scholarly journals Zinc absorption in the rat

1981 ◽  
Vol 46 (1) ◽  
pp. 15-27 ◽  
Author(s):  
M. J. Jackson ◽  
D. A. Jones ◽  
R. H. T. Edwards

1. A method of studying zinc absorption in rats has been developed in which binding of radioactive Zn to the intestinal mucosa and absorption into the carcass was determined at different times after administration by stomach tube.2. This technique has been used to evaluate different hypotheses concerning the control of Zn absorption and to examine the processes by which this occurs.3. The proportion of radioactive Zn absorbed into the carcass was found to be dependent on the Zn status of the animals but that found within the small intestinal wall was independent of this, indicating the existence of two mechanisms of Zn absorption.4. One of these two mechanisms has been shown to be induced by a low dietary Zn content while the other was shown to be insensitive to this. This latter mechanism predominated in rats of normal dietary Zn status and a study of the characteristics of this process indicated that the quantity of Zn absorbed was proportional to the dietary Zn content over the normal range of intake. This implies that normally Zn homeostasis in rats is achieved through variations in Zn excretion. The additional mechanism of Zn absorption only becomes fully active at levels of dietary Zn below 0.24 μmol/g diet.

1979 ◽  
Author(s):  
J. G. Kelton ◽  
P. B. Neame ◽  
I. Walker ◽  
A. G. Turpie ◽  
J. McBride ◽  
...  

Thrombotic thrombocytopenic purpura (TTP) is a rare but serious illness of unknown etiology. Treatment by plasmapheresis has been reported to be effective but the mechanism for benefit is unknown. We have investigated the effect of plasmapheresis in 2 patients with TTP by quantitating platelet associated IgG (PAIgG) levels prior to and following plasmapheresis. Both patients had very high levels of PAIgG at presentation (90 and A8 fg IgG/platelet respectively, normal 0-5). in both, the PAIgG levels progressively fell to within the normal range and the platelet count rose following plasmapheresis. One patient remained in remission with normal platelet counts and PAIgG levels. The other relapsed after plasmapheresis and the PAIgG level rose prior to the fall in platelet count. Plasmapheresis was repeated and resulted in normalization of both the platelet count and PAIgG level. It is suggested that plasmapheresis removes antiplatelet antibody or immune complexes which may be of etiological importance in this illness.


1979 ◽  
Vol 41 (3) ◽  
pp. 591-603 ◽  
Author(s):  
N. T. Davies ◽  
S. E. Olpin

1. Studies were carried out in vitro to examine the effects of phytate on the solubility of the trace elements zinc, copper and manganese. Appropriate volumes of a solution of sodium phytate were added to a mineral solution to achieve phytate: Zn values of from 0: 1 to 45:1. In a second series the same values for phytate: Zn were achieved by varying the amount of added Zn at a fixed phytate concentration.2. In both experiments > 85% of the Zn was rendered insoluble at pH 6.5 even at the lowest value for phytate:Zn (5:1). The effect of phytate on Zn solubility was greater than effects on Cu or Mn.3. In a dietary study, rats were offered a semi-synthetic egg-albumin-based diet with added phytate. Two series of diets were prepared, the first had a constant Zn content (18.5 mg Zn/kg) and the amount of sodium phytate varied so as to achieve values for phytate: Zn of from 0:1 to 40:1 (series 1). In the second series, the same values for phytate:Zn were achieved by adding a fixed amount of phytate (7.4 g phytic acid/kg) while the amount of Zn was varied (series 2).4. Dietary phytate caused significant reductions in growth rates, plasma Zn concentrations and hair Zn concentrations and greying of the coat at values for phytate:Zn of 15:1, 10:1, 10:1 and 15:1, respectively.5. While phytate was apparently slightly more effective in reducing Zn status when phytate:Zn values were achieved at the lower absolute levels of phytate and Zn (series I diets), the differences at equivalent phytate:Zn values were small. It was concluded that phytate:Zn values can be used as an indicator of Zn availability from phytate-rich diets.Rats offered three diets containing soya-bean-based textured-vegetable-protein (TVP) exhibited low rates of weight gain compared with rats offered an egg-albumen-based diet of similar Zn content (14.5 mg Zn/kg). Additional Zn supplied in drinking-water (25 mg Zn/l) was without effect on rats consuming the egg-albumin diet but significantly improved the weight gain of rats on the TVP diets.7. It was concluded that phytate naturally present in TVP behaves similarly to phytate added to an otherwise phytate-free diet and that the reduced availability of Zn in TVP diets can be accounted for entirely by their phytate contents.


