ANIMALS: Twenty adult dogs. METHODS: After a 6-week dietary equilibration period, dogs were randomized to receive E. faecium SF68 or placebo for 6 weeks, and then crossed over to the alternate treatment. We measured cyst shedding, fecal giardial antigen, fecal immunoglobulin A (IgA) concentration, and circulating leukocyte phagocytic activity at multiple timepoints to determine the effect of E. faecium SF68 on giardiasis and immune responses in these dogs. RESULTS: No differences were observed between placebo or E. faecium SF68 treatment for giardial cyst shedding, fecal antigen shedding, fecal IgA concentration, or leukocyte phagocytic activity. CONCLUSIONS: Short-term treatment with E. faecium SF68 of dogs with chronic naturally acquired subclinical giardiasis fails to affect giardial cyst shedding or antigen content and does not alter innate or adaptive immune responses.

Current management of patients taking herbal medicines: a survey of anaesthetic practice in the UK.

BACKGROUND AND OBJECTIVES: Increasing numbers of patients taking herbal medicine products are presenting for anaesthesia and surgery. Anaesthetists need to consider the perioperative implications of herbal medicines and should, therefore, have some knowledge of this subject. METHODS: A postal questionnaire survey was sent to a random 5% of practising members of the Association of Anaesthetists of Great Britain and Ireland residing in the UK, to identify attitudes, practice and knowledge regarding herbal medicines. RESULTS: From 341 questionnaires there were 221 replies, a 65% response rate. Ninety per cent stated that they seldom or never asked patients about herbal medicine usage, yet 65% felt that there could be potentially harmful effects of herbal medicines in the perioperative period. There was a very poor level of knowledge with respect to the current management of 10 well-known herbal medicines. However, 75% agreed that information about perioperative usage of herbal medicines is important, and 77% felt that herbal medicines should be in the undergraduate medical curriculum. Reading was the usual source of herbal medicine product information. Most (82%) felt their knowledge of herbal medicine products and the implications in patient care were inadequate. CONCLUSIONS: This sample of anaesthetists require education on herbal medicines. Suggestions for remedial action are given.

The epidemic of aging in renal replacement therapy: an update on elderly patients and their outcomes.

BACKGROUND: In the past 2 decades, a rapid growth has occurred in the number of patients over 65 years of age accepted for renal replacement therapy (RRT) with an increasing need for dialysis resources as a consequence. The aim of this study is to describe the trends in incidence, treatment and outcome of RRT of these elderly patients included in the new ERA-EDTA Registry database. METHODS: Data from 6 national renal registries have been included for the period 1985 - 1999, comprising data of 18,920 elderly patients starting RRT. We used Cox-proportional hazards regression to predict patient and technique survival. RESULTS: The incidence and prevalence of RRT showed a 4- to 5-fold increase over the period, resulting in 48% of the new patients being older than 65 years in 1999. However, the rates varied considerably between countries. The 2-year patient survival was 51% in dialysis patients. Mortality due to social causes increased with age. Multivariate analysis showed no change with time in patient survival on dialysis, but the risk of death following a first renal allograft between 1995 and 1999 was reduced by 31%, compared with the 1985 - 1989 time period (RR 0.69; 95% CI: 0.54 - 0.90). The relative risk of peritoneal dialysis technique failure was more than doubled in the 1995 - 1999 cohort compared to the 1985 - 1989 cohort (RR 2.38; 95% CI: 1.89 - 3.01), with the highest technique failure rate in the first 2 years of the 1995 - 1999 cohort. CONCLUSIONS: The number of elderly patients receiving RRT is rising rapidly. Patient survival on dialysis has been stable over the last 15 years, whereas transplant outcome has improved. The increased peritoneal dialysis technique failure and the high mortality due to social causes in the elderly age groups require further investigation. The challenge of the years ahead is to provide this life-prolonging therapy to all patients who need it in such a way that it improves quality of life and at a cost that a society can afford.

Renal replacement therapy in Europe: the results of a collaborative effort by the ERA-EDTA registry and six national or regional registries.

