Effects of nozzle types and 2,4-D formulations on spray deposition.

The objective of this study was to evaluate the effects of nozzle types and 2,4-D formulations on spray deposition on different targets. Two field experiments were carried out in a completely randomized design, and treatments were arranged in a factorial scheme. Species in experiment 1 were Sumatran fleabane (Conyza sumatrensis) and Brazil pusley (Richardia brasiliensis) and in experiment 2 were soybeans (Glycine max) and Benghal dayflower (Commelina benghalensis). For both experiments, the first factor corresponded to spray nozzles with different settings (AD 110.015 - 61 and 105 L ha-1; AD 015-D - 75 and 146 L ha-1; XR 110.0202 - 200 L ha-1; and ADIA-D 110.02 - 208 L ha-1) and the second factor consisted of two formulations of 2,4-D (amine and choline). The formulation of 2,4-D choline has contained Colex-D™ Technology. Similar or higher spray deposition was observed on the leaves and artificial targets when using 2,4-D choline as compared to the 2,4-D amine formulation, and these differences in deposition were more evident for nozzles applying lower spray volumes. Deposition was more affected by nozzle type when amine formulation was used, compared to choline formulation.

Pancreatic cell tracing, lineage tagging and targeted genetic manipulations in multiple cell types using pancreatic ductal infusion of adeno-associated viral vectors and/or cell-tagging dyes.

Genetic manipulations, with or without lineage tracing for specific pancreatic cell types, are very powerful tools for studying diabetes, pancreatitis and pancreatic cancer. Nevertheless, the use of Cre/loxP systems to conditionally activate or inactivate the expression of genes in a cell type- and/or temporal-specific manner is not applicable to cell tracing and/or gene manipulations in more than one lineage at a time. Here we report a technique that allows efficient delivery of dyes for cell tagging into the mouse pancreas through the duct system, and that also delivers viruses carrying transgenes or siRNA under a specific promoter. When this technique is applied in genetically modified mice, it enables the investigator to perform either double lineage tracing or cell lineage tracing combined with gene manipulation in a second lineage. The technique requires <40 min.

Metabolism and disposition of [(14)C]dimethylamine borane in male Harlan Sprague Dawley rats following gavage administration, intravenous administration and dermal application.

1. Dimethylamine borane (DMAB) is used as a reducing agent in the manufacturing of a variety of products and in chemical synthesis. National Toxicology Program is evaluating the toxicity of DMAB in rodents following dermal application. The objective of this study was to evaluate the metabolism and disposition of DMAB in male Harlan Sprague Dawley (HSD) rats. 2. Disposition of radioactivity was similar between gavage and intravenous administration of 1.5 mg/kg [(14)C] DMAB, with nearly 84%-89% of the administered radioactivity recovered in urine 24 h post dosing. At 72 h, only 1% or less was recovered in feces, 0.3% as CO2, and 0.5%-1.4% as volatiles and 0.3%-0.4 % in tissues. 3. The absorption of [(14)C]DMAB following dermal application was moderate; percent dose absorbed increased with the dose, with 23%, 32% and 46% of dose absorbed at 0.15, 1.5 and 15 mg/kg, respectively. Urinary and fecal excretion ranged from 18%-37% and 2%-4% of dose, respectively, and 0.1%-0.2% as CO2, and 1%-3% as volatiles. Tissue retention of the radiolabel was low ∼1%, but was higher than following the gavage or intravenous administration. 4. Following co-adminsitration of DMAB and sodium nitrite by gavage, N-nitrosodimethylamine was not detected in blood or urine above the limit of quantitation of the analytical method of 10 ng/mL. 5. Absorption of DMAB in fresh human skin in vitro was ∼41% of the applied dose: the analysis of the receptor fluid shows that the intact DMAB complex can be absorbed through the skin.

Randomized controlled trial of the combined monoaminergic and opioid investigational compound GRT9906 in painful polyneuropathy.