2006 ◽  
Vol 16 (1-2) ◽  
pp. 69-73 ◽  
Author(s):  
Yoshinari Takai ◽  
Toshihisa Murofushi ◽  
Munetaka Ushio ◽  
Shinichi Iwasaki

The time course of the recovery of subjective visual horizontal (SVH) after unilateral vestibular deafferentation by intratympanic instillation of gentamicin was studied. Six patients who underwent intratympanic gentamicin instillation therapy for Meniere's disease (1 man and 5 women, 32 to 69 years of age) were enrolled in this study. For comparison, SVH in 23 healthy subjects (12 men and 11 woman, 23 to 48 years of age) was also measured. The mean ± SD of SVH in healthy subjects was 0.0 ± 1.1 deg. All of the 6 patients showed significantly deviated SVH toward the injected side-down at the early stage after the therapy. Although one patient showed recovery of SVH to the normal range 25 days after the injection, the other patients required more time for recovery. Three patients did not show recovery to the normal range after 1 year. On the other hand, spontaneous nystagmus observed using an infrared CCD camera in total dark disappeared after 35 days (median). Patients who had normal vestibular evoked myogenic potentials before the therapy showed a tendency of delay of recovery of SVH. The reasons why the recovery of SVH took longer than the disappearance of spontaneous nystagmus are discussed in this report.


1999 ◽  
Vol 58 (2) ◽  
pp. 497-505 ◽  
Author(s):  
Mark L. Failla

Defining optimal dietary intakes of Cu and Zn throughout the life cycle continues to present a considerable challenge for nutrition scientists. Although the daily intake of these micronutrients is below that currently recommended for many groups, traditional biochemical indicators of nutritional status for these trace metals largely remain within the normal range. Thus, it is unclear whether the recommended daily intakes may be unnecessarily high, or if the commonly-used markers simply lack the necessary sensitivity and specificity that are required for accurately assessing Cu and Zn status. The increasing number of reports that daily supplements with these trace metals enhance the activities of selective metalloenzymes and specific cellular and organ processes further points out the need to differentiate between meeting the requirement and providing optimal nutriture. Results from recent studies suggesting that alternative molecular and functional markers possess sufficient sensitivity to better assess Cu and Zn status are discussed. Likewise, recent studies evaluating the impact of very low and excessive levels of dietary Mn and Mo on selective biochemical and metabolic indicators are reviewed.


2007 ◽  
Vol 135 (1-2) ◽  
pp. 80-84
Author(s):  
Milena Bakrac ◽  
Branka Bonaci-Nikolic ◽  
Natasa Colovic ◽  
Sanja Simic-Ogrizovic ◽  
Miodrag Krstic ◽  
...  

Enteropathy associated T-cell lymphoma (EATCL) is a high grade, pleomorphic peripheral T-cell lymphoma with usually cytotoxic phenotype. This is a case report of three patients with EATCL. The first patient was 50 year-old woman with four year history of gluten sensitive enteropathy (GSE). Diagnosis of lymphoma was confirmed after the resection of the jejunum (small intestine obstruction). Pathohistological (PAS, Reticulin, Giemsa) and immunohistochemical (anti-LCA, anti-CD20, anti- CD45RO, anti-CD3) methods revealed the diagnosis of EATCL: CD45RO+, CD3+. After the third cycle of chemotherapy, the disease progressed with massive lung infiltration. Patient died due to complications of bone marrow aplasia. The second patient was 23 year-old woman with long earlier history of GSE. She presented with the acute renal failure. According to established diagnosis of tubulointerstitial nephritis, she was treated with pulse doses of steroid therapy. After temporary improvement, she had dissemination of the disease. On MRI, small intestinal wall was thickened, and abdominal lymph nodes were enlarged with extraluminal compression of common bile duct. Laparotomy with mesenterial lymph node biopsy and consecutive pathohistological and immunohistochemical analyses revealed the diagnosis of EATCL. The patient received chemotherapy, but she died with signs of pulmonary embolization. The third patient was 53 year-old woman without previous history of GSE. Diagnosis of EATCL was revealed after the resection of jejunum because of small intestinal obstruction. She received two cycles of chemotherapy, but she died with signs of disease progression. IgA antiendomysial antibodies were detected in the serum of all patients. The overall survival of patients was 7 months. The possibility of lymphoma rising in patients with clinical progression of GSE despite gluten free diet must be kept in mind.


1990 ◽  
Vol 63 (3) ◽  
pp. 597-611 ◽  
Author(s):  
Pamela M. Manson ◽  
Patricia A. Judd ◽  
Susan J. Fairweather-Tait ◽  
John Eagles ◽  
Margret J. Minski

Fifteen adult women were given diets in which the intake of complex carbohydrates was increased from 20 to 30 g over a 12 week period. Metabolic balances were carried out, iron and zinc absorption tests performed using stable isotopes, and Fe and Zn status monitored. Although effects on bowel function were observed, the changed diet had no influence on any of the previously described variables. It was concluded that a moderate increase in cereals, fruit and vegetables did not have an adverse effect on Fe or Zn nutrition.


