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 919 records · Page 51Linked to original sources
PubMed1979

Prevention of stromal ulceration in the alkali-burned rabbit cornea by glued-on contact lens. Evidence for the role of polymorphonuclear leukocytes in collagen degradation.

Stromal ulceration of the alkali-burned rabbit cornea was found to be associated invariably with phagocytically active polymorphonuclear leukocytes (PMNs). A glued-on methylmethacrylate lens applied to corneas soon after burning, however, prevented re-epithelialization and also prevented PMN infiltration of the stroma and stromal ulceration. Subsequent partial detachment or complete removal of the lens resulted in epithelial resurfacing of the stroma, PMN infiltration, and stromal ulceration. Glued-on lenses applied to already ulcerating corneas arrested further ulceration by prohibiting additional PMN infiltration. Either surface debridement or glued-on methylmethacrylate rings also prevented re-epithelialization and ulceration in stromas not infiltrated by PMNs, but neither treatment was sufficient to prevent ulceration in corneas already containing numerous PMNs. The data suggest the possibility that the epithelium stimulates infiltration of the stroma by PMNs which then participate in stromal matrix degradation. Although no claim is made that only PMNs mediate matrix destruction in corneal ulceration, the efficacy of the lens would seem to be due to exclusion of the epithelium and the consequent prevention of stromal infiltration by PMNs.

Alkalies↗
PubMed1983

[Alkali resistance changes from use of water-in-oil- and oil-in-water emulsions].

Metal workers who up to 4 h prior to the alkali resistance (AR) test had applied different O/W-emulsions revealed a better mean AR on the forearms than those who had used W/O-emulsions or no protective skin ointments at all. Similar test results were achieved in 9 metal workers tested in a right-left comparison under standardized external conditions as in more than 300 workers of various industries. By a right-left comparison of an O/W- and W/O-emulsion with 14 students it was shown that all subjects with a low pre-test AR revealed an increased AR after the application of the ointment. Proved differences in AR-reactivity related to occupation and skin constitution of the subject tested are considered to be due to differences in the hydration rate of the horny layer.

Alkalies↗
PubMed1982

Effects of topical 10% ascorbate solution on established corneal ulcers after severe alkali burns.

When established corneal ulcers induced by alkali burning were treated with 10% ascorbate drops, no perforation occurred, in contrast to a 25% incidence in the control group. If perforations and descemetoceles were grouped together, these difference became insignificant (i.e., 14.2% ascorbate-treated vs. 25% control). Prolongation of descemetocele presence without perforation in the ascorbate-treated group indicated some therapeutic effect. We conclude that topical ascorbate does not substantially alter the outcome of established corneal ulcers.

Administration, Topical↗
PubMed1981

Chemical effects of alkali on polymethylmethacrylate intraocular lenses.

Polymethylmethacrylate intraocular lenses were left in 10% NaOH or 10% KOH for various periods of time. Contact angles were unaltered and electron spectroscopy for chemical analysis was unchanged. This concentration of alkali does not appear to chemically change the lens surface during the study period.

Alkalies↗
PubMed1980

Human tear responses to alkali.

With the use of a closed-chamber microelectrode system, the buffering capacities of over 100 tear samples were measured in response to alkali challenge of several strengths. Although distinctive variations were found among the seven subjects studied, a substantially greater buffer capacity was consistently noted in all their tear responses to pH conditions of near 10 and above. These results are consistent with the early observations of Friedenwald, who demonstrated the buffering capacity of corneal tissue when challenged in this higher pH range, and may here be due to the onset of protein denaturation in the tears.

Adult↗
PubMed1980

The efficacy of ascorbate treatment after severe experimental alkali burns depends upon the route of administration.

Rabbit eyes were subjected to severe alkali burns (35 sec, 12 mm, 1N sodium hydroxide). In one experiment, rabbits in the treated group received a daily subcutaneous injection of neutralized ascorbic acid solution (0.5 gm/kg body weight), while control animals received no treatment. At the termination of the experiment (30 days), 11 of 16 eyes (68.8%) in the control group had ulcerated or formed descemetoceles, and in the experimental (treated) group, 15 of 20 eyes (75%) had ulcerated, formed descemetoceles, or perforated. In a second experiment, burned rabbits received topical 10% ascorbic acid while control eyes were given the vehicle only. At the termination of the experiment (34 days), 16 of 20 eyes (80%) in the control group had ulcerated or perforated, compared to five of 18 eyes (27.8%) in the ascorbate treated groups. The failure of systemic administration of ascorbic acid to prevent corneal ulceration could be explained on the basis of inadequate penetration of ascorbic acid into the anterior segment of severely burned rabbit eyes. On the other hand, immediate topical treatment of identically burned rabbit eyes achieved greatly elevated aqueous humor ascorbate levels and provided substantial protection from corneal ulceration and perforation.