GRT9906 is an investigational novel compound with µ-opioid receptor agonism and inhibition of noradrenalin/serotonin re-uptake. In this randomized, double-blind, placebo-controlled, three-way cross-over trial in painful polyneuropathy, the efficacy and safety of GRT9906 was assessed and compared with tramadol. During 4-week treatment periods, daily oral doses of either GRT9906 120-240 mg, or placebo, or tramadol 200-400 mg were given. These were separated by 1-week washout periods. The primary endpoint was the average pain intensity (average of daily current pain intensity over the last 3 days of each treatment period rated on a 0 to 10-point numeric rating scale). One hundred seventeen patients were enrolled and 64 were randomized to one of six treatment sequences. Forty-seven patients qualified for the per protocol analysis. GRT9906 reduced average pain intensity by 2.1 points compared with a reduction of 0.6 points on placebo (p < 0.0001) and 2.4 points on tramadol. GRT9906 also improved scores on the sleep problem scale and the neuropathic pain symptom inventory and scored better than placebo on the patient global impression of change. Numbers needed to treat to obtain one patient with more than 50% pain relief was 3.9 (95% CI 2.4-11.5) for both GRT9906 and tramadol. The most frequently reported adverse events were nausea, fatigue, constipation and sleep disorder for GRT9906 and tramadol. Four patients dropped out due to adverse events during both GRT9906 and tramadol treatment and two dropped out during placebo treatment. In conclusion, in painful polyneuropathy, GRT9906 demonstrated analgesic efficacy with a magnitude of effect comparable with tramadol and was well tolerated.

Additive impairment of the barrier function and irritation by biogenic amines and sodium lauryl sulphate: a controlled in vivo tandem irritation study.

Biogenic amines are potential irritants e.g. in fish-, meat-, milk- and egg-processing professions like cooks, butchers and bakers. The aim of this study was to test the irritative and barrier-disrupting properties of the biogenic amines ammonium hydroxide (AM), dimethylamine (DMA) and trimethylamine (TMA). A repeated sequential irritation of 30 min twice per day was performed over a total of 4 days (tandem repeated irritation test) on the back of 20 healthy volunteers of both sexes with AM, DMA, TMA and sodium lauryl sulphate (SLS). The epidermal barrier function was assessed with a Tewameter TM 210, stratum corneum surface pH was measured with a Skin-pH-Meter 900, inflammation was assessed with a Chromameter CR-300 on the a* axis for redness and a visual score was recorded. All tested biogenic amines (AM, DMA and TMA) induced a barrier disruption and a pH increase paralleled with a 1-day-delayed onset of inflammatory signs. These effects were further enhanced and accelerated by a sequential application of SLS together with the biogenic amines, and inflammation occurred earlier than with the single compounds. Acetic acid (AA) in contrast did only show mild barrier disruption and no significant inflammatory signs. Our system allowed a ranking of the different compounds in their irritative potential in the tandem irritation with SLS: SLS > NaOH > TMA > AA > AM > DMA. The results are suggestive that in the food-processing industry the simultaneous contact with biogenic amines and harmful detergents like SLS should be minimized.

Nebulized nitric oxide/nucleophile adduct reduces pulmonary vascular resistance in mechanically ventilated septicemic sheep.

OBJECTIVE: To study the effects of a novel, intermittently administered, aerosolized nitric oxide donor, methyl-N-2-dimethylaminoethyl-3-aminoproprionid/nitric oxide (DMDE-NO), on pulmonary hemodynamic responses to sepsis. DESIGN: Prospective, randomized, controlled study in awake sheep. SETTING: Investigational intensive care unit of a university medical center. SUBJECTS: Thirteen instrumented merino ewes weighing 36 +/- 0.9 kg underwent a hemodynamic study 1 wk postoperatively. INTERVENTIONS: On the day of the experiment, the sheep received a tracheotomy and mechanical ventilation was subsequently started. Pseudomonas aeruginosa bacteria were infused intravenously, beginning at time 0 hrs and continuing throughout the 48-hr experiment. The animals were randomly assigned to receive nebulized DMDE-NO 1 mg/kg, dissolved in 8 mL of saline (DMDE-NO group, n = 7), or nebulized saline alone (control group, n = 6) delivered by a nebulizer. The nebulizations started at 2, 6, 20, 24, and 43 hrs after the baseline, each time lasting for 1 hr. MEASUREMENTS AND MAIN RESULTS: Inhaled aerosolized DMDE-NO reversibly reduced the sepsis-induced increase in pulmonary artery pressure by 13-17% and pulmonary vascular resistance index by 21-31% compared with the values registered before the administration of the drug. Systemic hemodynamics underwent an early hypodynamic phase followed by a gradual increase in cardiac index and a decrease in both mean arterial pressure and systemic vascular resistance index, but with no significant difference between groups. Gas exchange variables and plasma nitrite/nitrate did not differ significantly between groups either. CONCLUSIONS: In sheep, inhaled nebulized DMDE-NO reduces sepsis-induced changes in pulmonary hemodynamics with no change in systemic hemodynamics or gas exchange.

