Deprivation Of Vitamin Research Articles

Spinal Deformity in Vitamin D-Deprived Pigs: Why and What Next?: Commentary on an article by Matthew A. Halanski, MD, et al.: "Maternal Diets Deficient in Vitamin D Increase the Risk of Kyphosis in Offspring. A Novel Kyphotic Porcine Model".

Commentary In most children, the growing spine has minimal curvature in the coronal plane and sagittal curvatures in the normal range, in apparent defiance of gravity and prevailing muscular forces. Very little is known about how growth is regulated to achieve this, and conversely how growth is poorly regulated in those in whom progressive curvatures develop. In this paper, Halanski and colleagues focus on prenatal and postnatal diet and report a high prevalence of hyperkyphosis in piglets when both sows and the piglets are deprived of vitamin D. However, providing vitamin D in the post-weaning nursery diet was associated with a lower eventual prevalence. The various permutations of maternal vitamin-D and mineral diet during gestation and lactation, together with manipulation of the post-weaning nursery diet, indicate that maternal deprivation of vitamin D during gestation and lactation has a greater effect than the piglet’s post-weaning diet does. Pediatricians and orthopaedic surgeons should take note for 2 reasons identified by Halanski and colleagues: first, these findings may have implications for the health of human children (as both spinal deformity1,2 and maternal vitamin-D deficiency3 are quite common); and second, this paper proposes a novel mammalian model for subsequent use in evaluating procedures for treating spinal deformity. With regard to mechanisms, in these piglets the deformities are apparently idiopathic, in the sense of there being no structural vertebral defect, so this is apparently an abnormal fetal and postnatal development of an essentially normal skeleton. Conversely, infantile spinal deformities in humans are commonly associated with vertebral malformation4, while idiopathic deformities become apparent toward the end of skeletal growth2. Since discs are very narrow in the porcine thoracic spine, it is likely that these deformities result from vertebral rather than discal wedging; they result from altered bone growth. There is a complex interaction between vitamin D and growth hormones systemically5, but the effect on spinal growth here must be more local; apparently, the growth suppression affected only the thoracic vertebrae and only anteriorly. Here, the authors report that the influence of diet on vertebral bone density was subtle (8%) by mineral (ash) content, but not detectable by computed tomography (CT) radiodensity. A companion paper cites other affected traits, including an 11% reduction in body mass growth, a 25% reduction in whole-body bone mineral content, reduced femoral mechanical strength, and abnormalities in the growth plates of femora and vertebrae in piglets; it also gives measurements from maternal serum and milk of vitamin D, parathyroid hormone, and related metabolites6. Overall, the empirical findings provide few clues as to possible underlying mechanisms, so it is unclear how they further our understanding the causes of spinal deformity in humans and its management. Endocrinologists, dieticians, and epidemiologists would probably have to work together to determine whether anything similar is occurring in human populations. Could this model be used to study the treatment of pediatric deformities? Certainly, there is a great need for in vivo platforms for testing treatments. This mammalian model could be quite valuable, as the animals were apparently in good health with considerable spontaneous spinal deformity and substantial residual growth (with growth plates closing between 1 and 4 years of age). However, as a first step, the natural history should be determined more thoroughly. Here, documenting the post-weaning evolution of the kyphosis was hampered by methodological difficulties. Also, the postnatal nutritional regimen was complex (with weaning at 3 to 4 weeks, the nursery diet until 7 weeks, and then the standard diet from 7 to 17 weeks). It will be important to know whether the hyperkyphosis resolves or is retained in untreated animals before treatments can be studied. This is 1 paper in a series reporting on this animal model, but several questions about the relevance to human spinal deformity and its management remain unanswered. However, they are important questions, and pursuing the answers could be productive, valuable steps forward in understanding the clinical problem of the development of spinal deformity.