BACKGROUND: In June 2000 a new ERA-EDTA Registry Office was opened in Amsterdam. This Registry will only collect core data on renal replacement therapy (RRT) through national and regional registries. This paper reports the technical and epidemiological results of a pilot study combining the data from six registries. METHODS: Data from the national renal registries of Austria, Finland, French-Belgium, The Netherlands, Norway, and Scotland were combined. Patients starting RRT between 1980 and 1999 (n=57371) were included in the analyses. Cox proportional hazards regression was used to predict survival. RESULTS: The use of different coding systems for ESRD treatment by the registries made it difficult to merge the data. Incidence and prevalence of RRT showed a continuous increase with a marked variation in rates between countries. The 2-, 5- and 10-year patient survival was 67, 35 and 11% in dialysis patients and 90, 81 and 64% after a first renal allograft. Multivariate analysis showed a slightly better survival on dialysis in the 1990-1994 (RR 0.94, 95% CI 0.90-0.98) and the 1995-1999 cohort (RR 0.88, 95% CI 0.84-0.92) compared to the 1980-1984 cohort. In contrast, there was a much greater improvement in transplant-patient survival, resulting in a 56% reduction in the risk of death within the 1995-1999 cohort (RR 0.44, 95% CI 0.39-0.50) compared to the 1980-1984 cohort. CONCLUSIONS: This study provides support for the feasibility of a "new style" ERA-EDTA registry and the collection of data is now being extended to other countries. The improvement in patient survival over the last two decades has been much greater in transplant recipients than in dialysis patients.

Deaths within 90 days from starting renal replacement therapy in the ERA-EDTA Registry between 1990 and 1992.

BACKGROUND: Patients who die within 90 days of commencing renal replacement therapy (RRT) may be recorded by some centres and not others, and hence data on mortality and survival may not be comparable. However, it is essential to compare like with like when analysing differences between modalities, centres and registries. It was decided, therefore, to look at the incidence of deaths within 90 days in the ERA-EDTA Registry, and to try to define the characteristics of this group of patients. METHODS: Between 1 January 1990 and 31 December 1992, 78 534 new patients started RRT in 28 countries affiliated to the ERA-EDTA Registry. Their mean age was 54 years and 31% were over 65 years old. Eighty-two per cent of the patients received haemodialysis (HD), 16% peritoneal dialysis (PD) and 2% had preemptive transplantation as first mode of treatment. RESULTS: From January 1990 to March 1993 the overall incidence of deaths was 19% and 4% of all patients died within 90 days from the start of RRT. Among those dying within 90 days 59% were over 65 years compared to 53% over 65 years in those dying beyond this time (P<0.0001). The modality of RRT did not influence the distribution of deaths before and after 90 days. Vascular causes and malignancy were more common in those dying after 90 days, while there were more cardiac and social causes among the early deaths. Mortality from social causes was twice as common in the elderly, who had a significantly higher chance of dying from social causes within 90 days compared to those aged under 65 years. The overall incidence of deaths within 90 days was 3.9% but there was a wide variation between countries, from 1.8% to 11.4%. Finally, patient survival at 2 years was markedly influenced in different age groups when deaths within 90 days were taken into account. CONCLUSIONS: The incidence of deaths within 90 days from the start of RRT was 3.9%, with a marked variation between countries ranging from 1.8% to 11.4%, which probably reflects mainly differences in reporting these deaths, although variable selection criteria for RRT may contribute. Deaths within 90 days were significantly more frequent in elderly patients with more early deaths resulting from cardiac and social causes, while vascular causes of death and malignancy were more common in those dying after 90 days. Patient survival analyses should take into account deaths within 90 days from the start of RRT, particularly when comparing results between modalities, countries and registries.

Improved survival in renal replacement therapy in Europe between 1975 and 1992. An ERA-EDTA Registry study.

BACKGROUND: The prevalence of Renal Replacement Therapy (RRT) is rising steadily, worldwide and in Europe. One reason for this is an increasing number of patients starting RRT, but improving survival on RRT may also be contributing. MATERIAL AND METHODS: In an ERA-EDTA Registry study we have examined survival of patients with Standard Primary Renal Disease, or Diabetes, aged 20 to 75 years, who started RRT with haemodialysis (HD) or peritoneal dialysis (PD) between 1975 and 1992. Altogether close to a quarter of a million patients were included in the analysis which included conventional survival analysis of comparable subgroups of the whole cohort as well as Cox regression. RESULTS: After accounting for age, mode of initial treatment, and diagnosis, an improvement in survival of RRT patients was evident. From Cox regression it was calculated the risk for death decreased by about 5% annually during the time period 1975 1992. Patients who started RRT using PD experienced a higher mortality than those starting with HD. According to Cox regression the relative risk ratio for death was 1.25 for the whole period. The difference in survival between patients starting with PD or HD diminished during the observation period (1975-1992). DISCUSSION: The survival prospects of a patient presenting with end stage renal disease were considerably better in the early 1990s compared to the mid 1970s. This is reassuring despite the fact that mortality on RRT remains high. The higher mortality of RRT patients who started with PD is probably an 'historical' observation as the techniques of this treatment modality have improved considerably since the 1980s which was the time period from which came most of the data for the analysis.

Origin, distribution, and morphology of galaninergic fibers in the rodent trigeminal system.