Synthesis and inhibitory activity of dimethylamino-chalcone derivatives on the induction of nitric oxide synthase.

A series of nine dimethylamino-chalcone derivatives (1,3-diaryl-propenones) was synthesized and screened as potential inhibitors of NO and PGE(2) production in the RAW 264.7 macrophage cell line. 4-Dimethylamino-2',5'-dimethoxychalcone (6) was found to be the most potent and dual inhibitor (IC(50s) in the submicromolar range) of NO and PGE(2) production. 2',6'-Dimethoxylation appeared to be an effective requirement for selective and potent inhibition of nitric oxide synthase induction as it was confirmed by Western blot analysis. Chalcone (6) at 25 mg kg(-1) by oral route, inhibited significantly the formation of oedema in the carrageenan-induced model of inflammation in mice.

Toxicity and pharmacokinetics of 2-(2-dimethylaminoethoxy)ethanol following cutaneous dosing.

A 9-day repeated cutaneous toxicity study in the New Zealand White rabbit was conducted using 6-h occluded contact with 0 (water control), 50, 250 and 500 mg dimethylaminoethoxyethanol (DMEE)/kg. There were no clinical signs, and no effects on body weight, food consumption or serum chemistry. Hematological effects were limted to increased leukocyte count due to heterophil leukocytosis, increased platelet count, and decreased hemoglobin and hematocrit at the high dose. These findings are typical of the response of cutaneous inflammation. Histopathological findings were limited to the DMEE-treated skin, and consisted of acanthosis and ulcerative/necrotizing dermatitis. Thus, there was no evidence for cumulative percutaneous systemic toxicity for DMEE. The pharmacokinetics of DMEE was investigated in the Fischer 344 rats. Rats were given an intravenous dose of 15 or 150 mg/kg, or an occluded cutaneous dose of 150 mg/kg [14C]DMEE, and its fate was followed for 48-72 h. DMEE was readily absorbed through the skin (bioavailability=72-80%). Concentration in plasma rose steadily to a maximum at about 3.5 h after dosing, and then declined in a biphasic manner. 14C-DMEE-derived radioactivity was distributed throughout the body, with no apparent sequestration in any particular organ. The highest concentrations were observed in the kidney, liver and lung, and the lowest concentrations were found in the brain and fat. Urine was the major route of excretion, with minor amounts eliminated in the feces and as expired CO(2). The rate of excretion was moderate, with about 30% of the applied dose eliminated in the first 12 h, and by 72 h after dosing, less than 4% of the dose remained in the carcass. Unchanged DMEE was the principal component detected in the urine. This observation, together with the less than 1% of the dose excreted as CO(2), showed that metabolism was not an important process in the elimination of DMEE in the rat.

Percutaneous absorption of salicylic acid, theophylline, 2, 4-dimethylamine, diethyl hexyl phthalic acid, and p-aminobenzoic acid in the isolated perfused porcine skin flap compared to man in vivo.