Administration, Topical↗
PubMed1993

[The effect of fibronectin on re-epithelialization of rabbit cornea after alkali burn].

The authors found experimentally that (1) fibronectin enhanced the healing of rabbit corneal epithelium after alkali burn and prevented the secondary breakdown; (2) it rapidly deposited on the denuded basement membrane to disappear as epithelial cells slided over, and (3) ultrastructurally, the neighbouring epithelial cells became flattened, with filopodia at the advancing edge, and extended to the wound area 24 hours after the burn. However, the epithelial defect recurred 72 hours after the burn when the basement membrane vanished till after the 8th week, indicating that the latter was associated with the secondary epithelial breakdown.

Alkalies↗
PubMed1977

The effect of hypertonic ointments on corneal alkali burns.

Alkali-burned rabbit corneas were treated with 40% glucose or 5% sodium chloride ophthalmic ointments 3 times daily for 6 weeks and examined clinically and histologically. Treatment with hypertonic ointment as compared to untreated controls demonstrated decreased corneal neovascularization and ulceration. The possible nutritional advantage of hypertonic glucose did not prove beneficial compared to hypertonic sodium chloride.

Alkalies↗
PubMed1997

A case of esophagectomy for corrosive esophageal stricture caused by swallowing strong alkali. A case report.

We report herein the case of a 22-year old woman who underwent esophagectomy for corrosive esophageal stricture. This patient with mental disturbance swallowed a strong alkali in a suicide attempt and suffered from esophageal stenosis instead of steroid therapy. Because the stiffness and stricture of the esophagus proved to be refractory, transhiatal esophagectomy by blunt finger with gastroesophagostomy was performed four months after injury. Operative findings revealed severe stiffness and inflammation of the esophagus which had spread to the adjacent organs, especially the carina. As for pathological findings, most of the esophageal mucosa showed defects resulting from infiltration of inflammatory cells and capillary vascularization from the lamina propria to the extra-esophageal wall. The postoperative course was uneventful and perioperative psychological state had been stable leading to a decrease in tranquilizer dosage. This experience indicates that esophagectomy is the treatment of choice for such mental disturbed patients with severe stenosis.

Adult↗
PubMed1976

Ocular alkali burns in a large urban area.

A retrospective study of 63 ocular alkali burn victims revealed that black males in the 30 to 49 year age group were at highest risk, and that the burns were most commonly sustained via assault. One hundred eyes were involved, and in 38 cases there was bilateral involvement. There were 116 hospital admissions and 125 surgical procedures, yet 58% of the injured eyes had a final visual acuity of less than 20/200. Other demographic and socioeconomic factors were characterized to identify this event as a public health problem with well-defined risk factors and unsatisfactory treatment. Primary preventive measures are, therefore, necessary.

Adult↗
PubMed1999

Fragmentation of an alkali metal-attached peptide probed by collision-induced dissociation fourier transform mass spectrometry and computational methodology.

Collision-induced dissociation of metal-cationized N-CBZ-Gly-Pro-Gly-Pro-Ala was studied by Fourier transform mass spectrometry. Lithium-, sodium-, potassium- and rubidium-cationized peptide species were generated by matrix-assisted laser desorption/ionization (MALDI) using 2,5-dihydroxybenzoic acid as matrix, together with appropriate metal salts. The experimental mass spectrometric results were interpreted with the aid of Monte Carlo conformational searches using the Amber(*) force field, together with ab initio molecular orbital calculations with Gaussian-94 for the singly lithium- and potassium-cationized peptides. It is concluded that metal coordination plays a key role in guiding the gas-phase fragmentation of the cationized peptide. In contrast to lithium and sodium, potassium and rubidium apparently do not coordinate to the C-terminal carbonyl. When the peptide is cationized with the two smaller alkali metals, losses corresponding to alanine and CBZ are observed, while the coordination of potassium and rubidium results in only CBZ loss upon dissociation.

Amino Acid Sequence↗
PubMed1999

Novel Ternary Alkali Metal Silver Acetylides M(I)AgC(2) (M(I)=Li, Na, K, Rb, Cs).

