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Parlak G, Çolakoğlu N. Protective effects of benfotiamine on cyfluthrin-induced testicular damage and sperm characteristics during the prepubertal period. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:4663-4675. [PMID: 38112729 DOI: 10.1007/s00210-023-02896-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/05/2023] [Indexed: 12/21/2023]
Abstract
Cyfluthrin, a widely used synthetic pyrethroid insecticide, poses potential risks to both human health and the environment due to its extensive application in residential, agricultural, and outdoor settings. Conversely, benfotiamine, a fat-soluble derivative of vitamin B1, offers versatile therapeutic potential. This experimental study aimed to investigate the impact of cyfluthrin exposure during the prepubertal period on sperm characteristics and testicular tissue integrity in male rats, as well as to assess the protective effects of benfotiamine. A total of 32 4-week-old Wistar albino male rats were divided into four groups. Group I received daily oral gavage of 1 ml/kg/day of olive oil (control). Group II was administered cyfluthrin (54 mg/kg/day) dissolved in 1 ml of olive oil. Group III received both cyfluthrin (54 mg/kg/day) and benfotiamine (100 mg/kg/day) in olive oil. Group IV was given benfotiamine (100 mg/kg/day) in olive oil. After 5 weeks of treatment, the rats underwent evaluations for sperm motility, epididymal sperm density, and abnormal sperm rates. Additionally, their testicular tissues were examined histologically and immunohistochemically. This study underscores the potential hazards of cyfluthrin exposure on male reproductive health and highlights the protective role of benfotiamine in mitigating these effects. It emphasizes the importance of careful pesticide usage and dosage considerations to prevent potential public health issues, including infertility, associated with long-term exposure to pesticides like cyfluthrin.
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Affiliation(s)
- Gözde Parlak
- Faculty of Science, Department of Biology-Molecular Biology and Genetics Program, Firat University, 23119, Elazig, Turkey.
| | - Neriman Çolakoğlu
- Histology & Embryolgy, Firat University Medical Faculty, 23119, Elazig, Turkey
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2
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Jackson C, Furnes M, Rød‐Eriksen L, Yap KN, Davey M, Fossøy F, Flagstad Ø, Eide NE, Mjøen T, Ulvund K. Subclinical thiamine deficiency results in failed reproduction in Arctic foxes. Vet Med Sci 2024; 10:e1358. [PMID: 38356320 PMCID: PMC10867461 DOI: 10.1002/vms3.1358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/20/2023] [Accepted: 01/07/2024] [Indexed: 02/16/2024] Open
Abstract
Thiamine deficiency can result in life-threatening physiological and neurological complications. While a thiamine-deficient diet may result in the onset of such symptoms, the presence of thiaminase - an enzyme that breaks down thiamine - is very often the cause. In such instances, thiaminase counteracts the bioavailability and uptake of thiamine, even when food-thiamine levels are adequate. Here, we report on a case of failed reproduction in seven Arctic fox (Vulpes lagopus) breeding pairs kept at a captive breeding facility, including the presentation of severe thiamine deficiency symptoms in two male foxes. Symptoms included ataxia, obtundation, truncal sway, star-gazing and visual impairment. Blood tests were inconclusive, yet symptoms resolved following treatment with a series of thiamine hydrochloride injections, thereby verifying the diagnosis. A fish-dominated feed, which for the first time had been frozen for a prolonged period, was identified as the likely source of thiaminase and subsequent deterioration in the animals' health. Symptoms in the two males arose during the annual mating period. All seven breeding pairs at the captive breeding station failed to reproduce - a phenomenon never recorded during the captive breeding facility's preceding 17-year operation. Relating our findings to peer-reviewed literature, the second part of this case report assesses how thiamine deficiency (due to thiaminase activity) likely resulted in subclinical effects that impaired the production of reproduction hormones, and thereby led to a complete breeding failure. While previous work has highlighted the potentially lethal effects of thiamine deficiency in farmed foxes, this is, to our knowledge the first study showing how subclinical effects in both males and females may inhibit reproduction in foxes in general, but specifically Arctic foxes. The findings from our case report are not only relevant for captive breeding facilities, but for the welfare and management of captive carnivorous animals in general.
