Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “FASTING”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Fast spin echo and fast fluid attenuated inversion recovery sequences in multiple sclerosis].

Fast spin echo (FSE) and fast fluid attenuated inversion recovery (fast-FLAIR) MR sequences were compared with conventional spin echo (CSE) in quantitating multiple sclerosis (MS) lesion burden. For each sequence, the total number and volume of MS lesions were calculated in 38 remitting MS patients using a semiautomated lesion detection program. CSE, FSE and fast-FLAIR images were reported on randomly and at different times by two expert observers. Interobserver differences, the time needed to quantitate MS lesions and lesion signal intensity (contrast-to-noise ratio and overall contrast) were considered. The lesions were classified by site into infratentorial, white matter and cortical/subcortical. A total of 2970 lesions with a volume of 961.7 cm3 was calculated on CSE images. FSE images depicted fewer (16.6%; p < .005) and smaller (24.9%; p < .0001) lesions and the differences were statistically significant. Despite an overall nonsignificant reduction for fast-FLAIR images (.5% and 4.8% for lesion number and volume, respectively), significantly lower values (lesion number: p < .01; volume: p < .04) were observed for infratentorial lesions, while significantly higher values were seen for cortical/subcortical lesions (lesion number: p < .01; volume: p < .02). A higher lesion/white matter contrast (p < .002), a significant time saving for lesion burden quantitation (p < .05) and very low interobserver variability were found in favor of fast-FLAIR. Our data suggest that, despite the limitations regarding infratentorial lesions, fast-FLAIR sequences are indicated in MS studies because of their good identification of cortical/subcortical lesions, almost complete interobserver agreement, higher contrast-to-noise ratio and the limited time needed for semiautomated quantitation.

Adult↗
PubMed1992

Effects of fasting, refeeding, and fasting with T3 administration on Na-K,ATPase in rat skeletal muscle.

It is known that Na-K,adenosine triphosphatase (ATPase) in cell membranes represents an important consumer of cellular energy, eg, adenosine triphosphate (ATP), and that the concentration and activity of this enzyme change in a dose-dependent manner with serum thyroid hormone levels. To examine the hypothesis that low triiodothyronine (T3) syndrome represents a cellular adaptation in generalized severe illnesses that saves tissue energy expenditure, we measured the muscle Na-K,ATPase concentration and its activity in rats that led to low T3 syndrome induced by fasting. The Na-K,ATPase concentration was measured by 3H-ouabain binding to soleus muscle, and its activity was measured by 42K uptake in the contralateral soleus muscle. The effects of refeeding or T3 administration on Na-K,ATPase in soleus muscle in fasted rats were also examined. Na-K,ATPase concentration and activity were both increased in hyperthyroid rats and decreased in hypothyroid rats. In the fasting state, they were decreased to as low as the levels seen in hypothyroidism. Furthermore, with fasting + refeeding or fasting + T3 administration, Na-K,ATPase in soleus muscle returned to the normal level. These results suggest that tissue energy expenditure, as assessed by Na-K,ATPase, in skeletal muscles of fasted rats with low T3 syndrome is actually decreased to levels seen in hypothyroidism, due at least partly to the decrease in serum T3 concentrations, and that there exist some adaptation mechanisms in the peripheral tissues for the accommodation of energy metabolism in the body through decreased thyroxine (T4) to T3 conversion.

Adenosine Triphosphate↗
PubMed2000

[A case control study on the levels of lipid, fasting glucose, fasting insulin and sex hormones of hypertension in among elderly Uighur people in Hetian, Xinjiang].

OBJECTIVE: To detect the relationship between the levels of lipid, fasting glucose, fasting insulin, sex hormones and hypertension in the elderly Uighur people in Hetian, Xinjiang. METHODS: A case control study on 105 cases of hypertension was performed, including 58 males and 47 females, aged 60 - 106. RESULTS: Among the lipid analysis items, the decrease of high density lipoprotein-cholesterol (HDL-C) was the important factor related to the occurrence of the complications of hypertension (OR = 5.6214). The increases of both fasting glucose and fasting insulin levels were also risk factors of hypertension in the elderly Uighur people (OR = 2.4474 and OR = 2.5318). CONCLUSION: The risk factors of hypertension in the elderly Uighur people included decrease of HDL-C, high-level fasting glucose and fasting insulin.

Aged↗
PubMed1992

Effect of human mammary MX-1 tumor on plasma free fatty acids in fasted and fasted-refed nude mice.