Human risk assessment for topical exposure requires percutaneous absorption data to link environmental contamination to potential systemic dose. Human absorption data are not readily available, so absorption models are used. In vitro diffusion systems are easy to use but have proved to be somewhat unreliable and are not validated to man. This study compares percutaneous absorption in the isolated perfused porcine skin flap (IPPSF) system with that in man in vivo. The study design utilized the same compounds and the same dose concentration and vehicle in both systems. Methodology for each system was that which is routinely used ineach system. The skin surface was not protected during the absorption dosing period. Percutaneous absorption values were, for man and the IPPSF system, respectively: salicylic acid (6.5 +/- 5.0%; 7.5 +/- 2.6%), theophylline (16.9 +/- 11.3%; 11.8 +/- 3.8%), 2,4-dimethylamine (1.1 +/- 0.3%; 3.8 +/- 0.6%), diethyl hexyl phthalic acid (1.8 +/- 0.5%; 3.9 +/- 2.4%), and p-aminobenzoic acid (11.5 +/- 6.3%; 5.9 +/- 3.7%) (correlation coefficient was 0.78; p < 0.04). The skin surface wash recovery postapplication was similar for salicylic acid in man (53.4 +/- 6.3%) and the IPPSF system (48.2 +/- 4.9%). With the other compounds the majority of surface chemical was recovered in the surface wash and skin tape strip in the IPPSF system. With man, other than salicylic acid, only a few percent applied dose was recovered with surface washing and tape stripping. Since the wash procedure was effective with pig skin, we can assume that these chemicals in man were lost to adsorption to any clothing or bedding with the volunteers. The absorption in man was not less than that in the IPPSF. Assuming the dose was lost in man, it seems plausible that whatever compound was to penetrate human skin in solvent vehicle did so in the period of time before the chemical was removed. The IPPSF system appears to be a good model for predicting percutaneous absorption relative to man. This study design should be used to validate other systems to humans in vivo.

[Effect of n-nitrosodimethylamine (NDMA) on activity of selected enzymes in blood serum of the rat]. / Wplyw n-nitrozodimetyloaminy (NDMA) na aktywnosc wybranych enzymów w surowicy krwi szczura.

Changes in the activity of GOT, GPT, AP and GGTP in blood of rats intoxicated by low doses of N-Nitrosodimethylamine (NDMA) are presented. A significant increase in the activity of GOT and GPT was found after single doses (20 micrograms/kg b.w.) of NDMA as well as a significant increase in the activity of GOT, GPT, AP and GGTP after a prolonged intoxication per os by doses of 20 micrograms/dm3 given in drinking water.

Effects of repeated oral doses of Dikamin D (2,4-D-amine Na) on rats.

The toxic effects of repeated, increasing oral doses of Dikamin D (72% 2,4-D-amine Na), a broad leave herbicide product used world-wide, were evaluated on rats by the method of Lim et al. (1961). A comparison of the determined acute oral LD50 and the calculated subchronic oral LD50 values revealed a definite tolerance of the experimental animals to the test compound. This finding indicates that repeated oral treatment is capable of increasing the test animal's metabolizing capacity, which accounts for the development of tolerance.

Fate of dimethylamine in man.

1. The fate of [14C]-dimethylamine was investigated following oral administration to four male volunteers. 2. The major route of excretion was urine, with 94% of the administered radioactivity being voided over 3 days (87% during the first 24 h). Small amounts (1-3%) of radioactivity were found in the faeces and expired air. 3. Metabolism was limited with only 5% being demethylated to methylamine. The remainder of the dose was excreted unchanged. 4. Pharmacokinetic studies indicated rapid (t1/2ab = 8 min) and extensive absorption (bioavailability = 82%) from the gastrointestinal tract followed by widespread distribution and a fairly prompt excretion (t1/2el = 6-7 h) with a plasma clearance of 190 ml/min.

Percutaneous penetration of 2,4-dichlorophenoxyacetic acid and 2,4-D dimethylamine salt in human volunteers.

The percutaneous penetration of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-D dimethylamine salt (DMA) was evaluated separately in five male volunteers who participated in both experiments. Urine samples collected for 144 h following dermal applications of 10 mg to the dorsum of the hand (9 cm2) were analyzed for 2,4-D. Following the acid application, an average of 4.46 +/- 0.849% was recovered in the urine and a significantly lower amount of 1.76 +/- 0.568% following the DMA application. Significantly higher amounts of 2,4-D DMA (7.68 +/- 0.493 mg) were washed off the hand 6 h following application as compared with 2,4-D acid (5.35 +/- 0.384 mg). These results indicate that, in addition to the differences in physical and chemical properties of the two compounds that will affect absorption, the amount of the chemical absorbed is related inversely to the amount of washed off. Urinary excretion of 2,4-D was not complete in all volunteers 144 h following either application, but in all cases it was approaching the limit of detection. An average of 84.8 +/- 2.55% and 76.8 +/- 8.05% of the total recovered in 144 h was recovered in the urine 96 h following 2,4-D acid and 2,4-D DMA application, respectively. Average, approximated half-lives for excretion were 39.5 +/- 8.1 h for the acid application and 58.5 +/- 13.2 h for the DMA application.

