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PubMed1983

Indications for the role of the immune system in the pathogenesis of corneal alkali burns.

We produced alkali burns (1.5 N NaOH) in the right eyes of 63 mice. Three weeks later the left eye of each mouse was similarly burned. All eyes were followed up weekly for 4 weeks after the burn and were graded according to the severity of the lesion. The lesions developed much faster and were more severe in the left eyes. These results suggest that the body's immune mechanism participates in the pathogenesis of alkali corneal burns and adversely affects the development of this condition.

Alkalies↗
PubMed1997

Topical steroid use in the treatment of ocular alkali burns.

BACKGROUND: Ocular alkali burns can be associated with a poor visual outcome. The release of collagenases and proteases after the injury leads to corneoscleral melting. The role of topical steroids in such patients is controversial as they have been postulated to exacerbate corneoscleral melting. METHODS: 30 patients were reviewed retrospectively after admission to King's College Hospital with alkali burns between 1990 and 1993. All patients were treated with an intense and prolonged regimen of topical steroids and topical and systemic vitamin C. RESULTS: 22 patients had mild injuries and eight had severe injuries as estimated by the Roper-Hall grading system. 23 patients were treated with topical steroids for > 10 days and 22 patients were treated with topical vitamin C for more than 10 days. One patient with a severe injury developed corneoscleral melting. CONCLUSION: Prolonged treatment with topical steroids when used in conjunction with topical vitamin C is not associated with corneoscleral melting.

Administration, Topical↗
PubMed1976

Meningitis caused by an alkali-producing pseudomonad.

The clinical and microbiological features of a case of meningitis, due to an alkali-producing pseudomonad which closely resembles Pseudomonas pseudoalcaligenes, are described. A respiratory infection and a course of antibiotic therapy before admission to hospital may have been predisposing factors to opportunistic infection by this normally saprophytic organism. The problems of identifying alkali-producing pseudomonads are discussed.

Alkalies↗
PubMed1996

Effect of alkali therapy with NaHCO3 or THAM on cardiac contractility.

We examined the impact of alkali therapy on myocardial contractility in a model of myocardial ischemia in dogs using direct measurements of myocardial contractile function. Myocardial ischemia in the left anterior descending (LAD) artery territory was induced using a perfusion circuit from the internal carotid artery to the LAD artery. Myocardial contractile function was assessed using sonomicrometry for measurement of percent systolic shortening (%SS), preload recruitable stroke work (PRSW) slope, and end-systolic pressure-length relationship (ESPLR) area. Because the blood flow in LAD artery was diminished by approximately 70%, there was a significant decrease in O2 delivery and uptake by the ischemic myocardium. Ischemia led to a significant fall in LAD regional contractile function with %SS decreasing from 15 +/- 2 to 7 +/- 2%, PRSW slope from 82 +/- 10 to 37 +/- 5 mmHg, and ESPLR area from 121 +/- 2 to 48 +/- 14 mmHg.mm (P < 0.05). In six dogs, the intracoronary administration of NaHCO(3) resulted in a significant increase in pH in LAD arterial and venous blood. There was, however, no significant increase in %SS (6 +/- 2), PRSW slope (43 +/- 10 mmHg), or ESPLR area (60 +/- 13 mmHg.mm). Since administration of NaHCO(3) resulted in a significant increase in PCO2 in LAD arterial and venous blood, similar experiments were carried out in five dogs, but with the intracoronary infusion of the amine buffer THAM [tris(hydroxymethyl)aminomethane (Tris) buffer; 2-amino-2-hydroxyl-1,3-propandiol] instead of NaHCO3. Although administration of THAM resulted in a significant increase in pH and a significant decrease in PCO2, in both LAD arterial and venous blood, there was no significant improvement in any of the parameters used to assess myocardial contractile function. In conclusion, administration of alkali (NaHCO3 or THAM) does not enhance the contractile function of the ischemic myocardium.

Alkalies↗
PubMed1996

Alkali therapy extends the period of survival during hypoxia: studies in rats.

