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PubMed1994

Endothelial F-actin changes in the alkali burned rabbit cornea.

The healing mechanism of corneal endothelium after alkali burn was not completely understood. Rabbit cornea was burned with 1N sodium hydxoside for 1 minute. Endothelial F-actin was stained with NBD-phallacidin in regular sequence to find out the details of endothelial healing after alkali burn. F-actin was completely destroyed leaving a sharp margin against the unaffected area 1 hour after the burn. In the 3, 5 and 7 day specimens, highly active F-actin reactions were noted at the wound margin. New multiple F-actin layers, arising from the intact endothelium near the wound margin, were noted in the 9 day specimen. In the 8 1/2 month specimen, the endothelial defected area was covered by large primitive cells, each of which showed F-actin fiber bundles in the cytoplasm with a large nuclear shadow. Nearly all of the large primitive cells showed F-actin fibers arranged in shapes of cell junctions. Twelve months after the burn, endothelial defects were not found. Nearly all of the endothelial cells were normal in size and shape except for some mushroom-like projections toward the anterior chamber in some areas. Nineteen months after the burn, the endothelial cells were normal. Endothelial wound healing process can be continued even 1 year after the alkali burn in rabbit cornea.

Actins↗
PubMed2005

Removal of Pseudomonas putida biofilm and associated extracellular polymeric substances from stainless steel by alkali cleaning.

Alkali (NaOH)-based compounds are commonly used in the food industry to clean food contact surfaces. However, little information is available on the ability of alkali and alkali-based cleaning compounds to remove extracellular polymeric substances (EPS) produced by biofilm bacteria. The objectives of this study were to determine the temperature and NaOH concentration necessary to remove biofilm EPS from stainless steel under turbulent flow conditions (clean-in-place simulation) and to determine the ability of a commercial alkaline cleaner to remove biofilm EPS from stainless steel when applied under static conditions without heat. Biofilms were produced by growing Pseudomonas putida on stainless steel for 72 h at 25 degrees C in a 1:10 dilution of Trypticase soy broth. The biofilms were treated using NaOH at concentrations of 1.28 to 6.0% and temperatures ranging from 66 to 70 degrees C. Other biofilms were treated with commercial alkaline cleaner at 25 or 4 degrees C for 1 to 30 min. Removal of EPS was determined by direct microscopic observation of samples stained with fluorescent-labeled peanut agglutinin lectin. Treatment with 1.2% NaOH at 66 degrees C for 3 min was insufficient to remove biofilm EPS. A minimum of 2.5% NaOH at 66 degrees C and 2.0% NaOH at 68 degrees C for 3 min were both effective for EPS removal. Commercial alkaline cleaner removed over 99% of biofilm EPS within 1 min at 4 and 25 degrees C under static conditions. Selection of appropriated cleaning agent formulation and use at recommended concentrations and temperatures is critical for removal of biofilm EPS from stainless steel.

Bacterial Adhesion↗
PubMed2002

Phytosynthetic bacteria (PSB) as a water quality improvement mechanism in saline-alkali wetland ponds.

The efficiency of phytosynthetic bacteria (PSB) to improve the water quality in saline-alkali ponds was studied, the result showed that (1) PSB application could increase the content of DO, NO3-(-)N and effective phosphorus (EP) in ponds; (2) the changes of COD were not evident, just effective in later period after PSB application; (3) PSB application could decrease the contents of NH4-(-)N (NH3-N), NO2-(-)N; (4) PSB application could improve the structure of the effective nitrogen (EN) and EP, stimulate the growth of phytoplankton, and increase primary productivity, and finally increase the commercial profits of ponds because of the increase of EP and the decrease of EN contents; (5) the effect-exerting speed of PSB was slower, but the effect-sustaining time was longer; (6) the appropriate concentration of PSB application in saline-alkali wetland ponds was 10 x 10(-6) mg/L, one-time effective period was more than 15 days. So PSB was an efficient water quality improver in saline-alkali ponds.

Bacteria↗
PubMed2002

Thalidomide prevents donor corneal graft neovascularization in an alkali burn model of corneal angiogenesis.

