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[Burns from undisclosed acids in a liquid used by temporary workers. A recent problem in occupational medicine caused by a lack of information].

HISTORY: Two temporary labourers, on piece work without sufficient prior instructions, were employed to clean a house facade. During the work, at first limited to 5-10 minutes, they sustained chemical burns from the hydrofluoric and hydrochloric acids contained in the liquid used to clean the stone. Both workers had been left uniformed about the danger or kind of the material being used, because of their short-time employment. They only sought medical help several hours later. ADMISSION FINDINGS: At the areas of contact with the cleansing liquid (hands, lower arms and thighs, in case 1; additionally at first well circumscribed and very painful areas of erythema, developing within a few hours into blisters, in case 2; also erosions in both). INVESTIGATIONS: Chemical burns by hydrofluoric acid were only elucidated as the cause 24 hours after exposure. Repeat tests (ECG, blood gas analysis, electrolyte levels) provided no evidence of deep-seated burns at the contact areas or systemic poisoning. Radiology of the hand was normal. TREATMENT AND COURSE: As there was at first no indicative history, toxic contact dermatitis was suspected and treated topically with Clobetasol-17-propionate. Once the true cause became known treatment consisted of compresses with 10% calcium gluconate solution. All lesions healed completely within 4 and 6 days, respectively. INTERPRETATION: Temporary workers are often insufficiently instructed, despite clear legal regulations. Such lack of informations increases the risk of harm to workers and makes appropriate treatment more difficult.

Administration, Topical↗

Selection and optimization of hydrolysis conditions for the quantification of urinary metabolites of MDMA.

Recovery of 3,4-methylenedioxymethamphetamine (MDMA) urinary metabolites requires optimization of the hydrolysis of 4-hydroxy-3-methyoxymethamphetamine (HMMA), 4-hydroxy-3-methoxyamphetamine (HMA), and 3,4-methylenedioxyamphetamine (MDA) conjugates prior to chromatographic analysis. Acidic and enzymatic hydrolysis with beta-glucuronidase from Escherichia coli and Helix pomatia were evaluated. Acid hydrolysis yielded 40.0% and 39.3% higher HMA recovery compared to E. coli and H. pomatia hydrolysis, respectively (SE=9.8 and 11.4%). E. coli beta-glucuronidase hydrolysis MDA recovery was 17.1% and 26.5% greater than acid hydrolysis and H. pomatia beta-glucuronidase recovery (SE=3.3 and 6.1%), respectively. HMMA recovery by acid hydrolysis was 336.1% and 159.8% greater than E. coli and H. pomatia beta-glucuronidase (SE=72.8 and 31.6%), respectively. The effects of temperature, time, and acid amount on metabolite recovery were also evaluated. HMA and HMMA acid hydrolysis recoveries were improved at 100 degrees C and above. Effective hydrolysis could be conducted in a dry block heater, GC oven, or autoclave at temperatures from 100 to 140 degrees C. Optimal hydrolysis conditions for the measurement of MDMA metabolite conjugates were addition of 100 microL of hydrochloric acid to 1 mL urine and incubation at 120 degrees C in a GC oven for 40 min. Therefore, based on HMMA, HMA, and MDA recoveries, time efficiency, availability of instrumentation, and cost, acid hydrolysis was preferred to enzyme hydrolysis.

3,4-Methylenedioxyamphetamine↗

Effect of some organic acids in the incubation step on plasma renin activity.

The organic acids potassium hydrogen phthalate (KHphthalate), maleic, critic, acetic, formic, and oxalic were used to adjust the pH of plasma to 5.6 +/- 0.2 in the incubation step of the procedure for the determination of plasma renin activity (PRA). When compared to the PRA determined after pH adjustment with hydrochloric acid (HCl), it was found that KHphthalate and maleic acid produced a statistically significant increase in PRA. In comparison to HCl, KHphthalate and maleic acid showed a mean percent difference of 61% and 27% respectively for a one hour incubation; and, 57% and 34% respectively for a three hour incubation.

Acetates↗

Distinction of lower esophageal sphincter strength from sphincter competence.

