Kinetics of leaching of lead sulfate in sodium chloride solutions

A powder dissolution method is used to study the kinetics of leaching of lead sulfate from a lead cake in the temperature range 298–353 K and the concentration range 50–270 g/l of a sodium chloride solution. The results obtained are used to calculate the apparent activation energy (E _a = 12.41 kJ/mol); its value indicates that the process of leaching of lead sulfate from a lead cake occurs in a diffusion zone. This process is shown to be described by a first-order kinetic equation.     

Quantitation of carbenicillin disodium, cefazolin sodium, cephalothin sodium, nafcillin sodium, and ticarcillin disodium by high-pressure liquid chromatography

High-pressure liquid chromatographic (HPLC) methods for the quantitation of carbenicillin, cefazolin, cephalothin, nafcillin, and ticarcillin were developed. The stability of 2% solutions of the antibiotics in normal saline and in 5% dextrose in water were studied at 24 and 5 degrees. The assays were conducted using a previously reported colorimetric method, and some assays also were performed using HPLC. For discolored solutions of cephalothin, the colorimetric method was not stability indicating. The percent relative standard deviations by HPLC based on six injections were 1.69, 0.94, 1.30, 1.59, and 1.6 for carbenicillin, cefazolin, cephalothin, nafcillin, and ticarcillin, respectively. Both carbenicillin and ticarcillin apparently may be mixtures of two isomers at equilibrium with each other. The shelflives recommended by the manufacturers at 5 degrees may be too conservative.     

Stability of bethanechol chloride, pyrazinamide, quinidine sulfate, rifampin, and tetracycline hydrochloride in extemporaneously compounded oral liquids

The stability of five drugs commonly prescribed for use in oral liquids but not commercially available as such was studied. Bethanechol chloride 5 mg/mL, pyrazinamide 10 mg/mL, quinidine sulfate 10 mg/mL, rifampin 25 mg/mL, and tetracycline hydrochloride 25 mg/mL were each prepared in a 1:1 mixture of Ora-Sweet and Ora-Plus (Paddock Laboratories), a 1:1 mixture of Ora-Sweet SF and Ora-Plus, and cherry syrup and placed in 120-mL amber clear polyethylene terephthalate bottles. Three bottles of each liquid were stored at 5 degrees C and three at 25 degrees C, all in the dark. Samples were taken initially and at various times up to 60 days for analysis by high-performance liquid chromatography and assessment of appearance and odor; pH was measured. A mean of at least 90% of the initial drug concentration was retained for 60 days in the liquids containing bethanechol chloride, pyrazinamide, or quinidine sulfate and for 28 days in the rifampin-containing liquids and the mixture of tetracycline hydrochloride and Ora-Sweet-Ora-Plus at both 5 and 25 degrees C. Tetracycline hydrochloride concentrations of 90% or more of the initial concentration were retained in the liquids prepared with Ora-Sweet SF-Ora-Plus for 10 days at 5 degrees C and 7 days at 25 degrees C and in those prepared with cherry syrup for 7 days at 5 degrees C and 2 days at 25 degrees C. No substantial changes in the appearance, odor, or pH of any liquid were observed. At 5 and 25 degrees C, bethanechol chloride 5 mg/mL, pyrazinamide 10 mg/mL, and quinidine sulfate 10 mg/mL were stable in three extemporaneously compounded oral liquids for 60 days and rifampin 25 mg/mL was stable for 28 days. The stability of tetracycline hydrochloride 25 mg/mL varied with the vehicle.     

The physical state of nafcillin sodium in frozen aqueous solutions and freeze-dried powders

The purpose of this study was to develop a better understanding of the physical chemistry of freeze drying of lyotropic liquid crystals using nafcillin sodium as a model solute. Solutions and freeze-dried powders of nafcillin sodium were studied by polarized light microscopy, differential scanning calorimetry, x-ray powder diffraction, and water vapor adsorption. Differential scanning calorimetry thermograms of nafcillin sodium solutions contain a melting endotherm at approximately -5.5 degrees C and, depending on the concentration and heating rate, a crystallization exotherm immediately after this endotherm followed by the melting endotherm of ice. When the sample is annealed at -4 degrees C, both the endotherm and exotherm are eliminated, and a new endotherm appears at approximately -1 degree C on the shoulder of the ice-melting endotherm. The data are interpreted as melting of a liquid crystalline phase, followed by crystallization. X-ray powder diffractograms of unannealed freeze-dried nafcillin sodium are consistent with a lamellar liquid crystal. Diffractograms of annealed freeze-dried nafcillin sodium indicate crystalline material which is a different crystal form than the monohydrate starting material. Moisture adsorption isotherms of the freeze-dried annealed (crystalline) and unannealed (liquid crystalline) nafcillin sodium show different affinities for moisture compared to the crystalline starting material. Solid-state stability data demonstrate that the freeze-dried liquid crystalline form of nafcillin sodium is much less stable than the freeze-dried crystal-line material. The literature recognizes two types of solute behavior on freezing, where the solute either crystallizes from the freeze concentrate or remains amorphous. Lyotropic liquid crystal formation during freezing represents a separate category of freezing behavior, the physical chemistry of which is worthy of further investigation.     