OBJECTIVE: Thalidomide is a potent inhibitor of angiogenesis. We evaluated the effects of Thalidomide on corneal angiogenesis and on tissue survival of grafts in rabbit eyes with pre-existing neovascularization secondary to alkali burn. METHODS: Sixteen rabbits received alkali burns to one cornea. One month post-injury, assessments of corneal neovascularization were performed followed by corneal transplantation. Four rabbits received oral Thalidomide and ten got placebo (powdered sugar) for thirty days. Total corneal neovascularization (NV), clock hours (CH) involved in (NV), longest (NV) pedicle length (NVP) and the duration of time required for NV to develop were assessed. RESULTS: Thalidomide significantly decreased the total neovascularization (p<0.0072), the number of (CH) involved (p<0.0002) and the longest (NVP) length (p<0.0001). There was also a significant delay in the earliest development of NV in the test group (p<0.0064). The test group retained corneal clarity significantly longer than the control group (p<0.0008). CONCLUSION: Thalidomide is an effective inhibitor of corneal angiogenesis and prolongs graft survival as measured by graft clarity in donor corneas in eyes with previous neovascularization secondary to alkali injury. CLINICAL RELEVANCE: Thalidomide may be used as a modulator of corneal angiogenesis to prolong graft survival in eyes with pre-existing corneal neovascularization.

Angiogenesis Inhibitors↗
PubMed1992

[The effect of levels of alkali salts in Alginate-LF-250 on physico-mechanical properties of materials used in making impressions based on irreversible colloids].

The aim of this paper is the examination of physical-mechanical properties of alginate composition regarding the change of alkali salt alginate composition in the limits of the presence from 8 to 20%, and after the standard ISO 1563, 1978 (E). The combinations make homogenized mixtures of micronized powders of the basic component, retarders, accelerators, system stabilizators, the means for colloides and constituents lowering, which are prepared in the relation of 16 gr/40ml. The change of alkali salt alginate concentration from 8 to 20% does not effect the working time and the time of alginate mash binding, while percentage of permanent deformation of the binding material is larger than the allowed standard after ISO 1563, 1978 (E) in case when alginate alkali salts in the composition are present in the smaller quantity than 12%.

Alginates↗
PubMed1992

[Changes in sulfated proteoglycans in alkali injured rabbit cornea].

Morphological changes of sulfated proteoglycans (S-PGs) in the stroma of alkali injured rabbit corneas were examined electron-histochemically following cuprolinic blue (CB) dye binding. The injured eyes were followed for 2 months by slitlamp microscope and photographs. At 1 hour, 3 days, 1 week, 2 weeks, 1 month, and 2 months after the injury, the eyes were enucleated and studied. After 1 hour, while both collagen fibrils and the filaments of S-PGs had already become disarranged; the number of S-PGs appeared to decrease. From 3 days to 1 week after, the number as well as the electron-density of S-PGs were markedly decreased in all areas. After 2 weeks, CB-positive large filaments appeared in anterior stroma. These became larger, more abnormal in shape, and displayed a higher electron density 1 month later. Normally arranged S-PGs can be seen at 2 months later. It was concluded that S-PGs were diminished in alkali-injured corneas. Once they were replaced by abnormal filaments, they gradually recovered normal morphology. Further more the time course of S-PG change correlated with that of corneal transparency after alkali injury.

Animals↗
PubMed2004

Yeast as a model organism to study transport and homeostasis of alkali metal cations.

To maintain an optimum cytoplasmic K(+)/Na+ ratio, cells employ three distinct strategies: 1) strict discrimination among alkali metal cations at the level of influx, 2) efficient efflux of toxic cations from cells, and 3) selective sequestration of cations in organelles. Cation efflux and influx are mediated in cells by systems with different substrate specificities and diverse mechanisms, e.g. ATPases, symporters, antiporters, and channels. Simple eukaryotic yeast Saccharomyces cerevisiae cells proved to be an excellent model for studying the transport properties and physiological function of alkali-metal-cation transporters, and the existence of mutant strains lacking their own transport systems provided an efficient tool for a molecular study of alkali-metal-cation transporters from higher eukaryotes upon their expression in yeast cells.

Cations, Monovalent↗
PubMed1992

Effect of a metalloproteinase inhibitor on established corneal ulcers after an alkali burn.

