Kidney microsomal Na+, K+-ATPase was studied in rats infected with Trypanosoma congolense. There was an observable loss in affinity of Na+, K+, and ATP for the enzyme in the parasitized animals, as well as a change in the energy of activation (Ea) and transition temperature. The inhibition with vanadate was significantly higher in the parasitized animals compared with that in the control indicating a change in the enzyme's index of physiological efficiency (Vmax/Km). This observation is suggestive of membrane modification in the infected group, thus enhancing permeability to vanadate. In an allied experiment, the level of kidney Na+, K+-ATPase was observed to decline as the parasitemia became massive. This clearly indicates organ damage and the consequent release of quantities of the enzyme into the blood-stream. The relevance of these findings to kidney pathologies during chronic-stage trypanosomiasis is discussed.
The organotin compound Tri-n-butyltin oxide was found to possess trypanocidal activity against Trypanosoma brucei. In vitro studies with the drug at 200μg/ml immobilized and lysed the parasites. In vivo experiments in infected rats at a dosage of 10mg/kg/day for 4 consecutive days completely cleared the blood of the parasites. Pathological analysis of the brains, kidneys, and livers of the treated animals did not reveal any abnormalities 6 weeks post-treatment. However, parasite-altered kidney Na+, K+-ATPase kinetics was observed to be rectified post-treatment.
Hypothyroidism results in decreased urinary excretion of folates leading to enhanced tissue retention of folates. The proportion of polyglutamylfolates, which are better retained by tissues, is elevated in liver, blood, and bone marrow of hypothyroid rats. The hypothyroid condition is discussed in the light of the enhanced proportion of polyglutamylfolate cofactors and increased in vivo oxidation of histidine possibly resulting in under-utilization of one-carbon units of the folate pool leading to a decrease in weight gain.
In mammals, the hypothalamic suprachiasmatic nucleus (SCN), a circadian oscillator, receives the retinohypothalamic tract (RHT), which is essential for the synchronization of circadian rhythms by light-dark cycle; and nerve growth factor (NGF) receptors with low affinity have been detected in the SCN. Thus, we examined whether low-affinity NGF receptors (LNGFR) are present in the terminals of the RHT by studies on the LNGFR-like immunoreactive substance (LNGFRLIS) in the SCN of blind rats. LNGFRLIS in the SCN gradually decreased with age in control rats, though it could be observed until 16-20 weeks of age. After bilateral orbital enucleation of 4-week-old rats, the density of the LNGFRLIS gradually decreased on both sides of the SCN from week 4 after the operation, disappearing 7 weeks after the operation. In congenitally blind, hereditary microphthalmic rats, LNGFRLIS was not detectable in the SCN, but in half-blind hereditary microphthalmic rats LNGFRLIS was detectable on both sides of the SCN. 125I-NGF injected into the SCN was found in the optic nerve and the retina. Since NGF is suggested to be retrogradely transported and to support survival of neurons, these findings suggest that LNGFR is present at the terminal of the RHT, and raise the possibility that NGF or other growth factors such as brain-derived neurotrophic factor in or around the SCN plays a role in maintaining the retinal ganglion cells through LNGFR.
The effect of dietary safflower phospholipid (Saf-PL) and soybean phospholipid (Soy-PL) on plasma, lipid, and fecal lipids in rats fed a cholesterol-free diet was compared with that of a triglyceride mixture (control). The triglyceride mixture (SP-Oil) of safflower oil and palm oil (8:2) contained almost comparable amounts of linoleic acid to safflower phospholipid or soybean phospholipid. Concentrations of total cholesterol in plasma of rats fed the Saf-PL and Soy-PL diets were significantly decreased in comparison with that of the SP-Oil diet. Saf-PL induced a reduction in the concentration of liver cholesterol compared with SP-Oil. Soy-PL tended to reduce the liver cholesterol. The proportions of total cholesterol in all lipoprotein fractions were similar among the groups. The activity of plasma lecithin-cholesterol acyltransferase was increased in rats fed the phospholipid diets; Saf-PL indicated the highest value. Saf-PL and Soy-PL caused an enhanced excretion of not only neutral steroids but also acidic steroids into feces compared with SP-Oil. These results suggest that, in addition to soybean phospholipid, safflower phospholipid decreases plasma and liver cholesterol in rats fed a cholesterol-free diet and safflower phospholipid causes a favorable alteration in plasma and liver lipids compared with soybean phospholipid.
Effects of dietary palatinose (isomaltulose, α-D-glucopyranosyl-(1→6)-β-D-fructofuranose) and reduced-palatinose (isomalt, an equimolar mixture of α-D-glucopyranosyl-(1→6)-D-glucitol and α-D-glucopyranosyl-(1→6)-D-mannitol), compared with the effect of sucrose, on body composition were examined in adult rats fed a restricted amount of diet (60% of an unrestricted meal) for 45 days (Experiment 1). The relative efficiency of the dietary sweeteners in depositing body protein and fat were estimated in young rats by feeding graded levels of each compound as supplements to a fixed amount of a basal diet (Experiment 2). In both experiments, the body fat content showed a trend to be greater in the order of sucrose>palatinose>reduced-palatinose supplement groups, whereas body protein content was at the same level among the supplement groups. The available energy of dietary palatinose and reduced-palatinose calculated in Experiment 2 were 3.15 and 2.18kcal/g, respectively, compared with that of sucrose, 3.94kcal/g, indicating that the low-caloric values of palatinose and reduced-palatinose were largely responsible for the effects of these sweeteners on body fat. The findings suggest that palatinose and reduced-palatinose are sweeteners that may be suitable for people to reduce body fat.
Supeoxide dismutase, glutathione peroxidase, glutathione S-transferase, and the p-phenylenediamine oxidase activity of ceruloplasmin, as well as lipid peroxides in terms of malondialdehyde, were determined in the blood of 52 breast cancer patients and 29 healthy women. No differences except for superoxide dismutase were found regarding lipid peroxide level and antioxidant enzyme activities in blood plasma and red blood cells between breast cancer patients and matched control women. Superoxide dismutase activity was statistically significantly lower in breast cancer patients than in the control group (p<0.0002). We also found a statistically significant correlation between the p-phenylenediamine oxidase activity of ceruloplasmin and lipid peroxide concentration in the blood plasma of the patients with breast cancer (r=0.342, p<0.05).
Atherosclerotic diseases have been the major causes of mortality in Taiwan. It is evident that elevated plasma levels of cholesterol, smoking, obesity, and high blood pressure are main risk factors of atherosclerotic disease. However, dietary factors are believed to play a major role in the development of atherosclerotic diseases. Therefore, changes in dietary pattern were evaluated from the “Food Balance Sheet” prepared by the National Council of Agriculture (Taiwan). Nutrient availabilities such as energy, fat, cholesterol, animal protein and sucrose were found to have increased remarkably from 1945 to 1987. Risk factors of atherosclerotic diseases including the change in the dietary pattern together with the increased cigarette smoking, and possibly increased obesity of the general population, were noted. Effective dietary pattern manipulation and life style modification may be beneficial for lowering of the incidence of atherosclerotic disease in Taiwan.