Urinary Ascorbic Acid Research Articles

Ascorbic acid and glucose can cause significant interference on quantitative measurement of biochemistry analytes in urine.

Preanalytical errors due to interferences can lead to inaccurate results, necessitating an understanding of potential interferences for each test. This study explores the impact of elevated concentrations of ascorbic acid and glucose on urine analysis, a pivotal diagnostic tool. Conducted at the Clinical Institute of Chemistry, KBC Sestre milosrdnice, the research utilized a 24-hour urine sample. Parameters assessed included total proteins, albumin, amylase, sodium, potassium, chlorides, calcium, phosphates, magnesium, creatinine, urea, and uric acid. Various concentrations of added interferents were prepared for duplicate measurements using statistical analysis in Microsoft Excel. No statistically significant interferences were found in albumin, amylase, sodium, potassium, or phosphate concentrations. However, ascorbic acid interfered with chloride, calcium, and magnesium determinations. Conversely, elevated glucose affected total protein, calcium, magnesium, creatinine, urea, and uric acid determinations. Interference of ascorbic acid with chloride and interference of glucose with total proteins and uric acid displayed a linear relationship. Results suggest cautious analysis interpretation from certain parameters in patients with elevated glucose and/or ascorbic acid in urine. Whereas ascorbic acid interference may go unnoticed due to its infrequent measurement, routine determination of glucose in urine is crucial, especially for diabetes patients.

Suppressive Effect of Apple Juice Intake on Urinary Excretion of Ascorbic Acid: Unblinded Randomized Crossover Study in Healthy Japanese Subjects.

Ascorbic acid is essential for human health. As this vitamin is water-soluble, it cannot be stored in the body for a long time and is easily excreted in urine; therefore, it is necessary to ingest it in sufficient amounts every day. The fact that apples retain ascorbic acid in human bodies are known; however, this has not been experimentally demonstrated/documented. In this study, to clarify the effect of apple juice ingestion on the urinary excretion of ascorbic acid, we compared urinary ascorbic acid excretion in healthy women administered ascorbic acid alone or with apple juice. The experimental design was an unblinded randomized crossover study. Subjects ingested ascorbic acid in apple juice or ascorbic acid with water. Urine was collected after ingestion, and urinary ascorbic acid was measured. When ascorbic acid was ingested with apple juice, urinary excretion of ascorbic acid was significantly suppressed compared to when ascorbic acid was ingested alone. This suggests that apple juice intake can help retain ascorbic acid in the body.

Effects of Daily Ingestion of Two SunGold Kiwifruit for 6 Weeks on Metabolic and Inflammatory Biomarkers: A Randomized, Cross-Over, Exploratory Intervention Study.

Kiwifruit contain many components, some considered beneficial, such as vitamins, phytochemicals and dietary fibre, and others potentially harmful, such as fructose and glucose in fruit sugars. In a 6-week, randomised, crossover study aimed at exploring the net effects of daily consumption of kiwifruit, 23 healthy participants consumed two Actinidia chinensis var. chinensis 'Zesy002' (marketed as Zespri™ SunGold™ Kiwifruit) per day as part of their customary diet (intervention) or without kiwifruit (control) as their customary diet for 6 weeks in a cross-over study. Anthropometric data, venous blood, and urine samples were collected at the start and end of the 6-week intervention and control periods for the measurement of physical changes, plasma glucose, insulin, glycated haemoglobin, short-chain fatty acids, blood lipids, uric acid, inflammatory biomarkers, and urinary ascorbic acid. Variables were measured between the start and finish of interventions, and between intervention and control periods. Food diaries were completed on the 3 days before blood sampling to estimate dietary ascorbic acid and dietary fibre intakes. Despite urinary vitamin C and food diaries indicating compliance, and good precision in measurements, there were no appreciable changes in biomarkers during the study, either within or between intervention and control periods, that would indicate a change in health status. Thus, the sizes of any effects of kiwifruit ingestion were too small to become significant under the test conditions used, indicating a high probability that daily ingestion of two SunGold kiwifruit is safe with respect to metabolic health.