We hypothesized that tumor-bearing (TB) nude mice, because they are reported to have no detectable, circulating tumor necrosis factor (TNF)/cachectin, would regulate their plasma free fatty acid (FFA) levels normally when fasted and refed. We compared levels of individual plasma FFA in response to fasting (24 hr) and to refeeding (for 20 hr after fasting) a fat-free, 65% sucrose diet in control, nude mice and in mice bearing 1.3 +/- 0.4 g MX-1 tumors. Total plasma FFA levels were typically high in 24-hr fasted mice [mean concentrations in microM +/- SE (n); controls 515 +/- 63 (6); TB, 625 +/- 63 (6)]. FFA levels were reduced by 65% in each group in response to refeeding. Each major plasma FFA species fell in response to refeeding, except arachidonate, which did not change significantly (fasted vs. fasted-refed concentrations) in either controls or TB mice. In refed mice, the molar FFA ratio of oleate to linoleate rose; however, that of oleate to arachidonate fell markedly. TB nude mice had normal appetites. We conclude that all species of FFA were mobilized from adipose tissue in a normal manner in TB nude mice; therefore, regulation of adipose triacylglycerol fatty acid mobilization (as plasma FFA) by dietary sugar is probably not affected by MX-1 tumor growth in these mice. Our findings are consistent with the hypothesis that nude mice may be unable to secrete TNF/cachectin in response to tumor growth, but they do not establish whether or not endogenous, circulating TNF/cachectin increases FFA mobilization in any TB animal.

Adipose Tissue↗
PubMed1999

The sensitivity of thin-slice fast spin echo, fast FLAIR and gadolinium-enhanced T1-weighted MRI sequences in detecting new lesion activity in multiple sclerosis.

Fast fluid-attenuated inversion-recovery (FLAIR) and proton density/T2-weighted fast spin echo (FSE) brain images with 3-mm slices were acquired monthly for 7 months in 37 multiple sclerosis patients. New and enlarging lesions were counted and compared according to the site of lesions seen with each sequence. In addition, the number of new enhancing lesions seen on gadolinium-enhanced T1-weighted brain magnetic resonance imaging at the same time points was counted. All sequences used 3-mm contiguous axial slices. Overall, 126 new or enlarging lesions were seen on FSE and 135 on fast FLAIR (P = 0.25, Wilcoxon signed ranks test). Regional comparisons revealed significantly more fast FLAIR lesions only in the cortical/subcortical areas. There was a total of 295 new enhancing lesions over the same period -- a gain in the number of 'active lesions' of 234% seen with FSE and 218% with FLAIR. It is concluded that serial thin slice fast FLAIR is only slightly superior to FSE in detecting new and enlarging multiple sclerosis lesions but the difference is not sufficient to recommend that FLAIR should replace FSE in short-term, exploratory trials in MS using monthly scanning. Gadolinium-enhanced imaging is more then twice as sensitive as either FSE or fast FLAIR to new multiple sclerosis lesion activity, and enhancing lesions should provide the primary outcome measure in such studies.

Adult↗
PubMed1994

Short tau inversion recovery fast spin-echo (fast STIR) imaging of the spinal cord in multiple sclerosis.

The short tau inversion recovery fast spin-echo pulse sequence (fast STIR) combines the synergistic T1 and T2 contrast mechanism of conventional STIR with the reduced imaging time of fast spin-echo (FSE). We have compared fast STIR with T2-weighted FSE in evaluating the spinal cord lesions in 17 patients with multiple sclerosis and 12 healthy controls. Intrinsic lesions were seen only in patients. Twenty-five of the 58 lesions identified were more clearly demonstrated by fast STIR, 22 by FSE. Signal-to-noise and contrast-to-noise ratios were higher in all cases on FSE, suggesting other mechanisms, in particular choice of window settings and brightness of surrounding structures, must play a part in lesion conspicuousness. Fast STIR is a useful adjunct to FSE in the evaluation of multiple sclerosis in the spinal cord.

Adult↗
PubMedDate not supplied

Synthesis of fast myosin induced by fast ectopic innervation of rat soleus muscle is restricted to the ectopic endplate region.

Skeletal muscle fibres, long multinucleated cells, arise by fusion of mononucleated myoblasts to form a myotube that matures into the adult fibre. The two major types of mature fibre, fast and slow fibres, differ physiologically in their rate of isotonic shortening. At the molecular level these type-specific physiological properties are ascribed to different isoforms of myosin, a major protein involved in shortening. Differentiation of fast and slow fibres seems to be under the control of motoneurones, and mature fibres are innervated by only one motoneurone. When rat soleus muscle (SOL, a slow muscle) is dually innervated with a fast nerve, it acquires some properties of a fast muscle, that is, low sensitivity to caffeine and high glycogen content. We report here that in dually innervated soleus muscle the foreign fast nerve induces synthesis of fast isoforms of myosin, but only in the segment of the muscle fibre that is close to the foreign endplate. The localized influence of the nerve endplates suggest that factors controlling the phenotypic expression of the muscle fibre have a short range of activity.

