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 271 records · Page 15Linked to original sources
PubMed1991

In vitro studies on mild alkali induced lesions in DNA.

S1 nuclease hydrolysis, benzoylated naphthoylated DEAE cellulose (BND-cellulose) chromatography as well as certain immunological and genetic techniques have been used to evaluate the effect of mild alkali (pH10.0) on the DNA molecule. Native calf thymus DNA after exposure to alkaline pH10.0 when subjected to S1 nuclease hydrolysis released significant amount of acid soluble nucleotides as compared to the untreated control. With pBR322 DNA, the population of linear DNA species increased on S1 digestion with concomitant reduction in the supercoiled form. BND cellulose chromatographic studies also suggested the formation of single strandedness and/or distortions in the alkali treated DNA molecule. Antisera raised against the alkali treated DNA exhibited high cross-reactivity with both single stranded and Z DNA. Moreover, a significant reduction in transformation frequency of the treated DNA molecule compared with the untreated control further ascertained the structural alterations in DNA as a result of exposure to mild alkali.

Animals↗
PubMed1990

Inhibition of alkali-induced corneal ulceration and perforation by a thiol peptide.

Corneal ulceration and perforation following a severe alkali burn occur as a consequence of collagen destruction by locally released enzymes. A thiol peptide, which recently was shown to be a potent inhibitor of corneal collagenase in vitro, was tested in alkali-burned rabbit corneas to determine its effectiveness in inhibiting corneal ulceration. Following a standard alkali burn to one eye of each rabbit, ten animals were treated topically six times daily and subconjunctivally one time daily with a 1 mM solution of the peptide for a period of 3 weeks. A control group of ten rabbits was administered vehicle only using the same regimen as the experimental group. Corneal ulceration occurred in ten out of ten of the control eyes and seven out of ten progressed to perforation. The experimental group demonstrated ulcerations in four out of nine animals, only one of which was deep (one of nine), and no perforations. There was no significant difference when comparing the onset of ulceration between the two groups, but the difference was significant when comparing the total number of ulcerations (0.02 less than P less than 0.05), deep ulcerations (0.01 less than P less than 0.02) and perforations (0.001 less than P less than 0.01) between the two groups. Histologic examination of the corneas after 3 weeks of treatment revealed that the experimental, thiol-treated corneas that did not ulcerate contained relatively few PMNs, whereas the control corneas demonstrated a marked inflammatory infiltrate in the form of PMNs, most notably at sites of corneal ulceration. These findings demonstrate that a synthetic thiol peptide inhibits alkali-induced corneal ulceration and perforation in vivo.

Analysis of Variance↗
PubMed1990

Preferential DNA repair of alkali-labile sites within the active insulin gene.

DNA damage and repair were studied in a DNA fragment containing the insulin gene after treatment of cells with methylnitrosourea. For these studies, two clonal isolates from the same rat insulinoma cell line which differ in that the insulin gene is transcribed in one (RINr 38) and is silent in the other (RINr B2) were utilized. Both the determination of immunologically reactive insulin released and the expression of insulin mRNA were used to verify that the gene was transcribed in the RINr 38 cells and not in the RINr B2 cells. Repair kinetics for the removal of alkali-labile sites were comparable across the entire genome in the RINr 38 and RINr B2 cells as determined using alkaline sucrose gradient sedimentation and a 32P end-labeling assay for the quantitation of N7-methylguanine. Quantitative DNA blot analysis was utilized to assess the formation and repair of alkali-labile sites within the restriction fragment containing the insulin gene. Alkali-labile sites appeared to be formed equally within the restriction fragment containing the insulin gene in both the RINr 38 and RINr B2 cells. However, at 24 h, 60% of the lesions were removed from the fragment in the RINr 38 cells, where the gene was transcribed, compared to the removal of only 20% in the RINr B2 cells, where the gene was silent. Thus, it appears that alkali-labile sites induced by exposure to methylnitrosourea are repaired more efficiently in the DNA fragment containing the insulin gene when it is actively transcribed.