Retinol, α-Tocopherol and Vitamin D3 in White MuscleDisease

Vitamins are essential for the health of all living organisms. Vitamins E, A, D and K are known as fat-soluble vitamins, and deprivation of vitamin E causes various disorders, especially in the reproduction and cardiovascular systems and in muscle functions. Vitamin A, on the other hand, has roles in various biological functions – like eyesight – and the growth, reproduction and differentiation of epithelial cells. Vitamin A deficiency leads to the keratinization of the epithelium, and disorders related to the metaplasies of the genital and genitourinary systems. Conversely, vitamin D is defined as a pro-hormone and is responsible for Cahomeostasis, and thus indirectly affects the bone metabolism, bone structure, and cellular and neural functions of Ca. White muscle disease (WMD) can occur in newborn lambs, but is more commonly seen in lambs of up to 3 months of age. In this study, 30 lambs of 3 to 50-days-old from different flocks diagnosed with White Muscle Disease (WMD) were selected as research material, while the control group consisted of 8 healthy lambs. With the aim of clarifying the cause of WMD, serum fat-soluble vitamins, retinol, α-tocopherol and vitamin D3 levels were determined in 16 lambs. Gluteal and heart musclet issue samples also were taken from 30 lambs with WMD. The vitamin levels of the samples were analysed by HPLC. The levels of serum α-tocopherol, retinols, and vitamin D3 were foundto be low in the diseased animals, but only retinol (p<0.001) and α-tocopherol (p<0.0011) level differences were statistically relevant. Macroscopically, Zenker’s necrosis was determined in the heart muscles of 17 lambs, and in the gluteal and chest muscles of 6 lambs. 7 lambs displayed necrosis in both their heart and in gluteal muscles. The samples were analyzed microscopically to reach similar findings: swollen homogeneous pink muscles, pycnotic nuclei, and hyperaemic and haemorrhagic blood vessels in gluteal, chest and heart muscles. Hyaline degeneration and Zenker's necrosis, dystrophic regions in necrotic areas, cc was detected as a severe disease in lambs at an early stage of life with advanced degeneration in different muscle tissues. Deficiency of fat-soluble vitamins was also detected in the sick animals. Control group lambs had higher levels of α tocopherol and retinol (p<0.001) compared to the sick lambs. .

Retinol, α-tocopherol and vitamin D3 in White MuscleDisease

Vitamins are essential for the health of all living organisms. Vitamins E, A, D and K are known as fat-soluble vitamins, and deprivation of vitamin E causes various disorders, especially in the reproduction and cardiovascular systems and in muscle functions. Vitamin A, on the other hand, has roles in various biological functions – like eyesight – and the growth, reproduction and differentiation of epithelial cells. Vitamin A deficiency leads to the keratinization of the epithelium, and disorders related to the metaplasies of the genital and genitourinary systems. Conversely, vitamin D is defined as a pro-hormone and is responsible for Cahomeostasis, and thus indirectly affects the bone metabolism, bone structure, and cellular and neural functions of Ca. White muscle disease (WMD) can occur in newborn lambs, but is more commonly seen in lambs of up to 3 months of age. In this study, 30 lambs of 3 to 50-days-old from different flocks diagnosed with White Muscle Disease (WMD) were selected as research material, while the control group consisted of 8 healthy lambs. With the aim of clarifying the cause of WMD, serum fat-soluble vitamins, retinol, α-tocopherol and vitamin D3 levels were determined in 16 lambs. Gluteal and heart musclet issue samples also were taken from 30 lambs with WMD. The vitamin levels of the samples were analysed by HPLC. The levels of serum α-tocopherol, retinols, and vitamin D3 were foundto be low in the diseased animals, but only retinol (p<0.001) and α-tocopherol (p<0.0011) level differences were statistically relevant. Macroscopically, Zenker’s necrosis was determined in the heart muscles of 17 lambs, and in the gluteal and chest muscles of 6 lambs. 7 lambs displayed necrosis in both their heart and in gluteal muscles. The samples were analyzed microscopically to reach similar findings: swollen homogeneous pink muscles, pycnotic nuclei, and hyperaemic and haemorrhagic blood vessels in gluteal, chest and heart muscles. Hyaline degeneration and Zenker's necrosis, dystrophic regions in necrotic areas, cc was detected as a severe disease in lambs at an early stage of life with advanced degeneration in different muscle tissues. Deficiency of fat-soluble vitamins was also detected in the sick animals. Control group lambs had higher levels of α tocopherol and retinol (p<0.001) compared to the sick lambs. .

