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PubMed1995

Clinical evaluation of two different techniques for the removal of fluorosis stains.

Dental fluorosis or mottled enamel manifest itself as a brown, gray or black discolourations on the external enamel surfaces of the permanent teeth. The causative factor has been found to be the ingestion of fluorine in the drinking water more than 1 pp.m. In its most severe form the enamel discolouration provide a very displeasing appearance. Many times friends and relatives tease the patient that these stains are associated with smoking and/or poor oral hygiene. Such unwarranted, lose and inflicting personal remarks leads an individual into a severe psychological depression. A clinical study was under taken with its aims and objectives to evaluate the efficaciousness of 18% hydrochloric acid with pumice and McInnes solution with pumice in fighting the various forms of fluorosis stains and also observe and record their actions and reactions with the patients and the vitalities of the treated teeth.

Adolescent↗
PubMed1996

Keratinocyte growth factor reduces lung damage due to acid instillation in rats.

Acid aspiration is a serious complication of anesthesia and other forms of unconsciousness that can result in the adult respiratory distress syndrome (ARDS), which continues to have a very high mortality despite our current therapeutic interventions. This type of injury damages the alveolar epithelium, principally alveolar type I cells, and requires proliferation of alveolar type II cells to restore gas exchange units. Since keratinocyte growth factor (KGF) has been shown to be a potent mitogen for alveolar type II cells, we evaluated whether intrabronchial administration of KGF would minimize lung injury due to the unilateral instillation of 0.1 N hydrochloric acid (HCl). Rats were pretreated or post-treated by intrabronchial instillation of KGF (5 mg/kg) into the left lung before HCl instillation. All rats receiving KGF at 48 or 72 h before HCl instillation survived for the 7-day observation period, whereas the mortality rate for those receiving HCl alone or saline followed by HCl was 31% and 33%, respectively. Pretreatment with KGF at 72 h but not at 24 or 48 h considerably ameliorated morphologic damage produced by HCl. Inflammatory cells in bronchoalveolar lavage were markedly decreased 3 and 7 days after HCl instillation by the 72-h KGF pretreatment. Pretreatment with KGF at 72 h also attenuated the reduction of total lung capacity, decreased the alpha 1(I) procollagen mRNA levels, and diminished hydroxyproline accumulation due to HCl instillation. Saline pretreatment at 72 h had no significant effect on the HCl injury and subsequent physiologic abnormalities. Our attempts to improve outcome with post-treatment instillation of KGF were unsuccessful. We conclude that KGF pretreatment reduces lung injury due to acid instillation and can prevent subsequent pulmonary fibrosis.

Administration, Inhalation↗
PubMed1991

Fracture resistance of pin-retained amalgam, composite resin, and alloy-reinforced glass ionomer core materials.

This study investigated the influence of pins on the fracture resistance of three core materials. Two or four stainless steel pins were incorporated in either amalgam, composite resin, or alloy-reinforced glass ionomer specimens. Half of the pins were surface-treated with mercury, Panavia EX resin, or hydrochloric acid before they were incorporated in the respective materials. The pins were oriented in a direction relative to the tensile stress/axis of the specimen: parallel/perpendicular (PL/PR), perpendicular/parallel (PR/PL), or perpendicular/perpendicular (PR/PR). ANOVA tested significant differences in diametral tensile strength among materials, in number of pins, in pin orientations, in surface treatments, and in other interactions. Incorporation of pins weakened amalgam the most, followed by composite resin. Pins did not weaken amalgam-reinforced glass ionomer. Pin orientation improved the fracture resistance of some specimens by two times that of the controls. Orientation of pins parallel to the tensile stress was most favorable. As the number of pins increased, the fracture resistance of amalgam significantly decreased. Acid treatment of the pin surface enhanced the bond with composite resin. Both treatments resulted in significant improvement in fracture resistance.

Analysis of Variance↗
PubMed2003

SnO2 thin films prepared by dip-coating from microwave synthesized colloidal suspensions.

Tin(IV) oxide thin films have been prepared by dip-coating. The suspensions used for these depositions have been synthesized by microwave-induced thermohydrolysis of tin tetrachloride aqueous solutions in the presence of hydrochloric acid. Single or multiple depositions were tested, on glass substrates as well as on pure SiO2. The obtained thin films were characterized by optical microscopy, interferometric roughness measurements (Micromap), scanning electron microscopy, secondary ion mass spectroscopy, and scanning tunneling microscopy.

