Search PubMed⌕ Search

Biomedical subjects

R Reifen

Publications and source records attributed to R Reifen.

At least 19 recordsLinked to original sources
PubMed2006

Vitamin A deficiency enhances docosahexaenoic and osbond acids in liver of rats fed an alpha linolenic acid-adequate diet.

The synthesis of docosahexaenoic (DHA, 22:6n-3) and Osbond acid (OA, 22:5n-6) is regulated by the heterodimer of peroxisome proliferator-activated receptor and retinoid X receptor (RXR). 9-Cis retinoic acid, a metabolite of vitamin A, is the most potent ligand of RXR. We tested whether vitamin A deficiency impairs DHA and OA synthesis in rats fed a vitamin A- and alpha-linolenic acid (ALA)-sufficient (VASALAS), vitamin A-sufficient and ALA-deficient (VASALAD), vitamin A-deficient and ALA-sufficient (VADALAS), or vitamin A- and ALA-deficient (VADALAD) diet. After 7 wk of feeding, liver and colon choline (CPG) and ethanolamine (EPG) phosphoglyceride FA were analyzed. The VADALAS compared with the VASALAS rats had elevated levels of both DHA (P< 0.05) and OA (P < 0.005) in liver CPG and EPG. In contrast, the VADALAD group had a lower DHA (P < 0.01) and higher OA (P < 0.005) level in CPG and EPG of both tissues than their VASALAD counterparts. ALA deficiency reduced DHA and enhariced OA levels in liver and colon CPG and EPG in both the vitamin A-sufficient (VASALAS vs. VASALAD) and -deficient (VADALAS vs. VADALAD) rats (P < 0.005). The study demonstrates that ALA deficiency reduced DHA and enhanced OA levels in tissue membranes, and dietary vitamin A deficiency has a profound effect on membrane DHA and OA in rat tissues. Both vitamin A and DHA are involved in a myriad of vital physiological functions pertaining to growth and development and health. Hence, there is a need for a further study to unravel the mechanism by which vitamin A influences membrane DHA and OA.

Animals↗
PubMed2005

Quantitative trait loci governing carotenoid concentration and weight in seeds of chickpea (Cicer arietinum L.).

Chickpea is a staple protein source in many Asian and Middle Eastern countries. The seeds contain carotenoids such as beta-carotene, cryptoxanthin, lutein and zeaxanthin in amounts above the engineered beta-carotene-containing "golden rice" level. Thus, breeding for high carotenoid concentration in seeds is of nutritional, socio-economic, and economic importance. To study the genetics governing seed carotenoids in chickpea, we studied the relationship between seed weight and concentrations of beta-carotene and lutein by means of high-performance liquid chromatography in segregating progeny from a cross between an Israeli cultivar and wild Cicer reticulatum Ladiz. Seeds of the cross progeny varied with respect to their carotenoid concentration (heritability estimates ranged from 0.5 to 0.9), and a negative genetic correlation was found between mean seed weight and carotenoid concentration in the F(3). To determine the loci responsible for the genetic variation observed, the population was genotyped using 91 sequence tagged microsatellite site markers and two CytP450 markers to generate a genetic map consisting of nine linkage groups and a total length of 344.6 cM. Using quantitative data collected for beta-carotene and lutein concentration and seed weight of the seeds of the F(2) population, we were able to identify quantitative trait loci (QTLs) by interval mapping. At a LOD score of 2, four QTLs for beta-carotene concentration, a single QTL for lutein concentration and three QTLs for seed weight were detected. The results of this investigation may assist in improving the nutritional quality of chickpea.

Carotenoids↗
PubMed2004

Vitamin A deficiency reduces liver and colon docosahexaenoic acid levels in rats fed high linoleic and low alpha-linolenic acid diet.

