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Use of corrosion-resistant cladding can greatly extend the design life of structural components in many advanced reactor systems. However, there are currently no ASME design rules for cladded components to guard against creep-fatigue failure and ratcheting strain accumulation in elevated temperature nuclear service. This paper, presented in two parts, addresses this gap by proposing a design strategy for cladded components that do not require long-term testing of clad materials. The proposed approach relies on approximate design analysis methods for two types of clad materials—a soft clad that creeps much faster than and has lower yield stress than the class A base material and a hard clad that creeps much slower than and has higher yield stress than the class A base material. Part I discusses the approximate analysis strategies for the clad materials—treat a soft clad as perfectly compliant and a hard clad as linear elastic—and Part II develops a complete set of design rules for each of the two types of cladded components. Finite element analyses of representative high temperature reactor components show that the proposed design analysis methods can bound the design quantities in soft cladded components and approximate the design quantities in hard cladded components.

The challenge of using existing ASME Section III, Division 5, class A metallic materials for the construction of structural components of advanced reactors with corrosive coolants could be mitigated by allowing designers to use cladding to protect the base material from corrosion. However, the existing Section III, Division 5 rules provide no guidance on the evaluation of strain accumulation and creep-fatigue damage in cladded components. The availability of design rules for cladded components that do not require long-term clad material testing could promote the application of the cladding approach to accelerate the deployment schedule of these advanced reactor systems. To avoid long-term properties for the clad materials Part I of this work proposes two approximate design analysis methods for two types of clad materials—soft clads that creep much faster and have lower yield stress than the class A base material, and hard clads that creep much slower and have higher yield stress than the class A base material. The proposed analysis methods approximate the response of a soft clad by treating it as perfectly compliant and of a hard clad by treating it as linear elastic. Based on these approximate design analysis strategies this Part II develops a complete set of design rules for class A components cladded with either soft or hard clad materials. Part II discusses the reasoning behind the proposed design rules and uses example finite element analyses of representative reactor components to illustrate the use of these design methods.

The aggressive corrosive environment along with higher operating temperature in molten salt reactors present significant challenges to existing structural materials that have been qualified in the ASME Section III, Division 5 Code for high temperature cyclic service. Corrosion resistant claddings offer an attractive near-term solution to mitigate corrosion concerns and enable the use of ASME Code qualified materials for advanced reactor structural components. Nickel provides good corrosion resistance to molten salts as well as good thermal and mechanical compatibility with existing ASME Code qualified materials, and therefore can be used as a cladding material for structural components in molten salt reactors. However, there are currently no ASME design rules for cladded components to guard against creep-fatigue failure and ratcheting strain accumulation under high temperature cyclic service. Recently, we have developed new design rules for components cladded with creep-compliant materials (e.g. nickel clad on 316H base metal) for high temperature cyclic service. These design rules require design parameters that can be established through relatively short-term testing for the clad material. This work shows how the design parameters for nickel are developed using fatigue and creep-fatigue test data. Finally, the paper walks through a sample problem detailing the application of the design rules to 316H components cladded with nickel.

This paper discusses the development of design charts for creep-fatigue evaluation using an integrated elastic-perfectly plastic analysis (EPP) and Simplified Model Test (SMT) approach. The creep-fatigue damage evaluation approach in current ASME Section III, Division 5 rules requires separate evaluation of creep and fatigue damages and then considers the effect of creep-fatigue interaction with a creep-fatigue interaction diagram, also known as D-diagram. The EPP+SMT approach avoids the use of D-diagram by directly comparing the strain range determined from an EPP analysis with design charts, conceptually developed directly from creep-fatigue and SMT tests, to determine the creep-fatigue damage. The EPP+SMT approach provides much simpler creep-fatigue design evaluation process compared to current methods and is also expected to reduce the over-conservatism in current methods. Generating the EPP+SMT design charts requires extrapolating high strain range, short hold time test data to low strain range and long hold times, typically experienced by structural components in high temperature nuclear service. This work investigates several extrapolation approaches in the development of methodologies for constructing EPP+SMT design charts for Alloy 617 at temperatures between 800°C and 950°C. The design charts are validated using failure data from pressurized SMT tests and by comparing the EPP+SMT method with current design methods for representative high temperature nuclear reactor components.

The need for high-performance concrete with improved workability, higher strength, and greater longevity has risen in recent years to satisfy the current requirements for structural construction. Consequently, the development of self-compacting concrete in Bangladesh has recently become one of the most significant developments in the construction industry. To place and be able to flow under its weight, this innovative concrete does not require additional vibration. The main objective of this study was to investigate the SCC developed in this study using locally available materials incorporating different W/C ratios and different FM of fine aggregate in terms of both fresh and mechanical properties. For the necessary tests, nine mixtures were prepared with different W/C ratios and different FM of fine aggregate, and the same Super-plasticizer dosages. Slump flow, V-funnel, L -box, and T50 were involved in the fresh property tests. However, the experimental results showed that with the reduction of the W/C ratio, compressive strength was improved and the FM of fine aggregate shift is not too much of a compressive strength effect. In comparison, almost all fresh property prices meet the ACI requirements and the W/C ratio 0.4 and 0.45 and 0.5 meet the design specifications of the ACI mix. The compressive strength test is tested in concrete age is 7, 14, and 28 days total of 27 cubes are crushed in the universal testing machine. Therefore, it is invariably possible to use locally available materials to build SCC for sustainable development in Bangladesh.

