Low carbohydrate ketogenic diet prevents the induction of diabetes using streptozotocin in rats.

Diabetes continues to be an overwhelmingly prevalent endocrine disorder that leads to several micro- and macrocomplications. It has been widely accepted that changes in dietary habits could induce or prevent the onset of diabetes. It is shown that low carbohydrate ketogenic diet (LCKD) is effective in the amelioration of many of the deleterious consequences of diabetes. However, its role in preventing the onset of diabetes is not understood. Therefore, this study is focused on the effect of LCKD in preventing the induction of diabetes using streptozotocin (STZ) in rats by biochemical and histological methods. Forty-two Wistar rats weighing 150-250 g were used in this study. The animals were divided into three groups: normal diet (ND), low carbohydrate ketogenic diet (LCKD), and high carbohydrate diet (HCD). Specific diets ad libitum were given to each group of animals for a period of 8 weeks. Each group was further subdivided into normal control, sham control and diabetic groups. Animals in the diabetic group were given a single intraperitoneal injection of STZ (55 mg/kg). All the animals were sacrificed 4 weeks after the injection of STZ. Daily measurements of food and water intake as well as weekly measurement of body weight were taken during the whole 12 weeks of the experiment. After injecting with STZ, the blood glucose level of all the groups increased significantly except for the group fed on LCKD (p value<0.01). Also, food intake, water intake and urine output were significantly increased in all groups except for the LCKD group (p value<0.01). There was also a significant decrease in the weight gain of the animals that were fed on a LCKD as compared to other groups (p value<0.05). Although, substantial decrease in the number of ß cells was noticed in diabetic rats, there were no change in the number of ß cells in the LCKD treated diabetic animals as compared to LCKD control group. The results presented in this study, therefore, suggests that LCKD prevents the development of diabetes using streptozotocin in rats.

Transport kinetics of zinc, copper, selenium, and iron in perfused human placental lobule in vitro.

Transport characteristics of essential trace elements as zinc, copper, selenium and iron have been studied in maternal-fetal direction in normal pregnancies, using in vitro perfusion of human placental lobules. Solutions of trace elements corresponding to twice the physiological concentrations were injected (100 microl bolus) into the maternal arterial perfusate. Serial perfusate samples were collected every 30 sec from venous outflows for a study period of 5 min. Concentrations of these trace elements and their transport kinetics were determined. Transport fractions (TF) of zinc, copper, selenium and iron averaged 0.21, 0.49, 0.55 and 0.10% of maternal load respectively. Other parameters such as area under the curve, clearance, elimination constant, absorption and elimination rates showed some significant differences between the various elements. Copper and selenium appear to be transported passively in maternal-fetal direction, while for iron and zinc, role of active transport for transfer across the human placental membrane cannot be discounted. We speculate that alterations in copper: zinc TR50 (transport rate for 50% efflux) and TF ratios could serve as useful indicators for assessing placental transport status of these essential elements in complicated pregnancy states.

Brain selenium accumulation in rat pups of selenium supplemented mothers.

Selenium is essential for normal mammalian development. Being a component of antioxidant enzyme, glutathione peroxidase, it plays a major role in protecting the cells from free radical damage. The level of glutathione peroxidase was directly related to the amount of selenium present in various tissues and organs. A decrease in selenium leads to various pathological changes in humans as well as in various laboratory animals. The aim of the present study was to understand whether there is an increase in the level of selenium in different brain regions of rat pups whose mothers were supplemented with selenium, either 2 or 4 mg/l of their drinking water throughout the period of their pregnancy. There was a significant increase in the level of selenium in the cerebellum, cortex and hypothalamic and hippocampal tissues of selenium supplemented mothers as compared with those of non-supplemented mothers. The brain stem of these animals did not show any significant difference in the level of selenium. Furthermore, the differences in the level of selenium between the rat pups of 2 mg/l selenium supplemented mothers and 4 mg/l selenium supplemented mothers were not statistically significant. These studies suggest that supplementation of selenium to mothers during the period of their pregnancy can selectively increase the level of this trace element in different brain regions. Further studies are necessary to understand the significance of selective accumulation of selenium in specific brain regions on brain development and function.