Studies indicate that the transcription factor peroxisome proliferator-activated receptors (PPARs) regulate the activity of delta-6 and -5 desaturases and several key enzymes of peroxisomal beta-oxidation, including acyl-CoA oxidase. These enzymes are vital for the synthesis of docosahexaenoic (22:6 omega 3; DHA) and osbond (22:5 omega 6, OA) acids. An activated PPAR must form a hetrodimer with the obligate cofactor retinoid X receptor (RXR) to interact with a peroxisome proliferator responsive element (PPRE) of a target gene and to regulate transcriptional expression. The vitamin A metabolite, 9-cis retinoic acid, is the most potent ligand of RXR. We have tested the possibility that deficiency of vitamin A would compromise tissue levels of both DHA and OA in rats. Two groups of male Wistar rats were randomly distributed to receive vitamin A deficient (VAD) or sufficient (VAS) diet. After seven weeks of feeding, the rats were killed and colon and liver tissues removed for the analysis of fatty acids and antioxidant status. The VAD compared to the VAS rats had elevated levels of arachidonic (AA, P<0.001), adrenic acid (22:4 omega 6, P<0.005) and OA (P<0.0001) and reduced proportions of eicosapentaenoic (EPA, docosapentaenoic (DPA), DHA and total omega 3 fatty (P<0.0001) in colon choline phosphoglycerides (CPG). Similarly, liver CPG of the VAD rats had higher AA and adrenic acid and OA (P<0.0001), and lower EPA, DPA and DHA (P<0.0001) than the VAS rats. There was a similar fatty acid pattern in ethanolamine phosphoglycerides of the colon and liver tissues. These differences could not be explained by the conventional microsomal-peroxisomal pathway of the synthesis of the long-chain omega 6 and omega 3 polyunsaturated fatty acids. We postulate that deficiency of dietary vitamin A and the consequential depletion of retinoids inhibits DHA, and enhances OA, synthesis by differential effects on the independent synthetic pathways of the two fatty acids in the mitochondria. Various studies have documented that both DHA and vitamin A are vital for optimal visual and neural development and function. There is a need for further investigations to elucidate how vitamin A deficiency reduces membrane DHA level, and to delineate the synergistic effect of the two nutrients on vision, learning and memory.

Animal Feed↗
PubMed2004

Vitamin A and iron supplementation is as efficient as hormonal therapy in constitutionally delayed children.

OBJECTIVE: To assess the effect of nutritional supplementation on growth and puberty in constitutionally delayed children. PATIENTS: One hundred and two boys, 13.6-15.5 years of age, who were referred because of short stature and delayed puberty. METHODS: The boys were randomly allocated to one of the following treatment groups: oxandrolone therapy, 5 mg/day for 6 months (n = 15), testosterone depot, 100 mg monthly for 3 months (n = 15) or for 6 months (n = 20), nutritional programme (n = 17), oxandrolone and nutritional programme (n = 15) or passive observation (n = 20). Boys in the nutritional programmes received 12 mg/day iron and 6000 IU/week of vitamin A. Outcome measurements were of height, weight, pubertal signs, dietary intake, serum vitamin A, iron, GH and IGF-1. RESULTS: Six months of vitamin A supplementation induced growth acceleration similar to that seen in the oxandrolone- and testosterone-treated children, and significantly greater than in the observation group (9.3 +/- 2.9 vs. 4.0 +/- 0.9 crn/yr, P < 0.001). Whereas in the vitamin A-supplemented group, puberty (increase in testicular volume >/= 12 ml) was induced within 12 months. In all testosterone-treated patients, pubic hair was noted within 3 months and a testicular volume of >/= 12 ml was observed 9-12 months after the initiation of therapy. No pubertal signs were noted in the observation group during this time. CONCLUSIONS: Subnormal vitamin A intake is one of the aetiological factors in delayed pubertal maturation. Supplementation of both vitamin A and iron to normal constitutionally delayed children with subnormal vitamin A intake is as efficacious as hormonal therapy in the induction of growth and puberty.

Adolescent↗
PubMed2003

Small for gestational age: towards 2004.

Children born small for gestational age are a non-homogeneous group and etiology and diagnostic needs vary among subgroups. In view of the knowledge accumulated about immediate and future risk factors for these children it is important to study the etiology and to invest in long-term prevention programs. The aim of this report is to summarize the current knowledge on mechanisms leading to intrauterine growth retardation and to review the intervention procedures.

