Effect of Anticonvulsants on the Uptake of 5-Methyltetrahydrofolic Acid by the Choroid Plexus in Rabbits

1977 ◽  
Vol 53 (1) ◽  
pp. 75-80
Author(s):  
H. Taguchi ◽  
Z. Abdul-Cader ◽  
J. Perry ◽  
E. H. Reynolds ◽  
I. Chanarin

1. The isolated choroid plexus of the rabbit takes up 5-methyltetrahydrofolate from the incubation medium. 2. Other folate analogues (pteroylglutamic acid, methotrexate, 5-formyltetrahydrofolate = folinic acid) inhibited the uptake of 5-methyltetrahydrofolate. 3. The uptake of 5-methyltetrahydrofolate was inhibited by low temperature, anaerobic conditions and dinitrophenol. 4. The anticonvulsant drugs, diphenylhydantoin and phenobarbital, had no effect on 5-methyltetrahydrofolate uptake. 5. The inhibitory effect of pteroylglutamic acid on the uptake of 5-methyltetrahydrofolate by the choroid plexus may explain the effect of long-term folic acid therapy in aggravating vitamin B12 neuropathy in pernicious anaemia.

1998 ◽  
Vol 13 (1) ◽  
pp. 106-112 ◽  
Author(s):  
C. van Guldener ◽  
M. J. F. M. Janssen ◽  
J. Lambert ◽  
P. M. ter Wee ◽  
C. Jakobs ◽  
...  

1974 ◽  
Vol 32 (3) ◽  
pp. 491-501 ◽  
Author(s):  
B. Senewiratne ◽  
J. Hettiarachchi ◽  
Kamalini Senewiratne

1. The response to cyanocobalamin and folic acid therapy was studied in forty-seven subjects with severe nutritional megaloblastic anaemia; twenty-five were vitamin B12 deficient and, of these, ten were also folic acid deficient.2. In twenty-four of the subjects, absorption of orally administered cyanocobalamin was normal, and there was a haematological response to small doses of orally administered cyanocobalamin, indicating adequate absorption. In one subject there was impaired cyanocobalamin absorption although free gastric hydrochloric acid was present.3. The findings indicate that the absorptive function of the small intestine was unimpaired, with one exception, although there was a possible defect in nucleoprotein synthesis associated with a lack of vitamin B12 and folic acid. Addisonian pernicious anaemia was not found in any of the subjects.


2008 ◽  
Vol 85 (8) ◽  
pp. 1146-1150 ◽  
Author(s):  
Luciano Potena ◽  
Francesco Grigioni ◽  
Marco Masetti ◽  
Gaia Magnani ◽  
Fabio Coccolo ◽  
...  

2003 ◽  
Vol 73 (3) ◽  
pp. 215-220 ◽  
Author(s):  
de Gómez Dumm ◽  
Giammona ◽  
Touceda

Dyslipidemia and increases in plasma homocysteine usually occur at end-stage renal disease; both are recognized as risk factors for atherosclerosis. Folate administration reduces homocysteine concentration. In this study we determined the effect of a high dose of folic acid (40 mg intravenous injection three times a week) on plasma and red blood cell lipid profiles in twelve chronic renal failure patients on regular hemodialysis. Fasting blood samples were taken at the beginning of the study (baseline) and after 21, 42, and 64 days of treatment. Folic acid supplementation decreased plasma homocysteine. Plasma triglyceride levels decreased whereas polyunsaturated fatty acid values increased after 21 days; then they returned to baseline levels at the end of treatment. Total cholesterol and low-density lipoprotein (LDL) cholesterol were higher than those of the baseline during all the study, whereas high-density lipoprotein (HDL) cholesterol was reduced. In erythrocyte membranes, folic acid therapy enhanced cholesterol/phospholipid ratios and the fluorescence anisotropy of diphenyl-hexatriene. We conclude that large doses of folic acid produce a favorable effect, reducing plasma homocysteine levels and protecting patients from atherosclerosis. However, as this therapy induces significant alterations in both plasma and erythrocyte membrane lipid profiles, plasma lipid values should be controlled throughout the treatment of patients with renal failure.


2021 ◽  
pp. 1-19
Author(s):  
Vojtech Kouba ◽  
Juan Camilo Gerlein ◽  
Andrea Benakova ◽  
Marco Antonio Lopez Marin ◽  
Eva Rysava ◽  
...  

2021 ◽  
Vol 13 (9) ◽  
pp. 5223
Author(s):  
Miriam Benedetti ◽  
Daniele Dadi ◽  
Lorena Giordano ◽  
Vito Introna ◽  
Pasquale Eduardo Lapenna ◽  
...  

The recovery of waste heat is a fundamental means of achieving the ambitious medium- and long-term targets set by European and international directives. Despite the large availability of waste heat, especially at low temperatures (<250 °C), the implementation rate of heat recovery interventions is still low, mainly due to non-technical barriers. To overcome this limitation, this work aims to develop two distinct databases containing waste heat recovery case studies and technologies as a novel tool to enhance knowledge transfer in the industrial sector. Through an in-depth analysis of the scientific literature, the two databases’ structures were developed, defining fields and information to collect, and then a preliminary population was performed. Both databases were validated by interacting with companies which operate in the heat recovery technology market and which are possible users of the tools. Those proposed are the first example in the literature of databases completely focused on low-temperature waste heat recovery in the industrial sector and able to provide detailed information on heat exchange and the technologies used. The tools proposed are two key elements in supporting companies in all the phases of a heat recovery intervention: from identifying waste heat to choosing the best technology to be adopted.


1993 ◽  
Vol 137 (2) ◽  
pp. 247-NP ◽  
Author(s):  
H. F. Urbanski ◽  
M. M. Fahy ◽  
P. M. Collins

ABSTRACT The influence of excitatory amino acids (EAAs) on reproductive neuroendocrine function was investigated in adult male Syrian hamsters of the LSH/Ss Lak strain. Before the study, the animals were maintained in a sexually regressed condition, under short days (SD) and subsequently were either transferred to long days (LD) or kept under SD, for a further 4 weeks. In the former group, photostimulation produced a predictable elevation in the hypophysial contents and serum concentrations of FSH and LH. This was accompanied by an increase in testicular size, an elevation in serum testosterone levels and an increase in spermatogenic activity; the SD hamsters remained sexually quiescent throughout the study. In contrast, SD hamsters that were given daily injections of the EAA agonist, N-methyl-d,l-aspartate (NMA: 50 mg/kg body weight, s.c.), showed stimulatory responses that were generally even more pronounced than those shown by the LD group. Surprisingly, an identical NMA treatment paradigm failed to cause a similar activation of the reproductive axis in LD hamsters that were given daily afternoon injections of melatonin (25 μg, s.c), even though the inhibitory effect of this melatonin treatment is generally regarded as being comparable with that produced by exposure to SD. Although EAAs can acutely stimulate the neurocircuitry that controls LH-releasing hormone secretion, the present findings suggest that EAAs might also exert a long-term stimulatory action by acting further upstream in the photoneuroendocrine pathway. Journal of Endocrinology (1993) 137, 247–252


1993 ◽  
Vol 53 (3) ◽  
pp. 206-209 ◽  
Author(s):  
Kohei Notoya ◽  
Keiji Yoshida ◽  
Shigehisa Taketomi ◽  
Iwao Yamazaki ◽  
Masayoshi Kumegawa

Endocrinology ◽  
1995 ◽  
Vol 136 (3) ◽  
pp. 990-994 ◽  
Author(s):  
B Kanyicska ◽  
J D Livingstone ◽  
M E Freeman

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