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Affiliation(s)
- Craig Jackson
- Department of Terrestrial EcologyNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Marianne Furnes
- Department of Terrestrial EcologyNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Lars Rød‐Eriksen
- Department of Terrestrial EcologyNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Kang Nian Yap
- Department of BiologyNorwegian University of Science and TechnologyTrondheimNorway
| | - Marie Davey
- Department of Terrestrial BiodiversityNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Frode Fossøy
- Department of Aquatic BiodiversityNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Øystein Flagstad
- Department of Terrestrial EcologyNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Nina E. Eide
- Department of Terrestrial EcologyNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Toralf Mjøen
- Department of Terrestrial EcologyNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Kristine Ulvund
- Department of Terrestrial EcologyNorwegian Institute for Nature Research (NINA)TrondheimNorway
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Younes M, Aquilina G, Castle L, Engel K, Fowler PJ, Frutos Fernandez MJ, Fürst P, Gundert‐Remy U, Gürtler R, Husøy T, Manco M, Mennes W, Moldeus P, Passamonti S, Shah R, Waalkens‐Berendsen I, Boon P, Cheyns K, Crebelli R, FitzGerald R, Lambré C, Mirat M, Ulbrich B, Vleminckx C, Mech A, Rincon AM, Tard A, Horvath Z, Wright M. Follow‐up of the re‐evaluation of sulfur dioxide (E 220), sodium sulfite (E 221), sodium bisulfite (E 222), sodium metabisulfite (E 223), potassium metabisulfite (E 224), calcium sulfite (E 226), calcium bisulfite (E 227) and potassium bisulfite (E 228). EFSA J 2022; 20:e07594. [DOI: 10.2903/j.efsa.2022.7594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Saki J, Sabaghan M, Arjmand R, Teimoori A, Rashno M, Saki G, Shojaee S. Spermatogonia apoptosis induction as a possible mechanism of Toxoplasma gondii-induced male infertility. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:1164-1171. [PMID: 32963738 PMCID: PMC7491504 DOI: 10.22038/ijbms.2020.43535.10224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Objective(s): The protozoan Toxoplasma gondii as an intracellular protozoan is widely prevalent in humans and animals. Infection generally occurs through consuming food contaminated with oocysts and tissue cysts from undercooked meat. The parasite is carried in sexual fluids like semen but there is little information about the effect of T. gondii on the male reproductive system. In this study, we examined the effect of T. gondii tachyzoites on apoptosis induction in type B spermatogonia (GC-1) cells. Materials and Methods: Fresh tachyzoites taken of infected BALB/c mice, GC-1 spg cells were infected with increasing concentrations of tachyzoites of T. gondii, then apoptotic cells were identified and quantified by flow cytometry. The genes associated with apoptosis were evaluated by RT2 Profiler PCR Array. Results: PCR array analysis of 84 apoptosis-related genes demonstrated that 12 genes were up-regulated at least 4-fold and that one gene was down-regulated at least 2-fold in the T. gondii infection group compared with levels in the control group. The number of genes whose expression had increased during the period of infection with T. gondii was significantly higher than those whose expressions had decreased (18 versus 1) and Tnfrsf11b had the highest rate of gene expression. Conclusion: T. gondii induce in vitro apoptosis of GC-1 spg cells. This effect shows a trend of concentration-dependent increase so that with an increase in the ratio of parasite burden to spermatogonial cells, in addition to an increase in the number of genes whose expression has changed, the fold of these changes has increased as well.
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Affiliation(s)
- Jasem Saki
- Cellular and Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohamad Sabaghan
- Department of Parasitology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Reza Arjmand
- Department of Parasitology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Ali Teimoori
- Virology Department, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohammad Rashno
- Department of Immunology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Ghasem Saki
- Cellular and Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Physiology Research Center, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Saeedeh Shojaee
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Barkabi-Zanjani S, Ghorbanzadeh V, Aslani M, Ghalibafsabbaghi A, Chodari L. Diabetes mellitus and the impairment of male reproductive function: Possible signaling pathways. Diabetes Metab Syndr 2020; 14:1307-1314. [PMID: 32755827 DOI: 10.1016/j.dsx.2020.07.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/04/2020] [Accepted: 07/17/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND AIMS Today, it has been shown that diabetes mellitus (DM) can affect male fertility. Glucose metabolism is a vital process in spermatogenesis that is impacted by diabetes condition. But the mechanisms by which DM causes male infertility are not wholly clarified. The aim of this review is to provide brief information about the influence of hyperglycemia on male fertility and specific emphasis on the molecular signaling pathway that is involved. METHODS Broad literature search in the electronic database "Pubmed", "Google Scholar", the website of "World Health Organization" (WHO) and Control Disease and Prevention (CDC) took place. There was no time restriction. A key criterion for the selection of articles was English and language. Finally, one hundred thirty seven articles were included in the review. RESULTS Diabetes mellitus affects many signaling pathways that involved in the spermatogenesis. It seems that increased ROS and oxidative stress in the diabetes is the beginning of all fertility problems and affects all of involved signaling pathways in the spermatogenesis. CONCLUSIONS It seems that there was strong interconnected between oxidative stress and all of involved signaling pathways in the reproductive problems in diabetes. So, approaches that diminish oxidative stress in the testis can be effective in improving diabetes related infertility complications.