The goal of this study was to evaluate whether sodium bicarbonate might be a useful form of therapy for hypoxic L-lactic acidosis; our aim was to determine if alkali could extend the time of survival in this setting. Hypoxia was induced in anesthetized, paralyzed, artificially ventilated rats by lowering inspired O2 to 5.5%, an amount sufficient to develop a severe degree of L-lactic acidosis. Measuring arterial blood gases frequently permitted maintenance of a near-constant arterial O2 content. Three groups of hypoxic rats were studied: first, no infusions (n = 10); second, sodium bicarbonate at a rate equal to H+ production in the no-infusion group (n = 12); and third, a control for the Na load in the second group as NaCl (n = 17). Survival was close to twofold longer in the sodium bicarbonate group. Part of this beneficial effect seemed to be increased anaerobic glycolysis, producing ATP along with L-lactic acid. In addition, there was a large decrease in the metabolic demand (consumption of O2) in the 7- to 15-min period in the sodium bicarbonate group. Rats exposed to hypoxia and infused with NaCl for 15 min or alkali for 15, 27, or 40 min were then returned to room air; all survived for the subsequent experimental period of 150 min. We found that there is both a rationale and experimental evidence for giving sodium bicarbonate to prolong survival during hypoxia.

Acidosis, Lactic↗
PubMed2006

Alkali burns of the eye: effect of immediate copious irrigation with tap water on their severity.

PURPOSE: To examine the effect of immediate irrigation on ocular alkali burn. METHODS: Information on the injury, immediate irrigation, and ocular findings was retrospectively obtained from each patient's record. RESULTS: 36 patients (49 eyes) irrigated their eyes with tap water (the irrigation group) and 17 patients (29 eyes) did not (no irrigation group). The mean age of patients in the irrigation and no irrigation groups was 30 and 53 years, respectively. According to Hugher's classification, 76% of eyes in the irrigation group had grade 1 injury, while 86% of eyes in the no irrigation group had grade 2 injuries. Mean time from the injury until healing was 8 days in the irrigation group and 29 days in the no irrigation group, respectively. CONCLUSION: Immediate copious irrigation with tap water reduced the severity in alkali burns of the eye and shortened the healing time.

Adult↗
PubMed1986

Further evidence for the involvement of immunoregulatory processes in corneal alkali burns: effects of immunosuppression and convalescent serum.

Alkali burns were produced in one eye of a group of mice. Two, 3 and 4 weeks later the second eye of each mouse was similarly burned. The rate of perforation in the second-burned eyes was significantly higher than in the first eye. This effect was abolished by immunosuppressing the animals before the burning of the first eyes. This potentiation effect of an ocular burn on subsequent ones is transferable to other mice by intraperitoneal administration of convalescent serum prepared from mice that were previously burned. This evidence suggests that ocular alkali burns cause the appearance in the circulation of antigens not previously present there. The antibodies produced against these antigens exacerbate the subsequent burn lesion and perhaps also the condition of the original burn.

Alkalies↗
PubMed2004

Measurements of alkali-labile DNA damage and protein-DNA crosslinks after 2450 MHz microwave and low-dose gamma irradiation in vitro.

In vitro experiments were performed to determine whether 2450 MHz microwave radiation induces alkali-labile DNA damage and/or DNA-protein or DNA-DNA crosslinks in C3H 10T(1/2) cells. After a 2-h exposure to either 2450 MHz continuous-wave (CW) microwaves at an SAR of 1.9 W/kg or 1 mM cisplatinum (CDDP, a positive control for DNA crosslinks), C3H 10T(1/2) cells were irradiated with 4 Gy of gamma rays ((137)Cs). Immediately after gamma irradiation, the single-cell gel electrophoresis assay was performed to detect DNA damage. For each exposure condition, one set of samples was treated with proteinase K (1 mg/ml) to remove any possible DNA-protein crosslinks. To measure DNA-protein crosslinks independent of DNA-DNA crosslinks, we quantified the proteins that were recovered with DNA after microwave exposure, using CDDP and gamma irradiation, positive controls for DNA-protein crosslinks. Ionizing radiation (4 Gy) induced significant DNA damage. However, no DNA damage could be detected after exposure to 2450 MHz CW microwaves alone. The crosslinking agent CDDP significantly reduced both the comet length and the normalized comet moment in C3H 10T(1/2) cells irradiated with 4 Gy gamma rays. In contrast, 2450 MHz microwaves did not impede the DNA migration induced by gamma rays. When control cells were treated with proteinase K, both parameters increased in the absence of any DNA damage. However, no additional effect of proteinase K was seen in samples exposed to 2450 MHz microwaves or in samples treated with the combination of microwaves and radiation. On the other hand, proteinase K treatment was ineffective in restoring any migration of the DNA in cells pretreated with CDDP and irradiated with gamma rays. When DNA-protein crosslinks were specifically measured, we found no evidence for the induction of DNA-protein crosslinks or changes in amount of the protein associated with DNA by 2450 MHz CW microwave exposure. Thus 2-h exposures to 1.9 W/ kg of 2450 MHz CW microwaves did not induce measurable alkali-labile DNA damage or DNA-DNA or DNA-protein crosslinks.