Although an absolute correlation has been impossible to demonstrate, it has long been thought that the manometric magnitude of the lower esophageal sphincter pressure was a good index of lower esophageal sphincter strength, and hence its competence. To study this relationship, 12 adult mongrel cats were surgically fitted with gastric cannulas. The cats were studied by six-lumen, radially-oriented, rapid pullback manometry before and after administration of atropine, and before and after daily perfusion of the distal esophagus with 0.1 N hydrochloric acid. Lower esophageal sphincter strength was determined by the lower esophageal sphincter pressure vector cross-sectional area. This was computed by plotting the lower esophageal sphincter pressure on polar coordinates, and finding the area circumscribed by the vectors. Lower esophageal sphincter competence was determined by measurement of both the intragastric volume and intragastric pressure required to produce gross reflux. Atropine significantly decreased the mean lower esophageal sphincter pressure vector cross-sectional area from 7,963 +/- 2,469 mm Hg to 720 +/- 59 mm Hg (p less than 0.05) and decreased the mean lower esophageal sphincter opening pressure from 30.2 +/- 6.9 mm Hg to 13.2 +/- 4.1 mm Hg (p less than 0.05). However, acid perfusion significantly decreased the lower esophageal sphincter pressure vector cross-sectional area from 6,786 +/- 3,334 mm Hg to 715 +/- 720 mm Hg (p less than 0.05). This indicates that the lower esophageal sphincter has two components, one of which is acid-sensitive and both of which are atropine-sensitive.

Animals↗

Synchronous versus asynchronous differential lung ventilation with PEEP after unilateral acid aspiration in the dog.

Differential lung ventilation (DLV) with PEEP has been used to oxygenate patients with severe unilateral or asymmetrical lung disease. Many different ventilator systems have been used to deliver DLV, but the question of whether or not to synchronize the ventilation of the 2 lungs has not been answered. Twelve mongrel dogs were given a unilateral hydrochloric acid (HCl) injury and divided into 2 groups, one receiving synchronous and the other receiving asynchronous DLV. The assignment of synchronization and side of injury was allocated randomly. A computer-controlled DLV system was used to ventilate the dogs with equal tidal volumes to each lung. The respiratory rate was feedback controlled to maintain PaCO2 at 35 torr. After injury, 10 cm H2O of PEEP was applied to the injured lung and the dogs were ventilated with FIO2 = 0.40 for 4 h. There was no statistically significant difference in gas exchange ([PaO2, Qva/Qt, PaCO2, P(A-a)O2] or hemodynamics [mean arterial pressure (MAP), CVP, mean pulmonary arterial pressure (MPAP), mean pulmonary arterial wedge pressure (WP), cardiac output in triplicate (Q), heart rate (HR)] between the 2 groups. With this particular model, there is no need to synchronize the 2 ventilators when using DLV with unilateral PEEP.

Animals↗

A technique for removal of fluorosis stains.

Fluorosis stains can be removed permanently using the hydrochloric acid procedure described. The procedure is simple, results are immediate, and there is no patient discomfort.

Adolescent↗

Expressing and purifying an anti-atherosclerosis polypeptide vaccine in Escherichia coli.

A chimeric polypeptide of TTP-CETPC was successfully expressed as inclusion bodies in Escherichia coli by fusing it with the C-terminus of asparaginase and a basic amino acid-rich peptide (KR). After partially purified by washing with 0.5% (v/v) Triton X-100 in 10 mM PB, the pellet was solubilized in 8 M urea. The solution was precipitated with single volume and double volumes of cold ethanol for removing impurities. The fusion protein in solution was precipitated with triple volumes of ethanol to increase purity and then hydrolyzed with 50 mM hydrochloric acid at 55 degrees C for 72 h. The TTP-CETPC polypeptide was released after the unique acid-labile aspartylprolyl bond in the fusion protein was cleaved by acid. After impurities were removed by adjusting the hydrolysis solution pH to 9.45 and then to 8.37, the TTP-CETPC polypeptide was further purified by DEAE-cellulose column. The TTP-CETPC containing fractions were eluted at 60-80 mM NaCl. The purified TTP-CETPC cysteines were oxidized to form into intermolecular disulfide bonded dimers for immunizing mice. Specific anti-CETP antibodies in mice serum were assayed by ELISA and Western blot to verify that antibodies against CETP had been successfully induced and lasted for more than seventeen weeks in vivo.