Animals↗
PubMed1989

Restoration of fast muscle characteristics following cessation of chronic stimulation: physiological, histochemical and metabolic changes during slow-to-fast transformation.

Implantable electronic stimulators were used to subject fast-twitch tibialis anterior and extensor digitorum longus muscles of adult rabbits to a chronically increased level of use. Stimulation was discontinued after 6 weeks and physiological, histochemical and biochemical properties of the muscles were examined at intervals over the ensuing 20 weeks. Previous work had shown that 6 weeks of stimulation was sufficient to bring about a substantial transformation of type in fast-twitch muscles, which then exhibited much of the character of muscles of the slow-twitch type. The present experiments showed that these stimulation-induced changes were completely reversible. The time-course of reversion was such that the muscles had recovered their original fast properties by about 12 weeks after the cessation of stimulation. The contractile characteristics and post-tetanic potentiation typical of fast muscle returned rapidly, in only 3-4 weeks, and over the same period the proportion of histochemical type 1 fibres declined from about 70% to control levels. Changes in fatigue-resistance, capillary density and enzyme activity followed a more prolonged time-course; in particular, the decline in the activity of enzymes of oxidative metabolism corresponded closely to that already established for the mitochondrial volume fraction. Reacquisition of fast properties was not accompanied by any changes in specific force-generating capacity. Observations from these experiments and from a related morphological study fit into a 'first-in, last-out' pattern for the response to stimulation and recovery. The slow-to-fast reversion that takes place during the recovery period provides a further opportunity for testing causal associations within the events underlying type transformation. It has important consequences for therapeutic applications that make use of the fatigue-resistant character of chronically stimulated muscle.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed2005

Application of direct agglutination test (DAT) and fast agglutination screening test (FAST) for sero-diagnosis of visceral leishmaniasis in endemic area of Minas Gerais, Brazil.

BACKGROUND: The direct agglutination test (DAT) has proved to be a very important sero-diagnostic tool combining high levels of intrinsic validity and ease of performance. Otherwise, fast agglutination screening test (FAST) utilises only one serum dilution making the test very suitable for the screening of large populations. RESULTS: We have tested FAST and DAT for the detection anti-Leishmania antibodies in serum samples from patients with American visceral (AVL) and cutaneous leishmaniases (ACL) in Minas Gerais State, Brazil. The DAT on serum and blood samples of confirmed AVL patients found all samples positive at a serum dilution of > or = 1:800. This dilution was subsequently used as cut off value in the study. The blood and serum samples of these confirmed patients could also be clearly read in FAST using a 1:100 dilution with the same high sensitivity. DAT and FAST were not able to detect significant amounts of antibodies in samples from ACL patients and are not suitable for the diagnosis of this manifestation of the disease. CONCLUSION: We suggest that both DAT and FAST are very practical diagnostic tools for the sero-diagnosis of AVL under rural conditions as both serological tests do not require sophisticated equipment, a cold chain and are very simple to perform.

Journal Article↗
PubMed1998

Three-dimensional fast fluid attenuated inversion recovery (3D fast FLAIR): a new MRI sequence which increases the detectable cerebral lesion load in multiple sclerosis.

Two-dimensional (2D) fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging is superior to T2 weighted conventional spin echo (CSE), in certain areas of the brain but not in others, in detecting the lesions of multiple sclerosis (MS). The present study evaluates the ability of a recently developed three-dimensional fast FLAIR (3D fast FLAIR) sequence in detecting and quantifying the brain lesions of multiple sclerosis. The lesion volumes measured on the 3D fast FLAIR sequence with 1.5 mm thick slices were compared with those obtained from CSE brain images with 5 mm thick slices. The findings seen in 3D fast FLAIR brain images in 10 normal control subjects are also described. 3D fast FLAIR images showed an overall increase of 34% in lesion volume compared with CSE. The increase was most marked in the periventricular and "discrete" areas of the cerebral hemispheres. Lesion volumes seen in the subcortical areas were similar in both sequences. The CSE images displayed higher lesion volumes in the posterior cranial fossa. It is concluded that 3D fast FLAIR is a promising technique for quantifying cerebral pathology in MS which is not accessible to 2D CSE.