Three different packings of (1)(infinity)[Ag(C(2))(2/2)(-)] chains (represented by rods in the picture) have been found in the crystal structures of the first ternary alkali metal silver acetylides, which were obtained by the reaction of M(I)C(2)H (M(I)=Li-Cs) with AgI in liquid ammonia and subsequent heating of the remaining residue to 120 degrees C.

Journal Article↗
PubMed1980

Alkali-resistant hemoglobin (HbF) in cancer patients.

Elevated levels of alkali-resistant (fetal) hemoglobin were found in patients with cancer, in the absence of any overt hematologic disorders. This phenomenon was observed most frequently in patients with gonadal tumors and appears to reflect tumor burden and activity of disease.

Female↗
PubMed2000

The effect of alkali- and heat-treated titanium and apatite-formed titanium on osteoblastic differentiation of bone marrow cells.

This study was based on the hypothesis that osteogenesis is enhanced by growth of osteogenic cells on an apatitic surface. To test this hypothesis, the behavior of rat bone marrow cells on these surfaces was examined: commercially pure titanium (Cp Ti), alkali- and heat-treated titanium (AH Ti), and AH Ti incubated in a simulated body fluid to deposit crystalline hydroxyapatite on the surface (Ap Ti). The alkaline phosphatase (ALP) activity of the cells cultured on Ap Ti was significantly higher at day 7 and day 14 than the ALP activity observed for the other titanium surfaces. At day 14, the ALP activity on AH Ti was significantly increased compared with the ALP activity on Cp Ti. The amount of DNA per well increased nearly in parallel for each titanium. However, northern blot analysis at day 14 revealed that expression of osteocalcin and alpha1(I) collagen mRNA was higher in the cells cultured on Ap Ti than the cells cultured on AH Ti. The cells cultured on Cp Ti showed the lowest mRNA levels. After 7 days of cell-free culture in medium supplemented with 15% serum, X-ray photoelectron spectroscopy (XPS), and thin-film X-ray diffraction (TF-XRD) analysis showed that calcium phosphate had been deposited on the AH Ti (resulting in an increase in thickness with time). No phosphate was detected on the Cp Ti, even after day 14. This study indicates that Ap Ti provides the most favorable conditions for differentiation of bone marrow cells, and, at a later stage, AH Ti also provides favorable conditions, perhaps because of the formation of a surface layer of calcium phosphate. This potential for apatite formation may play an important role in osteoblastic differentiation.

Alkaline Phosphatase↗
PubMed2000

Alkali and alkaline-earth metal ketyl complexes: isolation, structural diversity, and hydrogenation/protonation reactions

The use of hexamethylphosphoric triamide (HMPA) as a stabilizing ligand allowed successful isolation of a series of structurally characterizable alkali metal and calcium ketyl complexes. Reaction of lithium and sodium with one equivalent of fluorenone and reaction of sodium with one equivalent of benzophenone in THF, followed by addition of two equivalents of HMPA, yielded the corresponding ketyl complexes 1, 2, and 11, respectively, as microketyl-bridged dimers. If one equivalent of HMPA was used in the reaction of sodium with fluorenone, a further aggregated complex, the mu3-ketyl-bridged tetramer 3, was isolated, whereas analogous reaction of benzophenone with sodium afforded the trimeric ketyl complex 13, rather than a simple benzophenone analogue of 3. In the reaction of potassium with fluorenone, the use of two equivalents of HMPA gave the tetramer 4, rather than a dimeric complex analogous to 1 or 2. Compared to the tetrameric sodium complex 3, there is an extra HMPA ligand that bridges two of the four K atoms in 4. When 0.5 equiv of HMPA was used in the above reaction, complex 5, a THF-bridged analogue of 4, was isolated. In the absence of HMPA, the reaction of sodium with an excess of fluorenone yielded the tetrameric ketyl complex 6, in which two of the four Na atoms are each terminally coordinated by a fluorenone ligand, and the other two Na atoms are coordinated by a THF ligand. Two bridging THF ligands are also observed in 6. Reaction of 1,2-bis(biphenyl-2,2'-diyl)ethane-1,2-diol (7) with two equivalents of LiN(SiMe3)2 or NaN(SiMe3)2 in the presence of four equivalents of HMPA easily afforded 1 or 2, respectively, via C-C bond cleavage of a 1,2-diolate intermediate. The reaction of calcium with two equivalents of fluorenone or benzophenone in the presence of HMPA gave the corresponding complexes that bear two independent ketyl ligands per metal ion. In the presence of 3 or four equivalents of HMPA, the fluorenone ketyl complex was isolated in a six-coordinate octahedral form (10), while the benzophenone ketyl complex was obtained as a five-coordinate trigonal bipyramid (13). The radical carbon atoms in both benzophenone ketyl and fluorenone ketyl complexes are still in an sp2-hybrid state. However, in contrast with the planar configuration of the whole fluorenone ketyl unit, the radical carbon atom in a benzophenone ketyl species is not coplanar with any of the phenyl groups; this explains why benzophenone ketyl is more reactive than fluorenone ketyl. Hydrolysis of 2 or 11 with 2N HCI yielded the corresponding pinacol-coupling product, while treatment of 2 or 11 with 2-propanol, followed by hydrolysis, gave the pairs fluorenone and fluorenol or benzophenone and benzhydrol, respectively. A possible mechanism for these reactions is proposed.