Vitamin C Depletion in Prenatal Guinea Pigs as a Model of Lissencephaly Type II.

Humans and guinea pigs are unable to produce vitamin C, with deficiency resulting in a well-known disorder of collagen synthesis. Pial basement membrane structure preservation is essential in the proper migration of neurons. In our study, intrauterine deprivation of vitamin C in guinea pig fetuses led to a collagen synthesis disorder, weakness, and finally a breach of pial basement membrane. We found excessive migration of the external germinal layer cells into the subarachnoid space of the cerebellum through defects in the pial basement membrane. The changes ranged from focal rupture of pial basement membranes to their complete disintegration. The loss of proper folia formation resulted in macroscopically visible flattening of the cerebellar surface. Different grades of dysplastic changes in the folia of the cerebellar cortex were observed in 2 experimental groups assigned different limits to mark the time of commencement and duration of vitamin C deprivation. The most severe form of dysplastic changes was characterized by marked irregularity of the cerebellar cortex similar to that in lissencephaly type II. Thus, prenatal vitamin C deficiency represents a novel animal model to study the effects of collagen synthesis on development of breaches in the pial basement membrane, disordered migration of neurons, dysplasia of cerebellar cortex, and the pathogenesis of lissencephaly.

English

The effects of different protein levels associated with vitamin deprivation have also been evaluated on tissues of high and low cell renewal. This study aimed to investigate the effects of available diet with 4% protein content associated with the maintenance of vitamin levels on the morphology of NADPH dp+ myenteric neurons of rats’ descending colon. Sixteen animals were randomly distributed into two groups, one that was fed with chow with 26% protein content (CG), and the other was fed with a 4% protein content diet (EG) during 12 weeks. Total preparations were utilized to make the myenteric plexus neurons of the descending colon evident when submitted to NADPH-diaphorase. The cellular bodies and nucleus of 300 neurons from each animal was measured. The diet with 4% protein and maintenance of vitamin and mineral content, similar to the ones found in normal protein diets, causes metabolic alterations that result in body weight loss. The myenteric neurons of the descending colon have non-significant reduction in the nucleus size whereas the cytoplasm presents a significant increase of the area. The importance of vitamin maintenance and the increase of the neuronal area is discussed as a possible compensating mechanism to keep the neurotransmitter synthesis