Detection of trace ascorbic acid in urine by “inhibition” fluorescent sensor based on periodate and highly luminescent N, B co-doped carbon dots

Herein, we presented an ingenious method for the detection of trace ascorbic acid (AA) using fluorescent sensing system, which was composed of periodate (IO4−) and nitrogen-boron co-doped carbon dots (N, B-CDs). Highly photoluminescent carbon dots with a quantum yield of 84.5% were synthesized by a one-step hydrothermal method using citric acid, ethylenediamine and boric acid as raw materials. The fluorescence of N, B-CDs could be statically quenched by IO4−, and non-fluorescent complexes were formed on the surface of carbon dots at the same time. With the pre-addition of ascorbic acid, the process of fluorescence quenching by IO4− was inhibited due to the preferential redox reaction between AA and IO4−. Based on the principle mentioned above, we designed the “inhibition” fluorescent sensor that can easily realize the detection of AA, and an extremely low limit of detection of 0.035 nM with a linear interval of 0–1600 pM was obtained. In addition, the sensing system has been applied to the detection of AA in human urine and obtained satisfactory results. The developed “inhibition” fluorescent sensor with high sensitivity and selectivity, has shown great potential and application prospects in the field of biosensing.

UDP Glucuronosyltransferase Gene Expression is Involved in the Stimulation of Ascorbic Acid Biosynthesis by Xenobiotics in Rats

Wistar-Shi (genotype +/+), heterozygous Gunn (j/+) and homozygous Gunn (j/j) rats was injected intraperitoneally with 3-methylcholanthrene (3MC) dissolved in corn oil. In rats of all genotypes the hepatic concentration of UDP glucuronosyltransferase (UDPGT) mRNA was increased at 48 and 96 h after the treatment with 3MC. Hepatic activity of 4-nitrophenol UDPGT was increased by 3MC in Wistar-Shi rats and heterozygous Gunn rats but not in homozygous Gunn rats. Urinary ascorbic acid excretion increased 72 and 96 h after the injection with 3MC in Wistar-Shi and heterozygous Gunn rats but not in homozygous Gunn rats. Ninety-six hours after the injection with 3MC, the hepatic concentration of ascorbic acid in Wistar-Shi rats was 90% higher than that in the corresponding control group, whereas in heterozygous and homozygous Gunn rats the increases were 70 and 30%, respectively. Wistar-Shi rats and homozygous Gunn rats were also injected daily for 3 d with sodium phenobarbital. In rats of both genotypes, the activity and hepatic concentration of chloramphenicol-UDPGT mRNA and liver and urine ascorbic acid concentration were increased by sodium phenobarbital. The data indicate that the stimulation of the expression of both the 4-nitrophenol and chloramphenicol UDPGT genes plays a key role in the ascorbic acid biosynthesis induced by 3MC and sodium phenobarbital.

Ascorbic acid in urine still compromises urinalysis results.

Background The aim of this work was to determine the frequency of ascorbic acid-positive urine samples and to evaluate the potential risk on patient safety. Materials and methods A total of 27,856 samples submitted for urinalysis in previous year were retrospectively analysed from the laboratory information system. Urinalysis was done on Iris IQ200 analyzer using 11-parameter iChem Velocity test strips. Risk analysis combined the impact of potentially erroneous results (due to ascorbic acid interference) on patient safety (severity – S) with their frequency (occurrence – O). Potential risk was identified as high, intermediate and low. Results One thousand one hundred and ninety-nine (4.3%) and 1646 (5.9%) samples were mildly (20 mg/dL, 1+) and highly positive (40 mg/dL, 2+) for ascorbic acid, respectively. Severity (S1 to S5) was assigned to four possible errors: false-negative glucose (U-Glc: S2), blood (U-Hb: S5), nitrite (U-Nit: S4) and bilirubin (U-Bil: S1). Based on the frequency of errors, occurrence was categorized as: O2 for U-Glc, and O3 for U-Bil, U-Nit and U-Hb. The risk analysis matrix revealed that false-negative U-Hb was associated with potentially high risk, false-negative U-Nit with intermediate risk, while false-negative U-Glc and U-Bil were associated with low risk on patient safety. Conclusions Positive ascorbic acid can cause potentially high risk for patient safety by missing positive blood in urine.