Colloids↗
PubMed1969

The gastrointestinal stimulus to insulin release. I. Secretin.

The gastrointestinal stimulus to the release of insulin has been investigated in man by the use of a radioimmunoassay for secretin. Serum secretin levels rose rapidly after the oral ingestion of glucose or protein and preceded the elevation of serum insulin. An intravenous infusion of highly purified secretin caused a release of insulin when the serum secretin levels were within the physiological range. Infusion of hydrochloric acid into the duodenum caused an elevation of serum secretin and serum insulin levels in normal subjects. A similar response of secretin and insulin was seen after intravenous infusion of pentagastrin even when the acid stimulus to the duodenum was prevented. The latter observation suggests that pentagastrin (and probably gastrin) releases secretin by a direct humoral effect which is later fortified by the arrival of gastric acid in the duodenum. These studies suggest that secretin participates in the augmentation of insulin release after oral stimuli, and that a rapid sequence of humoral events takes place, gastrin releasing secretin and secretin releasing insulin. Subsequently secretin release would be augmented by a local stimulus in the duodenum and insulin release by the rising level of blood glucose or amino acids. This humoral system, which could also involve other gastrointestinal hormones, would provide a mechanism for facilitating the release of insulin to coincide with the onset of metabolite absorption.

Adult↗
PubMed1974

Bacterial growth in vivo. An important determinant of the pulmonary clearance of Diplococcus pneumoniae in rats.

Lung clearance of Diplococcus pneumoniae was markedly reduced in rats with acute hemorrhagic pulmonary edema produced by instillation of hydrochloric acid. Bacterial clearance was enhanced in both control and acid-instilled animals by pretreatment with a bacteriostatic antibiotic, tetracycline, 30 mg/kg. From these data the contributions of bacterial multiplication and bacterial elimination to net lung bacterial clearance were estimated. In control animals the constant for exponential bacterial elimination was -1.4283 (fractional clearance = 76% per h), and the doubling time for the pneumococcus was 170 min. In acid-instilled rats the elimination constant was -0.5336 (fractional clearance = 41% per h), and the doubling time of the pneumococcus was 47 min, approximating the doubling time of 42 min observed with pneumococci grown in broth. These results indicate that, in the case of pneumococci, both bacterial elimination and bacterial growth contribute to lung bacterial clearance in normal animals as well as animals with damaged lungs. In the present study changes in both parameters were required to explain the observed results in acid-instilled animals. The pulmonary pathogenicity of some bacterial species may be determined by their capacity for growth in the lung, since infection of the lung occurs when bacterial multiplication exceeds the rate of elimination of viable organisms.

Aerosols↗
PubMed1979

Cytoprotection by prostaglandins in rats. Prevention of gastric necrosis produced by alcohol, HCl, NaOH, hypertonic NaCl, and thermal injury.

Oral administration to fasted rats of either absolute ethanol, 0.6 N hydrochloric acid, 0.2 N sodium hydroxide, 25% sodium chloride, or boiling water produced extensive necrosis of the gastric mucosa. Pretreatment with several prostaglandins of the A, E, or F type, either orally or subcutaneously, prevented such necrosis, and the effect was dose-dependent. This property of prostaglandins is called "cytoprotection." The protective effect against oral administration of absolute ethanol was already maximal 1 min after PGE2 given orally, and 15-30 min after PGE2 given subcutaneously. Cytoprotection by prostaglandins is unrelated to the inhibition of gastric acid secretion since, (a) it is maximal at doses that have no effect on gastric secretion, and (b) anti-secretory compounds (cimetidine, methscopolamine bromide) and antacids are not cytoprotective. Although the mechanism of gastric cytoprotection is unknown, prostaglandins appear to increase the resistance of gastric mucosal cells to the necrotizing effect of strong irritants. These results suggest that certain prostaglandins, by a mechanism other than the inhibition of gastric acid secretion, maintain the cellular integrity of the gastric mucosa, and might be beneficial in the treatment of a variety of diseases in which gastric mucosal injury is present.

Animals↗
PubMed1999

Spectrophotometric determination of some antidepressant drugs using 3-methylbenzothiazolin-2-one hydrazone.

A sensitive spectrophotometric method for the determination of amitriptyline hydrochloride, nortriptyline hydrochloride and doxepin hydrochloride in pure and dosage forms, is described. The method is based on the oxidative coupling of the drugs with 3-methylbenzothiazolin-2-one hydrazone in the presence of iron(III) chloride in 1 M hydrochloric acid. The commonly encountered excipients and additives do not interfere with the determinations. Results of the present method are comparable with those of official methods. The new method offers the advantage of simplicity and rapidity.

