PubMed · 4924725
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G C Ceschel, F Fontani. 1970. [Operculated capsules].. https://pubmed.ncbi.nlm.nih.gov/4924725/
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We recently evaluated the acetaminophen absorption test as a marker of graft rejection for small bowel transplantation(SBTX). Randomly bred male Wistar rats were used as recipients and donors. Rats (n=45) received heterotopic small intestinal transplants and were divided into three groups (n=15 for each group). In group A, a 10-cm segment of jejunum of was exteriorized as a Thiry-Vella loop. In group B, immunosuppression was not given after SBTX. In group C, rats were treated with FK506 after SBTX (0.3 mg/kg body weight, 0-6 postoperative days). Serum acetaminophen concentrations were measured 15 min after instillation of 0.15 g/kg acetaminophen into the intestinal loop on postoperative days 1, 3, and 7 (n=5 for each group). Blood flow and histology of the graft were also evaluated. In the SBTX group only, the grafts showed the histological change after acute rejection. On day 3, plasma acetaminophen concentrations in this group showed a significant decrease, which correlated with the mild histological changes of graft rejection. Graft blood flow of the SBTX group decreased significantly on day 7, following the severe graft destruction of advanced rejection. No remarkable changes were observed in the other two groups. The acetaminophen absorption test appears to be useful for the early detection of SBTX graft rejection.
1. We have previously assessed the contributions of diffusion and convection to net potassium reabsorption in the rat proximal convoluted tubule (PCT). The present study was conducted to evaluate the role of active transport in convective potassium reabsorption by measuring the transepithelial potassium reflection coefficient (sigmaK) in the presence and absence of cyanide in anaesthetized rats previously prepared for in vivo microperfusion. 2. Osmotic water permeability (Pf) was measured in double-perfused tubules (lumen and peritubular capillaries) by manipulating the applied transepithelial osmotic gradient between -30 and +40 mosmol (kg H2O)(-1) using raffinose added to or subtracted from luminal perfusates. Pf was unaffected by the presence of cyanide when the estimated dissipation of osmotic gradients along each tubule were taken into account. 3. The proportion of K+ (and Na+) convectively transported with water fluxes (i.e. sigmaK) was not affected by cyanide. In the absence of active transport and following correction for any diffusive component, sigmaK was 0.56 +/- 0.13, indicating substantial solvent drag which probably occurs via the paracellular pathway. 4. However, cyanide caused a reduction in net potassium flux over the entire range of fluid fluxes used in double-perfusion experiments. Subsequent single-perfusion experiments (tubule lumen only) using the specific K+-H+-ATPase inhibitor, SCH28080, failed to reveal any direct evidence for a primary active K+ transporting mechanism involved in K+ reabsorption in the PCT.
BACKGROUND: Calcium intake is believed to play an important role in the formation of kidney stones, but data on the risk factors for stone formation in women are limited. OBJECTIVE: To examine the association between intake of dietary and supplemental calcium and the risk for kidney stones in women. DESIGN: Prospective cohort study with 12-year follow-up. SETTING: Several U.S. states. PARTICIPANTS: 91,731 women participating in the Nurses' Health Study I who were 34 to 59 years of age in 1980 and had no history of kidney stones. MEASUREMENTS: Self-administered food-frequency questionnaires were used to assess diet in 1980, 1984, 1986, and 1990. The main outcome measure was incident symptomatic kidney stones. RESULTS: During 903,849 person-years of follow-up, 864 cases of kidney stones were documented. After adjustment for potential risk factors, intake of dietary calcium was inversely associated with risk for kidney stones and intake of supplemental calcium was positively associated with risk. The relative risk for stone formation in women in the highest quintile of dietary calcium intake compared with women in the lowest quintile was 0.65 (95% CI, 0.50 to 0.83). The relative risk in women who took supplemental calcium compared with women who did not was 1.20 (CI, 1.02 to 1.41). In 67% of women who took supplemental calcium, the calcium either was not consumed with a meal or was consumed with meals whose oxalate content was probably low. Other dietary factors showed the following relative risks among women in the highest quintile of intake compared with those in the lowest quintile: sucrose, 1.52 (CI, 1.18 to 1.96); sodium, 1.30 (CI, 1.05 to 1.62); fluid, 0.61 (CI, 0.48 to 0.78); and potassium, 0.65 (CI, 0.51 to 0.84). CONCLUSIONS: High intake of dietary calcium appears to decrease risk for symptomatic kidney stones, whereas intake of supplemental calcium may increase risk. Because dietary calcium reduces the absorption of oxalate, the apparently different effects caused by the type of calcium may be associated with the timing of calcium ingestion relative to the amount of oxalate consumed. However, other factors present in dairy products (the major source of dietary calcium) could be responsible for the decreased risk seen with dietary calcium.