Proteinase inhibitors have been shown to prevent corneal ulceration and perforation when used immediately after an experimental alkali burn injury. To evaluate the clinical efficacy of a synthetic metalloproteinase inhibitor, HSCH2CH[CH2CH(CH3)2]CO-Phe-Ala-NH2(SIMP), treatment with inhibitor was withheld until corneal ulceration ensued after a standard alkali injury to the rabbit eye. When topical therapy with a 1 mmol/l solution of SIMP was initiated after corneal ulceration had progressed to a mid-stromal level (clinical score of 2), there was no significant difference in the progression of corneal ulceration between the treated vs. control group after 6 d of therapy. In the second study in which treatment was initiated earlier at the onset of superficial ulceration (clinical score of 1), there was a significant difference in clinical scores between the two groups after 1 day of treatment until termination of the experiment at 21 d (P less than 0.005). In the inhibitor-treated group, 88.9% of the corneas showed a reversal or cessation of progression of the ulceration process. Eighty-seven-and-a-half percent of the control corneas progressed to descemetocele formation or perforation by day 14 of treatment. This study suggests that SIMP may be used for effective treatment of corneal ulcers resulting from an alkali burn injury in the human eye. It also shows that early and aggressive initiation of therapy is critical.

Administration, Topical↗
PubMed1991

Repair of alkali-labile sites within the mitochondrial DNA of RINr 38 cells after exposure to the nitrosourea streptozotocin.

Studies were initiated to investigate whether mechanisms exist within mitochondria to repair damage incurred by mitochondrial DNA after exposure to alkylating toxins. A clonal isolate from a rat insulinoma cell line was utilized to measure the formation and repair of alkali-labile sites within the mitochondrial genome after exposure to the alkylating antibiotic streptozotocin. Alkali-labile sites were formed in mitochondrial DNA in a dose-dependent fashion. Eight hours after exposure to the toxin, 55% of the lesions were removed. The level of repair increased to 70% after 24 h. In comparison, only 46% of N7-methylguanines were removed across the entire cellular genome. These studies demonstrate that streptozotocin causes appreciable mitochondrial DNA damage in a dose-dependent manner and provide the first evidence that a repair mechanism for alkali-labile sites is present within the mitochondrion.

Alkylating Agents↗
PubMed1990

[Effect of myosin alkali light chains on myosin subfragment 1 interaction with actin in solution and in ghost muscle fiber].

At low ionic strength (7-25 mM) Mg2(+)-ATPase of myosin subfragment 1 (S1) isoforms containing alkali light chain A1 [S1(A1)] is activated by actin 1.5-2.5 times as strongly as Mg2(+)-ATPase of S1 isoforms containing alkali light chain A2[S1(A2)]. Data from analytical ultracentrifugation suggest that at low ionic strength in the absence of ATP in solution S1(A1) displays a higher affinity for F-actin than S1(A2). Such a higher affinity of S1(A1) for F-actin was also demonstrated by experiments, in which the interaction of S1 isoforms fluorescently labeled by 1.5-IAEDANS with F-actin of ghost fibers (single glycerinated muscle fibers containing F-actin but devoid of myosin) was studied. Using polarization microfluorimetry, it was shown that the interaction of both S1 isoforms with ghost fiber F-actin induces similar changes in the parameters of polarized tryptophan fluorescence. At the same time the mobility of the fluorescent probe, 1.5-IAEDANS, specifically attached to the SH-group of Cys-374 in the C-terminal region of action is markedly decreased by S1(A1) and is only slightly affected by S1(A2). The data obtained suggest that S1(A1) and S1(A2) interact with the C-terminal region of the actin molecule in different ways, i.e. S1(A1) is attached more firmly than S1(A2). This may be due to the existence of contacts between the alkali light chain of A1 of S1(A1) and the C-terminal region of actin as well as to the absence of such contacts in the case of S1(A2).

Actins↗
PubMed1985

Studies on the mechanism of the lower esophageal sphincter pressure response to alkali ingestion in humans.

