Glomerular calcification induced by bolus injection with dibasic sodium phosphate solution in Sprague-Dawley rats

To elucidate the nephrotoxicity of phosphate, dibasic sodium phosphate solution was given to Sprague-Dawley rats by daily bolus intravenous administration at concentrations of 0, 1, 25, 250, or 360 mM (0, 1, 28, 284, or 408 mg/kg Na2HPO4) for 14 days, and the kidneys were pathologically examined. There were no remarkable changes in blood chemistry values; however, urinalysis revealed mild to moderate proteinuria in the 250 and 360 mM groups. The kidneys from the 360 mM group were macroscopically pale. Histopathology revealed panglomerular deposition of basophilic dense granules, which were positive for von Kossa's staining, accompanied by dose-dependent degeneration of the glomerular epithelium and parietal epithelium in the 250 and 360 mM groups. Electron microscopic examination showed fusion of podocytes and increased microvilli, with large amounts of debris in the Bowman's space. Low-density lamellar structures were present not only in the glomerular epithelium, basement membrane, mesangial matrix and parietal epithelium but also within the Bowman's space depending on the severity of the glomerular lesion. Phosphorus and calcium were detected by X-ray microanalysis as fine particles admixed with lamellar structures. These results suggest that high-dose phosphate used in this study transiently overloads the glomerular epithelium during filtration through glomerular capillaries and produces insoluble calcium salt and glomerular lesions, resulting in proteinuria.     

Effect of potassium solution on rehydration in rats: comparison with sodium solution and water

Thermally dehydrated rats were given isotonic KCl, NaCl solution, or tap water ad libitum for 17 h and the differences of the restoration rate in fluid and cation were compared between the groups to elucidate the effect of Na+ and K+ ions on the replacement of each body fluid compartment during rehydration. When rats were provided with NaCl solution, the gains of fluid and Na+ exceeded the amounts lost during the dehydration period, while in the isotonic KCl and tap water groups fluid gain was 70% of the fluid lost during the dehydration period. The recovery of extracellular fluid (ECF) volume was 178% of the loss in the NaCl group and 50% in the KCl group. The Na+ concentration of the ECF was regulated closely in all groups. The recovery in intracellular fluid (ICF) volume did not differ significantly between groups and never exceeded the control level, but tended to be higher in the KCl group than in the NaCl group. These results indicated that in the ECF the regulation of Na+ concentration preceded that of volume while in the ICF, volume regulation had priority. In addition, the effect of K+ supplementation on the recovery of ICF volume after thermal dehydration was shown to be modest, unlike the effect of Na+ on the recovery of ECF volume.     

Interaction of sodium dodecyl sulfate with poly(L-lysine) in aqueous solution

The interactions between a homopolypeptide, poly(L-lysine) [(Lys)_n], and an anionic surfactant, sodium dodecyl sulfate (NaDodSO₄), were studied by ¹³C NMR spectroscopy in D₂O solution. By observing the chemical shift of the ε-amino carbon of lysine monomer in D₂O solution at pH 7,3 in presence and absence of NaDodSO₄, direct evidence was found for electrostatic interaction between the protonated lysine ε-amino group and the head group of the anionic surfactant. At this pH, the (Lys)_n chain in NaDodSO₄ solution adopts the β-form conformation and the solubility of NaDodSO₄/(Lys)_n complexes is too small to observe ¹³C-spectra. At more alkaline solutions, where the (Lys)_n chain forms α-helices, the surfactant's polar group interacts with the uncharged lysyl side chain through hydrogen bonding. In the initial binding of the surfactant to (Lys)_n, both the surfactant head group and alkyl chain contribute to the association with (Lys)_n. With an excess of surfactant bound to α-helical (Lys)_n, NaDodSO₄/(Lys)_n complexes show high solubility and all carbon atoms of the surfactant molecules show micelle shifts. These results suggest that the surfactant molecules form micellelike clusters around the (Lys)_n helices exposing the surfactant polar head group to the medium and enhancing the solubility of NaDodSO₄/(Lys)_n complexes.     

Consumption of water and sodium chloride solution by rats after central injection of litorin and after immunization with litorin-bovine serum albumin conjugate

Bulletin of Experimental Biology and Medicine -     

Treatment of seasonal allergic rhinitis with 2% sodium cromoglycate (BP) solution

Forty patients with seasonal allergic rhinitis, not responding to antihistamines, were treated for 6 weeks, beginning 1 June 1972, with either a 2% solution of sodium cromoglycate or placebo in a double blind group comparative trial. The solution was administered intranasally by means of a spray pack. There was a statistical significance in favour of the active material (P<0.025) with regard to the success or failure.     

Evidence for two types of sodium conductance in axons perfused with sodium fluoride solution