WHEN VITAMIN DEFICIENCY MIMICS THROMBOTIC THROMBOCYTOPENIC PURPURA

To the Editor: Thrombotic thrombocytopenic purpura (TTP) is appropriately suspected in patients who have had acute peripheral thrombocytopenia and microangiopathic hemolysis associated with fluctuating neurological symptoms, renal failure, and fever. There is no criterion standard for diagnosis; a deficiency of von Willebrand factor–cleaving protease activity is found in up to 70% of patients with TTP, but its specificity for TTP diagnosis remains unknown.1 Once the diagnosis of TTP is seriously considered, urgent plasma exchange or infusion is indicated.1,2 We present a patient who was admitted into our intensive care unit for plasma exchange due to clinical and biological abnormalities suggesting a TTP. A 70-year-old man with no medical history of falls was admitted to the emergency department because of a fall in the street. On admission, the patient was confused, with no focal neurological deficit. All deep-tendon reflexes were absent, with flexor plantar responses. Blood pressure was about 100/50 mmHg, pulse was 70 beats per minute with a regular rhythm, and body temperature was 38°C. Significant laboratory findings included anemia, with a hemoglobin level of 4.5 g/dL and a mean corpuscular volume of 100 μm3, without leucopenia or thrombocytopenia. In addition, high total bilirubinemia (8.4 mg/dL), conjugated bilirubinemia (1.5 mg/dL), and serum lactic dehydrogenase (15,300 UI/L) were found. Serum iron and serum ferritin levels were normal. After a transfusion of three red blood cell units, the patient was transferred to a medical ward. Over the following 4 days, the patient remained confused, with fluctuating episodes of disorientation and agitation. Cerebral computed tomographic scan and electroencephalogram were found to be normal. No obvious source of infection was found. A few cutaneous purpuric and ecchymotic lesions progressively appeared, confined to the pressure points and the venous puncture sites. Over the 4 days, biological data showed a decrease in platelet count from 171 × 109/L to 41 × 109/L, the persistence of hemolytic anemia with a hemoglobin level of 7.5 g/dL associated with marked reduction of serum haptoglobin (below 0.008 g/L), and a lactic dehydrogenase of about 30,000 UI/L, although schistocytosis was not found. Moreover, acute renal insufficiency appeared with an increase of serum creatinine from 1.3 to 2.3 mg/dL, associated with microscopic hematuria. Because the association between thrombocytopenic purpura, massive hemolytic anemia, renal insufficiency, and fluctuating neurological disorders could suggest TTP, the patient was transferred to the intensive care unit to perform plasma exchange, but the macrocytic aspect of the red blood cells, the low reticulocyte count, and the absence of schizocytes on the peripheral blood film led to a bone marrow examination, which showed megaloblastic changes. So, it was hypothesized that a vitamin deficiency could have induced the symptoms and signs of this toothless old patient with a body mass index of 16. A low level of plasma ascorbic acid (2 mg/L; normal values: 7–12 mg/L) confirmed the diagnosis of scurvy and explained at least the ecchymotic and purpuric lesions. The serum vitamin B12 concentration of 140 ng/L (normal values: 211–911 ng/L) but a normal serum folic acid concentration (6.8 μg/l; normal values upper 5.3 μg/L) explained the megaloblastic anemia and hemolysis, thrombocytopenia, and neurological symptoms. Hyperhomocysteinemia (0.96 μg/L; normal values <0.11 μg/L) was found, as one would expect. Finally, his daughter revealed several days later that her father had been a vegan for at least 30 years and that his wife had committed suicide 6 months previously, which could account for depressive syndrome and accentuation of his diet. Balanced meals and an oral vitamin supplement quickly corrected renal insufficiency, thrombocytopenia, hemolysis with a reticulocytic crisis, and the clinical symptoms.3 An ophthalmic examination showed a cataract in each eye due to vitamin B12 deficiency. Gastroscopy was normal, and abdominal ultrasonographic study and different serum tumor markers did not provide evidence of malignancy. Improvement in his mental state was significant, with a Mini-Mental State Examination score of 20 of 30 after a few days. Vitamin B12 and folate deficiencies mimicking acute leukemia or the syndrome of hemolysis, elevated liver enzymes, and low platelets have been reported.4,5 The interesting part of this observation was that, when associated with ascorbic acid deficit leading to ecchymotic and purpuric lesions, these vitamin deficits may mimic TTP. Clinicians must be aware of unusual clinical presentations of TTP in patients with multiple vitamin deprivation. Noninstitutionalized elderly subjects, socially isolated patients, and food faddists are probably a high-risk population for such manifestations. Financial Disclosure: The authors declare that they received no financial support for this manuscript. Author Contributions: Bernard Tardy and Sandrine Bayle: acquisition of subjects and data and preparation of manuscript. Yves Page and Eric Diconne: acquisition of data. Fabrice Zeni and Jean C. Bertrand: preparation of manuscript. Sponsors' Role: None.

Role of retinoid signaling in the regulation of spermatogenesis

While the need for vitamin A for the normal progression of male germ cell differentiation has been known for many years, the molecular mechanisms underlying this requirement are poorly understood. This review will explore the aspects of the effects on spermatogenesis of dietary deprivation of vitamin A, in particular as to how they compare to the male sterility that results from the genetic ablation of function of the retinoid receptor RARα. The effects of other genes involved with retinoid synthesis, transport, and degradation are also considered. The possible cellular mechanisms that may be affected by the lack of retinoid signaling are discussed, in particular, cell cycle regulation and cell-cell interaction, both of which are critical for normal spermatogenesis.

Vitamin E deficiency does not induce compensatory antioxidant increases in central nervous system tissue of apolipoprotein E-deficient mice.

