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Citrate or ascorbate/citrate treatment of established corneal ulcers in the alkali-injured rabbit eye.

Immediate treatment of alkali-injured eyes with citrate or ascorbate has previously been shown to prevent corneal ulceration and perforation in the rabbit. Other experiments showed that while ascorbate treatment of established ulcers did not appear to lead to significant healing it did reduce perforations by prolonging the presence of descemetoceles. In the present experiment with established ulcers, alkali injuries were created with 1 N NaOH in a 12 mm corneal well for 35 seconds. Eyes were entered into the study with anterior, middle or posterior ulcers. When compared to controls, 10% citrate (q1/2 hr) significantly reduced the deepening of anterior stromal ulcers while 10% ascorbate/10% citrate (q1 hr/q1 hr-30 min apart) showed only a trend toward reduction of these ulcers (14 hr of dropping). The demonstration of healing (total vascularization or no ulcer) is significant when comparing the control group (8.3%) to the citrate treated group (58.3%, 0.01 less than P less than 0.009), but not the ascorbate/citrate group (18.2%). Sixty-seven percent of anterior stromal ulcers in the control group progressed to descemetocele or perforation, compared to 8.3% in the citrate treated (0.003 less than P less than 0.004), and 45.5% in the ascorbate/citrate treated group (not significant). While the numbers of ulcers entered as middle stromal were too few to analyze statistically, the reduced numbers of perforations and increased stability prior to perforation in both treatment groups suggest a positive effect by both citrate and ascorbate/citrate. Treatment of posterior stromal ulcers did not prevent the development of descemetoceles and perforations in either treatment group; however, the numbers in this category were too few to analyze.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Temperature and ionic strength dependence of the subunit interactions in vertebrate skeletal myosin. A comparison of the interaction between the alkali light and heavy chains of mammalian and avian myosin.

The stability of the interaction of A1 in myosin and subfragment 1 isolated from fast-twitch mammalian and avian muscles with respect to temperature and ionic strength has been examined. This was done by determining the extent of exchange of the endogenous free A1 light chain into these proteins from the two species. Whereas the extent of exchange at 37 degrees C into mammalian S1, occurring after 60 min, is about 80% of the theoretically expected amount at physiological ionic conditions, the level of exchange observed with the avian S1 is significantly lower. However, close to the theoretical limit is observed for the avian S1 when exchange is done at 43 degrees C which is close to average avian body temperature. A similar dependence with temperature is observed in the case of exchanges into avian myosin. In the case of mammalian myosin, 50% of the theoretical exchange is observed at 37 degrees C under physiological ionic strength, whereas the level of exchange observed under these conditions with the avian protein is much lower in agreement with recent observations (Waller, G. S., and Lowey, S. (1985) J. Biol. Chem. 260, 14368-14373; Pastra-Landis, S. C., and Lowey, S. (1986) J. Biol. Chem. 261, 14811-14816). If, however, the exchanges are done at 43 degrees C in physiological ionic strength, significant extents of exchange can be observed in avian myosin. These results suggest that at physiological ionic and temperature conditions relevant for the source of myosin and S1 being investigated, the alkali light chains are in dynamic equilibrium between free and heavy chain associated states. Therefore, the failure to observe alkali light chain exchange in avian myosin at 37 degrees C appears to be related to the higher temperature stability of its interaction with the heavy chain.

Animals↗

Alkali-stable oligosaccharides isolated by hydrazinolysis of M and N blood group glycoproteins.

Three alkali-stable oligosaccharides free of amino acids were purified from hydrazinolysis products of M or N blood group glycoprotein. These three oligosaccharides differed in the content of sialic acid and contained similar amounts of other carbohydrate components. The asparagine-linked oligosaccharides, obtained by strong alkaline degradation of M glycoprotein, showed similar electrophoretic mobilities and chemical composition to the oligosaccharides obtained by hydrazinolysis. It indicates that hydrazinolysis does not give a substantial degradation of carbohydrates of alkali-stable oligosaccharides of human red cell glycoprotein.

Chemical Phenomena↗

Fibronectin in alkali burns of the rabbit cornea.