Amino Acid Sequence↗

Tachykinins and airway microvascular leakage induced by HCl intra-oesophageal instillation.

Gastro-oesophageal reflux is a common clinical disorder associated with a variety of respiratory symptoms, including chronic cough and exacerbation of asthma. In this study, the potential role of acid-induced tachykinin release was examined in guinea pigs and rabbits, by examining the effects of the tachykinin NK1 and NK3 receptors antagonists (SR 140333 and SR 142801, respectively) (1-10 mg x kg(-1)) on plasma protein extravasation induced in airways by hydrochloric acid (HCl) infusion in the oesophagus. Guinea pigs were anaesthetised with urethane, while rabbits were subject to neuroleptoanalgesia with hypnorm. Airway vascular leakage was evaluated by measuring extravasation of Evans blue dye. All animals were pretreated with atropine (1 mg x kg(-1) i.p.), propranolol (1 mg x kg(-1) i.p.), phosphoramidon (2.5 mg x kg(-1) i.v.) and saline or tachykinin receptor antagonists (1-10 mg x kg(-1) i.p.). Infusion of 1 N HCl into the oesophagus led to a three- and five-fold increase in plasma extravasation in the main bronchi and trachea, respectively. This increase was largely prevented by the tachykinin NK1 and NK3 receptor antagonists SR 140333 and SR 142801 (1-10 mg x kg(-1)). These results suggest that protein extravasation in the airways, as induced by intraoesophageal HCl infusion, is mainly dependent on the release of tachykinins, and that both NK1 and NK3 tachykinin receptors are involved. The results suggest that HCl-induced sensory nerve stimulation may act in the periphery on intermediate neurons and/or ganglia where NK3 receptors have been shown to play an important role.

Animals↗

Loblolly pine and slash pine responses to acute aluminum and acid exposures.

In response to concerns about aluminum and HCl exposure associated with rocket motor testing and launches, survival and growth of full-sib families of loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) were evaluated in a nursery bed experiment. Each species was exposed to a single soil application of aluminum chloride (0.33 M AlCl(3), pH 2.5), hydrochloric acid (0.39 M HCl, pH 0.6) or water, with or without mycorrhizal inoculation with Pisolithus tinctorius (Coker and Couch). After 20 weeks without inoculation, survival in AlCl(3) and HCl treatments averaged 52% for loblolly pine and 72% for slash pine. Inoculation improved survival of loblolly pine, receiving HCl from 49 to 73%, and of those receiving AlCl3, from 55 to 90%. Inoculation also resulted in improved survival and growth of individual families in AlCl(3), but not in HCl treatments. Results illustrate the relative resistance of both pine species to the acute treatments supplied, the improvement in resistance associated with mycorrhizal inoculation and the importance of field testing, following hydroponic screening, to verify the resistance to soil-supplied stresses.

Aluminum Chloride↗

The binding of antihistone antibodies to Crithidia luciliae kinetoplasts is growth cycle-dependent.

The Crithidia luciliae immunofluorescence (CLIF) assay is widely used to test for native DNA (nDNA) antibodies in the diagnosis and management of systemic lupus erythematosus. However, sera from patients with drug-induced lupus erythematosus or rheumatoid arthritis, which should not contain nDNA antibodies, occasionally react with the CL kinetoplast. We examined 36 sera from patients with systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome, and drug-induced lupus erythematosus, who had positive CLIF tests. All 36 sera were also antinuclear antibody-positive with homogeneous and/or peripheral staining patterns on mouse kidney substrates. After hydrochloric acid extraction of the CL smears to remove histone and other nuclear protein antigens, 14 of the 36 sera no longer produced a positive result on the CLIF test. Ten of these 14 sera again gave a positive CLIF result after the hydrochloric acid-extracted Crithidia substrate had been reconstituted with purified histone. These studies demonstrated that kinetoplast binding was due to antihistone antibodies in at least 10 of 36 initially CLIF-positive sera. Antihistone antibodies were then purified with a histone-affinity column, and these purified antibodies were reactive with CL kinetoplasts. Thus, the CLIF test is not specific for nDNA antibodies. Additional studies using CL from different days of culture indicated that histone antigen expression in the CL kinetoplast was a function of the life cycle of this organism and is most readily detected 2 days after initiation of culture.