Compensatory upregulation in endogenous antioxidants has been shown to accompany certain genetic and dietary deficiencies that promote oxidative stress, including that related to Alzheimer's disease. We compared antioxidant levels in brain tissue of normal and transgenic mice lacking apolipoprotein E following dietary deprivation of vitamin E or folate. As described previously, ApoE-deficient mice displayed increased levels of the endogenous antioxidant glutathione as compared to normal mice, and increased these levels further following folate deprivation. By contrast, glutathione was depleted following vitamin E deprivation in brain tissue of normal and ApoE-deficient mice. TBAR analyses confirmed increased oxidative damage following vitamin E deprivation. However, combined deprivation of folate and vitamin E resulted in levels of glutathione intermediate between those observed following deprivation of either agent, indicating that the lack of compensatory increase in glutathione following vitamin E deprivation was not due to overt neurotoxicity. Similar results were observed for total antioxidant levels in brain tissue. The differential response to vitamin E and folate deprivation is consistent with the possibility that specific differences in oxidative damage may result from deficiencies in either of these agents. The lack of a compensatory response to vitamin E deprivation highlights the importance of dietary vitamin E in prevention of chronic neurodegeneration.

Vitamin E regulates mitochondrial hydrogen peroxide generation

The mitochondrial electron transport system consumes more than 85% of all oxygen used by the cells, and up to 5% of the oxygen consumed by mitochondria is converted to superoxide, hydrogen peroxide, and other reactive oxygen species (ROS) under normal physiologic conditions. Disruption of mitochondrial ultrastructure is one of the earliest pathologic events during vitamin E depletion. The present studies were undertaken to test whether a direct link exists between vitamin E and the production of hydrogen peroxide in the mitochondria. In the first experiment, mice were fed a vitamin E–deficient or–sufficient diet for 15 weeks, after which the mitochondria from liver and skeletal muscle were isolated to determine the rates of hydrogen peroxide production. Deprivation of vitamin E resulted in an approximately 5-fold increase of mitochondrial hydrogen peroxide production in skeletal muscle and a 1-fold increase in liver when compared with the vitamin E–supplemented group. To determine whether vitamin E can dose-dependently influence the production of hydrogen peroxide, four groups of male and female rats were fed diets containing 0, 20, 200, or 2000 IU/kg vitamin E for 90 d. Results showed that dietary vitamin E dose-dependently attenuated hydrogen peroxide production in mitochondria isolated from liver and skeletal muscle of male and female rats. Female rats, however, were more profoundly affected by dietary vitamin E than male rats in the suppression of mitochondrial hydrogen peroxide production in both organs studied. These results showed that vitamin E can directly regulate hydrogen peroxide production in mitochondria and suggest that the overproduction of mitochondrial ROS is the first event leading to the tissue damage observed in vitamin E–deficiency syndromes. Data further suggested that by regulating mitochondrial production of ROS, vitamin E modulates the expression and activation of signal transduction pathways and other redox-sensitive biologic modifiers, and thereby delays or prevents degenerative tissue changes.

Night blindness in Sorsby's fundus dystrophy reversed by vitamin A

Sorsby's fundus dystrophy (SFD) is an autosomal dominant retinal degeneration caused by mutations in the tissue inhibitor of metalloproteinases-3 (TIMP3) gene. Mechanisms of the visual loss in SFD, however, remain unknown. In a SFD family with a novel TIMP3 point mutation, we tested a hypothesis that their night blindness is due to a chronic deprivation of vitamin A at the level of the photoreceptors caused by a thickened membrane barrier between the photoreceptor layer and its blood supply. Vitamin A at 50,000 IU/d was administered orally. Within a week, the night blindness disappeared in patients at early stages of disease. Nutritional night blindness is thus part of the pathophysiology of this genetic disease and vitamin A supplementation can lead to dramatic restoration of photoreceptor function.