The neuropeptide galanin (Gal) is found throughout the central nervous system. Of particular interest is the fact that Gal is present within the majority of noradrenergic locus coeruleus (LC) neurons. However, very few, if any, Gal-immunoreactive fibers have been identified in many of the major efferent targets of LC, including sensory neocortex and dorsal thalamus. The goal of the present study was to examine the Gal fiber innervation of the rodent trigeminal somatosensory system and its connection to the LC. Our results show that at least two different morphological profiles of Gal-immunoreactive fibers are present within relay nuclei along the ascending trigeminal pathway. Numerous small caliber Gal-immunoreactive fibers with bouton-like swellings were noted within the barrel cortex, the ventroposterior medial (VPM) nucleus, the posterior medial (POm) nucleus, the zona incerta (ZI), the reticular nucleus (nRT) of the thalamus, and the principal (PrV) and spinal (SpV) nuclei of the trigeminal complex. Immunoreactive fibers were prevalent in, but not restricted to, layer I of the barrel cortex. Within the somatosensory thalamus, the density of Gal-immunoreactive fibers was higher in POm than in VPM. Laminae I and II of SpV and the nRT and ZI also contained dense, large-diameter Gal-immunoreactive fibers. These large-diameter Gal-immunoreactive fibers did not co-contain dopamine beta-hydroxylase (DBH). In contrast, virtually every small-caliber Gal-immunoreactive fiber colocalized with DBH. To determine whether Gal-immunoreactive fibers originated from LC, we combined immunohistochemical procedures with fluorescent tracing techniques. After retrograde tracer injections into several trigeminal relay nuclei, we observed that approximately 50% of the labeled LC neuronal population was immunoreactive for Gal. Our results suggest an extensive Gal-immunoreactive fiber innervation of the rodent trigeminal system, much of which may originate from LC neurons in the brainstem.

Identification and initial characterization of calcyclin and phospholipase A2 in equine conceptuses.

For development to proceed normally, the appropriate genes must be expressed in the correct tissues and in the correct time frame. Knowledge of gene expression during development provides information about the changes taking place within the conceptus as well as possible reasons for pregnancy failure. However, little is known about gene expression during development in the equine conceptus. In this study, we examined differences in gene expression between day 12 and day 15 equine conceptuses by suppression subtractive hybridization. This technique was used to isolate transcripts that are more abundantly expressed in day 15 conceptuses compared to day 12 conceptuses. Between day 12 and 15 of pregnancy in horses, maternal recognition of pregnancy occurs, gastrulation is taking place, and mesoderm is beginning to form. Fifty cDNA clones were isolated, sequenced, and compared to known sequences in the GenBank database. Two cDNA clones identified that were of primary interest were calcyclin and phospholipase A2. Calcyclin is a calcium-binding protein of the S-100 protein family that has been found in mouse decidua and trophoblast. Calcyclin was found to be expressed in both day 12 and 15 equine conceptuses, with approximately a 30-fold increase in transcript abundance between days 12 and 15. Phospholipase A2 is an enzyme that cleaves phospholipids to release fatty acids and is involved in arachidonic acid release needed for prostaglandin, thromboxane, and leukotriene synthesis. Multiple forms of PLA2, that appear to be differentially regulated in day 12 and 15 conceptuses, were detected by northern blotting.

Lateralization and functional organization of the locus coeruleus projection to the trigeminal somatosensory pathway in rat.

The primary goals of this study were to (1) examine the distribution of locus coeruleus (LC) neurons, which project to cortical and subcortical sites along the trigeminal somatosensory pathway in rats, and (2) determine the extent to which different regions within this ascending sensory system receive collateral projections from the same LC neuron. Long-Evans hooded rats received unilateral pressure injections of different combinations of retrograde fluorescent tracers into whisker-related regions of primary (SI) and secondary (SII) somatosensory cortices, the ventrobasal (VB) and posterior group (POm) nuclei of the thalamus, and the principalis nucleus of the trigeminal complex (PrV). Coronal sections (40-100 microm) through the LC were examined by fluorescence microscopy, and the distribution of retrogradely labeled cells was recorded. The major finding was that whisker-related regions of the cortex receive efferent projections from neurons concentrated in the caudal portion of the ipsilateral LC, whereas subcortical trigeminal somatosensory structures receive bilateral input from both LC nuclei. Despite the bilateral nature of the LC projection to subcortical sites, the majority of LC efferents to VB and POm thalamus originate in the ipsilateral LC nucleus, whereas projections to PrV originate primarily from the contralateral LC. An additional finding was that a relatively large proportion of LC cells, which project to a single somatosensory structure, also send axon collaterals to other relay sites along the same ascending somatosensory pathway. Taken together, these results suggest that the LC-noradrenergic system maintains a more selective relationship with functionally related efferent targets than has been previously appreciated.

The biosynthesis of omega 3 fatty acids from 18:2 omega 6 in Artemia spp.