1989 ◽  
Vol 6 (2) ◽  
pp. 135-141 ◽  
Author(s):  
John A. Cooney

AbstractThe Kleine-Levin Syndrome (KLS) a rare disorder comprising of periodic bouts of hypersomnia and megaphagia is reviewed. The syndrome chiefly affects males. The four accepted female cases in the literature are reviewed and a new female case described. This patient had an IQ in the normal range, unlike the other three female cases where the IQ was measured. She showed an abnormal Cortisol rhythm during both a well and an unwell phase replicating the findings of other workers in some KLS patients. This patient showed normal dexamethasone suppression, a test not previously reported on in KLS. The patient also smoked excessively during the bouts, an occurrence not previously remarked on in this disorder.


1987 ◽  
Vol 57 (1) ◽  
pp. 35-44 ◽  
Author(s):  
D. E. Coppen ◽  
N. T. Davies

1. Weanling male rats were maintained on diets containing 5, 10, 20, 40, 80 or 160 mg zinc/kg for 14 d. On day 15 they received 65Zn either by intraperitoneal injection or in a test meal containing 20 mg Zn/kg. After dosing, the rats were again maintained on the diets they had received previously.2. Whole-body 65Zn retention was measured immediately after dosing and daily for a further 9 d. From regression analysis of the semi-logarithmic plots of 65Zn retention from 0 to 192 h after 65Zn administration, the true extent of 65Zn absorption and the biological half-life (t1/2) of body 65Zn stores were calculated.3. At the end of the experiment, the rats were killed and the entire small intestines of some rats from each group were rapidly flushed out to remove food and faecal residues, frozen in liquid nitrogen and stored under an atmosphere of N2 at –20° before separation of cytosolic Zn-binding fractions by gel filtration on Sephadex G–75.4. The results suggest that rats which received diets that were either deficient(5 mg Zn/kg), marginal (10 mg Zn/kg) or adequate (20–80 mg Zn/kg) in Zn achieved homeostatic regulation of body Zn by changes in both the extent of Zn absorption and excretion. However, when Zn supply was excessive, increasing from 80 to 160 mg Zn/kg, no further changes were seen in Zn absorption, and homeostatic control appeared to be effected entirely by changes in rates of body Zn loss.5. Gel chromatography of intestinal cytosol on Sephadex G-75 revealed that Zn was associated with two major fractions. The first (peak 1) had a molecular weight (MW) > 75 kdaltons and the second (peak 2), a MW of approximately 10 kdaltons and was assumed to be metallothionein.6. There was no obvious relation between the amount of Zn bound to peak 1 and dietary Zn content. In contrast, the amount of Zn recovered in peak 2 increased linearly with increasing dietary Zn content.7. Comparisons between the effect of dietary Zn content on Zn bound to peak 2 and 65Zn retention may, depending on the range of Zn intakes, indicate possible roles for intestinal metallothionein in the control of Zn absorption or excretion.8. A study of the effects of dietary dose of 65Zn on the extent of 65Zn absorption in rats of normal Zn status indicated a possible biphasic relation. At low doses (5–40 mg Zn/kg) 65Zn absorption appeared to exhibit a curvilinear response to increasing 65Zn dose, indicating possibly a saturable process. At higher doses (40–160 mg Zn/kg) the capacity of this process appeared to be exceeded and 65Zn absorption increased in a linear fashion.


1979 ◽  
Author(s):  
J.G. Kelton ◽  
P.B. Neame ◽  
I. Walker ◽  
A.G. Turpie ◽  
J. McBride ◽  
...  

Thrombotic thrombocytopenic purpura (TTP) is a rare but serious illness of unknown etiology. Treatment by plasmapheresis has been reported to be effective but the mechanism for benefit is unknown. We have investigated the effect of plasmapheresis in 2 patients with TTP by guantitating platelet associated IgG (PAIgG) levels prior to and following plasmapheresis. Both patients had very high levels of PAIgG at presentation (90 and 48 fg IgG/platelet respectively, normal 0-5). In both, the PAIgG levels progressively fellto within the normal range and the platelet count rose following plasmapheresis. One patient remained in remission with normal platelet counts and PAIgG levels. The other relapsed after plasmapheresis and the PAIgG levelrose prior to the fall in platelet count. Plasmapheresis was repeated and resulted in normalization of both the platelet count and PAIgG level. It is suggested that plasmapheres is removes antiplatelet antibody or immune complexes which may be of etiologicalimportance in this illness.


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