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Affiliation(s)
- Sona Barkabi-Zanjani
- Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Vajihe Ghorbanzadeh
- Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Mohamadreza Aslani
- Lung Inflammatory Diseases Research Center, Faculty of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran; Neurogenetic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Leila Chodari
- Neurophysiology Research Center, Cellular and Molecular Medicine Institute,Urmia University of Medical Sciences, Urmia, Iran; Department of Physiology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
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6
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Hassan MH, Awadalla EA, Ali RA, Fouad SS, Abdel-Kahaar E. Thiamine deficiency and oxidative stress induced by prolonged metronidazole therapy can explain its side effects of neurotoxicity and infertility in experimental animals: Effect of grapefruit co-therapy. Hum Exp Toxicol 2020; 39:834-847. [PMID: 31997653 DOI: 10.1177/0960327119867755] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We aimed to explore the possible neurotoxicity and infertility mechanisms of prolonged metronidazole (MTZ) use and the effects of antioxidant grapefruit (GP) co-therapy on MTZ-induced complications. Sixty male albino Wistar rats were divided into four groups (n = 15 each). Group I (control group) received 1% dimethyl sulfoxide (27 ml/ kg/day), group II (MTZ group) received MTZ (400 mg/kg/day), group III (MTZ + GP) received MTZ (400 mg/kg/ day) plus GP juice (27 ml/kg/ day) and group IV (GP group) received GP juice (27 ml/kg) for 60 days. Semen analyses were performed. Free testosterone, gonadotrophin (follicle-stimulating hormone (FSH) and luteinizing hormone) and thiamine levels were measured. Samples of cerebellar, testicular and epididymal tissues were used for both colorimetric assays of oxidative stress markers and histopathological examinations. Significant decreases in the sperm count, percent total sperm motility, serum thiamine levels, free testosterone levels and FSH levels were observed in the MTZ and MTZ + GP groups (p < 0.05 for all parameters). Significantly higher oxidative stress levels (p < 0.05) were observed in the cerebellar and testicular tissue homogenates of these groups than in those of the control group, and associated disruptions in the cerebellar, testicular and epididymal structures were apparent compared to those of the control group. Although the GP group showed a significantly higher sperm count and significantly lower oxidative stress than the control group (p < 0.05), with histological similarity to the control group, the GP group exhibited significantly higher prolactin levels and lower free testosterone and FSH levels than the control group (p < 0.05). Oxidative stress and decreased thiamine levels could explain the MTZ-induced neurotoxicity and infertility side effects that aggravated by GP co-administration.
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Affiliation(s)
- M H Hassan
- Department of Medical Biochemistry, Faculty of Medicine, South Valley University, Qena, Egypt
| | - E A Awadalla
- Zoology Department, Faculty of Science, Aswan University, Aswan, Egypt
| | - R A Ali
- Zoology Department, Faculty of Science, South Valley University, Qena, Egypt
| | - S S Fouad
- Department of Clinical Pathology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt
| | - E Abdel-Kahaar
- Department of Medical Pharmacology, Faculty of Medicine, South Valley University, Qena, Egypt.,Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
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Metformin Ameliorates Testicular Damage in Male Mice with Streptozotocin-Induced Type 1 Diabetes through the PK2/PKR Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:5681701. [PMID: 31871550 PMCID: PMC6906848 DOI: 10.1155/2019/5681701] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/18/2019] [Accepted: 10/25/2019] [Indexed: 12/17/2022]
Abstract
Approximately 90% of male diabetes mellitus patients have varying degrees of testicular dysfunction. The molecular mechanism underlying diabetes-induced testicular damage has not been thoroughly elucidated. In this research, we sought to determine the influence of metformin (Met) on diabetes-induced testicular injury and the mechanism involved with a focus on testicular dysfunction, apoptosis, autophagy, and prokineticin 2 (PK2) signalling. In our study, C57BL/6J mice were randomly divided into the normal control group, the diabetes group, and the Met-treated group. Streptozotocin (50 mg·kg−1·d−1) was injected intraperitoneally into the mice for 5 days in a row to induce type 1 diabetes, which was diagnosed by a blood glucose level ≥ 16.7 mmol/L after 7 days. The experimental animals were orally administered Met (250 mg·kg−1·d−1) for 16 weeks. Properties of testicular function, including sperm motility and the total concentration of epididymal sperm, were assessed. Changes in testicular structure, such as the blood-testis barrier, histological pathology, and organelles, were observed. The levels of apoptosis and expression of related proteins, such as Bax and Bcl-2, were measured. Moreover, autophagy-related proteins, including Beclin-1, p62, and LC3B, as well as the PK2/PKR pathway, which consists of PK2, PKR1, PKR2, AKT, and GSK3β, were analysed. Upon the induction of diabetes, reproductive capacity was significantly impaired and a disordered arrangement of testicular seminiferous tubules and destroyed organelles in spermatogenic cells was observed. Met administration preserved testicular function and structure. In addition, in mice with diabetes, the levels of PK2, PKR2, p-Akt, and p-GSK3β were significantly decreased at different times, while that of PKR1 was markedly increased, and these changes were normalized by Met. Furthermore, diabetic mice showed increased apoptosis and decreased autophagy in the testes, the effects of which were nullified by Met. These results suggest that Met rescues diabetes-induced testicular damage by attenuating apoptosis and inducing autophagy. This effect is likely mediated by the PK2/PKR/AKT/GSK3β signalling pathway.