Amitriptyline↗
PubMed1994

[Elimination of Pseudomonas aeruginosa from an experimental nude mouse colony].

In order to eliminate Pseudomonas (P.) aeruginosa from a contaminated nude mouse colony, the following procedures were carried out: improvement of environmental sanitation using an effective disinfectant against the organism; supply of tap water acidified with hydrochloric acid at pH2.5-3.0; elimination of mice positive in isolation of P. aeruginosa from the nude mouse colony. The experimental results indicated that P. aeruginosa were successfully eliminated from the colony though a combination of the above three procedures.

Animals↗
PubMed2001

Synthesis and properties of dextran-nalidixic acid ester as a colon-specific prodrug of nalidixic acid.

Dextran-nalidixic acid ester (dextran-NA) with a varied degree of substitution (DS) was synthesized as a colon-specific prodrug of nalidixic acid (NA). Solubility in water (mg/ml) of dextran-NA with DS (mg NA/100 mg dextran-NA) of 7, 19, or 32 was 57.57 (equivalent to 4.00 mg NA/ml), 0.53 (equivalent to 0.10 mg NA/ml), or 0.03 (equivalent to 0.01 mg NA/ml), respectively, and that for NA was 0.03 at 25 degrees C. To ensure the chemical stability of dextran-NA at conditions similar to those of the stomach and small intestine, dextran-NA was placed in a solution of pH 1.2 hydrochloric acid buffer or pH 6.8 phosphate buffer and incubated at 37 degrees C; no NA was detected during the 6 h of the incubation period, which indicated that dextran-NA might be chemically stable during the transit through the gastrointestinal tract. Degree of depolymerization (%) by dextranase determined by the 2,4-dinitrosalicylic acid (DNS) method at 37 degrees C for dextran-NA with DS of 7, 19, or 32 was 81, 68, or 8, respectively, in 8 h, and that for dextran was 91. When dextran-NA (equivalent to 50 microg of NA) with a DS of 7 or 17 was incubated with cecal contents (100 mg) of rats at 37 degrees C, the extent of NA released in 24 h was 41% or 32% of the dose, respectively. NA was not liberated from the incubation of dextran-NA with the homogenate of tissue and contents of the small intestine.

Animals↗
PubMed1986

Pulmonary function and acid application in the esophagus.

The effect of acid application in the esophagus on pulmonary function was measured in three groups of patients in a double-blind investigation. Group 1 consisted of ten patients with esophagitis but without pulmonary disease, group 2 was 21 patients with bronchial asthma without esophagitis, and group 3 was eight patients with both esophagitis and bronchial asthma. Pulmonary function was assessed by total lung capacity (TLC), airway resistance (Raw), residual volume (RV), and peak expiratory flow (PEF). The four parameters were measured at the following five times during a single trial: before and after insertion of an esophageal catheter; after instillation of 50 ml of isotonic sodium chloride solution; after instillation of 50 ml of 0.1 N hydrochloric acid; and after intravenous injection of atropine (0.01 mg/kg of body weight). A significant decrease (the Wilcoxon test, p less than 0.02; and the Mann-Whitney test, p less than 0.002) in PEF and a significant increase (p less than 0.02 and p less than 0.002, respectively) in Raw after instillation of HCl were seen only in group 3. Changes in the other groups were small and without any regular pattern. Six of the patients in the third group accepted another trial after three days of pretreatment with atropine (0.01 mg/kg twice daily). Now instillation of acid did not produce any change in PEF or Raw (p less than 0.001). We conclude that a modest bronchoconstriction when acid is present in the esophagus is seen in patients with bronchial asthma and severe esophagitis. Atropine inhibits this bronchoconstriction, indicating vagal mediation.

Adult↗
PubMed1973

The effect of some molecules and ions on gastric function in the milk-fed calf.