Adult↗
PubMed1997

Non-breath-hold fast spin-echo versus breath-hold fast spin-echo and spoiled gradient-recalled echo MR imaging in the detection of hepatic tumors: correlation with surgical findings.

OBJECTIVE: Our objective was to compare the sensitivity of non-breath-hold T2-weighted fast spin-echo with and without fat suppression, breath-hold T2-weighted fast spin-echo without fat suppression, and spoiled gradient-recalled echo (GRE) MR imaging for detecting hepatic tumors using surgical findings as the standard of reference. SUBJECTS AND METHODS: Eighteen patients with 36 surgically proven hepatic tumors had non-breath-hold T2-weighted fast spin-echo (6000/117 [TR/effective TE; echo train length, 16) MR imaging with and without fat suppression, breath-hold T2-weighted fast spin-echo MR imaging (2700/105; echo train length, 20), and spoiled GRE images (10.1/1.9; flip angle, 30 degrees) obtained before and after injection of a gadolinium chelate. Images were analyzed separately by two independent readers, with disagreements resolved by consensus reading. RESULTS: Non-breath-hold T2-weighted fast spin-echo MR imaging with and without fat suppression depicted 22 (61%; 95% confidence interval [CI], 43-77%) and 20 (56%; 95% CI, 37-72%) of 36 hepatic tumors, respectively. Breath-hold T2-weighted fast spin-echo imaging allowed detection of 19 (53%; 95% CI, 35-69%) of 36 hepatic tumors. Unenhanced and gadolinium chelate-enhanced spoiled GRE images allowed depiction of 18 (50%; 95% CI, 33-67%) and 29 (81%; 95% CI, 63-91%) of 36 hepatic tumors, respectively. Gadolinium chelate-enhanced spoiled GRE images allowed depiction of significantly more hepatic tumors than any of the other pulse sequences. CONCLUSION: Gadolinium chelate-enhanced spoiled GRE imaging is more sensitive than T2-weighted MR imaging obtained with a breath-hold or a non-breath-hold technique.

Contrast Media↗
PubMed1982

Fasting portal vein plasma levels of gastric inhibitory polypeptide (GIP) and extractable fasting GIP in the duodenal wall in rats treated with methylprednisolone or alloxan compared with normal controls.

Ten rats were treated with methylprednisolone, another 10 rats with alloxan, and a final 10 control rats with saline. Compared with the controls, the methyl-prednisolone-treated rats had increased fasting levels of serum insulin, blood glucose, and plasma GIP; the alloxan-treated rats had decreased fasting levels of insulin and increased levels of fasting blood glucose and plasma GIP. After removal of the duodenum in the fasting state, the amount of GIP was measured in duodenal tissue specimens after extraction with ice-cold acetic acid, pH 3.0, and with neutralized acetic acid at 95 C. The duodenal content of GIP was 765.5 +/- 60.2 ng/g in the methylprednisolone-treated rats, 897.6 +/-37.3 ng/g in the alloxan-treated rats, and 923.1 +/- 72.9 ng/g in the saline-treated control rats. There were no significant differences in duodenal GIP content between the various groups, nor did the fasting plasma GIP and the amount of duodenal GIP in the individual rats correlate significantly (r=0.147, p less than 0.1). The elevated levels of fasting plasma GIP in the diabetic rats treated with methylprednisolone or alloxan may be due to factors regulating the secretion of GIP rather than to changes in the duodenal content of GIP.

Alloxan↗
PubMed1975

A new isoniazid preparation designed for moderately fast and "fast" metabolizers of the drug.

The bioavailability of a new isoniazid preparation consisting of 37% ordinary isoniazid (INH) and 63% matrix component was investigated in 11 slow, 8 moderately fast, and 9 "fast" acetylators of the drug. Initially, a 15 mg/kg dose of normal INH was administered to all the participants. In addition, the two groups of fast metabolizers received 30 and 45 mg INH-matrix/kg, respectively, with a one-week interval between the test doses. These high dosages of the INH-matrix could be given without encountering toxic reactions because of the delayed absorption of the matrix formulation. In moderately fast acetylators, with a triple dose of matrix isoniazid, it was possible to mimic the blood levels produced by 15 mg ordinary INH/kg in slow inactivators. However, in "fast" acetylators the blood concentrations achieved with the 45 mg/kg dose of INH-matrix were somewhat lower. This study also showed that a large input rate is essential to procure the required, high blood levels in fast metabolizers. The therapeutic implications of the results of this bioavailability trial are discussed.