Animals↗

Imaging gastric pennies in children.

Pennies are among the most common foreign objects ingested by children. This occurrence has traditionally been managed conservatively. However, more recent studies indicate that the higher zinc composition of pennies produced after 1982 may be more dangerous than previously believed. We reported earlier the in situ reaction of such pennies following immersion in hydrochloric acid at gastric pH. The present study examines the utility of radiographic examination of such pennies.

Child, Preschool↗

Prediction of complications following caustic ingestion in adults.

The records of 86 adults admitted to hospital following caustic ingestion were reviewed. Eighteen patients (21%) developed complications; of these, six were fatal. Patients without symptoms or signs did not develop complications. Complications occurred only following lye ingestion, or intentional ingestion of hydrochloric acid or ammonia water. Of patients with such ingestion, and two signs or symptoms or more, 70% developed complications. Oesophagoscopy did not significantly improve the prediction of complications. There was a strong trend, however, for more severe complications with more severe submucosal, circumferential oesophageal injuries (P = 0.003). The study suggests that only adults with symptoms or signs following strong alkali or strong acid ingestion are at risk of complications. In adults who are symptomatic following ingestion of strong acid or alkali, oesophagoscopy is important to identify the potentially fatal transmural injuries.

Administration, Oral↗

Sensory-motor responses to mechanical stimulation of the esophagus after sensitization with acid.

AIM: Sensitization most likely plays an important role in chronic pain disorders, and such sensitization can be mimicked by experimental acid perfusion of the esophagus. The current study systematically investigated the sensory and motor responses of the esophagus to controlled mechanical stimuli before and after sensitization. METHODS: Thirty healthy subjects were included. Distension of the distal esophagus with a balloon was performed before and after perfusion with 0.1 mol/L hydrochloric acid for 30 min. An impedance planimetry system was used to measure cross-sectional area, volume, pressure, and tension during the distensions. A new model allowed evaluation of the phasic contractions by the tension during contractions as a function of the initial muscle length before the contraction (comparable to the Frank-Starling law for the heart). Length-tension diagrams were used to evaluate the muscle tone before and after relaxation of the smooth muscle with butylscopolamine. RESULTS: The sensitization resulted in allodynia and hyperalgesia to the distension volumes, and the degree of sensitization was related to the infused volume of acid. Furthermore, a nearly 50% increase in the evoked referred pain was seen after sensitization. The mechanical analysis demonstrated hyper-reactivity of the esophagus following acid perfusion, with an increased number and force of the phasic contractions, but the muscle tone did not change. CONCLUSION: Acid perfusion of the esophagus sensitizes the sensory pathways and facilitates secondary contractions. The new model can be used to study abnormal sensory-motor mechanisms in visceral organs.

Adult↗

Effects of metabolic alkalosis on pulmonary gas exchange.

In order to investigate whether the changes in PaO2 reported during acid-base disturbances are due to modifications of ventilation/perfusion relationships or only to extrapulmonary factors, we studied the hemodynamics and blood gases of eight critically ill patients maintained in constant mechanical ventilation, before and after selective correction of metabolic alkalosis by infusion of 1 N hydrochloric acid (HCl). HCl infusion decreased arterial pH from 7.55 to 7.40 (p less than 0.001) and increased PaO2 from 76 to 98 mm Hg (p less than 0.05) at the end of the study. Cardiac output and oxygen consumption did not change. In patients with initial venous admixture (QS/QT) less than 20% (n = 4), QS/QT did not change, and hemoglobin saturation decreased, whereas PaO2 increased from 87 to 96 mm Hg (p less than 0.10), indicating a shift in the oxyhemoglobin dissociation curve caused by the Bohr effect. In patients with QS/QT greater than 20% (n = 4), QS/QT decreased from 27 to 22% (p less than 0.05), hemoglobin saturation increased from 93 to 96% (p less than 0.05), and PaO2 increased from 65 to 100 mm Hg (p less than 0.05), which reflects an improvement in ventilation/perfusion relationships, probably because of enhanced hypoxic pulmonary vasoconstriction. These data indicate that metabolic alkalosis deteriorates pulmonary ventilation/perfusion relationships in patients with marked respiratory failure (QS/QT greater than 20%), and that reversing this effect with HCl infusion can improve PaO2 significantly.