Alkali burns of the cornea were made bilaterally in 16 albino rabbits. The eyes were then treated four times a day in a masked fashion with a solution either of fibronectin (250 micrograms/ml) plus gentamicin (1.5 mg/ml) or of gentamicin (1.5 mg/ml) plus hydroxypropyl methylcellulose (Tears Naturale). The eyes were examined daily in a masked manner for evidence of a corneal epithelial defect. On days 6-14, the fibronectin-treated eyes had more healed corneal defects (p less than 0.05, McNemar's test for matched pairs) than the control eyes. Fibronectin aided the healing of corneal alkali burns by decreasing the peeling back of the healing epithelium and by allowing re-epithelialization if peeling back had occurred. These properties of fibronectin helped to preserve a stable, intact corneal surface.

Animals↗

Short-term re-epithelialization of the alkali-burned rabbit cornea.

Pfister and associates have shown that treatment with citrate solution reduces the incidence of stromal ulceration after alkali burn of the cornea. In the course of study of the effect of inhibitors of plasminogen activation on corneal re-epithelialization following alkali burns, we noted that when citrate was used in the medication, the healing process proceeded rapidly for three days; however, the denuded area became abruptly larger on the fourth day, and then resumed healing on the fifth day.

Aminocaproates↗

A study of selective adsorption of Na+ and other alkali-metal ions on isolated proteins: a test of the salt-linkage hypothesis.

According to the salt-linkage hypothesis (a part of the association-induction hypothesis), the binding of alkali-metal ions on isolated proteins may be low as a result of the masking of cation-binding fixed anionic groups by the formation of "salt linkages" between them and fixed cationic groups. This hypothesis has been verified in a quantitative manner by the measurement of free and adsorbed Na+ in solutions of bovine hemoglobin titrated with increasing concentration of NaOH. In addition this communication presents data indicating (1) wide variability in the extent of Na+ adsorption among different isolated proteins and even among different samples of the same protein, (2) auto-cooperativity in the pH titration and Na+ adsorption, and (3) selectivity of the liberated fixed anionic groups for different alkali-metal ions in the rank order Na greater than Li greater than K greater than Rb, Cs.

Adsorption↗

The milk-alkali syndrome. A case report.

A case of the milk-alkali syndrome is described. The patient presented with a raised serum calcium level without hypercalciuria, nephrocalcinosis and azotaemia. The alkali used was an antacid preparation containing calcium carbonate.

Animals↗

Conjunctival goblet cell frequency after alkali injury is not accurately reflected by aqueous tear mucin content.

Goblet cell counts have been used to evaluate the suitability of conjunctiva as a source of ocular surface epithelial cells. However, since tear mucin content can be determined without tissue excision, it seemed that the concentration of those compounds might be a useful indicator of conjunctival vitality. To test the extent to which aqueous tear composition reflects conjunctival goblet cell frequency, goblet cell frequency and aqueous tear mucin content were measured after alkali injury in rabbits. Mild alkali injury (0.1 N NaOH for 30 sec) caused a transient but substantial decrease in goblet cells (to 25% of normal at day 7) with a return to normal by six weeks. Tear mucin content was decreased to a lesser degree, from a normal value of 6.4 +/- 0.47 nmol oligosaccharide per microliter (n = 10) to a minimal value of 4.7 +/- 0.64 (n = 7) (73% of normal) at day 7, returning to normal 4 weeks after injury. Thus, the direction of the change was the same, but the magnitudes were quite different. These results suggest that conjunctival goblet cell frequency is not accurately reflected by aqueous tear mucin content, and therefore, that tear mucin content cannot be used directly as an indicator of conjunctival health.

Animals↗

Alkali ion transport of primycin modified erythrocytes.

The effects of the antibiotic primycin on alkali cation transport of human erythrocytes were investigated. Primycin selectively increases the permeability of erythrocytes to alkali-cations according to the sequence: Cs+ greater than Rb+ approximately K+ greater than Na+. The time course of the cation effluxes depends on the antibiotic concentration and can be altered by negatively charged SDS. Some evidence is given for the mechanism of primycin-membrane interaction.

Anti-Bacterial Agents↗

Ocular alkali burn associated with automobile air-bag activation.

Alkali burns of the eye can result in permanent visual impairment and are therefore potentially devastating. Immedicate diagnosis and treatment are essential to a good prognosis. The authors report the case of a 52-year-old woman who suffered alkali keratitis as the result of the activation of an automobile air bag. This type of injury will be seen more frequently as more cars are equipped with air bags and should be suspected in drivers and passengers involved in accidents in which air bags have been activated.

Air Bags↗

Synthesis, physico-chemical and biological properties of some alkali metals and quaternary alkylammonium salts of polyene antibiotics: amphotericin B, nystatin and aureofungin.