Animals↗
PubMed1988

Alkali secretion in the turtle bladder: up-regulation by the phospho-inositol cascade and inhibition by diphenylamine carboxylate (DPC).

The presently reported studies of factors involved in the regulation of acid-base excretory processes in isolated turtle urinary bladders have yielded the following data. (i) There exists in alkalotic and euhydric turtle bladders (but not in acidotic turtle bladders) a mechanism which drives a primary active electrogenic secretion of alkali; and the electrogenic output of this mechanism is up-regulated by exogenously added PDE inhibitors, such as theophylline or IBMX. (ii) VIP or cAMP up-regulates this alkali secretion in the presence of IBMX. (iii) Carbachol also initiates alkali secretion. But this action, independent of PDE activity, is probably associated with the phospho-inositol reaction cascade. (iv) Finally, low concentrations of mucosal DPC decreases the carbachol supported, but not the cAMP-supported alkali secretion.

1-Methyl-3-isobutylxanthine↗
PubMed1987

Caustic alkali ingestions by farm children.

Liquid lye drain cleaners responsible for a childhood epidemic of household ingestions in the early 1970s are now marketed in drastically reduced alkali concentrations and packaged in child-resistant containers. However, farm and industrial caustic agents continue to be sold without poison prevention safeguards, as exemplified by dairy pipeline cleaners (liquid NaOH/KOH concentrations 8% to 25%) used routinely on dairy farms. In this study, the ingestion epidemiology of farm/industrial v household caustic alkali products was compared in a population that included farm children. Forty-three children were admitted from 1973 to 1983 to four rural hospitals for nonintentional caustic alkali ingestion. Farm products constituted 23% of all products and 43% of all drain/pipe cleaners ingested. Dairy pipeline cleaners were the single most common causative substance, injuring ten toddlers (mean age 1.6 years), perforating the esophagus in two. Liquid dairy pipeline cleaners were usually ingested in tiny amounts from nonchild-resistant containers or drinking glasses at evening milking time. In contrast, household drain cleaners were associated with fewer ingestions, with all serious complications related to highly concentrated products not available on the consumer market after 1975. Poison prevention strategies successfully applied in the 1970s to household drain cleaners should be redirected and modified for farm-related caustic alkali agents. Preventive measures are suggested by the highly specific pattern of injury and the small, defined population at risk.

Burns, Chemical↗
PubMed1985

The 'milk-alkali' syndrome: two case reports with discussion of pathogenesis.

The milk-alkali syndrome is the association of hypercalcaemia and renal failure, with or without alkalosis, in the presence of absorption of excessive quantities of calcium, alkali, or both. Two patients with the milk-alkali syndrome are described, one representing an acute, reversible disorder and the other demonstrating a chronic syndrome with only partially reversible renal disease. Differential diagnosis is not difficult and is usually aided by the initial clinical evaluation as well as rapid response to conservative therapy. Because the initial stages of renal insufficiency are often fully reversible, the early identification and treatment of the milk-alkali syndrome can prevent progression to irreversible, chronic renal failure. Although non-absorbable antacids, H2 blockers, and sucralphate are the basis of modern treatment of peptic ulcer disease, the syndrome may still occur, especially in patients who self-treat symptoms of dyspepsia.

Acute Kidney Injury↗
PubMed1994

Recombinant tissue inhibitor of metalloproteinases type 1 suppresses alkali-burn-induced corneal ulceration in rabbits.

PURPOSE: To test if recombinant tissue inhibitor of metalloproteinases (TIMP-1) was effective in reducing corneal ulceration after alkali injury to the rabbit cornea. The effect of TIMP-1 was compared with that of a proven synthetic metalloproteinase inhibitor. METHODS: After a defined alkali injury to the rabbit cornea, a topical treatment regimen was followed for 24 days; one group was treated with vehicle only, a second group with recombinant TIMP-1, and a third group with the synthetic metalloproteinase inhibitor. Corneas were scored for ulceration during the 24-day period and the scores for the three groups were compared. RESULTS: The incidence and progression of ulceration and perforation, in the alkali-burned corneas receiving treatment with recombinant TIMP-1 or the synthetic inhibitor, were significantly less than in corneas receiving vehicle treatment alone. CONCLUSION: Recombinant TIMP-1 is as effective as a proven synthetic inhibitor in ameliorating corneal ulceration and perforation after an alkali injury.