Child Development↗
PubMed2002

Food allergy is a matter of geography after all: sesame as a major cause of severe IgE-mediated food allergic reactions among infants and young children in Israel.

OBJECTIVE: To determine the prevalence, importance, and the order of frequency of IgE-mediated food allergens among infants and young children in Israel. STUDY DESIGN AND PATIENTS: In a cross-sectional study, the prevalence of IgE-mediated food allergy was investigated in 9070 infants and young children (0-2 years) who were followed-up at 23 Family Health Centers (FHCs) in central Israel. Patients with suspected IgE-mediated food allergic reactions, were recruited for further evaluation (detailed questionnaire and skin-prick test (SPT)). RESULTS: We identified 150 out of 9070 (1.7%) patients with suspected IgE-mediated food allergy. Among them, 102/150 (67%) [59 males, 43 females; mean age 10.3 months] completed a detailed questionnaire and underwent SPT. Evaluation revealed 131 positive SPTs in 78/102 (76.5%) patients. Twenty-seven positive SPTs in 18 patients were considered clinically irrelevant based on previous consumption of the relevant foods without clinical symptoms. Thus, there were 104 relevant positive SPTs in 78 patients. The overall prevalence of clinically relevant IgE-mediated food allergic reactions among these patients is estimated to be 1.2% (104/9070). The most common food allergens were egg, cow's milk, and sesame. Anaphylaxis was the presenting symptom in 14/78 (18%) including six sesame-induced cases. A history of other atopic diseases was reported in 27 (35%) patients. In addition, 22 (28%) had a history of atopy in first-degree family members. CONCLUSIONS: We found sesame to be a major cause of IgE-mediated food allergy in Israel. In fact, it is second only to cow's milk as a cause of anaphylaxis. We recommend that testing for food allergens be tailored to each community based on local experience and should include sesame in appropriate populations.

Child Welfare↗
PubMed2002

Use of energy-dense formula for treating infants with non-organic failure to thrive.

OBJECTIVE: To evaluate if simply increasing the energy density of the formula will lead to increased energy intake and weight gain in infants with non-organic failure to thrive. DESIGN: In this hospital-based trial, 15 infants (mean age, 7.6+/-1.4 months) with non-organic failure to thrive were fed a regular strength formula (2.8 kJ/ml) for 3 days and then switched to the same formula with a higher energy density (4.18 kJ/ml) for 3 days after a 2 day 'wash-out' period. Daily nude weights and energy intakes were recorded for the two 3 day periods. RESULTS: During feeding with the higher density formula, nine (60%) infants had a significant increase in their energy intake and weight gain (both P<0.02); four (27%) showed no change in energy intake and self-regulated their intake by decreasing the volume of feeds consumed to maintain energy intake; and two (13%) infants consumed a significantly reduced amount of energy (P<0.02). CONCLUSION: Increasing the energy density of the formula may provide a useful intervention to increase the weight gain and energy intake of most infants with non-organic failure to thrive.

Analysis of Variance↗
PubMed2002

Vitamin A deficiency exacerbates inflammation in a rat model of colitis through activation of nuclear factor-kappaB and collagen formation.

Inflammatory bowel disease is characterized by oxidative stress, inflammation and tissue damage. Vitamin A is an antioxidant, a regulator of epithelial proliferation and differentiation and vital for optimal immune function. To investigate the effect of vitamin A on the course of colitis, it was induced by administration of trinitrobenzene sulfonic acid (TNBS) into the colons of rats fed for 7 wk vitamin A-deficient (VAD), sufficient (VAS) or supplemented (VASUP) diet, or VAS pair-fed (PF) to the VAD rats. Inflammation and fibrosis were examined by hematoxin and eosin, and Sirius red staining. Activation of nuclear factor-kappaB (NF-kappaB) and oxidative stress were determined by electrophoretic mobility shift and plasma malondialdehyde (MDA) and RBC Cu/Zn-superoxide dismutase activity, respectively. Vitamin A deficiency in the noncolitic rats impaired food consumption and weight gain (P < 0.05) and increased plasma MDA, (P = 0.01) activity of NF-kappaB (P < 0.05) and deposition of collagen in the colon. Our data suggest that vitamin A deficiency induces colonic inflammation. Colitis is amplified by deficiency and ameliorated by supplementation of the vitamin. These findings have implications for the management of inflammatory bowel disease.