13,14-Dihydroxy-retinol, a New Bioactive Retinol Metabolite

Deprivation of vitamin A (retinol) leads to reduced potential of B cell proliferation and nearly complete block of T cell activation in vitro. Retinol, which is thought to function as a pro-hormone, is enzymatically converted into intracellular messenger molecules. Thus, 14-hydroxy-retro-retinol (14-HRR) is an intracellular messenger molecule linked to activation and growth regulation of lymphocytes; whereas, anhydroretinol, another natural retro-retinoid, is an antagonist of 14-HRR effects. In this article, we describe the isolation, structure determination, synthesis, and biological properties of a new intracellular retinol derivative, 13,14-dihydroxy-retinol (DHR), which also supports the viability of retinol-deprived lymphocytes. DHR is found in numerous cell lines representing a large cross-section of tissues and animals from insects to mammals. In T lymphocytes the production of DHR and 14-HRR is up-regulated by phorbol ester. DHR is converted to 14-HRR by mild acid treatment, but not by cells; therefore DHR is not a biosynthetic intermediate in the conversion of retinol to 14-HRR. DHR is a distinct end point of retinol metabolism. Although it is linked to cell proliferation, its biological role remains to be determined.

Activity of rhodopsin in vitamin A-deprived rats: light-dependent binding of G-protein

Levels of rhodopsin in the photoreceptors of Long-Evans rats were reduced by approximately 55% through dietary deprivation of vitamin A. The interaction of visual pigment with G-protein was examined in receptor outer segment (ROS) membranes obtained from these animals. A binding assay was used to quantitate affinity of the visual pigment in unbleached and bleached ROS membranes for the alpha and beta subunits of exogenous G-protein. Extents of binding were similar to those observed for ROS membranes of rats raised on a normal (vitamin A-supplemented) diet. The results are consistent with a normal capacity for G-activation by photoactivated rhodopsin (R*) in vitamin A-deprived animals. They further indicate that "free opsin" arising in vitamin A deficiency, unlike R*, has relatively low affinity for G-protein.

Vitamin D status regulates 25-hydroxyvitamin D3-1 alpha-hydroxylase and its responsiveness to parathyroid hormone in the chick.

We asked this question: Under normal or near-normal metabolic conditions, does the prevailing normal or near-normal vitamin D status dampen the activity of 25-hydroxyvitamin-D3-1 alpha-hydroxylase (1 alpha-hydroxylase) such that it determines not only its "basal" activity but also its responsiveness to stimulation by increased circulating concentrations of parathyroid hormone (PTH)? To answer this question, we measured the activity of 1 alpha-hydroxylase in chicks, with and without administration of PTH, immediately before and during deprivation of vitamin D. Before deprivation of vitamin D, 1 alpha-hydroxylase activity increased only slightly with administration of PTH. With deprivation of vitamin D for 5 and 10 d, while the plasma concentrations of calcium and phosphorus persisted normal and unchanged, 1 alpha-hydroxylase activity not only increased progressively but also became sharply and increasingly responsive to stimulation by administration of PTH. But after 15 d of vitamin D deprivation, and the supervention of hypocalcemia, 1 alpha-hydroxylase activity was not further increased by the administration of PTH. With deprivation of vitamin D, the progressive increase in 1 alpha-hydroxylase correlated inversely with circulating levels of 1,25-dihydroxyvitamin D (1,25-[OH]2D), and the decreasing calcemic response to PTH correlated inversely with the responsiveness of 1 alpha-hydroxylase to PTH (in chicks deprived of vitamin D for 1-10 d). These results demonstrate that: under normal metabolic conditions, the normal vitamin D status regulates the activity of 1 alpha-hydroxylase so as to dampen both its "basal" activity and its responsiveness to stimulation by PTH; and vitamin D deprivation insufficient to cause hypocalcemia enhances both the "basal" activity of 1 alpha-hydroxylase and its responsiveness to stimulation by PTH. The results suggest that the normal dampening of 1 alpha-hydroxylase and both of the demonstrated enhancements of its activity are mediated by normal and reduced levels of circulating 1,25-(OH)2D, respectively. The finding that PTH fails to further stimulate 1 alpha-hydroxylase when vitamin D deprivation is sufficient in duration to cause hypocalcemia confirms the findings of other investigators and again demonstrates that observations made during abnormal metabolic circumstances may bear little on the physiologic regulation of 1 alpha-hydroxylase under normal or near-normal metabolic circumstances.

