Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ALKALIES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1991

Deposition of alkali-soluble fluoride on enamel surface with or without pellicle.

Deposition of alkali-soluble fluoride on enamel in the presence and absence of an acquired pellicle was studied in vitro during a single topical application of a 2% sodium fluoride solution at neutral pH. Five experimental groups of repeated measures design were established. The amount of alkali-soluble fluoride formed on enamel (i.e., calcium fluoride) was measured by chemical assessments and by SEM. The results showed that there were no differences among the groups demonstrating the incapacity of pellicle to interfere with deposition of alkali-soluble fluoride on enamel. The fluoride ions are thus able to reach the enamel in spite of the presence of the pellicle.

Alkalies↗
PubMed1989

Corneal alkali wound healing in the monkey.

Healing of a corneal alkali wound was followed in the monkey eye (Macaca fascicularis) for 4 months. A corneal alkali wound was inflicted in one eye in each of 30 monkeys under general anesthesia. A round filter paper, 5.5 mm in diameter, soaked in 1 N NaOH was put centrally on the cornea for 60 seconds. The alkali wounded all layers in the cornea underlying the filter paper, including the endothelium. Epithelial and endothelial healing was assessed morphometrically from photographs and micrographs, respectively. Stromal healing was documented using quantitative microradiography. During the observation period the wounds regained complete transparency. The epithelium showed few complications after primary healing during the first three days. The stroma regained normal thickness and dry mass content within one week. The endothelium resurfaced within one week and then remained intact. The role of the endothelial healing behaviour for the wound healing process is emphasized.

Alkalies↗
PubMed1969

Single chain alkali resistance in hemoglobin Rainier: beta 145 tyrosine-histidine.

The mechanism of alkali resistance in hemoglobin Rainier, an adult human hemoglobin variant (beta 145 tyrosinie --> histidinie), has been investigated. Alkali denaturation kinetics, electrophoretic and hybridization study. and ultracentrifuge analysis provided evidence for a monomeric beta Rainiier chain resisting denaturation at alkaline pH. These data provide evidence for a previously unrecognized effect of a single amino acid substitution, that is, the change of the alkali denaturation properties of monomneric chains.

Alkalies↗
PubMed2001

Ipsilateral limbal translocation for treatment of partial limbal deficiency secondary to ocular alkali burn.

BACKGROUND/AIM: Chemical ocular burn, especially by alkali, may result in damage to the limbal stem cells, fundamental in maintaining the integrity of ocular surface. Clinically, patients manifest abnormal conjunctival-corneal healing with peripheral neovessels, chronic epithelial defect, severe stromal inflammation, and conjunctivalisation of the corneal, which is characteristic of limbal deficiency. Penetrating keratoplasty has a poor prognosis in these cases. Available therapeutic options included limbal autograft and allograft transplantation associated or not with human amniotic membrane transplant. The authors propose an alternative treatment with ipsilateral autologous limbal transplantation, transferring the healthy portion of the limbus from the partially burned eye to the deficient area in patients with partial limbal deficiency secondary to alkali burn. METHODS: Ipsilateral limbal autografts were performed in five patients with partial limbal deficiency secondary to alkali burn, transferring the healthy portion of the limbus to the burned area of the same eye, without intervening in the contralateral eye. RESULTS: All cases had regression of the limbal deficiency with improvement of visual acuity to a minimum of 20/60-20/20 (partial), without complications during the follow up period (range 7-11 months). CONCLUSION: Ipsilateral autologous limbal autograft is a therapeutic option for partial limbal deficient eyes.

Adolescent↗
PubMed2002

Coordinated regulation of gastric chloride secretion with both acid and alkali secretion.

Gastric secretion of hydrochloric acid requires protons and chloride, yet the mechanisms and regulation of gastric chloride secretion remain unclear. We developed an in vivo technique to simultaneously measure acid/base and chloride secretion into the gastric lumen of anesthetized rats. The cannulated stomach lumen was perfused with weakly pH-buffered chloride-free solution containing a chloride-sensitive fluorophore [5 microM N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE)]. Gastric acid and chloride secretion was detected in gastric effluents by 1) flow-through pH electrode and 2) MQAE fluorescence. Gastric effluent was also collected at 1-min intervals for independent determination of chloride amount by chloridometer. In all conditions, both optical and chemical determinations of chloride report similar amounts of secreted chloride. During luminal perfusion with pH 5 solution, net acid and chloride secretion into the lumen was observed. Pentagastrin stimulated both secretions. In contrast, proton pump inhibition (omeprazole) caused alkalinization of the gastric effluent, but chloride secretion was not diminished. During luminal pH 3 perfusion, net alkali secretion was observed, and chloride secretion at luminal pH 3 was greater than pH 5. When tissue is pretreated with omeprazole at luminal pH 3, the addition of prostaglandin E2 synchronously stimulates both alkali and chloride secretion. Results suggest that both acid and alkali secretions are separately coupled with chloride secretion.