1. Voltage clamp experiments were carried out on squid giant axons internally perfused with 300 mM-NaF + sucrose. K-free artificial sea-water, -0.3 to 3.5 degrees C, was used externally.2. Membrane currents were corrected for capacitative and leakage components, and the resulting Na current was converted to Na conductance, g(Na). An attempt was made to fit changes in g(Na) according to the Hodgkin-Huxley model, namely [Formula: see text].According to the model g(Na) is a constant, m(infinity) and h(infinity) are steady-state values which depend only on voltage, tau(m) (-1) and tau(h) (-1) are rate constants which also are functions only of voltage.3. Stepwise depolarizations from the holding potential (-67 to -83 mV) to a potential which varied from -10 to +63 mV resulted in an exponential decline of h from its initial level to a final, non-zero level. If the test depolarization was preceded by a positive prepulse (duration, 19-105 msec; voltage, -6 to 94 mV) the rate constant for h, tau(h) (-1), was increased roughly threefold with practically no change in the final level.4. The steady-state level of h was studied by using prepulses of varying amplitude followed by a test depolarization. In one such experiment a value of 0.34 was obtained for a 105 msec prepulse to -49 mV. The same value for the steady level of h was obtained from analysing a record taken at +52 mV. If the potential was switched from -49 to +52 mV there was a transient increase in g(Na) although h(infinity) had the same value at these two potentials.5. Recovery from depolarization was studied by repolarizing the fibre for varying lengths of time, then applying a test depolarization. If the first depolarization was strongly positive (for example, 70 mV), so that the steady level of h was large (0.39), the currents associated with the test pulse could not be fitted on the basis of an exponential increase in h during the recovery period. Rather, the results suggested that on repolarization h rapidly decreased initially, then slowly increased.6. These results can be explained by assuming that h is given by the sum of two components, h(1) and h(2). Changes are represented kinetically by h(1) right harpoon over left harpoon x right harpoon over left harpoon h(2), where x signifies the inactive state. The distribution is shifted to the left at negative potentials and to the right for positive ones. The resulting Na conductance is comprised of two types: the first type, g(Na)m(3)h(1), is similar to the Hodgkin-Huxley system and underlines the usual transient increase in g(Na) associated with depolarization; the second type, g(Na)m(3)h(2), is maintained with depolarization and gives rise to a steady level of g(Na).     

Blood pressure and heart rate changes in streptozotocin diabetic rats, with special reference to postural hypotension.

Blood pressure and heart rate changes were recorded on supine or prone head-up tilt and on carotid artery occlusion in normal and streptozotocin diabetic rats (65 mg/kg). In general supine tilt induced a larger blood pressure fall, slower blood pressure recovery from the fall and larger heart rate fall than prone tilt, both in normal and diabetic rats. Heart rate recovery from the fall was slightly larger in prone than in supine tilt in normal rats. The blood pressure fall and heart rate fall accompanying the tilt were statistically larger in diabetic than in normal rats. Furthermore, blood pressure recovery from the fall was statistically more rapid and larger in normal than in diabetic rats. The exaggerated blood pressure fall with the tilt of diabetic rats might correspond to postural hypotension. Blood pressure rise and heart rate rise with carotid artery occlusion were smaller in diabetic than in normal rats. Blood pressure changes with cervical sympathetic or vagus stimulation were almost the same in normal and diabetic rats. However, in diabetic rats such cervical autonomic nerve stimulation produced larger heart rate changes than in normal rats.     

Swelling of poly(2-methyl-5-vinylpyridine) gel in linear sodium poly(vinylsulfonate) solution

The interaction of a poly(2-methyl-5-vinylpyridine) hydrochloride gel (1 a) with the aqueous solution of a linear sodium poly(vinylsulfonate) (2) was investigated. It was established that the gel collapse takes place as a consequence of the formation of a polyelectrolyte complex (1 a-2) between oppositely charged groups. The binding degree θ of the linear polymer with the gel was determined to be 0,4. The kinetics of the interaction process was examined. With increasing pH and ionic strength value a discrete phase transition both of the gel volume and of the polycomplex is induced. The collapse of the latter has increasingly sharp character.     

Dilute solution properties of poly(allylammonium chloride) in aqueous sodium chloride solutions

Ten fractions of poly(allylammonium chloride) were investigated at 25°C in sodium chloride solutions of various concentrations, c_s, by viscosity and light scattering techniques. The molecular weight (M_w)-intrinsic viscosity [η] relationships were established at four NaCl concentrations. The unperturbed dimensions estimated from the Stockmayer-Fixman plot are independent of c_s. The second virial coefficient A₂ and the excluded volume parameter B as well as [η] were found to be proportional to c and to have negative values in the limit of infinite c_s. In addition, it was found that the electrostatic part of the expansion factor can be expressed in terms of a reduced parameter (M_w/c_s)^1/2 in a fairly wide range of M_w and c_s.     

Effect of sodium succinate on histomorphological changes of autodermic grafts in rats

Sodium succinate was found to increase the viability of epithelial cells in autodermic transplants. It stimulated the proliferation of epidermal cells of the basal layer, enhanced the activity of succinate dehydrogenase, lactate dehydrogenase and adenosine triphosphatase, intensified the formation of keratin, and activated the ingrowth of blood vessels through the generation of functioning endothelial cells. Translated fromByulleten' Experimental'noi Biologii i Meditsiny, Vol. 126, No. 11, pp. 555–560, November, 1998     

Disruption of the PTHLH regulatory landscape results in features consistent with hyperparathyroid disease

Parathyroid hormone like hormone (PTHLH) signaling is essential for the proper formation of bone and its elevation or disruption has been directly implicated in several different skeletal dysplasias. We report a patient with a 2.802 Mb deletion upstream of the PTHLH coding sequence who presents with multiple fractures, metaphyseal changes, and overall features consistent with hyperparathyroid like disease. Analysis of the deleted region revealed the loss of putative regulatory regions adjacent to PTHLH and the possible gain of a limb enhancer. Furthermore, PTHLH expression appeared to be mis‐regulated in fibroblasts derived from the patient. Altogether, we find that the disruption of the regulatory landscape of PTHLH likely results in its inappropriate expression and this novel clinical presentation.     

Morphological changes in the lymphoid organs induced by diphenylhydantoin sodium (DPH)

Summary In rats injected with DPH the morphological changes induced in the thymus and lymph nodes were studied. In the thymus, features suggesting block of cellular differentiation were found, and in lymph nodes depletion of the paracortical zone and intense plasma cell hyperplasia could be observed. The correlation of these findings with the functional changes in the immunological response induced by the drug, and the possible implications of these changes in the induction of lymphoma are discussed.