Restoration of mucociliary tracheal epithelium following deprivation of vitamin A. A quantitative morphologic study.

In order to learn more about the respective roles played by basal cells and mucous cells in the maintenance of tracheal mucociliary epithelium, cell kinetics and epithelial cell morphology were characterized over a 7-day period, during which dietary vitamin A was restored to previously deprived hamsters. Hamsters were reared from birth to 35 days of age on vitamin A-replete or deficient diets. Deprived hamsters were made replete by 5 mg vitamin A-acetate orally, plus a vitamin A-replete diet. Colchicine and 3HTdR were given 6 h before death. The numbers of basal cells, mucous cells, preciliated cells and ciliated cells, and mitotic rates (MR) and labeling indices (LI) of basal cells and mucous cells, were quantified in glycol methacrylate sections stained with PAS-lead hematoxylin. Vitamin A-deprivation decreased replication of basal cells and mucous cells in tracheal epithelium which showed minimal morphological change. The proportion of basal cells was increased and proportions of mucous, preciliated and ciliated cells were decreased. Following restoration of vitamin A to the diet, the basal cell MR remained below control level throughout the experimental period, but the mucous cell MR started to rise on day 2-replete, and on day 3-replete and thereafter the mucous cell MR was within the control range. Basal cell and mucous cell LI's showed similar trends. Preciliated cells were reduced or absent in vitamin A-deprived epithelium. Their number had risen by day 3-replete and thereafter they were generated within the control range. These cells matured into ciliated cells. By day 4-replete, the proportion of basal cells had decreased markedly and the proportions of mucous cells, and preciliated plus ciliated cells had increased, so that at this time cellular proportions were within or near control values. This trend continued so that by day 7-replete, a nearly normal mucociliary epithelium was restored. The results show that vitamin A-levels modulate replication rates of basal cells and mucous cells and indicate that mitotic division of mucous cells is a prerequisite for the genesis of preciliated cells and new mucous cells and for restoration of the mucociliary epithelium following deprivation of vitamin A in the diet.

Activity of alkaline phosphatase in the serum of normal and ascorbic-acid-deficient guinea pigs.

Guinea pigs well supplied with vitamin C show a linear relation between serum alkaline phosphatase activity and body weight. Investigations in guinea pigs induced to low ascorbic-acid levels by two different procedures (complete and partial deprivation of vitamin C) demonstrated that the activity of the alkaline phosphatase is not generally decreased in the serum of ascorbic-acid-deficient guinea pigs. Decreases of the serum enzyme levels reported in guinea pigs completely deprived of vitamin C, i.e. in acute deficiency, may be due to stress factors.

Nuclease accessibility of chromatin from normal, vitamin B 12 deprived and refed Euglena cells

Conformational changes that occur in chromatin of Euglena gracilis Z. at different stages of the cell cycle or during the course of vitamin B 12 deprivation have been probed by micrococcal nuclease digestion. The results indicate no significant differences in the digestion behavior of nuclei from G 1 to S phase. In contrast, the initial rate of digestion increases and the limit plateau of acid solubility is markedly higher than normal in chromatin from vitamin B 12 starved cells and intermediate in chromatin from B 12 refed cells during the first burst of mitosis. Electrophoretic analysis of DNA sizes indicates that the average DNA repeat length (225 base pairs ± 13) is roughly maintained whatever the growth conditions of the cells are. However the extensive digestion pattern yields a set of subnucleosomal fragments which are increased after B 12 starvation. These data show that, although the basic nucleosomal organization is maintained, the nuclease accessibility of chromatin from B 12 starved cells and just after vitamin resupply is increased. The results are in accordance with the drastic structural dispersion of chromosomes already observed in Euglena during vitamin deprivation. Micrococcal nuclease digestion reveals such higher order modifications.