1. The abomasum of the milk-fed calf has been examined using an adaptation of the Serial Test Meal method devised by Hunt & Spurrell (1951). The emptying process, acid secretion and pepsin secretion were studied.2. Using serial test meals of simple solutions instilled into the abomasum via a cannula, our investigation leaves no doubt that the osmolarity of the abomasal contents significantly modifies the rate of abomasal emptying.3. Hypotonic and isotonic solutions of sodium chloride and sodium bicarbonate increase abomasal emptying but bicarbonate is most effective.4. Increasing the concentration of solutes in the abomasal contents slows abomasal emptying. Sodium chloride, sodium bicarbonate, ammonium chloride and urea do not delay abomasal emptying until hypertonic concentrations are attained. Hypotonic solutions of potassium chloride, calcium chloride, glucose, lactose, hydrochloric acid and acetic acid delay abomasal emptying.5. The results obtained in the calf show that the abomasum is under restraint probably from duodenal receptors as is the simple stomach (Hunt & Knox, 1968) and that an osmoreceptor as postulated by Hunt (1956) is an important factor in this mechanism.6. Acid secretion is inhibited when hypertonic solutions are instilled into the abomasum.7. Pepsin secretion is not affected by simple solutions in the abomasum.8. Gastric function in the milk-fed calf appears to be controlled by mechanisms essentially similar to those already demonstrated in the simple stomach.

Abomasum↗
PubMed1989

Effect of whole-body pH changes on thoracic duct lymph flow in anesthetized sheep.

Physiologic alterations of pH in vitro produce alterations of the oncotic pressure of both plasma and interstitial proteins, the effect being more marked in the latter. Therefore we postulated that by changing an animal's pH we could produce alterations in fluid distribution and affect the whole-body lymph flow rate. To test this hypothesis, we infused seven acutely nephrectomized anesthetized sheep with 2% body weight/volume isosmotic lactated Ringer's solution and bicarbonate (200 mEq) after a 30-minute control period. The fluid was infused over a 10-minute period with 20-minute recovery intervals. To another group of seven ewes, we infused the same volume of lactated Ringer's solution and hydrochloric acid (40 mEq). Throughout the experiment, we continuously measured arterial and venous pressures and lymph flow rate. Every 10 minutes we obtained samples for arterial pH, for hematocrit, and for plasma and lymph protein and osmolality. The infusion of bicarbonate was associated with a comparatively lower peak lymph flow rate (383% over baseline compared with 757% for acid infusion). Also the lymph flow rate after acid infusion started to increase approximately 5 minutes after the beginning of the infusion, as compared with approximately 10 minutes after the base infusion. Acid infusion did not increase arterial pressure, in contrast to the other infusions. The changes in pH obtained with the infusions were insignificant for the Ringer's infusion, +0.17 for the base, and -0.16 for the acid. The plasma/lymph protein concentration ratios at the end of the infusion were no different for acid or base: 112.4% +/- 4.4% and 101.9% +/- 5% (difference from control, mean +/- SEM) respectively (p greater than 0.1). In conclusion, minimal alterations of pH produced alterations in the cardiovascular and lymph flow rate responses to fluid challenge in anesthetized animals.

Anesthesia↗
PubMed2003

Dynamic mechanical consequences of deep inflation in mice depend on type and degree of lung injury.

In a previous study (Allen G, Lundblad LK, Parsons P, and Bates JH. J Appl Physiol 93: 1709-1715, 2002), our laboratory used deep inflations (DI) in mice to show that recruitment of closed lung units can be a very transient phenomenon in lung injury. The purpose of this study was to investigate how this transience of lung recruitment depends on the nature and degree of acute lung injury. Mice were administered 50 microl of either saline (n = 8), 0.01 M (n = 9) or 0.025 M (n = 8) hydrochloric acid, or 50 microg (n = 10) or 150 microg (n = 6) of LPS and were mechanically ventilated 24-48 h later. At various levels of positive end-expiratory pressure, two DIs were delivered, and forced oscillations were used to obtain a measure of lung stiffness (H) periodically over 7 min. After LPS exposure, pressure-volume curve hysteresis and recovery in H after DI were no different from saline-exposed controls despite 500 times more neutrophils in bronchoalveolar lavage fluid. Pressure-volume hysteresis and recovery in H were increased in acid-exposed mice (P < 0.001) and were correlated with bronchoalveolar lavage fluid protein content (R = 0.81). Positive end-expiratory pressure reduced recovery in H in all groups (P < 0.01) but reduced pressure-volume hysteresis in the acid-injured groups only (P < 0.001). We conclude that the effects of DIs in acute lung injury depend on the degree of lung injury but only to the extent that this injury reflects a disruption of the air-liquid interface.

Animals↗
PubMed1988

Duodenal resistance to the emptying of various solutions from the isolated cat stomach.

