Solubility of enamel powder following treatments with 1% sodium dodecyl sulphate in the presence and absence of fluoride

Deionized water exerts a solubility effect on enamel which is increased in the presence of sodium dodecyl sulphate (SDS), at a concentration used in dentifrices. As expected, incorporation of fluoride by enamel decreases the solubility effect of the detergent in water and acidic buffer. With duration of treatment, the detergent has a lesser effect than demineralized water alone on subsequent solubility of enamel in acidic buffer.     

Bile acid receptors in colorectal cancer

Bile acids are thought to be involved in both the aetiology and development of colorectal cancer. In this study the existence of specific bile acid receptor proteins has been postulated. A receptor assay which involved labelling with 14C-deoxycholic acid was performed as well as autoradiography using 3H-deoxycholic acid. In an initial study resected colorectal cancer and adjacent histologically normal colorectal mucosa from 39 patients were studied, as were samples of normal gastric mucosa, cancers and benign colorectal tumours. Specific receptors to deoxycholic acid were detected in 12 (30.8 per cent) of the colorectal cancers, but in only 1 (2.6 per cent) of the samples from normal colorectal mucosa (X2 = 11.16, P less than 0.005). No deoxycholic acid receptors were detected in any other tissue studied. Autoradiographs of colorectal cancers showed binding of 3H-deoxycholic acid in receptor-positive tumour tissue. These findings might provide some explanation for the evidence linking bile acids with the disease.     

Histological, histochemical and electron microscopic changes of the placenta induced by maternal exposure to hyperthermia in the rat.

Both clinical and experimental investigations have shown that maternal hyperthermia during critical stages of embryo development can induce malformations in the offspring. Studies of the effect of heat stress on the placental functions are limited to the ewes, but that on microscopic structure is unknown. In the present study, rats were exposed to 41 or 42 degrees C for 1 h on gestation day (GD) 9. The controls were sham treated. Fetuses and placentas were collected on GD 20. Intrauterine growth retardation (IUGR) and several craniofacial malformations were observed in the fetuses of the heat-treated group. The placentas of the 42 degrees C group were significantly lighter in weight than those of the control. Light microscopy (LM) revealed thickening, hyalinization and occasional lymphocytic infiltration of the decidua basalis. Giant cells were prominent and glycogen cells had degenerated, leaving behind large cysts in the basal (spongy) zone. Best's carmine stain with or without diastase indicated the reduction in number and degeneration of glycogen cells and cyst formation. The labyrinthine zone was relatively thin in comparison to that of the controls. Perivascular fibrosis and paucity of vascularization were other features of the placentas of the hyperthermia group. Electron microscopy (EM) revealed lipid droplet accumulation in the trophoblast, the presence of myelin bodies and an increased production of collagen in the basal zone. Perivascular fibrosis appeared to have contributed to placental barrier thickening. EM also revealed accumulation of glycogen and lipid droplets in the trophoblasts and fibrin secretion into the extracellular space of the labyrinthine zone. These data suggest that placental pathology possibly contributes to fetal growth retardation in maternally heat-stressed rat fetuses.     

A method for the determination of projection areas of GABA immunoreactive neurons in the invertebrate nervous system.

Axonal transport of metallic salts (nickel or cobalt chloride) has been widely used for the anatomical mapping of neural pathways. We show here that when nickel is introduced into GABAergic neurons it completely eliminates GABA immunolabelling. We have used this property to determine the axonal projections of GABAergic neurons in the stomatogastric system of Crustacea. For example, following nickel backfills from either cut axons or from terminals, GABA immunostaining labels only those GABA-immunoreactive neurons which had not been retrogradely labelled with nickel and hence did not project in the cut nerve or to the neuropile uptake site. By comparing such immunolabelled preparations with those not pretreated with nickel the projection patterns of all the GABA immunoreactive neurons in a given system can be revealed. This effect of nickel appears to be selective for GABA immunostaining, insofar as it does not interfere with the immunodetection of either the peptide proctolin or a FMRFamide-like peptide. This method may prove to be a useful tool for analyzing GABAergic neuronal pathways in the nervous systems of invertebrates.     

Transfer of 45Ca and 36Cl at the blood-nerve barrier of the sciatic nerve in rats fed low or high calcium diets

Unidirectional fluxes of 45Ca, 36Cl, and of [3H]mannitol from blood into the sciatic nerve and cerebral cortex were determined from 5- and 15-min uptakes of these tracers after an intravenous (i.v.) bolus injection in awake rats. Rats were fed diets for 8 wk, that had either a low (0.01% wt/wt), normal (0.67%), or high (3%) Ca content. Plasma [Ca] was 32% less and 11% more in rats fed low (LOCA) and high Ca diets (HICA), respectively, than in rats fed a normal Ca diet (CONT). The mean permeability-surface area product (PA) of 45Ca at the blood-nerve barrier was about eightfold higher than at the blood-brain barrier in the same animals and did not differ significantly between groups (greater than 0.05). Mean PA ratios of 45Ca/36Cl for the blood-nerve and blood-brain barriers in CONT rats, 0.52 +/- 0.04 and 0.40 +/- 0.02, respectively, were not significantly different from corresponding ratios in LOCA and HICA groups, and corresponded to the aqueous limiting diffusion ratio (0.45). Our results show no evidence for concentration-dependent transport of Ca over a plasma [Ca] range of 0.8-1.4 mmol/liter at the blood-nerve barrier of the rat peripheral nerve, and suggest that Ca and Cl exchange slowly between nerve and blood via paracellular pathways.     

The determination of alpha-tocopherol in blood serum]

A modified method for measuring vitamin E is described, making use of thin-layer chromatography with Silufol plates. Effects of various storage conditions of the blood serum on its vitamin E levels were examined. Vitamin E proved to be sufficiently stable at storage at -10 degrees C and defrosting under 20 degrees C. Comparison of this mode of storage with other ones has demonstrated its advantages. The method was tried in clinical practice in examinations of patients with pulmonary tuberculosis, chronic alcoholism, females suffering from infertility due to inflammations and healthy ones (controls) and found to be accurate, reproducible, and informative.     

Common origin of inferior mesenteric and main renal artery

The first case of a common origin of both the inferior mesenteric and single main renal artery, angiographically documented in a patient with primary ipsilateral ectopic kidney, is reported. Embryologic as well as surgical aspects are mentioned.     

The effect of bismuth subnitrate on cisplatin toxicity

Bismuth subnitrate (BSN), a bismuth compound medically used for antidiarrheics, was orally administered to see whether it can reduce CDDP nephrotoxicity or not. Thirteen patients aged 19 approximately 60 with ovarian cancer entered this BSN-CDDP trial. A total of thirty three courses of BSN-CDDP treatment was undergone. BSN was administered orally at a dose of 50 mg/kg for five days before CDDP therapy. CDDP was infused for two hours. No vigorous hydration or diuresis was performed. Only 2,000 ml of saline with 20 mEq per liter of KCl was given for post-hydration. The median dose of CDDP was 100 mg/m2. The renal toxicity of BSN-CDDP treatment was minimum. 82% of the courses at the sixth day after the treatment had creatinine clearance levels which were more than 80% of those before the treatment. But twenty-four hour NAG and beta 2-microglobulin excretion were significantly increased. Bone marrow suppression and gastrointestinal disturbance were commonly observed. The results of our study indicate that BSN pretreatment reduces the renal toxicity of CDDP to some extent.