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8
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Ruthig VA, Nielsen T, Riel JM, Yamauchi Y, Ortega EA, Salvador Q, Ward MA. Testicular abnormalities in mice with Y chromosome deficiencies. Biol Reprod 2017; 96:694-706. [PMID: 28339606 DOI: 10.1095/biolreprod.116.144006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 01/10/2017] [Indexed: 11/01/2022] Open
Abstract
We recently investigated mice with Y chromosome gene contribution limited to two, one, or no Y chromosome genes in respect to their ability to produce haploid round spermatids and live offspring following round spermatid injection. Here we explored the normalcy of germ cells and Sertoli cells within seminiferous tubules, and the interstitial tissue of the testis in these mice. We performed quantitative analysis of spermatogenesis and interstitial tissue on Periodic acid-Schiff and hematoxylin-stained mouse testis sections. The seminiferous epithelium of mice with limited Y gene contribution contained various cellular abnormalities, the total number of which was higher than in the males with an intact Y chromosome. The distribution of specific abnormality types varied among tested genotypes. The males with limited Y genes also had an increased population of testicular macrophages and internal vasculature structures. The data indicate that Y chromosome gene deficiencies in mice are associated with cellular abnormalities of the seminiferous epithelium and some changes within the testicular interstitium.
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Affiliation(s)
- Victor A Ruthig
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Torbjoern Nielsen
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM - Hôpital du Sacré-Coeur de Montréal, Montréal, Que., Canada.,Department of Psychiatry, Université de Montréal, Montréal, Que., Canada H3T 1J4
| | - Jonathan M Riel
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Yasuhiro Yamauchi
- Department of Gastroenterological Surgery, Fukuoka University Faculty of Medicine, Fukuoka, Japan
| | - Egle A Ortega
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | | | - Monika A Ward
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
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9
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Shayakhmetova GM, Bondarenko LB, Voronina AK, Kovalenko VM. Comparative investigation of methionine and novel formulation Metovitan protective effects in Wistar rats with testicular and epididymal toxicity induced by anti-tuberculosis drugs co-administration. Food Chem Toxicol 2017; 99:222-230. [DOI: 10.1016/j.fct.2016.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/25/2016] [Accepted: 12/02/2016] [Indexed: 12/12/2022]
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10
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Comparison of endpoints relevant to toxicity assessments in 3 generations of CD-1 mice fed irradiated natural and purified ingredient diets with varying soy protein and isoflavone contents. Food Chem Toxicol 2016; 94:39-56. [PMID: 27234134 DOI: 10.1016/j.fct.2016.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/10/2016] [Accepted: 05/21/2016] [Indexed: 01/31/2023]
Abstract
Diet is an important variable in toxicology. There are mixed reports on the impact of soy components on energy utilization, fat deposition, and reproductive parameters. Three generations of CD-1 mice were fed irradiated natural ingredient diets with varying levels of soy (NIH-41, 5K96, or 5008/5001), purified irradiated AIN-93 diet, or the AIN-93 formulation modified with ethanol-washed soy protein concentrate (SPC) or SPC with isoflavones (SPC-IF). NIH-41 was the control for pairwise comparisons. Minimal differences were observed among natural ingredient diet groups. F0 males fed AIN-93, SPC, and SPC-IF diets had elevated glucose levels and lower insulin levels compared with the NIH-41 group. In both sexes of the F1 and F2 generations, the SPC and SPC-IF groups had lower body weight gains than the NIH-41 controls and the AIN-93 group had an increased percent body fat at postnatal day 21. AIN-93 F1 pups had higher baseline glucose than NIH-41 controls, but diet did not significantly affect breeding performance or responses to glucose or uterotrophic challenges. Reduced testes weight and sperm in the AIN-93 group may be related to low thiamine levels. Our observations underline the importance of careful selection, manufacturing procedures, and nutritional characterization of diets used in toxicological studies.
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11
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Manimaran P, Subramanian VS, Karthi S, Gandhimathi K, Varalakshmi P, Ganesh R, Rathinavel A, Said HM, Ashokkumar B. Novel nonsense mutation (p.Ile411Metfs*12) in the SLC19A2 gene causing Thiamine Responsive Megaloblastic Anemia in an Indian patient. Clin Chim Acta 2015; 452:44-9. [PMID: 26549656 DOI: 10.1016/j.cca.2015.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anemia (TRMA), an autosomal recessive disorder, is caused by mutations in SLC19A2 gene encodes a high affinity thiamine transporter (THTR-1). The occurrence of TRMA is diagnosed by megaloblastic anemia, diabetes mellitus, and sensorineural deafness. Here, we report a female TRMA patient of Indian descent born to 4th degree consanguineous parents presented with retinitis pigmentosa and vision impairment, who had a novel homozygous mutation (c.1232delT/ter422; p.Ile411Metfs*12) in 5th exon of SLC19A2 gene that causes premature termination of hTHTR-1. PROSITE analysis predicted to abrogate GPCRs family-1 signature motif in the variant by this mutation c.1232delT/ter422, suggesting uncharacteristic rhodopsin function leading to cause RP clinically. Thiamine transport activity by the clinical variant was severely inhibited than wild-type THTR-1. Confocal imaging had shown that the variant p.I411Mfs*12 is targeted to the cell membrane and showed no discrepancy in membrane expression than wild-type. Our findings are the first report, to the best of our knowledge, on this novel nonsense mutation of hTHTR-1 causing TRMA in an Indian patient through functionally impaired thiamine transporter activity.