Experiments were conducted to determine to what extent the duodenum resists the emptying of various solutions from the isolated stomach. Cat stomachs were maintained in Krebs solution in vitro, and filled with 100 ml isotonic saline solution, isotonic glucose, hypertonic saline solution, hypertonic glucose, or dilute acid. Gastric pressure was constantly monitored; gastric output was collected constantly by a cannula in the proximal or distal duodenum. For all solutions, cumulative gastric output at all times was considerably less with the distal than the proximal cannula position. This difference was almost entirely caused by a smaller fractional gastric output during the first minute of gastric emptying, and by reduced amplitude of the gastric stroke volume with the distal cannula position. Some differences were observed in the gastric emptying rate for the various solutions; isotonic saline solution emptied particularly slowly and hydrochloric acid emptied particularly fast. In addition, the various solutions produced different gastric pressure patterns, which could not be entirely explained by differences in residual gastric volume. We concluded that the cat duodenum provides a resistance to gastric emptying over and above that generated by the pylorus, and that the duodenal resistance is caused by limitations in duodenal capacity. It is furthermore concluded that the mechanical activity of the isolated stomach and duodenum is affected by the chemical composition of their luminal contents.

Animals↗
PubMed2000

Intraesophageal acid perfusion sensitizes the esophagus to mechanical distension: a Barostat study.

OBJECTIVE: The pathogenesis of noncardiac chest pain is unclear. Increased gastroesophageal reflux and decreased pain thresholds to intraesophageal balloon distension have been demonstrated in a proportion of such patients. We aimed to investigate whether acid exposure sensitizes esophageal mechanoreceptors in healthy volunteers. METHODS: After an overnight fast, an infinitely compliant balloon, 4.5 cm in length and mounted on a multilumen transnasal manometry catheter, was placed 8.5 cm above the lower esophageal sphincter in 12 healthy male volunteers aged 18-39 yr. After determination of the minimal distending pressure, the balloon was inflated up to 48 mm Hg by means of a computer-controlled barostat (G & J Electronics, Canada). Graded stepwise distensions were interspersed with random decreases in pressure to two-thirds of the previous value. At each pressure level, the subjects were asked to report on sensation and the presence of pain. Baseline distension was repeated to determine reproducibility of the pressure/volume relationship and also the perception and pain thresholds. After the baseline distension sequence, the esophagus was perfused for 20 min (at 7 ml/min) with either normal saline (control) or 0.1 N hydrochloric acid at 37 degrees C on a random basis. RESULTS: Basal sensory thresholds varied widely (first perception 5-36 mm Hg, pain 8 > or = 43 mm Hg). Two subjects did not experience pain up to the maximum distending pressure (42 and 43 mm Hg, respectively, after correction for the minimal distending pressure). Esophageal body compliance was similar on repeat distension. Sensory thresholds were reproducible with different distensions (perception r = 0.99, pain r = 0.95). Saline resulted in no significant changes in perception or pain thresholds. Acid perfusion reduced first perception (median before and after acid, 15 mm Hg and 8 mm Hg, respectively, p = 0.05) and pain threshold (median before and after acid, 32.5 mm Hg and 26.5 mm Hg, respectively, p = 0.05). When compared to changes after saline perfusion, acid perfusion reduced the perception threshold (median change, -3.8 mm Hg vs 0 mm Hg, p = 0.04) and tended to reduce the pain threshold (median change, -3.75 mm Hg vs +0.75 mm Hg, p = 0.09). CONCLUSIONS: Intraesophageal balloon distension using a barostat is a reproducible method of measuring esophageal body compliance and sensory thresholds. Acute exposure to acid seems to sensitize the esophagus to perception from intraluminal balloon distension.

Adolescent↗
PubMed1986

Effect of dietary fiber on proteolytic pancreatic enzymes in vitro.

Chymotrypsin, trypsin, carboxypeptidase A and B, elastase and enterokinase activities were measured in buffer solutions and in human duodenal juice after incubation with wheat bran, cellulose, guar gum, pectin, psyllium and lignin. The different types of dietary fiber led to inhibition of enzymatic activity in most experiments, e.g., lignin could totally ablish the activity of isolated trypsin and chymotrypsin. Only in enterokinase was there no influence. Inhibition depended on incubation time; the effect was proportional to fiber concentration and inversely related to enzyme level. Treatment of fiber with hydrochloric acid (pH 1.5) and heat (95 degrees C) destroyed inhibitory activity in some experiments. The effect of lignin on one enzyme (trypsin) was reduced by the addition of another enzyme (chymotrypsin). It is concluded that dietary fiber could affect digestion by inhibiting proteolytic pancreatic enzymes.

Chymotrypsin↗