To clarify the lower esophageal sphincter (LES) pressure response to alkali ingestion, normal subjects and postantrectomy patients with either a gastroduodenostomy or gastrojejunostomy were studied in a double-blind controlled fashion. LES pressure and serum gastrin concentrations were measured after ingestion of a 100 ml bolus of either 0.4 M NaHCO3 or 0.4 M NaCl. In addition, the effect of a therapeutic dose (30 ml) of a commercial antacid preparation was studied in a double-blind fashion in 14 patients with gastroesophageal reflux disease. Peak increases in LES pressure above basal were significantly higher (p less than 0.05) after NaHCO3 than after NaCl in normal subjects and in patients with vagotomy and Billroth I antrectomy, but not in patients with vagotomy and Billroth II antrectomy. Serum gastrin concentrations were unaffected by alkali. Thirty milliliters of liquid antacid containing aluminum and magnesium hydroxide resulted in a small sustained rise in LES pressure over the first 50 min after ingestion, but this was not statistically different than the placebo response. It is suggested that: 1) neither the antrum nor intact vagi nor gastrin were required for NaHCO3 ingestion to increase LES pressure; 2) the increase in LES pressure with NaHCO3 ingestion appears to rely upon an intact duodenum and may relate to volume and osmolarity of the alkali load; and 3) therapeutic doses of a liquid commercial antacid does not significantly increase LES pressure in the presence of an intact stomach.

Adult↗
PubMed1988

Comparison between the DNA precipitation and alkali unwinding assays for detecting DNA strand breaks and cross-links.

A new DNA precipitation assay used together with the alkali unwinding assay may provide a rapid means of detecting DNA damage in addition to strand breaks based on the relative amount of damage measured by the two assays. X-rays, Adriamycin, 4-nitroquinoline-N-oxide, N-methyl-N'-nitrosoguanidine, bleomycin, RSU 1172, and five other drugs produced the same relative amount of strand breakage by using the DNA precipitation and alkali unwinding assays. However, strand breaks produced by the bifunctional alkylating agents bis(2-chloroethyl)nitrosourea, RSU 1069, and RSU 1131 were detected with greater efficiency by the DNA precipitation assay, while the unwinding assay measured more strand breaks than the precipitation assay after damage by the topoisomerase inhibitors VP-16 and VM-26 and the DNA-condensing agents acridine orange and pyronin Y. Based on the reported mechanisms of action of these drugs, and studies with known DNA cross-linking agents, it appears that in addition to DNA strand breaks, the alkali unwinding assay is more sensitive to interstrand than to DNA-protein cross-links, while the DNA precipitation assay can be used to detect both types of cross-links. While quantification of specific lesions is not possible with this approach, the concomitant use of these two assays may provide a rapid and simple method for screening genotoxic drugs for DNA damage, and may also help to differentiate between DNA lesions which include strand breaks, interstrand and protein cross-links, DNA-phosphate adducts, and DNA-drug precipitates.

Animals↗
PubMed1988

The milk-alkali syndrome in pregnancy. Case report.

We present a case of the milk-alkali syndrome occurring in pregnancy, an association not described in the medical literature. Ingestion of calcium carbonate and calcium-containing food was precipitated by the hyperemesis of pregnancy. Complications--hypercalcemia, dehydration, renal insufficiency, and pancreatitis--resolved within days. Here, the milk-alkali syndrome was the cause of the hypercalcemia of pregnancy. This case illustrates a rare cause of and complications from the milk-alkali syndrome.

Adult↗
PubMed1988

Myosin alkali light chain and heavy chain variations correlate with altered shortening velocity of isolated skeletal muscle fibers.

This study examines the myosin isozyme heterogeneity (in terms of both alkali light chains and myosin heavy chains) among skeletal muscle fibers of the rabbit and correlates these isozyme differences with the differences in a contractile property, the velocity of unloaded shortening, of the fibers. The mean velocities of unloaded shortening (pCa 4.3; 12 degrees C) were as follows: psoas IIb fibers, 2.07 fiber lengths/s (n = 25); tibialis anterior (IIb) fibers, 1.63 fiber lengths/s (n = 18); vastus intermedius IIa fibers, 0.98 fiber lengths/s (n = 15); fibers (IIa) from chronically stimulated tibialis anterior, 0.86 fiber lengths/s (n = 16). Peptide maps of the myosins showed that the myosin heavy chains of the two groups of IIb fibers were indistinguishable from each other, but different from the heavy chains of the IIa fibers. However, the difference in maximal shortening velocity of the two groups of IIb fibers was correlated with a difference in the alkali light chain ratio deduced from the intensity ratio of myosin isoforms separated by gel electrophoresis under nondenaturing conditions. The vastus intermedius (IIa) and chronically stimulated tibialis anterior (IIa) fibers were indistinguishable in terms of either velocities of unloaded shortening or myosin isozyme contents. Soleus fibers contained only slow-twitch myosin. Thus, among fibers that contained a variety of myosin isozymes, differences in shortening velocities were correlated with the alkali light chain ratio, myosin heavy chain type, or a combination of both.