Stability of cidofovir in 0.9% sodium chloride injection and in 5% dextrose injection

The stability of cidofovir in i.v. admixtures under refrigerator and room temperature conditions was studied. Admixtures of cidofovir 0.21 and 8.12 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection and of 0.085 and 3.51 mg/mL in 5% dextrose and 0.45% sodium chloride injection were prepared in triplicate in polyvinyl chloride (PVC) or polyethylene-polypropylene containers and i.v. administration sets and stored for 24 hours at 2-8 or 30 degrees C. The lower concentration of cidofovir corresponded to an assumed dose of 0.5 mg/kg for a 40-kg patient, and the higher concentration to an assumed dose of 10 mg/kg for a 100-kg patient. Samples were removed at 0 and 24 hours and analyzed for cidofovir concentration by high-performance liquid chromatography. Physical compatibility was also studied. The stability of cidofovir in 0.9% sodium chloride injection and in 5% dextrose injection at low- and high-dose concentrations was unaffected by storage at either temperature. All admixtures were clear, colorless, and free of visible particles or precipitation. There were no substantial changes in pH or number of particles of > or = 10 microns in diameter. Cidofovir 0.21 and 0.12 mg/mL was stable in 0.9% sodium chloride injection and 5% dextrose injection in PVC and polyethylene-polypropylene containers and i.v. administration sets for up to 24 hours at 2-8 and 30 degrees C. Cidofovir was compatible with the injectable solutions studied.     

Neutron attenuation characteristics of polyethylene, polyvinyl chloride, and heavy aggregate concrete and mortars

Polyethylene and polyvinyl chloride pellets were introduced into concrete to improve its neutron attenuation characteristics while several types of heavy coarse aggregates were used to improve its gamma ray attenuation properties. Neutron and gamma ray attenuation were studied in concrete samples containing coarse aggregates of barite, pyrite, basalt, hematite, and marble as well as polyethylene and polyvinyl chloride pellets in narrow-beam geometry. The highest neutron attenuation was shown by polyethylene mortar, followed by polyvinyl chloride mortar; barite and pyrite concrete showed higher gamma ray attenuation than ordinary concrete. Broad-beam and continuous (infinite) medium geometries were used to study the neutron attenuation of samples containing polymers at different concentrations with and without heavy aggregates, the fitting equations were established, and from these the neutron removal coefficients were deduced. In a radiation field of neutrons and gamma rays, the appropriate concentration of polymer and heavy aggregate can be selected to give the optimum total dose attenuation depending on the relative intensities of each type of radiation. This would give much better design flexibility over ordinary concrete. The compressive strength tests performed on mortar and concrete samples showed that their value, in general, decreases as polymer concentration increases and that the polyvinyl chloride mortar showed higher values than the polyethylene mortar. For general construction purposes, the compression strength was considered acceptable in these samples.     

Activity of serum sodium, potassium and calcium in vertebrates]

Of 49 patients undergoing operation for benign spontaneous pneumothorax, 28 (57%) were found to have a sharp first or second rib. In a series of 100 patients undergoing thoracotomy for other conditions, only eight (8%) were found to have a sharp rib. The association between sharp ribs, apical scars and bullae, and spontaneous pneumothorax is discussed.     