Administration, Topical↗
PubMed1993

Alkali-degraded cornea generates a low molecular weight chemoattractant for polymorphonuclear leukocytes.

PURPOSE: The current study was designed to determine if a polymorphonuclear leukocyte (PMN) chemoattractant is derived from alkali-degraded whole cornea and to establish a range for its molecular weight. METHODS: We utilized a collagen gel-visual chemotactic assay to quantify the directional movement of PMN exposed to alkali-degraded corneas (30 min or 24 hr). In this experiment, the sample to be tested for chemotactic activity passed through a 14,000 molecular weight cutoff membrane into a collagen gel in which resting neutrophils were suspended in a random fashion. Cell movement was videotaped and subsequently tracked by digitizing the centroid of the cells at 30-sec intervals. Computer analysis of these tracks illustrated many behavioral characteristics, including directional movement. RESULTS: Alkali-degraded whole bovine corneas produced a chemotactic response in neutrophils within 5 min. Dilution of the 24-hr sample to 1:7 yielded a significant chemotactic response. The chemotactic response of both the 30-min and 24-hr samples followed a dose-response curve. CONCLUSIONS: This agent may be one of the inflammatory mediators that trigger the early neutrophil response after an alkali-injury to the eye.

Animals↗
PubMed1996

Collagen types in healing alkali-burned corneal stroma in rabbits.

We evaluated the change in the type of collagen found during healing in the alkali-burned corneal stroma of rabbits. We estimated the relative proportions of alpha chains in pepsin-solubilized collagen, using sodium dodecylsulfate polyacrylamide gel electrophoresis. Bands of alpha 1(I), alpha 2(I), alpha 1(V), and alpha 1(III) chains stained with Coomassie Blue were separated. The alpha 1(III) and alpha 1(V) chains showed a transient proportional increase in healing corneal stroma in the area exposed to alkali. No significant alterations in collagen alpha chains were detected in peripheral corneal stroma that had not been directly exposed to alkali. Our results suggest that the keratocytes which repopulate the alkali-injured corneal stroma early in healing synthesize a higher proportion of collagen types III and V than type I, and then switch to synthesizing predominantly type I collagen as stromal healing progresses. Collagen types III and V thus appear to be of primary importance in the healing of the corneal stroma.

Animals↗
PubMed1998

Implantation of PHEMA keratoprostheses after alkali burns in rabbit eyes.

PURPOSE: We have previously examined histologically the healing of a PHEMA core-and-skirt keratoprosthesis (the Chirila KPro) as a full-thickness implant in healthy animal corneas. The present study was carried out to determine whether a diseased cornea could also generate biocolonization of the skirt region of a KPro. METHODS: Ten KPros were placed as full-thickness corneal implants under conjunctival flaps in 10 alkali-burned rabbit corneas. Histological findings at intervals from 2 weeks to 6 months postoperatively were compared with earlier findings in 10 rabbits that had received identical KPros without prior alkali injury. RESULTS: Despite severe corneal injury and the reduced keratocyte population present, there were no clinically detected complications in 60%. Histological findings established that, compared with healthy host tissue, skirt biocolonization and KPro-cornea healing after an alkali burn were impaired, with evidence of epithelial downgrowth in 40%. One animal required euthanasia earlier than the planned end point, but no KPro extrusions occurred. CONCLUSION: Biocolonization of a KPro skirt is reduced but not prevented in an alkali-induced corneal inflammation model. Although no extrusions occurred, close follow-up and anticollagenolytic medication would be required to minimize the complication rate.

Animals↗
PubMed1981

Superoxide radical scavenging agents in treatment of alkali burns. An experimental study.

To test the hypothesis that superoxide radicals are involved in tissue destruction after alkali burns, superoxide dismutase, ascorbic acid, and glutathione were used as superoxide radical scavenging agents. Daily subconjunctival injections were given in rabbit eyes after alkali burns. Both superoxide dismutase and ascorbic acid were effective in preventing corneal perforations. Glutathione did not show any beneficial effect. These experiments suggest that superoxide radical scavenging agents may be useful in the treatment of ocular alkali burns.