Alkalies↗
PubMed1990

High dietary calcium to phosphorus ratio and alkali-forming potential as factors promoting silica urolithiasis in sheep.

Sheep were used to study factors previously found to promote silica urolithiasis in a rat model. In addition to high silica, these dietary factors included elevated calcium, a high calcium to phosphorus ratio and alkali-forming effects. Wether lambs had ad libitum access to a diet of 50% of grass hay and 50% ground oats plus supplement. Diet analysis was 3.4% total SiO2, .29% calcium, .25% phosphorus, 11.3% CP and 28% ADF. Treatments (40 lambs/treatment) consisted of a control (C), limestone to increase dietary calcium to .6% (L), L + 1% sodium bicarbonate (LS) and L + 1% ammonium chloride (LA). After a 91-d experimental period followed by a 56-d postexperimental finishing period, silica kidney deposits were found in all treatments, and SiO2 made up 74% to 97% of the urolithic ash. Kidney urolith incidences in the four treatments were C, 7/40; L, 12/40; LS, 20/40; and LA, 9/40. A higher urolith incidence in LS (LS vs C, P less than .05) and a trend toward a higher incidence in L (L vs C, P less than .2), accompanied by elevated urine pH (L = LS greater than C greater than LA, P less than .01), lend support to the concept that high-silica diets having high calcium to phosphorus ratios and alkali-forming potentials contribute to silica urolithiasis.

Alkalies↗
PubMed1994

Digestibility of alkali-treated wheat straw measured in vitro or in vivo using Holstein heifers.

Three experiments were conducted to determine the effect of different alkali solutions on in vitro degradation and in vivo digestibility of wheat straw. In Exp. 1, ground wheat straw was treated with 15 different alkali solutions grouped as NaOH, NH4OH, urea, and Ca(OH)2. The greatest (P < .05) 48-h in vitro NDF degradability was obtained with 5% NaOH and the combination of 2.5% NaOH + 2.5% Ca(OH)2. In Exp. 2, chopped wheat straw was treated with one of the following: 1) untreated; 2) 2.5% NaOH; 3) 5% NaOH; 4) 2.5% Ca(OH)2 + 2.5% NaOH; or 5) 5% Ca(OH)2. Five Holstein heifers were fed diets that contained 60% straw, 20% alfalfa hay, and 20% concentrate mix (DM basis) fed as total mixed rations in a 5 x 5 Latin square design. The greatest in vivo NDF digestibility (P < .05) was obtained with the NaOH and NaOH+Ca(OH)2 treatments. The 5% Ca(OH)2 treatment had higher fiber digestibility than the control and was equivalent to the 2.5% NaOH and 2.5% NaOH+Ca(OH)2 treatments. Rate of passage of straw was not affected by chemical treatment, whereas rate of passage of dietary alfalfa hay increased with NaOH. In Exp. 3, wheat straw ground through a 2-mm screen was treated with one of the following chemicals: 1) untreated (control); 2) 5% NaOH; 3) 5% NH4OH; 4) urea supplying N equivalent to 5% NH4OH; and 5) 5% Ca(OH)2 (all on DM basis).(ABSTRACT TRUNCATED AT 250 WORDS)

Alkalies↗
PubMed1987

Modified alkali digestion method for pulmonary asbestos fibre counts.

In using the standard alkali digestion method for pulmonary asbestos fibre count, it was found that carbonaceous particles often obscured the presence of asbestos bodies (coated fibres) rendering their quantification inaccurate, particularly in lungs with a high soot particle content and a low fibre count. We applied the chloroform-ethanol separation technique from the bleaching agent digestion method to the alkali digestion method to remove the carbonaceous particles. It was found that coated fibres are much easier to visualize and count. The uncoated fibre count was nevertheless more accurate with the original method. The coated and uncoated fibre counts from 21 lung specimens were compared using both methods. The total fibre count was considered better derived from using both techniques.

Alkalies↗
PubMed1978

Effect of addition of inorganic acids or alkalis on gelation of polyvinyl alcohol aqueous solution by gamma-ray irradiation.--Color development with iodine--.