Effect of deprivation of vitamin A on the basic proteins of the nuclei of rat testes

Summary The relative concentrations of the major histones, namely, H1, TH1, H 2 A, H 2 B, H3 and H4 are not significantly changed in the testes of the vitamin A-deficient rats, as compared to those in the normal controls. But the testis-specific protein, TP, which is synthesized at the mid-spermatid stage, is markedly reduced in the testes of the deficient rats. On supplementation of the deficient rats with retinyl acetate for 28 days, there was a 50% recovery in the relative concentration of the TP with respect to the total amounts of H1 and TH1.

Effects of Vitamin B-12 Deprivation on Phospholipid Fatty Acid Patterns in Liver and Brain of Rats Fed High and Low Levels of Linoleate in Low Methionine Diets

Experiments were conducted to determine how 20 weeks of deprivation of vitamin B-12 (B-12) would influence polyunsaturated fatty acid (PUFA) patterns in cerebral and liver phospholipids of female rats. All experimental diets included 24% soybean protein and either 3.5 of 0.35% of linoleate (18:2). Deprivation of B-12 and restricted intakes of 18:2 significantly inhibited growth of the rats. Rats depleted of B-12 had 6.7 times more methylmalonic acid in their liver, and significantly more odd-numbered acids (15:0 + 17:0) were present in phosphatidyl choline (PC) of their liver and cerebrum. Deprivation of B-12 promoted 63.3 to 97.3% increases of 18:2 in PC and phosphatidyl ethanolamine (PE) of the liver. Rats deprived of B-12 had significantly less arachidonate (20:4 omega 6) and 22:5 omega 6 in their liver PC, as well as smaller amounts of 20:4 omega 6 and 22:6 omega 3 in their cerebral PC. Some of the observed changes appear to be due to a significant interaction between the effects of B-12 and linoleate. Changes in PUFA patterns of cerebral and hepatic PC suggest that B-12 deprivation may interfere with the conversion of 18:2 omega 6 leads to 20:4 omega 6 leads to 22:5 omega 6. Some of the observed changes may also be related to an inhibited ability to convert PE to PC.

Hypercalcemic Effect of Insulin in the Chick*

There are conflicting reports on the effect of insulin on plasma Ca concentration in rats. Low doses appear to decrease and higher doses to increase plasma Ca. Since birds are known to be very sensitive to parathyroid hormone and have resistance to the hypoglycemic effects of insulin, the effect of commercial and highly purified insulin on plasma Ca concentration was studied in 10-day-old chicks 60 min after the administration of the hormone. Both commerical bovine and purified porcine insulin provoked a dose-related elevation of plasma Ca. Although hypophosphatemia was observed with the highest dose of insulin used (0.4U), hypercalcemia was observed with 0.05 U insulin, a dose that did not modify plasma phosphate concentration. The slopes of the dose-response curves of insulin and parathyroid hormone were indistinguishable and different from that of 1 alpha-hydroxyvitamin D3. Neither propranolol nor deprivation of vitamin D altered the hypercalcemic response to insulin. Unexpectedly, propranolol (40 microgram/chick) provoked elevation of plasma Ca. It is concluded that insulin raises plasma Ca concentration in the chick by a mechanism(s) not yet elucidated.

Effects of thiamine deprivation on the growth and metabolism of the phytoflagellatePolytomella agilis

The effects of thiamine deprivation on the growth, respiration, and activity of several enzymes of the phytoflagellate protozoanPolytomella agilis were studied. Vitamin deprivation had no effect on the exponential growth rate; the peak population of cultures grown without thiamine was 50% of the control level. The rates of oxygen consumption in control and thiamine-deprived cultures were not significantly different from each other. The activities of pyruvate dehydrogenase and oxoglutarate dehydrogenase in vitamin-deprived cells were 14% and 30%, respectively, of the control values. In these cells, the succinic dehydrogenase activity was 10% and mitochondrial ATPase activity was twice that of control cells. Vitamin deprivation had no effect on the activities of malate dehydrogenase and isocitrate lyase, but pyruvic carboxylase activity increased fourfold. These results indicate a complex role for thiamine in the regulation of growth, respiration, and metabolism in this organism.