A fast, sensitive, single-step colorimetric dipstick assay for quantifying ascorbic acid in urine

The presence of ascorbate in human urine has been shown to be a useful dietary, fruit or vitamin C intake biomarker. More recently it has been discovered that ascorbate levels in urine can be used to facilitate the detection of precancerous colorectal polyps. While there are a number elaborate HPLC, MS or multi-step enzymatic “kit” methods to detect and quantify urinary ascorbate, these are time consuming and expensive. There are also a number of low-cost paper-based ascorbate detection dipsticks. However, the limits of detection and quantification accuracy for these dipsticks are not adequate for applications with human urine. To address these limitations, we have developed a fast, sensitive, single-step colorimetric assay that can be used to quantify ascorbate in urine and other biological fluids. The assay uses the tetrazolium salt, methylthiazolyldiphenyl-tetrazolium bromide (MTT), with the electron carrier phenazine methosulfate (PMS), in a chelated acidic phosphate-buffer to produce a vivid purple color in the presence of ascorbate. Confirmation of the performance of the assay and of its standard curve in human urine was also done using independent LC-MS/MS and NMR analyses. The lower limit of detection of the ascorbate dipstick assay described here was found to be 3.2 μM. The paper dipsticks are stable over a wide range of temperatures and can be stored for up to 150-days.

Assessment of еnergy expenditure and energy intake of the military institute of physical training cadets associated with their academic and professional activities

High energy expenditure of daily activity of cadets trained at the Military Institute of Physical Training sets certain demands for cadets’ diet and correspondence of energy and nutrition value of the diet to energy expenditure. Calculated data on energy expenditures of daily routine activities of the Military Institute of Physical Training cadets, energy costs of academic training and sport-related activities are presented. Along with energy expenditure another issue of balance, namely energy intake, is considered. Calculated findings on nutrition and caloric value of a cadets’ food ration and the Military Institute of Physical Training cadets’ diet and energy consumption of cadets are presented. It is shown that cadets’ diet corresponds to average energy expenditure. A comparison of the energy value of the daily ration of cadets and their energy expenditure revealed that the food ration compensates the average energy expenditure. The exceptions are intensive training in the framework of improving athletic skills (2 trainings per day), as well as periods when individual training takes place at the same time with high energy expenditures of a daily routine (for example, snow cleaning). In these cases daily energy expenditure (up to 5000 kcal) was recorded, exceeding the energy cost of food rations and requiring increased energy supply. In addition, the vitamin status of cadets was investigated. No signs of vitamins deficiency in the food ration were revealed. However, in the spring period, a decrease in the content of ascorbic acid in urine is shown in 80% of the subjects.

Ascorbic acid deficiency in patients with lichen planus

ABSTRACTObjectives. Recent studies have highlighted the role of oxidative stress in the pathogenesis of lichen planus (LP). In the present study, the interest of the authors is focused on the investigation of ascorbic acid status in patients with LP and identification of parameters that might influence the level of this vitamin.Material and method. We analyzed the level of urinary ascorbic acid (reflectometric method) in 77 patients with LP (cutaneous LP (CLP)—49 cases; oral LP (OLP)—28 cases) and 50 control subjects. The evaluation of all participants included clinical examination and laboratory and imaging tests.Results. Compared to the control group (19.82 mg/dl) the level of ascorbic acid was significantly lower both in patients with CLP (8.47 mg/dl, p = 0.001) and in those with OLP (8.04 mg/dl, p = 0.001). In patients with LP it was found that the deficiency of ascorbic acid increases with age (r = -0.318, p = 0.032). The urinary concentrations of ascorbic acid were significantly lower in patients with LP associated with infections compared to patients with LP without infections.Conclusions. The urinary ascorbic acid level may be a useful parameter in identifying patients with LP who are at risk of developing viral or bacterial infections.