Animals↗
PubMed2001

Lycopene supplementation attenuates the inflammatory status of colitis in a rat model.

The aim of this study was to examine the influence of lycopene and beta-carotene on the inflammatory status in a rat model of induced-colitis. Using the 2,4,6-trinitrobenzenesulfonic acid (TNBS) model, colitis was induced in thirty-two male Wistar rats divided into four groups. Each group received a different diet regime in parallel with the induction of colitis and was sacrificed after seven days. The groups were divided as follows: Group A: without colitis and fed a normal chow diet; Group B: induced with colitis and fed a diet supplemented with lycopene (300 micrograms/rat/day); Group C: induced with colitis and fed a diet supplemented with beta-carotene (300 micrograms/rat/day); Group D: induced with colitis and fed a normal chow diet. Colonic inflammation following TNBS induction was characterized by hemorrhagic necrosis and fibrosis of the mucosa, increased colonic wall thickness, infiltration of inflammatory cells, and increased myeloperoxidase (MPO) activity. Supplementation of lycopene in the diet had a beneficial effect on the various macroscopic parameters examined including: colonic thickness, colon weight, and total area of inflammation. Furthermore, the level of myeloperoxidase (MPO) was significantly lower in the lycopene-treated group compared to the control group. In terms of microscopic changes, a more attenuated inflammatory reaction was observed in the group fed a diet supplemented with lycopene. No significant effect was noted in the beta-carotene-supplemented group. Therefore, we propose that the dietary supplementation of lycopene may be an effective approach for reducing the level of oxidative stress and improving the inflammatory status of colitis.

Analysis of Variance↗
PubMed2001

Interrelationship between insulin, leptin and growth hormone in growth hormone-treated children.

OBJECTIVES: The aim of the study was to examine insulin homeostasis during growth hormone (GH) therapy, and to investigate the effect of GH treatment on insulin and leptin concentration in obese children. SUBJECTS: Nineteen obese children (8 with Prader-Willi Syndrome (PWS)) were treated with GH 0.1 IU/kg/day dose for 3 months and were compared with 29 non-treated age and sex matched obese children (9 PWS) and 49 GH treated non-obese short children. Mean age of the children was 10.3+/-1.8 (6.7-13.8) y, with body mass index of 23.6+/-10.4 (11.5-47) kg/m2. RESULTS: Leptin concentration decreased and was correlated inversely with initial leptin value (r2=-0.374, P<0.001) and decreased body mass (r2=0.338, P=0.001). Insulin sensitivity index was not significantly changed during therapy. Leptin decrease after 3 months of GH administration was correlated inversely with the increase in first phase insulin response to intravenous glucose tolerance test (IVGTT) (r2=-0.595, P<0.001). Results of long-term follow-up of treated patients demonstrated a decrease in insulin concentration after cessation of therapy. In GH-treated subjects, the glucose increase in response to glucose load appeared to be higher than in untreated subjects. CONCLUSION: The high insulin response to glucose load seen in GH-treated subjects was appropriate to their glucose concentration and the insulin sensitivity index was unchanged relative to the pretreatment period. Increased insulin dosage in our patients did not induce an increase in leptin concentrations as had been hypothesised.

Anthropometry↗
PubMed2001

Vitamin A during pregnancy.

Vitamin A is an essential micronutrient throughout life. In areas of developing countries where vitamin A deficiency is endemic, an estimated 40% of the children are likely to be sub clinically deficient of the vitamin. Yet, the traditional view that preschool age children represent the main population at risk of vitamin A deficiency has been replaced by the growing awareness that sub clinical and even clinical vitamin A deficiency also occurs in women of reproductive age and infants less than 6 month of age. During the period of early foetal development the supply of vitamin A must be carefully managed to ensure that the developing foetus is exposed to neither too little not too much vitamin A because either condition can have teratogenic consequences. Towards the end of gestation, adequate maternal vitamin A status and dietary intakes are important to maximize the vitamin A transferred to the foetus in preparation for parturition and lactation. A review of the current knowledge and prospects for future research is presented.