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Affiliation(s)
| | - Veedamali S Subramanian
- Departments of Medicine, Physiology/Biophysics, University of California, Irvine, CA; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, USA
| | - Sellamuthu Karthi
- School of Biotechnology, Madurai Kamaraj University, Madurai 625 021, India
| | | | | | - Ramasamy Ganesh
- Kanchi Kamakoti CHILDS Trust Hospital, Nungambakkam, Chennai 600 034, India
| | - Andiappan Rathinavel
- Department of Cardiothoracic Surgery, Madurai Medical College, Madurai 625 020, India
| | - Hamid M Said
- Departments of Medicine, Physiology/Biophysics, University of California, Irvine, CA; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, USA
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12
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Thiamine and magnesium deficiencies: keys to disease. Med Hypotheses 2014; 84:129-34. [PMID: 25542071 DOI: 10.1016/j.mehy.2014.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 12/06/2014] [Indexed: 10/24/2022]
Abstract
Thiamine deficiency (TD) is accepted as the cause of beriberi because of its action in the metabolism of simple carbohydrates, mainly as the rate limiting cofactor for the dehydrogenases of pyruvate and alpha-ketoglutarate, both being critical to the action of the citric acid cycle. Transketolase, dependent on thiamine and magnesium, occurs twice in the oxidative pentose pathway, important in production of reducing equivalents. Thiamine is also a cofactor in the dehydrogenase complex in the degradation of the branched chain amino acids, leucine, isoleucine and valine. In spite of these well accepted facts, the overall clinical effects of TD are still poorly understood. Because of the discovery of 2-hydroxyacyl-CoA lyase (HACL1) as the first peroxisomal enzyme in mammals found to be dependent on thiamine pyrophosphate (TPP) and the ability of thiamine to bind with prion protein, these factors should improve our clinical approach to TD. HACL1 has two important roles in alpha oxidation, the degradation of phytanic acid and shortening of 2-hydroxy long-chain fatty acids so that they can be degraded further by beta oxidation. The downstream effects of a lack of efficiency in this enzyme would be expected to be critical in normal brain metabolism. Although TD has been shown experimentally to produce reversible damage to mitochondria and there are many other causes of mitochondrial dysfunction, finding TD as the potential biochemical lesion would help in differential diagnosis. Stresses imposed by infection, head injury or inoculation can initiate intermittent cerebellar ataxia in thiamine deficiency/dependency. Medication or vaccine reactions appear to be more easily initiated in the more intelligent individuals when asymptomatic marginal malnutrition exists. Erythrocyte transketolase testing has shown that thiamine deficiency is widespread. It is hypothesized that the massive consumption of empty calories, particularly those derived from carbohydrate and fat, results in a high calorie/thiamine ratio as a major cause of disease. Because mild to moderate TD results in pseudo hypoxia in the limbic system and brainstem, emotional and stress reflexes of the autonomic nervous system are stimulated and exaggerated, producing symptoms often diagnosed as psychosomatic disease. If the biochemical lesion is recognized at this stage, the symptoms are easily reversible. If not, and the malnutrition continues, neurodegeneration follows and results in a variety of chronic brain diseases. Results from acceptance of the hypothesis could be tested by performing erythrocyte transketolase tests to pick out those with TD and supplementing the affected individuals with the appropriate dietary supplements.
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13
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Yuen BTK, Bush KM, Barrilleaux BL, Cotterman R, Knoepfler PS. Histone H3.3 regulates dynamic chromatin states during spermatogenesis. Development 2014; 141:3483-94. [PMID: 25142466 DOI: 10.1242/dev.106450] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The histone variant H3.3 is involved in diverse biological processes, including development, transcriptional memory and transcriptional reprogramming, as well as diseases, including most notably malignant brain tumors. Recently, we developed a knockout mouse model for the H3f3b gene, one of two genes encoding H3.3. Here, we show that targeted disruption of H3f3b results in a number of phenotypic abnormalities, including a reduction in H3.3 histone levels, leading to male infertility, as well as abnormal sperm and testes morphology. Additionally, null germ cell populations at specific stages in spermatogenesis, in particular spermatocytes and spermatogonia, exhibited increased rates of apoptosis. Disruption of H3f3b also altered histone post-translational modifications and gene expression in the testes, with the most prominent changes occurring at genes involved in spermatogenesis. Finally, H3f3b null testes also exhibited abnormal germ cell chromatin reorganization and reduced protamine incorporation. Taken together, our studies indicate a major role for H3.3 in spermatogenesis through regulation of chromatin dynamics.