Alkalies↗
PubMed2003

Thromboresistance of alkali- and heat-treated titanium metal formed with apatite.

Fibrin deposition and platelet adhesion onto alkali- and heat-treated titanium metal (AH-Ti), alkali- and water-treated titanium metal (Wa-Ti), and alkali- and heat-treated titanium metal formed with apatite (Ap-Ti) in simulated body fluid (SBF) were evaluated by exposure to anticoagulated blood or washed platelet suspension (WPS) under static conditions and subsequent observation with scanning electron microscopy (SEM). The results were compared with those for commercially pure titanium metal (cp-Ti). Thrombus formation on AH-Ti and Wa-Ti, which were exposed to heparinized whole blood for 1 h, was significantly less than that on cp-Ti, on which pronounced depositions of fibrin-erythrocytes and lymphocytes were observed. No thrombus was observed on Ap-Ti, possibly because of a high adsorption of heparin. Morphological change of platelets attached to surfaces via adsorbed plasma proteins was found to a significant extent on AH-Ti and Wa-Ti exposed to WPS. However, there was almost no difference between cp-Ti and Ap-Ti in round morphology of adherent platelets. These findings suggested that Ap-Ti exhibits stronger antithrombogenic characteristics than cp-Ti and other materials examined in heparinized blood.

Adsorption↗
PubMed1982

The enzymatic activities in the alkali-burnt rabbit cornea.

Alkali-burnt corneas of the rabbits with 1 N NaOH were studied periodically for enzymatic activities by biochemical methods. There was significant increase of aldolase (ALD) activity both in corneal epithelium and stroma 1, 2, 3 and 4 weeks after alkali burns. Glucose-6-phosphate dehydrogenase (G6PD) activity was significantly decreased in epithelium and was absent in stroma. Thus the breakdown of glucose would be present preferably in the Embden-Meyerhoff pathway instead of the pentose phosphate shunt. Lactate dehydrogenase (LDH) activity of corneal epithelium and stroma was significantly decreased 1, 2, 3, and 4 weeks after alkali burns and the possible pathway of glycolysis might channel to citric acid cycle, in which malate dehydrogenase (MDH) could indicate the important role in this pathway.

Alkalies↗
PubMed1976

Myocardial ischemia and cell acidosis: Modification by alkali and the effects on ventricular function and cation composition.

Myocardial cell pH was measured with 5, 5 dimethyl-2, 4-oxazolidinedione (DMO) in intact anesthetized dogs by a transient indicator dilution technique. Bolus injections of labeled DMO, vascular, extracellular and water indicators were made into the left anterior descending coronary artery, and blood samples were collected from the great cardiac vein. The steady state distribution of DMO between cells and plasma was calculated from the mean transit times of the indicator. Normal myocardial cell pH averaged 6.94 and changed by 58% of the concomitant alterations in plasma pH after infusions of acid or alkali. Myocardial ischemia induced by inflation of a balloon tip catheter in the left anterior descending coronary artery resulted in progressive decreases in cell pH to 6.59 by 1 hour. Infusions of sodium carbonate diminished intracellular acidosis. Hemodynamic studies during 4 hours of ischemia with blood pH at 7.55 to 7.60 indicated a significantly reduced left ventricular end-diastolic pressure and increased stroke volume by comparison with findings in animals given infusions of saline solution. Ventriculograms revealed improved wall motion in the ischemic segment after infusion of alkali. Precordial mapping showed a significant reduction in the number of leads with S-T segment elevation as well as in the sum of S-T segment elevations, but R wave amplitudes did not differ from those in control studies. Calculations of extracellular space, tissue water and cation content revealed a reduced gain of cell sodium ion and loss of cell potassium ion during ischemia after alkali treatment. The latter may account for the S-T segment responses, whereas enhanced ventricular performance may be related to reduced competition of hydrogen ion with calcium ion for binding sites on contractile protein.