Female↗
PubMed2001

Beta-carotene attenuates experimentally induced liver cirrhosis in rats.

OBJECTIVE: To study whether retinolpalmitate, beta-carotene or lycopene could prevent liver cirrhosis induced by thioacetamide in rats. METHODS: In the control group liver cirrhosis was induced in male Wistar rats by intraperitoneal injections of TAA 200 mg/kg for 12 weeks. The three study groups received in addition to TAA either beta-carotene, lycopene or retinopalmitate by gavage through an orogastric tube. Histopathological analysis and determination of the hydroxyproline contents of the livers were performed at the end of the protocol. RESULTS: Rats treated with beta-carotene and TAA had lower histopathologic scores and reduced levels of hepatic hydroxyproline (P = 0.02) than those treated by TAA alone. A trend of decreased fibrosis was observed in the rats treated with lycopene and TAA although this lacked statistical significance. CONCLUSIONS: Beta-carotene attenuated liver cirrhosis induced by TAA in rats. The mechanism may be related to effects on hepatic stellate cells or to scavenging of free radicals by beta-carotene. Retinolpalmitate and lycopen had no significant beneficial effect.

Analysis of Variance↗
PubMed2000

Linseed oil suppresses the anti-beta-2-glycoprotein-I in experimental antiphospholipid syndrome.

The immunomodulatory potential of a diet enriched with n-3 polyunsaturated fatty acids was analysed in naïve mice with experimental antiphospholipid syndrome (APS) induced by active immunization with H-3, a human anti-beta-2-glycoprotein-I (anti-betaGPI) monoclonal antibody (mAb). Fetal loss and other clinical manifestations of APS were prevented in the group of APS mice upon exposure to the enriched n-3 diet compared to the control group. The titers of anti-betaGPI were significantly lower (in O.D. at 405 nm, 1.387+/-0.232 in comparison to non-treated mice 0.637+/-0. 111, P< 0.05). The reduced titer of anti-betaGPI antibodies in the sera of the treated mice was associated with a reduced number of anti-betaGPI forming cells in cultured splenocytes (84+/-14, antibody-forming cells (AFC)/10(5)cells in comparison to 37+/-4 AFC/10(5)cells (P< 0.02).In addition to the suppression of the humoral response in mice with experimental APS fed with linseed oil, we also observed an inhibitory effect on the cellular response. The T-cell response to anti-betaGPI was lower in comparison to mice immunized with H-3 anti-betaGPI mAB, which were kept on a normal diet. These results indicate that polyunsaturated fatty acids may improve clinical and laboratory parameters of APS. The beneficial effects of diets enriched with n-3 should be further examined as a potential mode of therapy for patients with APS.

Animals↗
PubMed2000

Iron supplementation may aggravate inflammatory status of colitis in a rat model.

Iron supplementation is one of the principal therapies in inflammatory bowel disease. Iron is a major prooxidative agent; therefore therapeutic iron as well as heme iron from chronic mucosal bleeding can increase the iron-mediated oxidative stress in colitis by facilitating the Fenton reaction, namely production of hydroxyl radicals. In the present study colitis was induced in the iodoacetamide rat model. Forty male Whistar rats were divided into four groups, each group receiving a different diet regimen in parallel with colitis induction: Malondialdehyde was measured to assess the degree of tissue oxidative stress. There were microscopic changes, and significantly more severe colitis was seen in colonic biopsies when iron was supplemented. It was concluded that iron supplementation can amplify the inflammatory response and enhance the subsequent mucosal damage in a rat model of colitis. We suggest that the resultant oxidative stress generated by iron supplementation leads to the extension and propagation of crypt abscesses.