Below the critical concentration of polyvinyl alcohol, the effect of inorganic acids or alkalis on gelation of polyvinyl alcohol aqueous solution was investigated by color development with iodine after gamma-ray irradiation. The absorbances of the polyvinyl alcohol-iodine complex decreased remarkably in the presence of nitric or perchloric acid. These acids decompose and form oxygen or hydrogen peroxide which oxidize the polymer and leads to a fading of the color. On addition of sulfuric, phosphoric and hydrochloric acids, the absorbances decrease in the order that agrees with that of the acidity of these acids at the same molarity. In the alkaline solution the absorbances decrease by the addition of sodium hydroxide and aqueous ammonia in the order that agrees with that of the basicity of these alkalis. These results indicate that the gel formation is caused by the radiolysis of water. As a result of chemical analysis, these additives are considered not to be attached to the polymer.

Acids↗
PubMed2000

[An experimental study on treatment of limbal alkali burn by allograft transplantation with cultured stem cells on amniotic membrane].

OBJECTIVE: To study the treatment of rabbit limbal alkali burn by cultured limbal stem cells growing on amniotic membrane for allograft transplantation. METHODS: After the primary culture of the rabbit corneal stem cells, they were cultured on amniotic membrane in DMEM/HamF12 medium for one week. Corneal stem cells and amniotic membrane were transplanted on the limbal and scleral area of the rabbit model with alkali burn. The corneal changes were observed by a slitlamp everyday, and the corneal pathological changes were examined. RESULTS: Cultured rabbit corneal stem cells continued to proliferate, differentiate and form multiple cell layers on amniotic membrane. After transplantation with cultured stem cells and amniotic membrane, the rabbit epithelium showed corneal phenotype and progressive decrease of vascularity and stromal infiltration in the limbal and peripheral zone. Pathological examination verified that the limbal and peripheral corneal epithelium was composed of multilayer cells, the neo-vascularization was reduced and stromal inflammatory cells were decreased. CONCLUSIONS: Allograft transplantation with cultured limbal stem cells can restore corneal epithelial cell composition, decrease neovascularization, maintain limbal cellular barrier function and provide better condition for keratoplasty later.

Alkalies↗
PubMed1999

[Observation of the endothelial healing in rabbit corneal alkali wounds by alizarin red S-trypan blue staining method].

PURPOSE: To study the healing of the corneal endothelial cells in rabbit corneal alkali wounds. METHODS: 26 New Zealand white rabbits were used. A alkali wound was created with a round filter paper, 8 mm in diameter, which was soaked in 0.5 N NaOH for 5 seconds and was placed centrally on the cornea for 60 seconds. The rabbits were killed in 20 minutes; 1, 2, 6, 12 h; 1, 2, 3, 5, 7, 10, 14, 30 days after injury. The corneal endothelium was examined in the light microscope using a lizarin red S-trypan blue staining method. RESULTS: Twenty minutes after the wound, the corneal endothelial cells were destroyed. 72 hours following the wound, the endothelial cells surrounding the burns became larger, irregular and started to migrate onto the denuded descemet's membrane. The endothelial cells covered the burn with the spindle-shaped cells 7 days after wound. CONCLUSION: The endothelial damage is healed by the division and migration of remaining endothelial cells at the margin of the wound, which has some characters of fibroblast.

Alkalies↗
PubMed1992

Localization of collagen (I) and collagenase mRNA by in situ hybridization during corneal wound healing after epikeratophakia or alkali-burn.

The expression and localization of type I collagen and collagenase gene were studied by in situ hybridization using rabbit cornea during wound healing following epikeratophakia or alkali-burn. In corneas 24 days after epikeratophakia, alpha 1(I) collagen mRNA was detected in keratocytes which had migrated from the host cornea into the keratolens. In contrast, collagenase mRNA was detected in cells which seemed to be inflammatory cells around the suture between the host stroma and the keratolens. The increase of alpha 1(I) collagen mRNA in keratocytes was observed in corneas 94 days after epikeratophakia and in alkali-burned corneas 1-2 months after the burn. These results provide evidence that keratocytes synthesize collagen and that this synthesizing activity lasts for a long period during corneal wound healing.

Alkalies↗
PubMedDate not supplied

Chronic psychological effects of exposure to mercury vapour among chlorine-alkali plant workers.