Maternal-fetal transport kinetics of copper, selenium, magnesium and iron in perfused human placental lobule: in vitro study.

Transport characteristics of certain inorganic elements such as copper, magnesium, selenium and iron have been studied in maternal-fetal direction in normal pregnancies, using in vitro perfusion of isolated placental lobules. Copper, selenium, magnesium and iron salts corresponding to twice physiological concentrations were injected as a 100 microl bolus, into the maternal arterial perfusate. Serial perfusate samples were collected from venous outflows for a study period of 5 min. Concentrations of various inorganic elements and their transport kinetics were determined. Transport fractions of copper, selenium, magnesium and iron averaged 0.14, 0.19, 0.06 and 0.23% of maternal load respectively. The pharmacokinetic parameters such as area under the curve, clearance, elimination constant, and time for maximum response showed some significant differences between the various elements. We speculate that copper and selenium share the same transport pathway along a concentration gradient in maternal-fetal direction, while for iron and magnesium, active transport plays a predominant role for element transfer across the human placental membrane.

Pre- and postnatal tissue selenium of the rat in the growing state.

The aim of this study is to quantify the selenium (Se) content (in microg/g) during different gestational periods in rat fetal tissues, and to follow up the changes in the Se content of the placenta, fetal head, liver and lung during gestation and postpartum periods. Locally reared virgin female Wistar rats were mated. Pregnant rats were sacrificed on days 15, 18 and 21 of pregnancy. Newborn pups at the age of 3 days and rats at the age of 1 month were also investigated. There was a gradual increase in placental and whole head Se content as gestation proceeded compared to day 15; however, the differences between the groups were not statistically significant. The liver Se content at day 18 of gestation was significantly higher than at day 21 of gestation and in rats at 3 days of age, but lower than the Se content of the liver of rats at the age of 1 month and the differences were statistically significant. The lung Se content was higher at day 18 of gestation than at day 21 and in the 3-day-old rats, and all differences between all groups were statistically significant except when the lung Se content at day 18 is compared to that of 1-month-old animals. The continuous increase in the Se content of the placental tissues and the whole head, although not significant statistically, may indicate that the fetus relies heavily on its supply of Se from the maternal blood and in part on the supply of thyroid hormones which are important for brain development, as evidence exists that T(4) and T(3) are present in the fetal brain in early fetal life before the onset of fetal thyroid function. The higher content of Se on day 18 and its decline on day 21 of gestation in the liver may imply that it is stored and being utilized partly in other tissues for other functions and particularly for thyroid hormone synthesis, metabolism and functions.

Responses to exercise, fluid, and energy balances during Ramadan in sedentary and active males.

This study compares the effects of the Ramadan fast (RF) on body and plasma compositions, hematology, and responses to steady state submaximal exercise in six physically active (A, 35.5+/-1.6 y) and seven sedentary (S, 37.6+/-2.3 y) Kuwaiti men. Subjects were evaluated: 1) 1 wk before RF (pre-RF); 2) 2 wk after the start of RF (mid-RF); 3) at the 4th wk of RF (end-RF). Total body weight and body fat decreased insignificantly (<1.5%, P>0.3) in both groups. At the end of Ramadan, significant increases in osmolarity (P<0.05), Na (P<0.05) and bicarbonate (P<0.05), and a decrease in serum iron were noted in sedentary but not in active subjects. Platelet count was lower in both groups by the end of RF (P<0.05). Body weight and percent fat changed little (<1.5%) in either group. During RF, submaximal exercise heart rate declined insignificantly in group S but significantly (P<0.05) in group A. The respiratory exchange ratio R during steady state submaximal exercise decreased markedly (P<0.001) by the end of RF in both groups. It is concluded that energy balance is well maintained during RF both in S and in A subjects. Metabolic adaptations during RF result in lower exercise R due to increased lipid usage. Deficits or redistribution of specific micronutrients (iron, vitamins) may account for reductions in serum iron and platelet counts, particularly in sedentary subjects that need to limit intake to maintain body weight. The decrease in submaximal exercise heart rate indicates that during RF, cardiovascular adaptation to conditioning is adequate in the more physically active group. Body fluid balance was better maintained in active than in sedentary subjects.

Spot urine concentrations of type I collagen cross-linked N-telopeptides and deoxypyridinoline in psoriatic arthritis.