Polymeric nanoparticle of copper(II)-4,4′-dicyanamidobiphenyl ligand: Synthetic, spectral and structural aspect; application to electrochemical sensing of dopamine and ascorbic acid

In this research, new polymer of 4,4′-dicyanamidobiphenyl (bpH2)-Cu(II) complex, [Cu(bp)(H2O)2]n, has been synthesized and characterized by FT-IR, UV–vis spectroscopy and elemental analysis. The spherical morphology of Cu nanoparticles was confirmed by scanning electron microscopy (SEM) image and the transmission electron microscopy (TEM) image showed that the particle size dimensions of Cu nanoparticles were about 80nm. Thermal gravimetric analysis (TGA) results indicated that this polymer was thermally stable. Hence, the prepared polymer was used as a modifier for the electrochemical determination of dopamine (DA) and ascorbic acid (AA). Compared to the bare carbon paste electrode (CPE) and multiwall carbon paste electrode (CNTPE), bpCu modified CPE (bpCu-CPE) exhibits much higher electrocatalytic activities toward the oxidation of dopamine and ascorbic acid with an increase in peak currents and a decrease in oxidation overpotentials. The effects of scan rate, concentration and pH were also studied. Differential pulse voltammetry results show that DA and AA could be detected selectively and sensitively at bpCu-CPE with peak-to-peak separation of 200mV. Relative standard deviations for AA and DA determinations were less than 2.5%, and the linear response ranges of the electrode were 0.05–30.0μmolL−1 for AA and DA, respectively. The calculated detection limits were 0.02 and 0.04μmolL−1 (S/N=3) for AA and DA, respectively. In addition, the presented method was successfully applied for the simultaneous determination of DA and AA in urine and blood samples with reliable recovery.

Simultaneous detection of dopamine and ascorbic acid in urine using the H-point standard addition method

A highly sensitive H-point standard addition method (HPSAM) was investigated for identification of dopamine and ascorbic acid in some synthetic and pharmaceutical samples in an aqueous medium at pH 9.2 using a universal buffer. The most suitable wavelengths for dopamine and ascorbic acid detection are 260:271 nm and 248:270 nm respectively. Recovery values are between 99.0–101 %. Also, the effect of most common interferents was studied. Detection ranges for dopamine and ascorbic acid are 2·10–6–5·10–5 M and 6·10–6–3·10–5 M respectively with an RSD range between 1.3 and 2.0 %. The method was used to determine both reagents in real and synthesized samples.

Ascorbic Acid Levels in Various Tissues, Plasma and Urine of Mice during Aging

Here we quantified ascorbic acid (AA) levels in 14 tissues, plasma and urine of C57BL/6 male mice to track its turnover during 3 to 30 mo of aging. The AA content of adrenal glands and testes decreased somewhat with age, and eventually rose, but increased in the spleen, lungs, eyes and heart. AA levels rose in the liver, skin and skeletal muscles from 6 to 12 mo of age, but declined from 12 to 24 mo. In the cerebellum, cerebrum, small intestine, kidney and plasma, amounts of AA remained almost constant as the animals aged. Most notably, urinary AA decreased markedly until becoming almost undetectable at 24 and 30 mo of age. Collectively, these results, which compare changes in AA levels in specific physiologic targets throughout the aging process, strongly suggest that the AA synthesizing capacity declines over time to become a major factor in senescence-related diseases.

Absorption and Excretion of Ascorbic Acid Alone and in Acerola (Malpighia emarginata) Juice: Comparison in Healthy Japanese Subjects

It has been suggested that some food components, such as bioflavonoids, affect the bioavailability of ascorbic acid in humans. Since little is known in Japan about the effective intake of this dietary requirement, we tested young Japanese males after the ingestion of commercial ascorbic acid or acerola (Malpighia emarginata DC.) juice to compare the quantities absorbed and excreted. Healthy Japanese subjects received a single oral dose of ascorbic acid solution (50, 100, 200 or 500 mg) and received distilled water as a reference at intervals of 14 d or longer. All subjects were collected blood and urine until 6 h after ingestion and evaluated for time-dependent changes in plasma and urinary ascorbic acid levels. Predictably, the area under the curve (AUC) values in plasma and urine after ingestion increased dose-dependently. Next, each subject received diluted acerola juice containing 50 mg ascorbic acid. Likewise, their plasma and urinary ascorbic acid concentrations were measured. In plasma, the AUC value of ascorbic acid after ingestion of acerola juice tended to be higher than that from ascorbic acid alone. In contrast, the urinary excretion of ascorbic acid at 1, 2 and 5 h after ingestion of acerola juice were significantly less than that of ascorbic acid. These results indicate that some component of acerola juice favorably affected the absorption and excretion of ascorbic acid.