The effects of a potassium citrate, cetylpyridinium chloride, sodium fluoride mouthrinse on dentine hypersensitivity, plaque and gingivitis. A placebo-controlled study

Home-use studies on dentine hypersensitivity have most commonly involved toothpastes and rarely have mouthrinses been employed. Potassium and/or fluoride toothpastes have been shown effective in the treatment of dentine hypersensitivity. The aim of this study was to evaluate the effectiveness of a total formulation, containing potassium citrate, sodium fluoride, cetylpyridinium chloride mouthrinse compared to the base rinse minus actives in the reduction of dentine hypersensitivity. The study was a randomised placebo controlled, double blind parallel design. At a screening visit, 90 adult subjects were recruited who were suffering from dentine hypersensitivity from at least 1 tooth responding to tactile stimulation (45gm pressure) and had at least 2 teeth responding to evaporative stimulation (air blast). During a washout period of 28 days and throughout the 56-day study period, subjects used a soft filament toothbrush and standard fluoride toothpaste. At baseline (day 1), threshold sensitivities to incremental tactile (10 g to 70 g) and evaporative stimuli were determined. Gingival health was assessed by recording bleeding on probing at 25 g pressure at mesiobuccal and lingual sites. Plaque scores from buccal and lingual surfaces of disclosed teeth were also measured. Subjects then used the prescribed rinse, 10 ml for at least 30 s after brushing 2x per day returning on days 28 and 56 for rescoring of sensitivity, gingivitis and plaque. Data from 88 subjects were used with the intent to treat analyses and 83 in the completely evaluable analyses. Groups were well balanced for demographic data and product returns suggested good compliance. Both groups showed highly significant improvements in tooth sensitivity. The pattern was for greater improvement in the test compared to the control group (statistically significant for the plaque score), whereas bleeding scores, already low, showed no change in either group. By definition, the placebo rinse could not have exerted any therapeutic action; the study therefore provides clear direct evidence as to the magnitude (30%-40%) of the little studied, but assumed, placebo response in dentine hypersensitivity trials.     

Blood pressure and diurnal variation in sodium, potassium, and water excretion

This study was designed to investigate the prevalence of Cilia-associated respiratory (CAR) bacillus infection in rabbits reared for meat production in Italy and to correlate the presence of CAR bacillus with inflammatory lesions of the respiratory tract. Seventy health, 3-month-old, New Zealand White rabbits, raised in 10 different rabbitries in Northern Italy were randomly selected at slaughter. No gross lesions were found at necropsy in any rabbit. In each animal, the trachea and lungs were sampled, fixed in 10% formalin, embedded in paraffin and stained with the Warthin-Starry method to evaluate the presence of CAR bacillus, and with haematoxylin and eosin to evaluate the presence of inflammatory lesions. CAR bacillus was present in 50 out of 70 rabbits (71.4%) with a prevalence of the infection that varied from 30% to 100% in the seven rabbitries. CAR bacillus was present both in the trachea and bronchi in 23 cases (32.8%), only in the trachea in 24 cases (34.3%) and only in the bronchi in three cases (4.3%). Inflammatory lesions were found in the trachea (22 cases, 31.4%) and the bronchi (58 cases, 82.8). There was a strong, statically significant correlation between the presence of CAR bacillus in the bronchi and bronchial inflammatory lesions (P < 0.0001). This study indicates that CAR bacillus infection is widespread in conventionally reared rabbits in Italy and that a possible correlation exists between the presence of CAR bacillus and bronchial inflammatory lesions.     

In vivo modification of 3'-phosphoadenosine 5'-phosphosulfate and sulfate by infusion of sodium sulfate, cysteine, and methionine

The importance of tissue sulfate concentrations in regulating 3'-phosphoadenosine 5'-phosphosulfate (PAPS) synthesis is not known. Therefore, this study was conducted to determine the influence of increased availability of inorganic sulfate on steady-state PAPS concentrations in various tissues. To increase tissue sulfate concentrations, 2-16 mmol/kg of sodium sulfate and sulfur-containing amino acids (cysteine or methionine) were infused intravenously for 2 hr into pentobarbital-anesthetized rats. Serial blood samples were taken during the infusion and analyzed for sulfate concentrations. After 2 hr of infusion, liver, kidney, and brain were removed for quantification of tissue PAPS and sulfate concentrations. Infusion of sodium sulfate, cysteine, and methionine increased serum and tissue sulfate concentrations in a dose- and time-dependent manner. Serum sulfate concentrations increased from 0.8 to 14 mM during the infusion of sodium sulfate, whereas infusions of cysteine and methionine increased serum sulfate concentrations to 4.8 and 2.0 mM, respectively. Tissue sulfate concentrations also increased during sulfate infusion. Liver sulfate concentration increased from 0.8 to 4.8 mM, kidney concentration increased from 0.6 to 31 mM, and brain concentration increased from 0.1 to 0.6 mM. Similar to the serum sulfate concentrations, sulfate infusion was the most effective in increasing tissue sulfate concentrations, cysteine was intermediate, and methionine the least effective. Although sulfate concentrations in liver, kidney, and brain increased 6-, 50-, and 6-fold by infusing sulfate, respectively; tissue PAPS levels were not altered markedly. Hepatic PAPS concentrations increased significantly (30-35%) only when infused with the higher doses (8 or 16 mmol/kg/2 hr) of sodium sulfate.(ABSTRACT TRUNCATED AT 250 WORDS)     