Dermal absorption of the phenoxy herbicide 2,4-D dimethylamine in humans: effect of DEET and anatomic site.

Percutaneous absorption of the 14C-ring-labeled phenoxy herbicide 2,4-D-amine (2,4-dichlorophenoxyacetic acid dimethylamine) was examined following topical applications of the herbicide to the palm and forearm of human volunteers. The effect of two vehicles (water and acetone) and the mosquito repellent DEET (N,N-diethyl-m-toluamide) on dermal absorption of 2,4-D-amine also was investigated. The total percent dermal absorption was calculated from the mean percent urinary recoveries and was not corrected for nonurinary excretion. The data revealed 14 +/- 4.5% (standard deviation) and 10 +/- 11.5% palmar absorption of 2,4-D-amine applied in water, with and without DEET, respectively, and 7 +/- 6.2% and 13 +/- 5.0% forearm absorption of the herbicide applied in water or acetone, respectively. Soap-and-water skin washes conducted at 24 h posttreatment removed up to 34% of the applied dose. Successive tape strips of skin taken at 24 h posttreatment demonstrated generally decreasing herbicide levels in the outer layers. The data bring into question the complete validity of the rhesus monkey model to predict human dermal absorption.

Effects of skin preapplication treatments and postapplication cleansing agents on dermal absorption of 2,4-dichlorophenoxyacetic acid dimethylamine by Fischer 344 rats.

Various methods of preparing dermal application sites in Fischer 344 rats prior to exposure to 2,4-dichlorophenoxyacetic acid dimethylamine salt (2,4-D amine) and the effect of various cleansing agents following exposure were examined by measuring recoveries of 14C-labeled 2,4-D amine in skin, postapplication cleansing solution, blood, and urine. The middorsal area of the rat was the site of application for four treatments tested: (1) hair clipping only, (2) hair clipping followed by an epilatory cream, (3) hair clipping plus shaving with an electrical razor, and (4) as in treatment 3 followed by washing with soap and water. A last preparation was the rat's tail thoroughly brushed with soap and water. The results indicated that the tail retained greater than 75% of the material, thus preventing its absorption into the blood stream and subsequent removal by cleansing. With treatment 1 the dense short hair remaining after clipping impaired the absorption of 2,4-D as evidenced by considerably lower blood and urinary levels than treatments 2-4. With preparations 1-4, 45-61% of the dose was removed with the 7-h postapplication cleansing and a further 5-6% with the subsequent 23-h cleansing. In other studies using preparation 3 above, the following cleansing agents were tested: soap and water, water, isopropanol, acetone, and Rad-Con, a foam-producing cleanser. Rad-Con removed more 2,4-D from the skin than other cleansing agents after 7 h of exposure and more than soap and water after 23 h. The percentages of 2,4-D left on the skin following either 7- or 23-h cleansing with Rad-Con were 8-12%, nearly half those following the other cleansing agents. Cleansing agents other than Rad-Con presented little advantage over soap and water. With all cleansing agents, delaying cleansing from 7 to 23 h after exposure resulted in higher blood and urinary levels of 2,4-D measured 24 h after application.

The acute toxicity of tris(dimethylamino)silane.