Alkalies↗
PubMed1999

Effect of Na-hyaluronan on stromal and endothelial healing in experimental corneal alkali wounds.

The healing of stroma and endothelium after a standardized corneal alkali wound was evaluated in sodium-hyaluronan (Na-HA)-treated eyes. Alkali wounds were produced in one eye of each rabbit by applying a 5.5-mm round filter paper soaked in 1 N NaOH onto the central cornea for 60 s. Eyes were then treated with either 1% Na-HA (the treatment group) or phosphate-buffered saline (the control group) 4 times per day for 3 weeks. Endothelial wound morphometry was performed after alizarin red and trypan blue staining, while stromal healing was assessed by counting polymorphonuclear leukocytes (PMNs) and keratocytes in the central and marginal wound areas. During the early healing period the stroma treated with Na-HA had less PMNs than that of the control group. The size of the endothelial defect area measured 5 days after injury was significantly smaller in the Na-HA group than in the control corneas. The present findings indicate that topically applied 1% Na-HA affects stromal and endothelial healing during the early repair process after corneal alkali wounds.

Alkalies↗
PubMed1988

Effect of sodium lauryl sulfate on the deposition of alkali-soluble fluoride on enamel in vitro.

There are indications that sodium lauryl sulfate may reduce the cariostatic effect of fluoride when present together with sodium monofluorophosphate during topical application. The aim of the present study was to examine the in vitro deposition of alkali soluble fluoride on enamel during topical application with sodium fluoride in combination with sodium lauryl sulfate. It was found that increasing amounts of lauryl sulfate decreased the amount of alkali soluble fluoride deposited on the enamel. The amount of fluoride deposited from toothpaste supernatants was less than that from aqueous solutions of NaF with the same concentration of fluoride. Enamel pieces, pretreated with sodium lauryl sulfate showed a reduced deposition of alkali-soluble fluoride after incubation in a fluoride solution. It was also observed that the presence of lauryl sulfate increased the solubility of CaF2 in water.

Administration, Topical↗
PubMed1997

Histochemical study of leukocyte elastase activity in alkali-burned rabbit cornea.

In order to contribute to a better understanding of the role of leukocyte elastase in corneal melting after a severe alkali burn, the in situ appearance and activity of this enzyme in the rabbit cornea was examined. For this reason, a histochemical approach using cryostat sections on membranes and a gel incubation medium with the very sensitive substrate Mu-Ala-Ala-Pro-Val-7-amino-4-trifluoromethylcoumarin (Enzyme Systems Products, Livermore, Calif., USA) was employed. In contrast to the normal rabbit cornea where leukocyte elastase activity was absent, in alkali-burned cornea a high enzyme activity in inflammatory cells (particularly polymorphonuclear leukocytes) was present. The extracellular release of leukocyte elastase into the substantia propria of the corneal stroma was associated with disintegration of the corneal stroma and the appearance of corneal ulcers. These results show that leukocyte elastase is associated with corneal destruction after a severe alkali burn.

Alkalies↗
PubMed1970

Hemoglobin stability: observations on the denaturation of normal and abnormal hemoglobins by oxidant dyes, heat, and alkali.

Several unstable mutant hemoglobins have alterations which affect areas of the molecule involved in the attachment of heme to globin. Loss of heme from globin has been demonstrated during the denaturation of some of these unstable mutants. The importance of heme ligands for the stability of hemoglobin was illustrated in the present experiments on the denaturation of several hemoglobins and hemoglobin derivatives by heat, oxidative dyes, and alkali. Heating of normal hemolysates diluted to 4 g of hemoglobin per 100 ml at 50 degrees C for 20 hr in 0.05 M sodium phosphate, pH 7.4, caused precipitation of 23-54% of the hemoglobin. Dialysis against water or dilution of the sample decreased denaturation to 12-20%. Precipitation was decreased to less than 3.5% by the presence of 0.015 M potassium cyanide. Increasing the ionic strength of the medium increased precipitation. Cyanide prevented the formation of inclusion bodies when red cells containing unstable hemoglobin Philly, beta35 tyr --> phe, were incubated with the redox dye new methylene blue. Conversion to methemoglobin increased the rate of alkali denaturation of hemoglobin but the presence of potassium cyanide returned the denaturation rate to that of ferrohemoglobin. The ability of cyanide to decrease heat precipitation of hemoglobin may depend on a dimeric or tetrameric state of the hemoglobin molecule. Purified beta-chains, which exist as tetramers, were stabilized but purified monomeric alpha-chains were not rendered more heat resistant by the ligand. Stabilization of hemoglobin by cyanide required binding of the ligand to only one heme of an alphabeta-dimer. Hemoglobin Gun Hill, an unstable molecule with heme groups present only on the alpha-chains was quite heat stable in the presence of cyanide. The binding of cyanide to the iron atom in methemoglobin is thought to be associated with increased planarity of the heme group and increased stability of the heme-globin complex. The stabilizing effect of cyanide in the above experiments suggests that Heinz body formation, heat precipitation of hemoglobin, and the increased alkali denaturation of methemoglobin depend on changes of heme-globin binding.