Adaptogenic and nootropic activities of aqueous extract of Carum carvi Linn. (Caraway) fruit: An experimental study in Wistar rats

In the present investigation the aqueous extract of Carum carvi was evaluated for antistress activity in normal and stress induced rats. The extract was studied for nootropic activity in rats and in vitro antioxidant potential to correlate its antistress activity. For the evaluation of antistress activity groups of rats were subjected to forced swim stress one hour after daily treatment of Carum carvi extract. Urinary vanillylmandelic acid (VMA) and ascorbic acid were selected as non invasive biomarkers to assess the antistress activity. The 24 h urinary excretion of vanillylmandelic acid (VMA) and ascorbic acid was determined in all groups under normal and stressed conditions. The nootropic activity of the extract as determined from acquisition, retention and retrieval in rats was studied by conditioned avoidance response using Cook’s pole climbing apparatus. The in vitro antioxidant activity was determined based on the ability of Carum carvi to inhibit lipid peroxidation in liver and brain homogenates. Daily administration of Carum carvi at doses of 100, 200 and 300 mg/kg body weight one hour prior to induction of stress inhibited the stress induced urinary biochemical changes in a dose dependent manner. However no change in the urinary excretion of VMA and ascorbic acid was observed in normal animals at all the doses studied. The cognition, as determined by the acquisition, retention and recovery in rats was observed to be dose dependent. The extract produced significant inhibition of lipid peroxide formation in comparison with ascorbic acid in a dose dependent manner in both liver and brain. The present study provides scientific support for the antistress (adaptogenic), antioxidant and nootropic activities of Carum carvi extract and substantiates its traditional use as a culinary spice in foods as beneficial and scientific in combating stress induced disorders.

Short-term oral toxicity of three biodiesels and an ultra-low sulfur diesel in male rats

Male rats were administered one of three biodiesels – soy oil methyl ester (SoME-2), canola oil methyl ester (CaME-2), and methyl ester of animal frying oil (FrAME-1) at 5, 50 and 500 mg/kg, or ultra-low sulphur diesel (ULSD) at 500 mg/kg. Control was administered the vehicle (corn oil) only. After 4-week treatment, serum methanol and formic acid were unchanged or minimally elevated in all treatment groups. Mild histopathological changes in the liver were observed in animals receiving 500 mg/kg biodiesels and ULSD but hepatomegaly, increased phase I and II drug-metabolizing enzyme activities and urinary ascorbic acid were found only in the ULSD group. The ULSD group had increased kidney weight, changes in kidney histopathology, and increased urinary albumin and N-acetylgluocosaminidase activity. Biodiesels and ULSD caused increase in hepatic acyl-CoA oxidase activity. ULSD and FrAME-1 caused decrease in serum free fatty acid while CaME-2 caused decreases in both serum triglycerides and free fatty acids. FrAME-1 produced an increase in liver protein carbonyls and ULSD caused increased liver glutathione. The results indicated that ULSD caused more histopathological and biochemical effects than biodiesels. Biodiesels produced lipid effects and oxidative stress that were feedstock-dependent. The mechanisms and significance of increased hepatic acyl-CoA oxidase activity required further study.