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Affiliation(s)
- Benjamin T K Yuen
- Department of Cell Biology and Human Anatomy, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Genome Center, University of California Davis School of Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Institute of Pediatric Regenerative Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA
| | - Kelly M Bush
- Department of Cell Biology and Human Anatomy, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Genome Center, University of California Davis School of Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Institute of Pediatric Regenerative Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA
| | - Bonnie L Barrilleaux
- Department of Cell Biology and Human Anatomy, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Genome Center, University of California Davis School of Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Institute of Pediatric Regenerative Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA
| | - Rebecca Cotterman
- Department of Cell Biology and Human Anatomy, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Genome Center, University of California Davis School of Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Institute of Pediatric Regenerative Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA
| | - Paul S Knoepfler
- Department of Cell Biology and Human Anatomy, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Genome Center, University of California Davis School of Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA Institute of Pediatric Regenerative Medicine, Shriners Hospital For Children Northern California, Sacramento, CA 95817, USA
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Subramanian VS, Subramanya SB, Said HM. Relative contribution of THTR-1 and THTR-2 in thiamin uptake by pancreatic acinar cells: studies utilizing Slc19a2 and Slc19a3 knockout mouse models. Am J Physiol Gastrointest Liver Physiol 2012; 302:G572-8. [PMID: 22194418 PMCID: PMC3311432 DOI: 10.1152/ajpgi.00484.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Thiamin is essential for normal function of pancreatic acinar cells, and its deficiency leads to a reduction in pancreatic digestive enzymes. We have recently shown that thiamin uptake by rat pancreatic acinar cells is carrier-mediated and that both thiamin transporter (THTR)-1 and THTR-2 are expressed in these cells; little, however, is known about the relative contribution of these transporters toward total carrier-mediated thiamin uptake by these cells. We addressed this issue using a gene-specific silencing approach (siRNA) in mouse-derived pancreatic acinar 266-6 cells and Slc19a2 and Slc19a3 knockout mouse models. First we established that thiamin uptake by mouse pancreatic acinar cells is via a carrier-mediated process. We also established that these cells as well as native human pancreas express THTR-1 and THTR-2, with expression of the former (and activity of its promoter) being significantly higher than that of the latter. Using gene-specific siRNA against mouse THTR-1 and THTR-2, we observed a significant inhibition in carrier-mediated thiamin uptake by 266-6 cells in both cases. Similarly, thiamin uptake by freshly isolated primary pancreatic acinar cells of the Slc19a2 and Slc19a3 knockout mice was significantly lower than uptake by acinar cells of the respective littermates; the degree of inhibition observed in the former knockout model was greater than that of the latter. These findings demonstrate, for the first time, that both mTHTR-1 and mTHTR-2 are involved in carrier-mediated thiamin uptake by pancreatic acinar cells.
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Abstract
One of the earliest vitamins to be discovered and synthesized, thiamin was originally spelled with an "e". The terminal "e" was dropped when it was found that it was not an amine. It is still spelled with and without the "e" depending on the text. This chapter provides a brief historical review of the association of thiamin with the ancient scourge of beriberi. It emphasizes that beriberi is the model for high calorie malnutrition because of its occurrence in predominantly white rice consuming cultures. Some of the symptomatology of this ancient scourge is described, emphasizing the difference from that seen in starvation. High calorie malnutrition, due to excessive ingestion of simple carbohydrates, is widely encountered in the U.S.A. today. Thiamin deficiency is commonly associated with this, largely because of its cofactor status in the metabolism of glucose. The biochemistry of the three phosphorylated esters of thiamin and the transporters are discussed and the pathophysiology of thiamin deficiency reviewed. The role of thiamin, and particularly its synthetic derivatives as therapeutic agents, is not fully appreciated in Western civilization and a clinical section describes some of the unusual cases described in the scientific literature and some experienced by the author. The possible role of high calorie malnutrition and related thiamin deficiency in juvenile crime is hypothesized.
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Thiamine status in humans and content of phosphorylated thiamine derivatives in biopsies and cultured cells. PLoS One 2010; 5:e13616. [PMID: 21049048 PMCID: PMC2963613 DOI: 10.1371/journal.pone.0013616] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 09/30/2010] [Indexed: 12/19/2022] Open
Abstract
Background Thiamine (vitamin B1) is an essential molecule for all life forms because thiamine diphosphate (ThDP) is an indispensable cofactor for oxidative energy metabolism. The less abundant thiamine monophosphate (ThMP), thiamine triphosphate (ThTP) and adenosine thiamine triphosphate (AThTP), present in many organisms, may have still unidentified physiological functions. Diseases linked to thiamine deficiency (polyneuritis, Wernicke-Korsakoff syndrome) remain frequent among alcohol abusers and other risk populations. This is the first comprehensive study on the distribution of thiamine derivatives in human biopsies, body fluids and cell lines. Methodology and Principal Findings Thiamine derivatives were determined by HPLC. In human tissues, the total thiamine content is lower than in other animal species. ThDP is the major thiamine compound and tissue levels decrease at high age. In semen, ThDP content correlates with the concentration of spermatozoa but not with their motility. The proportion of ThTP is higher in humans than in rodents, probably because of a lower 25-kDa ThTPase activity. The expression and activity of this enzyme seems to correlate with the degree of cell differentiation. ThTP was present in nearly all brain and muscle samples and in ∼60% of other tissue samples, in particular fetal tissue and cultured cells. A low ([ThTP]+[ThMP])/([Thiamine]+[ThMP]) ratio was found in cardiovascular tissues of patients with cardiac insufficiency. AThTP was detected only sporadically in adult tissues but was found more consistently in fetal tissues and cell lines. Conclusions and Significance The high sensitivity of humans to thiamine deficiency is probably linked to low circulating thiamine concentrations and low ThDP tissue contents. ThTP levels are relatively high in many human tissues, as a result of low expression of the 25-kDa ThTPase. Another novel finding is the presence of ThTP and AThTP in poorly differentiated fast-growing cells, suggesting a hitherto unsuspected link between these compounds and cell division or differentiation.