Polyene antibiotics are known for their remarkable antifungal properties. The alkali metal and quaternary alkylammonium salts of amphotericin B, nystatin and aureofungin have been prepared by ion-exchange method. The physico-chemical and biological properties of these salts have been studied with a view to evaluate their therapeutic advantages over the parent compounds. While the majority of the salts reported herein showed more water solubility; triethylammonium salts, unlike the other alkali metal salts, possessed marginally improved or similar bioactivity in comparison to their parent antibiotic having reduced toxicity.

Amphotericin B↗

Mapping of the region of the heavy chain of myosin subfragment 1 that can be crosslinked to the alkali light chains.

Earlier studies have shown that the presence of MgATP considerably diminishes the efficiency of crosslinking of the alkali light chains to the heavy chain of myosin subfragment 1 (S1) with dithiobis (succinimidylpropionate) (DSP). To localize the region of the nucleotide-induced change, a non-cleavable analog of DSP, disuccinimidyl suberate (DSS) was used. The products of crosslinking between the alkali light chains and the 27 kDa tryptic fragment of the heavy chain were isolated and further cleaved with N-chlorosuccinimide (NCS) or with formic acid. Mapping of the resulting peptides on SDS gels locates the crosslinking site(s) in the heavy chain region spanning residues 42-112.

Adenosine Triphosphate↗

[Histochemical studies on the glycoconjugates of experimental alkali burned cornea in rabbit].

The model of experimental alkali burn of cornea in rabbit was obtained using 1 mol/L NaOH solution. After being burned for 1, 3, 7 and 14 days, the histochemical changes of these models were studied by using labelled concanavalin A (ConA-FITC) and wheat germ agglutinin (WGA-FITC). The results showed that after being burned, the amount of glycoconjugates interacted with these lectins decreased, and increased gradually after 7 days, then reached the level higher than that in the normal cornea. These changes were related to the recovery of alkali burned cornea.

Animals↗

Renal tubular acidosis due to the milk-alkali syndrome.

A 60-year-old man with a history of excessive ingestion of calcium carbonate presented with azotemia, hypercalcemia and hyperphosphatemia. His acid-base status was initially normal. Following the cessation of calcium carbonate treatment, the hypercalcemia and azotemia disappeared, and the patient was found to be in metabolic acidosis with blunted acid excretion and a urine pH of 6.1. Kidney biopsy showed focal tubular calcification; the tubular damage was apparently caused by hypercalcemia and had resulted in renal tubular acidosis. During the three months of observation since that time there has been a tendecy for spontaneous remission of the renal tubular acidosis. Impaired renal hydrogen ion excretion prevented the development of metabolic alkalosis despite ingestion of alkali initially, and was later responsible for the metabolic acidosis. Renal tubular acidosis occurring as a sequel to the milk-alkali syndrome may aggravate the danger of nephrocalcinosis in this syndrome.

Acidosis, Renal Tubular↗

[Effect of a binuclear rhenium complex on the conductivity of lipid bilayer membranes for alkali metal ions].

Conductivity of bilayered lipid membrane (BLM) for the ions of alkali metals under action of binuclear rhenium complex (V) [Re2(Ph3P)2 (AHK)2O3Cl4] has been analyzed. It is found that BLM conductivity sharply increases in presence of lithium ions, then it drops and slowly increases again up to maximum value which is not changed. If sodium, rubidium and caesium chlorides are used as electrolytes the BLM conductivity almost does not change. The mechanisms of change of BLM conductivity is suggested for the ions of alkali metals under interaction with binuclear complex of rhenium.

Cesium↗

Alkali retinopathy.

Two patients were seen with intense alkali burns of the eye and prominent chorioretinal damage. The course of one case illustrates the development of such lesions. The second case suggests that retinal damage can be the limiting factor in the visual prognosis following such burns.

Adult↗

Endocrine influences on ulceration and regeneration in the alkali-burned cornea.

Subconjunctival dibutyryl 3',5' cyclic adenosine monophosphoric acid (DBcAMP) produced a statistically significant reduction of ulceration in the alkaliburned rabbit cornea. No effect on epithelial cell growth was observed. DBcAMP also caused a statistically significant acceleration of corneal neovascularization in the first two weeks postburn. Medroxyprogesterone acetate also affected the development of corneal ulcers postalkali burn, but in a less well-defined manner. Dinoprost and indomethacin did not seem to influence this lesion. Cyclic adenosine monophosphoric acid may therefore possess a potential for use in the alkali-burned human eye.

Alkalies↗