Hepatoprotective activity of leaves of Rhododendron arboreum in CCl4 induced hepatotoxicity in rats

The study was designed to evaluate the hepatoprotective activity of pre-treatment with ethanolic extract of leaves of Rhododendron arboreum against carbon tetrachloride-induced hepatotoxicity in Wistar rat model. Liver damage was induced in experimental animals by administering CCl4. The ethanolic extract of R. arboreum (40, 60 and 100 mg/kg, po) was given for five days. Silymarin (100 mg/kg, po) was given as the reference drug. Hepatoprotective effect was studied by assaying the activities of serum marker enzymes like SGPT, SGOT, ALP, direct and total bilirubin, triglycerides, cholesterol and estimation of ascorbic acid in urine. The activities of all the marker enzymes registered a significant elevation in CCl4 treated rats, which were significantly recovered towards an almost normal level in animals co-administered with ethanolic extract of leaves of R. arboreum at a dose of 60 and 100 mg/kg. Ethanolic extract of leaves of R. arboreum prevented decrease in the excretion of ascorbic acid in CCl4 induced hepatotoxicity in rats. Histopathological analysis confirmed the biochemical investigations. The results indicate that leaves of R. arboreum possess hepatoprotective property possibly because of its reported anti-oxidant activity. This property may be attributed to the quercetin related flavonoids, saponins and phenolic compounds present in the leaves of R. arboreum.

Urinary ascorbic acid and serum concentrations of circulating immune complexes and albumin in HIV infected subjects.

The aim of the present study was to determine the presence or absence of ascorbic acid in urine and serum levels of circulating immune complexes (CIC) and albumin in HIV infected subjects. A total of 90 participants (30 Symptomatic HIV infected subjects on antiretroviral therapy (ART), 30 Symptomatic HIV infected subjects not yet on ART and 30 HIV seronegative control subjects) were recruited for the study. Urine samples from participants were used to assess for ascorbic acid while blood samples were used to determine the serum CIC and albumin levels. The result showed that the mean serum concentration of CIC (mg/dl) of Symptomatic HIV subjects on ART was 693±606, for the symptomatic HIV subjects was 535±305 and 84±28 for control subjects (f=19.492; p Keywords : HIV; ART; ascorbic acid; albumin and CIC. Journal of Biomedical Investigation Vol. 4 (2) 2006 pp.54-59

Short-term oral toxicity of butyl ether, ethyl hexyl ether, methyl heptyl ether and 1,6-dimethoxyhexane in male rats and the role of 2-methoxyacetic acid

A 4-week oral study was conducted in male rats to characterize and compare the toxicity of four aliphatic ethers (butyl ether, BE; ethyl hexyl ether, EHxE; methyl heptyl ether, MHpE; and 1,6-dimethoxyhexane, DMH) which have been proposed as high-cetane diesel additives. Male Sprague-Dawley rats (280 ± 20 g) were divided into groups of seven animals each and were administered by gavage low (2 mg/kg body weight), medium (20 mg/kg) or high (200 mg/kg) doses of BE, EHxE, or MHpE, 5 days per week for 4 weeks. Another group of animals was administered DMH at 200 mg/kg while the control group received the vehicle (corn oil at 1 ml/100 g bw) only. At the end of the treatment period, relative testis weights and thymus weights were significantly decreased in the DMH group but not in animals receiving BE, EHxE, or MHpE. Microscopic examination revealed degeneration of the seminiferous tubules and reduction of sperm density in the epididymides in the DMH treatment group. Urinary creatine/creatinine ratio, a sensitive indicator of testicular damage, was markedly elevated in the DMH treated animals but not in those treated with BE, EHxE, or MHpE. In the bone marrow, DMH caused mild dyserythropoiesis and dysthrombopoiesis, while BE, EHxE, and MHpE produced mild increases in granulocytes and myelocyte/erythrocyte ratio. All four ethers at 200 mg/kg caused mild histological changes in the thyroid but no significant modulation in the circulating thyroxin (T4) or triiodothyronine (T3) levels. All four ethers produced hepatic effects at 200 mg/kg consisting of mild, adaptive histological changes, increased urinary ascorbic acid output, and elevation in the activities of one or more xenobiotic metabolizing enzymes (benzyloxyresorufin- O-dealkylase, UDP-glucuronosyltransferase, glutathione- S-transferases). The level of 2-methoxyacetic acid (MAA), a known testicular and developmental toxin, was significantly increased in the urine and plasma of animals treated with DMH but not in those administered the high dose BE, EHxE, or MHpE. Amomg the individual rats treated with DMH, the MAA level appeared to correlate with the severity of toxicity such as testicular and thymic weights, and urinary creatine/creatinine ratio. It is concluded that BE, EHxE, and MHpE differed from DMH in that they did not produce testicular or thymic toxicity. All four ethers at high dose caused changes to the thyroid, liver and bone marrows that were mild and adaptive in nature. MAA appeared to be the proximal toxicant in DMH treated animals but the route by which DMH is metabolized to MAA remains to be elucidated.