BACKGROUND: Quantitative assessment of nervous system function is essential in characterising the nature and extent of impairment in individuals experiencing symptoms following work-place mercury vapour exposure. OBJECTIVES: The purpose of this study was the application of standardised tests of behavioural, psychomotor and memory function to understand the neuropsychological effects of mercury in occupationally exposed chlorine-alkali plant workers. SUBJECTS AND METHODS: The study comprised 45 workers at a chlorine-alkali plant with the mean age of 39.36 +/- 5.94 years, who had been exposed to daily inhalation of mercury vapour over long-term employment of 16.06 +/- 4.29 years. The cumulative mercury index was 155.32 +/- 95.02 micrograms/g creatinine, the mean of urinary mercury concentrations on the first day of the study was 119.50 +/- 157.24 micrograms/g creatinine, and the mean of urinary mercury concentrations 120 days after cessation of exposure was 21.70 +/- 26.07 micrograms/g creatinine. The analysis included tests of behavioural, psychomotor and memory function. The behavioural test battery consisted of: Environmental Worry Scale (EWS), Minnesota Modified Personal Inventory (MMPI-2), Purdue standard 25 minute test, and adapted, 10 minutes test, Bender's Visual-Motor Gestalt test (BGT), and Eysenck Personality Inventory (EPQ). The data were compared to a control group of 32 not directly exposed workers. RESULTS: In the mercury vapour exposed workers with relatively high level exposure to inorganic mercury vapour (TWA/TLV = 0.12 mg/m3/0.025 mg/m3) we identified somatic depression-hypochondria symptoms with higher scores for scales: hysteria (P < 0.001), schizoid and psycho-asthenia (MMPI-2). The mercury-exposed workers had introvert behaviour (EPQ, MMPI-2). The cognitive disturbances in mercury-exposed workers were identified as: concentration difficulty, psychomotor, perceptual and motor coordination disturbances, and brain effects. We identified fine tremor of the hands in 34 out of 45 mercury-exposed workers (BGT). CONCLUSIONS: The results point to a relationship between the duration of mercury exposure and the long-term, probably irreversible, psychological disturbances.

Adult↗
PubMed2005

[Study on the rat models of corneal neovascularization induced by alkali burn].

PURPOSE: The aim of this series of experiments was to test appropriate rat models of corneal neovascularization (CNV) induced by alkali injury. METHODS: All animals (n=48) were randomly assigned to four groups, each consisting of twelve eyes. Alkali injury was induced on day 0 by application of iN NaOH to right eyes of S-D rats for 15 30 AG and 6Os respectively. Biomicroscopic features including corneal neovascularization, corneal ulceration and hyphema were observed for 28 days. RESULTS: Corneal neovascularization began to invade pericornea on day 3 and flourished on day 7, then reached its developmental peak on day 14, and regressed gradually after day 14. The induced rate of CNV for groups 15s, 30s, 40, 60s, were 16.7%, 75%, 100%, 100% respectively, the induced rate of corneal neovascularization in all groups increased with time prolonging. CNV distributed sparsely in group iSs and its length was more shorter. CNV in group 30s reached the margin of burn area and distributed sparsely. There had uniform growth of CNV in group 40s and the hyphema was not more excessive than that of group 60s which was difficult to observe CNV. Significant difference (P < 0.05) was found between Group 30s and 40s in length and area of CNV respectively. The rate of hyphema was 16.7%, 83.3% respectively between Group 40s and 60s and significant difference (P < 0.05) was also found. The rate of corneal ulceration and perforation was 50% and 33.3% respectively in Group 60s. CONCLUSIONS: The appropriate induced time for S-D rat models of corneal neovascularization by using filter paper which diameter is 3 mm and inmerged solution of 1 mol/L sodium hydroxide was 40s. It's an ideal animal model for CNV induced by chemical injuries.

Alkalies↗
PubMed1989

Degradation of bovine corneal collagen by alkali.

This study was undertaken to demonstrate the effect of alkali on the molecular size of collagen. Type I and V collagen from bovine cornea were incubated with different concentrations of NaOH at room temperature and 37 degrees C for various times. The samples were then neutralized and analyzed by high-pressure liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Degradation of collagen molecules to a heterogeneous mixture of peptides with molecular weights less than 20,000 daltons occurred at concentrations greater than 0.25N, and the effect of alkali was much faster at 37 degrees C than at room temperature. In contrast, the molecular size of collagen was not affected by similar concentrations of HCl under similar conditions of time and temperature.

Alkalies↗