The main objectives of this study were to investigate whether the spot urine concentrations of type I collagen cross-linked N-telopeptides (NTx) and deoxypyridinoline (Dpd) can be used to distinguish between active and suppressed disease in psoriatic arthritis (PsA) and to study the relationship between these markers of bone resorption and disease activity indices. Using enzyme-linked immunosorbent assays, concentrations of NTx and Dpd were estimated in spot urine samples from 25 patients with active disease, 10 patients with suppressed disease and 35 age- and sex-matched healthy control subjects. In patients with active disease, urine concentrations of NTx and Dpd were significantly elevated (p<0.001) compared with healthy controls and there were no significant differences (p>0.05) when compared with those with suppressed disease. In active disease, there was no significant positive correlation between urinary NTx and erythrocyte sedimentation rate (ESR) (r = 0.025, p>0.05) nor between Dpd and ESR (r = -0.208, p>0.05). In conclusion, NTx and Dpd concentrations in spot urine have no association with disease activity in patients with PsA.

Urine levels of type 1 collagen cross-linked N-telopeptides and deoxypyridinoline correlate with disease activity in rheumatoid arthritis.

OBJECTIVES: The aim of this study was to find out whether spot urinary concentrations of type 1 collagen cross-linked N-telopeptides (NTx) and deoxypyridinoline (Pyrilinks-D) can differentiate between active and inactive disease in rheumatoid arthritis (RA) and to investigate the extent to which they correlate with indices of disease activity. METHODS: Using enzyme-linked immunosorbent assays, the concentrations of NTx and Pyrilinks-D were estimated in spot urine samples from 25 females with active disease, 25 females with inactive disease, and in 25 controls. RESULTS: In Patients with active disease, urinary concentrations of NTx and Pyrilinks-D were significantly higher (p < 0.01) than in those with inactive disease or in healthy controls. In active disease there were significant positive correlation between urinary NTx and ESR, the swollen joint count, the tender joint count, and the patient's global assessment.

Changes in collagen content of the diaphragm in rats of different ages.

Rat diaphragm showed a nine to ten-fold increase in the dry and wet weights and a four-fold increase in its surface area between 21 and 540 days of age. The increase was the most rapid between days 21 and 90, thereafter a non-significant trend of increase was maintained at least up to 360 days of age followed by a tendency to decrease. The total collagen content of the diaphragm paralleled the increase in surface area with progressing age. The collagen content significantly dropped when expressed relative to the dry weight of the diaphragm, between 21 and 90 days of age. This trend was maintained till 180 days of age but thereafter significantly rise was seen. These later changes may be due to elenated synthesis and/or reduced degradation of collagen, and may contribute to the decline in contractility of the diaphragm as age advances.

Collagen of the dystrophic hamster diaphragm.

The collagen content of the diaphragm was measured in normal and dystrophic hamsters aged 130 and 270 days. The diaphragm collagen content was greater in dystrophic hamsters than in control hamsters of the same age. The effect was greater in the older hamsters whether the collagen content was expressed in terms of the percentage of dry weight, in relation to surface area, or as total collagen. This increase was apparently at the expense of muscle tissue and may be a major factor contributing to respiratory muscle weakness as dystrophy advances.

Facial vessels of desert camel (Camelus dromedarius): role in brain cooling.

The reactivity of the superficial veins of the camel was investigated in vitro in response to stretch, heat, norepinephrine, and transmural nerve stimulation (TNS). Stretch at 30 degrees C or 37 degrees C produced a maintained tone and phasic contractions of the facial and nasal veins. The developed tone increased significantly with increasing the temperature (from 30 to 45 degrees C), especially in the proximal part of the buccal facial vein. Norepinephrine caused a constrictor response in the facial vein with the proximal part showing a lower maximum. TNS evoked a constrictor response in proximal segment and a dilator response in the more proximal segment of the buccal facial vein. Either responses were blocked by bretylium or tetrodotoxin. Morphological examination of the vasoactive segment of the facial vein showed a thick muscular layer and a valve in the proximal segment of the buccal facial vein. These results show functional variation in the distribution of adrenoceptors in the facial vein. The high-temperature sensitivity of the buccal facial vein suggests that this part could serve as a temperature-sensitive sphincter that diverts cool nasal blood to the brain for selective cooling of the camel brain during heat stress.