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Hermo L, Pelletier RM, Cyr DG, Smith CE. Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 4: intercellular bridges, mitochondria, nuclear envelope, apoptosis, ubiquitination, membrane/voltage-gated channels, methylation/acetylation, and transcription factors. Microsc Res Tech 2010; 73:364-408. [PMID: 19941288 DOI: 10.1002/jemt.20785] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
As germ cells divide and differentiate from spermatogonia to spermatozoa, they share a number of structural and functional features that are common to all generations of germ cells and these features are discussed herein. Germ cells are linked to one another by large intercellular bridges which serve to move molecules and even large organelles from the cytoplasm of one cell to another. Mitochondria take on different shapes and features and topographical arrangements to accommodate their specific needs during spermatogenesis. The nuclear envelope and pore complex also undergo extensive modifications concomitant with the development of germ cell generations. Apoptosis is an event that is normally triggered by germ cells and involves many proteins. It occurs to limit the germ cell pool and acts as a quality control mechanism. The ubiquitin pathway comprises enzymes that ubiquitinate as well as deubiquitinate target proteins and this pathway is present and functional in germ cells. Germ cells express many proteins involved in water balance and pH control as well as voltage-gated ion channel movement. In the nucleus, proteins undergo epigenetic modifications which include methylation, acetylation, and phosphorylation, with each of these modifications signaling changes in chromatin structure. Germ cells contain specialized transcription complexes that coordinate the differentiation program of spermatogenesis, and there are many male germ cell-specific differences in the components of this machinery. All of the above features of germ cells will be discussed along with the specific proteins/genes and abnormalities to fertility related to each topic.
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Affiliation(s)
- Louis Hermo
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, 3640 University Street, Montreal, QC Canada H3A 2B2.
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Reidling JC, Lambrecht N, Kassir M, Said HM. Impaired intestinal vitamin B1 (thiamin) uptake in thiamin transporter-2-deficient mice. Gastroenterology 2010; 138:1802-9. [PMID: 19879271 PMCID: PMC4916904 DOI: 10.1053/j.gastro.2009.10.042] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/28/2009] [Accepted: 10/15/2009] [Indexed: 01/19/2023]
Abstract
BACKGROUND & AIMS Intestinal thiamin uptake process is vital for maintaining normal body homeostasis of the vitamin; in vitro studies suggest that both thiamin transporter-1 (THTR-1) and -2 (THTR-2) are involved. Mutations in THTR-1 cause thiamin-responsive megaloblastic anemia, a tissue-specific disease associated with diabetes mellitus, megaloblastic anemia, and sensorineural deafness. However, in patients with thiamin-responsive megaloblastic anemia, plasma thiamin levels are within normal range, indicating that THTR-2 (or another carrier) could provide sufficient intestinal thiamin absorption. We tested this possibility and examined the role of THTR-2 in uptake of thiamin in the intestine of mice. METHODS THTR-2-deficient mice were generated by SLC19A3 gene knockout and used to examine intestinal uptake of thiamin in vitro (isolated cells) and in vivo (intact intestinal loops). We also examined intestinal thiamin uptake in THTR-1-deficient mice. RESULTS Intestine of THTR-2-deficient mice had reduced uptake of thiamin compared with those of wild-type littermate mice (P < .01); this reduction was associated with a decrease (P < .01) in blood thiamin levels in THTR-2-deficient mice. However, intestinal uptake of thiamin in THTR-1-deficient mice was not significantly different from that of wild-type littermate animals. Level of expression of THTR-1 was not altered in the intestine of THTR-2-deficient mice, but level of expression of THTR-2 was up-regulated in the intestine of THTR-1-deficient mice. CONCLUSIONS THTR-2 is required for normal uptake of thiamin in the intestine and can fulfill normal levels of uptake in conditions associated with THTR-1 dysfunction.
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Comparative evaluation of different in vitro systems that stimulate germ cell differentiation in human embryonic stem cells. Fertil Steril 2010; 93:986-94. [DOI: 10.1016/j.fertnstert.2008.10.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 10/14/2008] [Accepted: 10/17/2008] [Indexed: 01/15/2023]
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Mee L, Nabokina SM, Sekar VT, Subramanian VS, Maedler K, Said HM. Pancreatic beta cells and islets take up thiamin by a regulated carrier-mediated process: studies using mice and human pancreatic preparations. Am J Physiol Gastrointest Liver Physiol 2009; 297:G197-206. [PMID: 19423748 PMCID: PMC2711754 DOI: 10.1152/ajpgi.00092.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Thiamin is essential for the normal function of the endocrine pancreas, but very little is known about uptake mechanism(s) and regulation by beta cells. We addressed these issues using mouse-derived pancreatic beta-TC-6 cells, and freshly isolated primary mouse and human pancreatic islets. Results showed that thiamin uptake by beta-TC-6 cells involves a pH (but not Na+)-dependent carrier-mediated process that is saturable at both the nanomolar (apparent K(m) = 37.17 +/- 9.9 nM) and micromolar (apparent K(m) = 3.26 +/- 0.86 microM) ranges, cis-inhibited by thiamin structural analogs, and trans-stimulated by unlabeled thiamin. Involvement of carrier-mediated process was also confirmed in primary mouse and human pancreatic islets. Both THTR-1 and THTR-2 were found to be expressed in these mouse and human pancreatic preparations. Maintaining beta-TC-6 cells in the presence of a high level of thiamin led to a significant (P < 0.01) decrease in thiamin uptake, which was associated with a significant downregulation in level of expression of THTR-1 and THTR-2 at the protein and mRNA levels and a decrease in transcriptional (promoter) activity. Modulators of intracellular Ca2+/calmodulin- and protein-tyrosine kinase-mediated pathways also altered thiamin uptake. Finally, confocal imaging of live beta-TC-6 cells showed that clinical mutants of THTR-1 have mixed expression phenotypes and all led to impairment in thiamin uptake. These studies demonstrate for the first time that thiamin uptake by the endocrine pancreas is carrier mediated and is adaptively regulated by the prevailing vitamin level via transcriptional mechanisms. Furthermore, clinical mutants of THTR-1 impair thiamin uptake via different mechanisms.