To examine the biosynthesis of omega 3 fatty acids from 18:2 omega 6, reference Artemia (RAC III, Artemia Reference Center, Gent, Belgium) were fed rice bran supplemented with [1(-14)C]18:2 omega 6 for 2 days following 48 hours starvation since cyst hydration and 1, 2, or 3 days following 72 hours of starvation, under axenic conditions. Artemia fatty acids were analyzed by gas chromatography, AgNO3 thin layer chromatography and high performance liquid chromatography and fatty acid fractions were collected for radioisotope counts. No significant differences were observed in the omega 3 fatty acid content of Artemia cultured under axenic and xenic conditions. Radioisotope studies showed that radioactivity from [1(-14)C]18:2 omega 6 was incorporated into other fatty acids, including 18:3 omega 3, 18:4 omega 3 and 20:5 omega 3. The conversion rate was less than 5% for the two day feeding period. In the three day feeding experiment, the amount of radioactivity recovered in both 18:3 omega 3 and 20:5 omega 3 increased by 2.2- and 1.8-fold, respectively, over the three day feeding period. These results demonstrated that Artemia synthesized these omega 3 polyunsaturated fatty acids from 18:2 omega 6.

Pancreatic function following partial pancreatectomy and anastomosis of the pancreatic duct to the stomach or duodenum in dogs.

The effects of pancreatic duct anastomosis to stomach (stomach group) or duodenum (duodenal group) on pancreatic function were examined in dogs following two thirds pancreatectomy. Normal fasting blood glucose concentrations were maintained in both groups despite significant reductions in glucose tolerance in the stomach group, and reductions in fasting insulin and insulin peak response in both groups. Pancreatic exocrine function was significantly decreased in both groups, though plasma p-aminobenzoic acid (PABA) concentrations were generally higher in the duodenal group. A correlation was found between plasma trypsin-like immunoreactivity (TLI) and pancreatic weight. These results indicate that anastomosis of the pancreas to bowel can be undertaken with minimal postoperative complications and that the site of the anastomosis influences pancreatic function. They suggest that preservation of more than one third of the pancreas is required for optimal function. The complementary information provided by the PABA and TLI tests suggests their dual application will be clinically useful for the detection and characterisation of naturally occurring pancreatic diseases.

A study of patients with alcoholic liver disease by 31P nuclear magnetic resonance spectroscopy.

1. Patients with a history of alcohol abuse were studied by 31P n.m.r. spectroscopy of the liver in vivo, and the results were related to the pattern of disease assessed by standard biochemical and histological techniques. 2. The ratios of metabolites measured from the 31P n.m.r. spectra were abnormal in patients with alcoholic hepatitis but not in those with fatty change or cirrhosis in the absence of hepatitis. In particular, the levels of phosphomonoesters were raised, with respect either to Pi, or to adenosine 5'-triphosphate. The level of phosphomonoesters showed a significant positive correlation with the severity of alcoholic hepatitis, assessed by histology. 3. The ratio of Pi to adenosine 5'-triphosphate was used as a measure of the energy status of the hepatocytes, and was unchanged between patients and controls.

The effect of high ascorbic acid supplementation on body iron stores.

The level of assimilation of dietary iron is believed to have an important influence on iron status. To examine the effect of enhancing the availability of dietary iron on iron balance, 17 adult volunteer subjects were given 2 g of ascorbic acid daily with meals for 16 weeks. Serum ferritin levels before and after the study averaged 46 and 43 micrograms/L, respectively, indicating a negligible effect on iron stores. When vitamin C supplementation was continued for an additional 20 months in five iron-replete and four iron-deficient subjects, serum ferritin determinations again failed to indicate any significant effect of the vitamin C on iron reserves. These findings were not explained by intestinal adaptation to the enhancing effect of the vitamin, because radioisotopic measurements of nonheme iron absorption showed no reduction in the enhancing effect of 1 g of ascorbic acid after four months of megadoses of vitamin C. It is concluded that altering the availability of nonheme dietary iron has little effect on iron status when the diet contains substantial amounts of meat.

The inhibitory effect of bran on iron absorption in man.

The effects of whole wheat bran and its components on the absorption of nonheme dietary iron were measured using a double isotope technique in human volunteers. When 12 g bran was added to a light meal, absorption decreased by 51 to 74%; this inhibitory effect of bran was shown for meals of both high and low iron availability. Inhibition was not explained by monoferric phytate, the major form of iron in bran, because labeled iron from monoferric phytate was absorbed at least as well as the common pool of nonheme dietary iron. Furthermore, removal of phytate from bran by endogenous phytase did not in itself alter the inhibitory effect of the bran on iron absorption. Studies in which dephytinized bran was separated into a soluble, phosphate-rich fraction and an insoluble, high-fiber fraction indicated that the soluble fraction was more inhibitory than the insoluble fraction.