The acute handling hazards of tris(dimethylamino)silane [TDMAS] were investigated. The acute male rat peroral LD50 (with 95% confidence limits) was 0.71 (0.51-0.97) ml/kg, and the acute male rabbit percutaneous LD50 was 0.57 (0.35-0.92) ml/kg. The liquid was severely irritating to the rabbit eye and skin, and the vapor severely irritating to the rat eye. The dynamically generated saturated vapor Lt50 in female rats was 12 (9.7-15) min. The effect of varying the atmospheric concentration of vapor from TDMAS on acute inhalation toxicity was investigated by passing ordinary moist air countercurrent to liquid TDMAS metered into a slightly heated glass tube. Based on nominal concentrations, the 4 hr-LC50 for vapor from TDMAS was 734 (603-893) ppm in female rats by this procedure. Stoichiometrically, this accords with toxicity due to liberation of dimethylamine (DMA) from TDMAS. In a subsequent study designed to assess the influence of relative humidity on vapor toxicity, nitrogen was passed over heated liquid TDMAS and the resultant atmosphere was introduced into the air intake duct of the inhalation exposure chamber. Gas chromatographically measured TDMAS concentrations (+/- SD) were 395 +/- 111, 127 +/- 25, 62 +/- 8 and 23 +/- 21 ppm; the corresponding DMA vapor concentrations were 112 +/- 171, 31 +/- 43, 10 +/- 6 and 26 +/- 44 ppm. The 4-hr LC50 (males and females) was 38 (34-43) ppm TDMAS vapor. Thus, TDMAS is of moderate acute peroral and percutaneous toxicity, a severe primary skin and eye irritant, an aspiration hazard, and of high intrinsic acute inhalation toxicity, but in moist air conditions lethal toxicity may be reduced and in such circumstances DMA may be a significant factor in toxicity.

Neurotoxicologic examination of rats dermally exposed to 2,4-D amine for three weeks.

There was no evidence of peripheral neuropathy or other neurotoxicity in rats dermally treated with a 12% aqueous solution of the amine salt of 2,4-dichlorophenoxyacetic acid (2,4-D amine). Male and female Fischer 344 rats were treated on the skin of all four limbs with 2,4-D amine for 2 hr/day, 5 days/week, for 3 weeks. Measurements were: body weights, hindlimb grip strength, accelerating rod performance, single and paired pulse electrophysiology of the caudal and sciatic nerves, hindfoot H-reflexes, light microscopy of brain, spinal cord, sciatic nerve, tibial nerve, digital nerve, and electron microscopy of the tibial nerve. The experiment continued for up to one month postexposure. Treatment caused a weight loss in both male and female rats and caused minor skin changes during treatment in both sexes. No other treatment-related effects were found.

[Effect of small amounts of 2,4-dichlorophenoxyacetic acid derivatives on thiamine and riboflavin metabolism in the animal body]. / Vliianie malykh kolichestv proizvodnykh 2,4-dikhlorfenoksiuksusnoi kisloty na obmen tiamina i riboflavina v zhivotnom organizme.

Administration of the herbicide 2,4-DN (amine salt of 2,4-dichlorphenoxyacetic acid) to weanling rats in a dose of 1/20.000 and 1/2000 of the LD50 for 3 months brought about a 40-50% reduction of thiamine content in the organs and tissues of experimental animals as compared with control. The herbicide was introduced into a balanced formula diet. In the liver of rats given 2,4-DA, there was a 2-fold decrease in the content of flavine adeninedinucleotide, whereas the content of flavine mononucleotide showed a 2-fold rise. Besides, the rats given a lesser herbicide dose manifested a reduced excretion of riboflavine with urine, and an inhibition of liver succinate dehydrogenase. The same animals demonstrated an increase in the relative mass of the adrenals with a concurrent diminution in them of ascorbic acid content.

In vivo stability of nitrite and nitrosamine formation in the dog stomach: effect of nitrite and amine concentration and of ascorbic acid.

Formation of N-nitrosodimethylamine (NDMA) from the precursors nitrate and dimethylamine has been studied in the chronically fistulated dog stomach. Measurements have also been made as a function of time for nitrite stability and gastric pH, and a nonabsorbable marker has been used to correct for gastric emptying and dilution. In the fasting animal NDMA forms within minutes after addition of the reactants if the pH is below 5. The presence of food in the stomach slows the reaction, and the additional presence of ascorbic acid greatly depresses the amount of NDMA formed. The concentration of nitrite in gastric juice declines rapidly after its introduction, but the concentration of NDMA declines even more rapidly than nitrite. This suggests that NDMA is probably rapidly absorbed directly from the dog stomach, in contrast to earlier results in rodent experiments.