Animals↗
PubMed1988

Use of oral sodium polyacrylate in rat gastrointestinal alkali burns.

Alkali-induced injuries of the esophagus and stomach are currently medically managed with steroids and antibiotics. We investigated whether treatment with sodium polyacrylate (PANa), a proposed mucosal protectant, could decrease the deleterious effect of alkali injuries or prevent alkali injuries. Rats were randomized in 4 groups. Group I (control; n = 7) received 0.1 ml normal saline via gastric gavage. Groups II-IV received 0.1 ml 25% NaOH. Group II (n = 22) received no further treatment. Group III (n = 9) received 0.25% PANa ad lib in drinking water for 3 days prior to NaOH. Group IV received 0.25% PANa for 6 days after NaOH. Animals were weighed daily. At 6 days post NaOH, stomachs were removed from animals in Groups II-IV and burn lesions were outlined on tracing paper. 1 x 1 cm sections of burned areas were fixed, stained with H&E and histologically evaluated. In another study, 0.1 ml of 10% NaOH was given to 2 groups of animals. Group I (n = 22) received no other treatment, while Group II (n = 13) received PANa ad lib in drinking water for 3 days prior to NaOH. Of the animals treated with 25% NaOH, only those in Group II showed a decrease mean weight which was statistically significant on Day 4, p = 0.016. Mean burn areas were statistically greater in Group II than in Group IV (p = 0.025), while histologically, lesions were similar. Pretreatment with PANa prior to 10% NaOH prevented the weight loss which occurred daily in the control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗
PubMed1986

Milk-alkali syndrome in patients treated with calcium carbonate after cardiac transplantation.

Heart and heart-lung transplant recipients at Stanford (Calif) University Medical Center were routinely prescribed long-term calcium carbonate antacid therapy to aid in the prevention of peptic ulcer disease and osteoporosis associated with glucocorticoid immunosuppressive therapy. Patients consumed 4 to more than 10 g/d of elemental calcium. Since calcium carbonate also provides the essential ingredients for the development of the milk-alkali syndrome, the laboratory flow sheets of 297 heart and heart-lung transplant recipients were reviewed to examine the incidence of hypercalcemia. Sixty-five patients developed significant hypercalcemia after transplantation. Thirty-one patients were alkalotic at the time of hypercalcemia; 37 had impairment in renal function. It is likely that most of these patients had the milk-alkali syndrome. While most patients became eucalcemic by discontinuing calcium carbonate therapy, intravenous hydration and forced diuresis were used to treat severe cases. It is possible that the incidence of the milk-alkali syndrome will increase with the current popularity of prescribing calcium carbonate for the prevention and treatment of osteoporosis.

Adult↗
PubMed1985

Myosin subunit interactions. Localization of the alkali light chains.

Myosin homodimers, molecules containing either the A1 or the A2 light chain, do not exchange their light chains under conditions approximating physiological temperature and ionic strength. Myosin heterodimers, molecules containing both A1 and A2 light chains, are therefore formed at the time of synthesis rather than by a labile subunit exchange. Antibodies specific for the amino-terminal region of the alkali light chains were used to localize these subunits in myosin by immunoelectron microscopy. The close proximity of the alkali light chain to the 5,5'-dithiobis-(2-nitrobenzoic acid) light chain in the "neck" region of the myosin head is consistent with the finding that the 5,5'-dithiobis-(2-nitrobenzoic acid) light chain influences subunit interactions between the alkali light chain and heavy chain in vertebrate skeletal muscle myosin.

Adenosine Triphosphate↗
PubMed1984

High ratio of alkali-sensitive lesions to total DNA modification induced by benzo(a)pyrene diol epoxide.

The ratio of alkali-labile lesions to total DNA adducts for DNA modified by an active metabolite of benzo(a)pyrene was investigated using DNA sequencing methodology. About 40% of the adducts formed result in alkali-labile sites. About 25% of the lesions were alkali-labile at positions of guanine, 10% at adenine, and 5% at cytosine. This study highlights the potential role of adducts other than the N2-substituted guanine in mutagenic and carcinogenic effects of benzo(a)pyrene.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