Acidosis↗
PubMed1980

Quantitative analysis of the mixed activating effects of the alkali metal ions on intestinal brush-border sucrase at pH 5.2.

The activation of rabbit brush-border sucrase by the alkali metal ions, Li+, Na+ and K+, was analyzed using the equations of the random-order allosteric model previously proposed for sucrase (Mahmood, A. and Alvarado, F. (1975) Arch. Biochem. Biophys. 168, 585). The alkali metals have mixed activating effects in tert-butylamine buffers at pH 5.2, including: 1. Affinity-type activation, where the apparent Km decreases as a hyperbolic function of the metal concentration. 2. Capacity-type activation, where the apparent V increases with the metal concentration. These two effects were analyzed quantitatively: firstly, by using linear transformations that allowed us to solve each partial equation separately and secondly, by iteration of the general equation, which permits treating the mixed effects as a whole. Results are consistent with the interpretation that a single metal-binding (activator) site suffices to explain the simultaneous occurrence of the two types of kinetic effect. Nevertheless, complicating factors exist that may require the postulation of additional sites for monovalent cations. In particular, the tert-butylammonium ion appears to interface with the effects of the alkali metals, especially Li+.

Allosteric Site↗
PubMed1985

The "divided stomach"--a model for separate acid and alkali collection in the pig.

Bile duct ligation (BDL) in the pig results uniformly in fatal oesophago-gastric ulceration which appears to be related to hypersecretion of acid. The presence of bile in normal porcine gastric juice may interfere with studies of acid secretion. The present studies were conducted in pigs with the stomach divided into two separate pouches (proximal and antral) which allowed individual collection of acid or alkali secretion. In normal pigs, division of the stomach resulted in a 30-50% decrease in secretion, rather than any increase in measureable acid. In BDL pigs, there was an 8- to 15-fold increase in alkali collection by antral pouches which may have been in response to acid hypersecretion, or merely duodenal or pancreatic juice reflux. No normal pigs with divided stomachs developed significant ulceration suggesting that such ulcers were not related to exclusion of bile from the stomach. It is proposed that a total gastric fistula may be used in the pig for studies of acid secretion, and that the model with divided stomach may be used for assessment of the effects of secretagogues or hormones upon individual acid or alkali secretion.

Alkalies↗
PubMed1984

Neuropsychiatric manifestations of alkali metal deficiency and excess.

The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigated for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.

Cesium↗
PubMed1994

Detection of phosphotyrosine in glutaraldehyde-crosslinked and alkali-treated phosphoproteins following their partial acid hydrolysis in gels.

Soluble fractions and particulate extracts from human prostate, and extracts from rat-liver membranes were used as a source of kinases to phosphorylate endogenous proteins in the presence of gamma- 32P-labeled ATP. Histone was also added as a substrate in order to compare the direct partial acid hydrolysis of phosphoproteins in gels to an indirect procedure involving partial acid hydrolysis after extraction in sodium dodecyl sulfate followed by precipitation with acetone. These procedures led to recoveries of 32P-labeled material of 90% and 40%, respectively, with a similar proportion of radiolabeled phosphoamino acids. Several 32P-labeled phosphoproteins separated in gels were therefore directly HCl-hydrolyzed and their phosphoamino acids were quantitated either prior to, or after glutaraldehyde crosslinking, with and without alkali treatment. By preventing protein losses occurring in hot alkali, glutaraldehyde crosslinking increased by an average factor of 6.5 the 32P-labeled material available for phosphoamino-acid analyses. For eight phosphoproteins analyzed, the overall effect of combined glutaraldehyde and alkali treatments was a relative decrease in phosphoserine (up to 8-fold), with concomitant relative increases in phosphotyrosine and phosphothreonine (up to 62- and 6-fold, respectively). This method will especially be useful for the detection of pTyr, a less abundant phosphoamino acid, in proteins which suffer from poor transfer efficiency in Western blot, are weakly antigenic towards anti-phosphotyrosine antibodies, can hardly be extracted from a gel and for identification of protein tyrosine kinases renatured in gels.

Acrylic Resins↗