Adult↗

Adverse effects of large tidal volume and low PEEP in canine acid aspiration.

When normal lungs are ventilated with large tidal volumes (VT) and end-inspired pressures (Pei), surfactant is depleted and pulmonary edema develops. Both effects are diminished by positive end-expiratory pressure (PEEP). We reasoned that ventilatory with large VT-low PEEP would similarly increase edema following acute lung injury. To test this hypothesis, we ventilated dogs 1 h after hydrochloric acid (HCl) induced pulmonary edema with a large VT (30 ml/kg) and low PEEP (3 cm H2O) (large VT-low PEEP) and compared their results with dogs ventilated with a smaller VT (15 ml/kg) and 12 cm H2O PEEP (small VT-high PEEP). The small VT was the smallest that maintained eucapnia in our preparation; the large VT was chosen to match Pei and end-inspired lung volume. Pulmonary capillary wedge transmural pressure (Ppwtm) was kept at 8 mm Hg in both groups. Five hours after injury, the median lung wet weight to body weight ratio (WW/BW) was 25 g/kg higher in the large VT-low PEEP group than in the small VT-high PEEP group (p less than 0.05). Venous admixture (Qva/Qt) was similarly greater in the large VT-low PEEP group (49.8 versus 23.5%) (p less than 0.05). We conclude that small VT-high PEEP is a better mode of ventilating acute lung injury than large VT-low PEEP because edema accumulation is less and venous admixture is less. These advantages did not result from differences in Pei, end-inspiratory lung volume, or preload (Ppwtm).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effect of temperature on chlorproguanil and proguanil hydrochloride solutions: a chemical stability study.

Chlorproguanil and proguanil hydrochloride solutions in 0.5 M hydrochloric acid, water and 1 M ammonium hydroxide were subjected to different temperatures (22-80 degrees C) for 68 h. The decomposition rate constants for chlorproguanil ranged from 1.60 to 47.6 x 10(3) h-1 in acid, 3.5 to 18 x 10(3) h-1 in water and 3.87 to 32.5 x 10(3) h-1 in base, between 50 degrees C and 80 degrees C. The activation energy Ea was 96.5, 52.12 and 62.1 kJ mol-1 in acid, water and base respectively. The proguanil decomposition rate constant ranged from 1.72 to 18.5 x 10(3) h-1 in acid, 1.58 to 9.67 x 10(3) h-1 in water and 2.34 to 15.77 x 10(3) h-1 in base, between 50 degrees C and 80 degrees C, with Ea values of 54.7, 73.3 and 62.5 kJ mol-1. Three unidentified degradation products were separated in the acid solution for each of the compounds. Chlorproguanil and proguanil are stable (t1/2 values over 30 days and up to 287 days respectively) in acid, water and base at temperatures below 22 degrees C.

Ammonium Hydroxide↗

Cardio-oesophageal reflex in humans as a mechanism for "linked angina'.

The aim of this study was to investigate the hypothesis that oesophageal acid stimulation reduces coronary blood flow in humans as a result of the presence of a cardio-oesophageal reflex which may provide a mechanism for "linked angina'. We studied the effect of oesophageal acid stimulation on coronary blood flow in 35 syndrome X patients and 24 heart transplant patients. A fine tube was positioned into the patient's distal oesophagus. An intracoronary Doppler catheter was positioned in the proximal left anterior descending coronary artery for coronary blood flow measurements. Oesophageal instillation of 0.1 M hydrochloric acid was performed (60 ml over 5 min) and the measurements were repeated. The coronary blood flow was significantly reduced by acid oesophageal stimulation in the syndrome X group [pre-acid 78.9 +/- 36.4 ml. min-1, post-acid 50.8 +/- 32.9 ml.min-1 (P = 0.0001)]. However, coronary blood flow in the heart transplant group, in whom the heart is denervated, was unaffected by acid infusion. We conclude that oesophageal acid stimulation can produce angina and significantly reduce coronary blood flow in humans. The lack of any significant effect in the heart transplant group, in whom the heart is denervated, suggests a neural reflex.

Adult↗