硫酸铵-碘化钾-孔雀石绿体系分离金

研究了金在硫酸铵-碘化钾-孔雀石绿体系中的分离行为。试验结果表明,体系可分离金,且在选定的条件下金的分离率为100%,合成样的分离结果表明,该方法可从大量Fe(Ⅲ）、Pb（Ⅲ）、Cu(Ⅱ）、Zn（Ⅱ）、Ca（Ⅱ）等常见贱金属基体中分离Au（Ⅲ）。     

Early postglomerular plasma concentrations of chloride, sodium, and inulin in the rat kidney

Sodium, chloride, and inulin concentrations were measured in plasma collected from the terminal portions of long efferent vessels at the subcapsular surface of the rat kidney. Sodium concentration equaled and the concentrations of chloride and inulin were less than those in peripheral plasma. During benzolamide infusion, chloride concentration equaled while inulin concentration remained less than in peripheral plasma. In free-flow micropuncture samples collected randomly during control conditions, chloride concentration rose rapidly in the early proximal tubule and then remained elevated and constant throughout the remainder of the proximal tubule accessible to micropuncture. These experiments indicate that normally tubular reabsorbate low in chloride and inulin is added to the blood traversing the early postglomerular vessels before reaching the kidney surface. Bases on the analyses of proximal tubular fluid, this type of reabsorbate appears available only from the early proximal tubular segment. We conclude that a close functional relationship exists between the first segment of the proximal tubule and the early postglomerular blood supply characteristic of the superficial cortical nephron.     

Concentrations of sodium, potassium and cortisol in saliva, and self-reported chronic work stress factors

One hundred and fifteen electronics factory employees completed questionnaires relevant to work stress, and gave unstimulated saliva samples. As previously found, Perceived Coping Incapacity correlated very significantly with self-reported emotional upset and psychosomatic complaints. Salivary [Na+] correlated significantly with Perceived Coping Incapacity (rho = -0.30, p < 0.01), and also with emotional upset (rho = -0.19, p < 0.05). Raised [K+] tended to be associated with reduced fatigue (rho = -0.21, p < 0.05) and lower self-medication (rho = -0.21, p < 0.05) together with a greater perceived personal work responsibility (rho = 0.19, p < 0.05)-all consistent with the perception of work demands as positive challenges rather than stressors. Self-reported fatigue and emotional upset at work gave higher correlations with [K+] and [Na+] than either did on its own. Salivary [cortisol] was uncorrelated with self-reported work stress indices, and with [K+] and [Na+].     

Distinct roles for sodium, chloride, and calcium in excitotoxic dendritic injury and recovery

The postsynaptic neuronal dendrite is selectively vulnerable to hypoxic-ischemic brain injury and glutamate receptor overactivation. We explored the glutamate receptor pharmacology and ionic basis of rapid, reversible alterations in dendritic shape which occur in cultured neurons exposed to glutamate. Dendrite morphology was assessed with the fluorescent membrane tracer, DiI, or immunofluorescence labeling of the somatodendritic protein, MAP2. Cortical cultures derived from 15-day-old mouse embryos underwent segmental dendritic beading when exposed to NMDA, AMPA, or kainate, but not to metabotropic glutamate receptor agonists. Varicosity formation in response to NMDA or kainate application was substantially attenuated in reduced sodium buffer (substituted with N-methyl-D-glucamine). Furthermore, veratridine-induced sodium entry mimicked excitotoxic alterations in dendrites and additionally caused varicosity formation in axons. Solutions deficient in chloride (substituted with Na methylsulfate) and antagonists of chloride-permeable GABA/glycine receptors reduced NMDA- or kainate-induced varicosity formation. An increase in dendrite volume was observed as varicosities formed, and varicosity formation was attenuated in sucrose-supplemented hypertonic media. Despite marked structural changes affecting virtually all neurons, dendrite shape returned to normal within 2 h of terminating glutamate receptor agonist application. Neurons exposed to kainate recovered more rapidly than those exposed to NMDA, and neurons exposed to NMDA in calcium-free buffer recovered more rapidly than cells treated with NMDA in normal buffer. While sodium, chloride, and water entry contribute to excitotoxic dendritic injury acutely, calcium entry through NMDA receptors results in lasting structural changes in damaged dendrites.