Alkalies↗
PubMed1988

Alkali solubility of calcium fluoride pre-exposed to inorganic orthophosphate at pH 6.8.

The dissolution behavior in 1 M KOH solution of calcium fluoride which had been pre-exposed to inorganic orthophosphate at pH 6.8 was investigated. Chemically pure calcium fluoride (50 mg) was incubated in 5 ml of 2 mmol/l sodium phosphate buffer, pH 6.8, for 24 h or 120 h and subsequently incubated in 5 ml 1 M KOH for 24h. Control samples were incubated in distilled water before KOH exposure. Pre-treatment with phosphate caused a significantly reduced dissolution rate of calcium fluoride in alkali. Longer exposure to phosphate resulted in further reduction of the dissolution rate in alkali. Calcium fluoride formed on teeth in vitro and in vivo will always be exposed to phosphate. The alkali method thus has limitations because calcium fluoride that has been exposed to phosphate will be underestimated.

Alkalies↗
PubMed1978

The effect of oral local anaesthetic and alkali on basal and food-stimulated serum gastrin levels in patients with duodenal ulcer.

Twelve patients with duodenal ulcers were each given on separate days and in random order an oral local anaesthetic (oxethazaine), an alkali (aluminium hydroxide and magnesium hydroxide), a combination of local anaesthetic and alkali (Mucaine), and a similar volume of water (control) followed one hour later by a solution of meat extract (Oxo). The effect of these treatments on serum gastrin levels was measured. None of the treatments altered the normal basal gastrin levels. The gastrin response to ingestion of protein extract was significantly lower in patients who had been pre-treated with local anaesthetic than those who had received alkali, with or without local anaesthetic, or water.

Administration, Oral↗
PubMed1989

Effect of the luminal hydrogen ion on alkali and mucus secretion in the rat stomach.

This study was designed to investigate the effect of luminal H+ on alkali and mucus secretion in the isolated rat stomach. At various luminal pHs, the thickness and the pH gradient of the mucus gel layer were measured. The maximum pH and calculated alkali secretion showed that the latter was stimulated in parallel with an increase in luminal H+ concentration, especially when the luminal pH became less than 3.5. Mucus secretion, however, was not significantly affected by the luminal H+ concentration. These results suggest that alkali and mucus secretion in the stomach are not regulated by the same mechanism, but different ones.

Alkalies↗
PubMed1975

Delayed cataract formation after alkali burn.

A small posterior subcapsular cataract developed almost a year after a moderately severe alkali burn of the eye. The cornea recovered completely. Cataract and glaucoma following alkali burns are discussed. The development of delayed cataract should be kept in mind in compensation cases before a final disability report is made. Topical steroids may potentiate the detrimental effect of alkali on the eye.

Administration, Topical↗
PubMed2000

[Immunologic experimental studies on the alkali burn of cornea in rats].

OBJECTIVE: To investigate the immune reaction of severe corneal alkali burns. METHODS: The models of severe corneal alkali burns were induced in rats. Immunohistochemistry was carried out on wholemounts of the cornea and iris at different time points after corneal burns to detect T-lymphocytes and their subpopulation, macrophages, dendritic cells and MHC class II -positive cells. RESULTS: In the early stage of the burns, there were small increasing number of T-lymphocytes and MHC class II-positive cells in the cornea and iris. At the period of corneal melting and perforation, a massive influx of lymphocytes (CD(+)(3), CD(+)(4), CD(+)(8)), macrophages and dendritic cells was seen in the cornea adjacent to the limbus and iris. CD(+)(4) lymphocytes were much more than CD(+)(8) in number. T-cells and MHC class II-positive cells were observed not only at the limbus but also in the melting area and corneal center. Morphological changes of these cells were also noted. In the restoration stage, a number of positive cells were still found in the iris. CONCLUSION: Immunological mechanism is involved in the pathological changes of the damage induced by corneal alkali burns, especially in the pathogenesis of the corneal melting and perforation.

Alkalies↗
PubMed2002

[Expression and significance of vascular endothelial growth factor in rat cornea after cautery with alkali].