Effects of Excess Pantothenic Acid Administration on the Other Water-Soluble Vitamin Metabolisms in Rats

To acquire the data concerning the tolerable upper intake level which prevents health problems from an excessive intake of pantothenic acid, an animal experiment was done. Rats of the Wistar strain (male, 3 wk old) were fed on a diet which contains 0%, 0.0016% (control group), 1%, or 3% calcium pantothenate for 29 d. The amount of weight increase, the food intake, and the organ weights were measured, as well as the pantothenic acid contents in urine, the liver and blood. Moreover, to learn the influence of excessive pantothenic acid on other water-soluble vitamin metabolism, thiamin, riboflavin, a vitamin B6 catabolite, the niacin catabolites, and ascorbic acid in urine were measured. As for the 3% addition group, enlargement of the testis, diarrhea, and hair damage were observed, and the amount of weight increase and the food intake were less than those of the control group. However, abnormality was not seen in the 1% addition group. The amount of pantothenic acid in urine, the liver, and blood showed a high correlation with intake level of pantothenic acid. It was only for 4-pyridoxic acid, a vitamin B6 catabolite, in urine that a remarkable difference was observed against the control group. Moreover, the (2-Py+4-Py)/MNA excretion ratio for these metabolites of the nicotinamide also indicated a low value in the 3% pantothenic acid group. As for the calcium pantothenate, it was found that the 3% level in the diet was the lowest-observed-adverse-effect-level (LOAEL) and the 1% level was the no-observed-adverse-effect-level (NOAEL).

Effects of an ethanol-gasoline mixture: results of a 4-week inhalation study in rats

The inhalation toxicity of an ethanol-gasoline mixture was investigated in rats. Groups of 15 male and 15 female rats were exposed by inhalation to 6130 ppm ethanol, 500 ppm gasoline or a mixture of 85% ethanol and 15% gasoline (by volume, 6130 ppm ethanol and 500 ppm gasoline), 6 h a day, 5 days per week for 4 weeks. Control rats of both genders received HEPA/charcoal-filtered room air. Ten males and ten females from each group were killed after 4 weeks of treatment and the remaining rats were exposed to filtered room air for an additional 4 weeks to determine the reversibility of toxic injuries. Female rats treated with the mixture showed growth suppression, which was reversed after 4 weeks of recovery. Increased kidney weight and elevated liver microsomal ethoxyresorufin-O-deethylase (EROD) activity, urinary ascorbic acid, hippuric acid and blood lymphocytes were observed and most of the effects were associated with gasoline exposure. Combined exposure to ethanol and gasoline appeared to exert an additive effect on growth suppression. Inflammation of the upper respiratory tract was observed only in the ethanol-gasoline mixture groups, and exposure to either ethanol and gasoline had no effect on the organ, suggesting that an irritating effect was produced when the two liquids were mixed. Morphology in the adrenal gland was characterized by vacuolation of the cortical area. Although histological changes were generally mild in male and female rats and were reversed after 4 weeks, the changes tended to be more severe in male rats. Brain biogenic amine levels were altered in ethanol- and gasoline-treated groups; their levels varied with respect to gender and brain region. Although no general interactions were observed in the brain neurotransmitters, gasoline appeared to suppress dopamine concentrations in the nucleus accumbens region co-exposed to ethanol. It was concluded that treatment with ethanol and gasoline, at the levels studied, produced mild, reversible biochemical hematological and histological effects, with some indications of interactions when they were co-administered.