Journal Article↗
PubMed2001

Titanium alkali metal nitrido complexes.

Treatment of [(Ti(eta5-C5Me5)(mu-NH))3(mu3-N)] with alkali metal bis(trimethylsilyl)amido reagents in toluene afforded the complexes [M(mu3-N)(mu3-NH)2[Ti3(mu5-C5Me5)3(mu3-N)]]2 (M = Li (2), Na, (3), K (4)). The molecular structures of 2 and 3 have been determined by X-ray crystallographic studies and show two azaheterometallocubane cores [MTi3N4] linked by metal-nitrogen bonds. Reaction of the lithium derivative 2 with chlorotrimethylsilane or trimethyltin chloride in toluene gave the incomplete cube nitrido complexes [Ti3(eta5-C5Me5)3(mu-NH)2(mu-NMMe3)(mu3-N)] (M = Si (5), Sn (6)). A similar reaction with indium(I) or thallium(I) chlorides yielded cube-type derivatives [M(mu3-N)(mu3-NH)2[Ti(eta5-C5Me5)3(mu3-N)] (M=In (7), Tl (8)).

Journal Article↗
PubMed2002

Exploring and expanding the three-dimensional structural diversity of supramolecular dendrimers with the aid of libraries of alkali metals of their AB(3) minidendritic carboxylates.

The synthesis of the alkali metal salts of 3,4,5-tris(n-alkan-1-yloxy)benzoic acid [(3,4,5)nG1-CO(2)M, where n is the number of methylenic units in the alkane group for n=12, 14, 16, 18 and M=Li, Na, K, Rb, Cs] is described. The structural analysis of these AB(3) molecules by a combination of methods which includes X-ray diffraction experiments was performed. These experiments have demonstrated that (3,4,5)nG1-CO(2)M self-assemble at low temperatures into supramolecular cylinders and at high temperatures into spheres which subsequently self-organize into two-dimensional c2mm rectangular columnar, p6mm hexagonal columnar, three-dimensional Pm(-)3n and Im(-)3m cubic lattices. In addition a novel unidentified liquid crystalline lattice was also discovered. The dependence between the symmetry of the lattice and the molecular structure of (3,4,5)nG1-CO(2)M was established. (3,4,5)nG1-CO(2)M represents one of the AB(3) minidendrons (i.e., first-generation monodendron attached to the periphery of larger generation dendrons) that is responsible for the control of the three-dimensional structures created from libraries of larger generations of dendrimers. Therefore, the molecular structure-lattice dependence elaborated here will aid the rational design of the three-dimensional shapes from larger generations of supramolecular dendrimers and of their lattices. In addition, the temperature responsive shape change of these supramolecular objects may generate new supramolecular concepts and technological applications.

Journal Article↗
PubMed2001

Isolation and characterization of a novel leaf-inhabiting osmo-, salt-, and alkali-tolerant Yarrowia lipolytica yeast strain.

Salt-excreting leaves of Atriplex halimus plants harvested in the central Negev Highlands of Israel were screened for yeasts inhabiting their surfaces. Several aerobic, moderately salt- and alkali-tolerant yeasts were isolated. One of the isolates (tentatively designated S-8) was identified as Yarrowia lipolytica (Wick.) van der Walt and Arx, on the basis of its morphological, biochemical/physiological characteristics, and of quantitative chemotaxonomic and molecular marker analyses. However, the strain is distinguished from the known members of the type Y. lipolytica strain by its pronounced osmo-, salt-, and pH tolerance. Cells displayed a unique capacity to grow over a wide pH range (from 3.5 to 11.5) with a pH optimum at 4.5 to 7.5. It is proposed that the S-8 strain be assigned to a single Y. lipolytica species as its anamorpha, or as a new variety, Y. lipolytica var. alkalitolerance. The ecophysiological properties and biotechnological potentials of the new strain are discussed.

Atriplex↗