Animals↗
PubMed2000

Vitamin A deficiency interferes with proliferation and maturation of cells in the chicken small intestine.

1. The effect of vitamin A on the small intestine was examined in vitamin-A-deficient meat-type chickens. 2. Maturation and activity of the small intestinal cells were assayed by detection of proliferating cells with proliferating cells nuclear antigen, goblet cells with Alcian blue, mature cells with alkaline phosphatase and extent of RNA expression with dot blot analysis. 3. Vitamin A deficiency caused hyperproliferation of enterocytes, a decrease in the number of goblet cells, decreased alkaline phosphatase activity and decreased expression of 2 brush-border enzymes. 4. Our findings suggest that the absence of vitamin A interferes with the normal growth rate in chickens because it influences functionality of the small intestine by altering proliferation and maturation of cells in the small intestinal mucosa.

Aminopeptidases↗
PubMed2000

Comparison of assays for anti-endomysial and anti-transglutaminase antibodies for diagnosis of pediatric celiac disease.

BACKGROUND: Anti-endomysial antibodies are sensitive and specific markers for celiac disease. This antibody has recently been identified as an antibody to tissue transglutaminase, an enzyme that cross-links and stabilizes extracellular matrix proteins. OBJECTIVES: To evaluate the clinical usefulness of an enzyme-linked immunoassay for anti-transglutaminase antibodies, and to compare the results with those of AEA, the current gold standard serological test for celiac disease. METHODS: Serum samples were collected from 33 patients with biopsy-proven celiac disease and AEA tests were performed. Control samples for anti-transglutaminase were obtained from 155 patients. An ELISA test for immunoglobulin A anti-transglutaminase utilizing guinea pig liver transglutaminase was developed and performed on all sera. Cutoff values for the test were performed using logistic regression and receiver operating curves analysis. RESULTS: An optical density cutoff value of 0.34 was established for the assay. The mean value was 0.18 +/- 0.19 optical density for controls, and 1.65 +/- 1.14 for patients with celiac disease (P < 0.001). Sensitivity and specificity of the assay were both 90%, while AEA had a sensitivity and specificity of 100% and 94%, respectively. CONCLUSIONS: A tissue transglutaminase-based ELISA test is both sensitive and specific for detection of celiac disease.

Analysis of Variance↗
PubMed1999

Biochemical but not clinical vitamin A deficiency results from mutations in the gene for retinol binding protein.

BACKGROUND: Two German sisters aged 14 and 17 y were admitted to the Tübingen eye hospital with a history of night blindness. In both siblings, plasma retinol binding protein (RBP) concentrations were below the limit of detection (<0.6 micromol/L) and plasma retinol concentrations were extremely low (0.19 micromol/L). Interestingly, intestinal absorption of retinyl esters was normal. In addition, other factors associated with low retinol concentrations (eg, low plasma transthyretin or zinc concentrations or mutations in the transthyretin gene) were not present. Neither sibling had a history of systemic disease. OBJECTIVE: Our aim was to investigate the cause of the retinol deficiency in these 2 siblings. DESIGN: The 2 siblings and their mother were examined clinically, including administration of the relative-dose-response test, DNA sequencing of the RBP gene, and routine laboratory testing. RESULTS: Genomic DNA sequence analysis revealed 2 point mutations in the RBP gene: a T-to-A substitution at nucleotide 1282 of exon 3 and a G-to-A substitution at nucleotide 1549 of exon 4. These mutations resulted in amino acid substitutions of asparagine for isoleucine at position 41 (Ile41-->Asn) and of aspartate for glycine at position 74 (Gly74-->Asp). Sequence analysis of cloned polymerase chain reaction products spanning exons 3 and 4 showed that these mutations were localized on different alleles. The genetic defect induced severe biochemical vitamin A deficiency but only mild clinical symptoms (night blindness and a modest retinal dystrophy without effects on growth). CONCLUSIONS: We conclude that the cellular supply of vitamin A to target tissues might be bypassed in these siblings via circulating retinyl esters, beta-carotene, or retinoic acid, thereby maintaining the health of peripheral tissues.

Adolescent↗