OBJECTIVE: To investigate the expression of vascular endothelial growth factor (VEGF) in rat cornea after cautery with alkali. METHODS: In Sprague-Dawley rats, inflammatory corneal neovascularization was induced by cautery with alkali. VEGF was detected in corneal samples at different times by Western-blot, and immunohistochemistry method was used to investigate the distribution of VEGF at rat cornea after cautery with alkali. RESULTS: The normal rat corneas did not express VEGF. The expression of VEGF increased with time after corneal cautery. The rat corneas were infiltrated by massive inflammatory cells that, especially adjacent to the cautery lesion, showed staining for VEGF. CONCLUSION: VEGF production by inflammatory cells participates in inflammatory angiogenesis in rat corneas. VEGF has the effects on the induction and supporting of cautery-induced angiogenesis in rat cornea.

Alkalies↗
PubMed1999

[The experimental investigation of epithelial healing in rabbit central corneal alkali wounds].

PURPOSE: To observe the morphologic changes of epithelium in the alkali wounds at the central corneal of rabbits. METHODS: 38 rabbits weighing 2.5 kg were used. A alkali wound of the corneas was performed in the right eye of 38 New Zealand white rabbits with round filter paper, 8 mm in diameter, which were soaked in 0.5 mol/L NaOH for 5 seconds and then were placed centrally on the cornea for 60 seconds. The corneal burns were examined and photographed after the staining of 2% fluoresent staining with a slit lamp every day. The excised corneas were examined in the light microscope, electron microscope. RESULTS: The epithelial cells had rapidly disappeared in the burned area. The epithelial cells regrowth started at 8 hours following the burn, and 1-2 layers epithelial cells covered the burned area by 24 hours. The epithelial defects occured again on the 4th day. The desmosome and microvilli of the regenerating epithelium had a reduced number. There was no basement membrane between the regenerating epithelium and the strom. There were increased intercellular spaces between the regenerating epithalial cells. CONCLUSION: The epithelial healing were achieved through the division and migration of epithelial cells at the margin of the wound in rabbit central corneal alkali wound. The decrease of the junctions and the increase of intercellular spaces between the regenerating epithalial cells may be responsible for the second epithelial defects.

Alkalies↗
PubMed2003

Autologous limbal autograft for alkali-burned corneas in rabbit: an experimental study.

OBJECTIVE: To evaluate the effect of autologous limbal transplantation in the treatment of alkali-burned corneas in rabbits and assess the possible influence of this operation on the donor eye. METHODS: Animal models of alkali-burned corneas of the right eye were established in 32 rabbits, and 7 days after the injury, transplantations of the corneal limbal stem cells were per- formed, with the transplanted limbal coverage of the whole, 3/4, 1/2 and 1/4 of the recipient limbal circumference respectively. RESULTS: Four weeks after the operation, all the 8 recipient eyes with whole circumference limbal autografting recovered normal sight, while in those receiving 3/4, 1/2 and 1/4 circumference transplantation, 87.5%(7/8), 37.5%(3/8) and 0.00% (0 of 8) attained the recovery, respectively. The donor eyes with wholly circumferential resection of the limbal all had epithelial erosion, pseudopterygium lesions and neovascularization, and among those with 3/4 and 1/2 exsection, 75%(6/8) and 12.5%(1/8) developed the lesions, while 1/4 exsection did not affect the final healing of the donor eyes. CONCLUSION: Corneal limbal stem cells autografting is effective for treating alkali-burned corneas, but no more than 1/2 circumference resection of the donor cornea is recommended for the smooth healing of the donor eye after the operation.

Alkalies↗
PubMed2004

[Amelioration of secondary bare alkali-saline patches in Songnen Plain through inserting cornstalk].

Based on the field experiment on Songnen grassland, a new method was established to ameliorate the secondary bare alkali-saline patches (SAP) through inserting cornstalk. The experiment was rested on the assumption that through inserting cornstalk in the secondary bare alkali-saline patches (SAP) to retain seeds moving over its surface, the necessary seed source could be gained; and these seeds should be able to germinate and survive successfully on the cornstalk itself or in its neighborhood, where should be more fit to grow than other sites in SAP, due to the decomposition of cornstalk and its special role, so that, the aim to restore vegetation of SAP could be achieved at a pretty low cost and rapid speed. The results showed that the seed bank in soil was increased significantly, owing to the inserted cornstalk and its operating processes. The seed number in ameliorated soil was 4020.0 +/- 1773.6 seeds x m(-2), while that in the secondary bare alkali-saline patches (SAP) was only 10.0 +/- 31.6 seeds x m(-2). Although the soil chemical and physical characters in ameliorated zone were improved to some extent, the overall situation of soil was still bad for plant growth, as the pH, soluble saline ion and organic matter were concerned. Most of Chloris virgata grew around or on the cornstalk, the plants around each cornstalk being 3.9 +/- 2.2, and the total being 48.64 +/- 38.72 g x m(-2). Therefore, this method demanded a few resources, and needed simple technology and low cost, which is potentially deserved to popularize.

Alkalies↗