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Affiliation(s)
- Lisa Mee
- Veterans Affairs Medical Center-151, 5901 E. 7th St., Long Beach, CA 90822, USA.
| | - Svetlana M. Nabokina
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - V. Thillai Sekar
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - Veedamali S. Subramanian
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - Kathrin Maedler
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - Hamid M. Said
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
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Nixon PF. Glutamate Export at the Choroid Plexus in Health, Thiamin Deficiency, and Ethanol Intoxication: Review and Hypothesis. Alcohol Clin Exp Res 2008; 32:1339-49. [DOI: 10.1111/j.1530-0277.2008.00727.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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West JA, Park IH, Daley GQ, Geijsen N. In vitro generation of germ cells from murine embryonic stem cells. Nat Protoc 2006; 1:2026-36. [PMID: 17487192 DOI: 10.1038/nprot.2006.303] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The demonstration of germ cell and haploid gamete development from embryonic stem cells (ESCs) in vitro has engendered a unique set of possibilities for the study of germ cell development and the associated epigenetic phenomenon. The process of embryoid body (EB) differentiation, like teratoma formation, signifies a spontaneous differentiation of ESCs into cells of all three germ layers, and it is from these differentiating aggregates of cells that putative primordial germ cells (PGCs) and more mature gametes can be identified and isolated. The differentiation system presented here requires the differentiation of murine ESCs into EBs and the subsequent isolation of PGCs as well as haploid male gametes from EBs at various stages of differentiation. It serves as a platform for studying the poorly understood process of germ cell allocation, imprint erasure and gamete formation, with 4-6 weeks being required to isolate PGCs as well as haploid cells.
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Affiliation(s)
- Jason A West
- Graduate Program of Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts, USA
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Lonsdale D. A review of the biochemistry, metabolism and clinical benefits of thiamin(e) and its derivatives. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2006; 3:49-59. [PMID: 16550223 PMCID: PMC1375232 DOI: 10.1093/ecam/nek009] [Citation(s) in RCA: 207] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Thiamin(e), also known as vitamin B1, is now known to play a fundamental role in energy metabolism. Its discovery followed from the original early research on the ‘anti-beriberi factor’ found in rice polishings. After its synthesis in 1936, it led to many years of research to find its action in treating beriberi, a lethal scourge known for thousands of years, particularly in cultures dependent on rice as a staple. This paper refers to the previously described symptomatology of beriberi, emphasizing that it differs from that in pure, experimentally induced thiamine deficiency in human subjects. Emphasis is placed on some of the more unusual manifestations of thiamine deficiency and its potential role in modern nutrition. Its biochemistry and pathophysiology are discussed and some of the less common conditions associated with thiamine deficiency are reviewed. An understanding of the role of thiamine in modern nutrition is crucial in the rapidly advancing knowledge applicable to Complementary Alternative Medicine. References are given that provide insight into the use of this vitamin in clinical conditions that are not usually associated with nutritional deficiency. The role of allithiamine and its synthetic derivatives is discussed. Thiamine plays a vital role in metabolism of glucose. Thus, emphasis is placed on the fact that ingestion of excessive simple carbohydrates automatically increases the need for this vitamin. This is referred to as high calorie malnutrition.
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Affiliation(s)
- Derrick Lonsdale
- Preventive Medicine Group, Westlake, OH 44145, USA. dlonsdale@@pol.net
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Abstract
Many insights into mammalian germ cell development have been gained through genetic engineering and in vivo studies, but the lack of an in vitro system for deriving germ cells has hindered potential advances in germ cell biology. Recent studies have demonstrated embryonic stem cell differentiation into germ cells and more mature gametes, although significant unanswered questions remain about the functionality of these cells. The derivation of germ cells from embryonic stem cells in vitro provides an invaluable assay both for the genetic dissection of germ cell development and for epigenetic reprogramming, and may one day facilitate nuclear transfer technology and infertility treatments.
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Affiliation(s)
- Jason A West
- Graduate Program of Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA
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