The collagen composition of the dystrophic hamster diaphragm.

1. Diaphragms from BIO 14.6 dystrophic hamsters had lower dry weights and higher collagen content than did controls, BIO F1B. 2. The increase in pepsin-solubilized collagen affected mainly types III and V, and there was a concomitant decrease in the beta and high molecular weight (HMW) collagen aggregates. 3. These findings are similar to the observations in myotonia congenita and imply that the dystrophic process increases collagen synthesis. 4. In addition, there is possibly a genetic mutation of amino acids at points of contact of collagen monomers. 5. Alternatively, there may be reduced hydroxylation of lysine residues and hence in the degree of glycosylation of collagen resulting in decreased cross-linking and aggregation.

Changes in amniotic fluid cathepsins with gestational age.

Activities of the cysteine proteinases cathepsins B and H and of the chymotrypsin-like cathepsin G were determined in amniotic fluid of rats during the last third of gestation. Activities of cathepsins B and G were found to significantly increase with increasing gestational age while cathepsin H activity decreased. It was concluded that cathepsins may participate in the destabilization of fetal membranes and therefore may contribute to their rupture.

Comparison of performance of students from different high school systems in medical sciences at Kuwait University.

Data, although limited, question the validity of the formula applied for admission to the medical school in which high school grades are the only preselection variable applied. Comparison between two groups of students from two different high school systems in Kuwait was carried out to determine if the admission criteria used currently for entry to the medical school are equally valid for both groups. The results are based on the students' performances in the first three-semester programme of medical sciences. Subjects covered were anatomy, physiology, biochemistry and behavioural sciences. The group derived from the High School National Diploma performed significantly better with a percentage pass rate of 82% while of those who were derived from the Course Credit System only 61% passed the final examination. In addition, only one of the latter group attained total marks of more than 80% compared to 12 students from the National Diploma group. The percentage failure according to subjects was consistently higher among the Course Credit graduates in all the subjects. All differences between the two groups are statistically significant (P less than 0.001).

Heterogeneity of the histological features along the course of the facial vein of the desert camel (Camelus dromedarius): relevance to brain cooling.

Sections from different parts along the facial vein of the camel (Camelus dromedarius) were examined by light microscopy. The results demonstrated heterogeneity among the various segments. Particular attention was paid to a specific area in the buccal region which was previously shown by physiological experiments to have a temperature-dependent myogenic tone. The morphology of that area showed highly thickened media with prominent bands of circularly disposed smooth muscles infiltrating both the intima and the adventitia. The morphology described in this study correlates well with the function and gives further credence to the proposed role of the facial vein in cranial thermoregulation particularly under heat stress.

Muscle collagen content in diabetic rats.

Collagen content (mg/dl of dry weight) was measured biochemically in the extensor digitorum longus and the soleus muscle in rats. Comparison of muscles from diabetic (induced by intraperitoneal streptozotocin injection /60 mg/kg body weight/) and non diabetic controls showed an increase in the collagen content of the extensor digitorum longus, and little change in the soleus. The differences did not attain statistical significance indicating that the accelerated collagen ageing attributed to diabetes may not necessarily be true in all tissues.

Effect of taurine on the lung collagen content in myopathic hamsters.

The effect of taurine, Guanidino Ethyl Sulfonate (G.E.S.) and NaCl on the lung mass and collagen content in BIO 14.6 strain of the Syrian hamster was investigated. Lungs from healthy and cardiomyopathic hamsters showed no change in mass or collagen content as a result of the various treatments.

Premature rupture of fetal membranes changes in collagen type.

Collagen from the chorioamnion units from premature and term pregnancies was solubilized by limited pepsin digestion and subjected to SDS-PAG electrophoresis. Collagen types were quantitated by densitometry. It was found that collagen type III decreases and collagen type V tends to increase as gestational age advances. Investigating the relative abundance of collagen types at various membrane sites from term pregnancies revealed that type V decreases in the amnion as the rupture site is approached. It is concluded that since type V collagen is more resistant to collagenases, its decrease may predispose that particular site to rupture.