Acetylation↗
PubMed1997

Localization of glycogen phosphorylase activity in liver of fasted normal and adrenalectomized rats and in fasted adrenalectomized rats after injection of dexamethasone.

BACKGROUND: The intralobular distribution of activity of glycogen phosphorylase (GP), a key enzyme in the breakdown of glycogen, was evaluated to determine changes during early glycogen synthesis. Hepatic GP activity was localized in normal and adrenalectomized (ADX) rats after fasting overnight and in fasted ADX rats stimulated to synthesize glycogen by administration of dexamethasone (DEX) 2-8 h prior to sacrifice. METHODS: Cryostat sections were incubated in medium containing appropriate substrate for demonstration of GP activity as indicated by glycogen synthesized by the enzyme during incubation. RESULTS: In sections from fasted normal rats, GP activity in hepatocytes varied from undetectable to substantial amounts with no notable periportal to pericentral gradient evident. In contrast, GP activity in sections from adrenalectomized fasted rats was concentrated in discrete aggregates in random hepatocytes throughout lobules. Two hours after DEX injection, GP enzyme activity occurred as single aggregates or in a dispersed pattern in many hepatocytes. By 4 h after DEX administration, most cells displayed GP enzyme activity, the concentration of which appeared to be greater in pericentral cells than in periportal cells. Eight hours after injection of DEX, GP enzyme activity had increased and appeared more evenly distributed throughout the lobules. CONCLUSIONS: These results suggest that GP activity became concentrated in limited regions of selected hepatocytes in fasted ADX rats. DEX stimulation of glycogen synthesis in these rats resulted in increased GP activity that was concentrated in pericentral cells after 4 h. After 8 h, activity increased and was more evenly distributed throughout the lobules. The increase in GP enzyme activity concurrent with overall glycogen synthesis suggests that the enzyme may participate in glycogen turnover.

Adrenalectomy↗
PubMed2002

Effects of fasting and intermittent fasting on rat hepatocarcinogenesis induced by diethylnitrosamine.

The influences of fasting on DEN-initiation and of intermittent fasting (IF) on the rat liver chemical carcinogenesis process were evaluated in a 52-week long assay. Three groups of adult male Wistar rats were used: Groups 1 to 3 were treated with a single i.p. injection of 200 mg/kg of diethylnitrosamine (DEN). Group 2 was submitted to 48 h fasting prior to DEN treatment. After the 4th week, Group 3 was submitted to IF, established as 48 h weekly fasting during 48 weeks, while Groups 1 and 2 were fed ad libitum until the 52nd week. All animals were submitted to 70% partial hepatectomy and sacrificed at the 3rd and 52nd weeks, respectively. Fasting prior to DEN-initiation did not influence the development of altered foci of hepatocytes (AFHs) and of hepatic nodules (Group 2 vs. Group G1). IF inhibited the development of preneoplastic lesions, since this dietary regimen decreased the number and the size of glutathione S-transferase (GST-P) positive foci and the number and size of liver nodules (Group G3 vs. Group G1). The inhibitory effect of IF was also reflected in the development of clear and basophilic cell foci. These results indicate that long-term IF regimen exerts an anti-promoting effect on rat hepatocarcinogenesis induced by DEN.

Alkylating Agents↗
PubMed1987

Fasting gastrinemia and elevated supersaturation with hydroxyapatite of fasting urine--observations in renal calcium stone patients and controls.

We evaluated serum gastrin, acid-base status, variables of mineral metabolism in fasting blood, as well as pH, relative supersaturation of stone forming constituents, and crystalluria in the associated fasting urine, of control subjects (n = 12), and in age- and weight-matched male normocalciuric (n = 12) and hypercalciuric (n = 12) patients with idiopathic recurrent calcium urolithiasis (RCU). In RCU, mineral metabolism and acid-base data are unchanged, whereas mean serum gastrin is only insignificantly higher as compared to controls. Subclassification of all participants into categories with either high-normal or low-normal gastrin reveals that in RCU with low-normal gastrin there is a higher-than-normal urinary pH and significantly elevated supersaturation of urine with hydroxyapatite. Crystalluria and stone analysis support the assumption that the physico-chemical environment accompanied by low gastrin levels predisposes to urinary precipitation of calcium phosphate with subsequent formation of a stone nidus. pH in fasting urine and integrated fasting serum gastrin correlate significantly, suggesting that low fasting serum gastrin in RCU patients may be considered a risk factor for calcium phosphate stone formation.

Acid-Base Equilibrium↗