Elephant endotheliotropic herpesviruses (EEHVs) are the cause of acute hemorrhagic disease in endangered Asian and African elephants. In the present study, we report the incidence of EEHV infection and associated mortality in the captive elephant of Assam, India. Our result showed the gross morphology and histopathological changes of EEHV infection in the elephant. Moreover, the phylogenetic analysis of the polymerase, helicase, and GPCR genes from the infected tissue samples suggested the presence of EEHV1A virus.

There is a way to describe a family of plane curves different from that using Cartesian or polar co-ordinates. This is a trigonometric equation involving two angles. In this article, we highlight the fact that trigonometric equations are convenient to describe certain one-parameter families of plane curves. In some cases, the trigonometric form makes it easier to characterize the family than if one were to use the equivalent Cartesian or polar representations.

Timely diagnosis of tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), is only achieved for ~58% cases. An improved, accurate, time- and cost-effective method for bacteriological confirmation of MTB is necessary. We evaluated Mycotube, a new variant of Lowenstein-Jensen (LJ) culture medium, by comparing it with Mycobacterium Growth Indicator Tube (MGIT) 960 (gold standard), local LJ, and bioMerieux LJ-T in terms of isolation rate and time-to-growth. Pulmonary and extra-pulmonary samples from treatment-naive suspects (n = 207) were decontaminated by the N-acetyl-L-cysteine-sodium hydroxide method and used to inoculate the four media. Subjective and objective parameters were used for evaluation. Mycotube yielded 140 positive results, compared to 162, 69, and 141 from MGIT, local LJ, and LJ-T, respectively. Of these, 139 (67%) were true-positive results and 1 (0.5%) was false-positive. The mean time-to-growth detection was 17.4 days for Mycotube, compared to 14.5, 28.1, and 16.5 days for MGIT, local LJ, and LJ-T, respectively. The mean time-to-growth for local LJ significantly differed from that for MGIT, but not those for LJ-T and Mycotube. No contamination was observed. Mycotube had a sensitivity of 85.8% and a specificity of 97.8% as compared to MGIT. Mycotube offers good results, comparable with those observed for conventional LJ. It requires only basic laboratory infrastructure. The overall cost of the test should be nearly three times lower than that of MGIT. Mycotube helps with TB diagnosis and generates pure isolates for drug susceptibility testing.

The objective of the present study was to determine marginal vitamin A deficiency (VAD) by testing the hydrolysis of retinoyl glucuronide (RAG) to retinoic acid (RA) in children. Previous studies in rats showed that hydrolysis occurred when rats were vitamin A deficient. Children (n 61) aged 3–18 years, were divided into two groups, I and II. Blood was collected from the children in Group I (n 19) who were not dosed with RAG. Children in Group II (n 42) were administered all-trans retinoyl glucuronide (RAG) orally, and blood was collected 4 h after the dose. All serum samples were analysed for retinoids and carotenoids. RA was detected in serum only when serum retinol was 1 μmol/l in six children. Mean serum retinol in sixty-one children was 0·522 (sd 0·315) μmol/l. Mean β-carotene (0·016 (sd 0·015) μmol/l) was far below normal compared to the level of lutein (0·176 (sd 0·10) μmol/l) in sixty-one children. A low β-carotene level might be due to a low intake of carotene but high demand for vitamin A. The RAG hydrolysis test may prove to be a useful approach for the determination of marginal VAD with no clinical or subclinical signs of VAD. High prevalence of VAD amongst certain communities in Assam cannot be ruled out.

Retinoic acid (RA) is involved in the development of both the conducting airway and alveolar portions of the lung. RA plays a key role in the induction of the formation of alveolar septa. Retinoyl β-glucuronide (RAG), an endogenous retinoid, acts like RA, but is much less cytotoxic. We examined the effect of daily intraperitoneal doses of RA and RAG (1.66 μmol/kg) in dimethyl sulfoxide (DMSO) and cotton seed oil on the stores of retinol and retinyl ester (RE) in the lung of rats. In two separate experiments, one involving normal rats, and the other involving elastase-treated rats, there was up to a 9-fold increase in REs content in the lungs of rats that received RA or RAG for 12 days as compared to Control rats. The accumulation was most profound when RA was injected in DMSO and least when RAG was injected in cotton seed oil. The reason for the accumulation of REs in the lung is not clearly known.

Numerous reports have indicated that the biological activity of all-trans retinoyl beta-glucuronide (RAG) is similar to that of all-trans-retinoic acid (RA), but without the toxic side effects of RA. In the present series of studies, we report new findings that support the contention that RAG can function as a nontoxic substitute for RA in a variety of clinic settings. One study on the effects of s.c. injected graded doses of RA and RAG (20-480 micromol/kg BW) into pregnant Sprague-Dawley rats showed that any differences between RAG and RA could be observed only at the highest dose levels of 360 and 420 micromol/kg BW, with RAG being much less toxic than RA. Similarly, daily topical application of RAG (0.16-1.6%) and RA (0.1-0.5%) to shaved swine dorsal skin for six mo resulted in redness and scabbing in RA-treated patches, and to a lesser extent in 1.6% RAG-treated, but not in other RAG-treated patches. Histological scores were significantly higher in the dermis and epidermis of RA-treated pigs than in RAG-treated pigs. Studies to document the pharmacokinetics of chronically administered RAG in mice indicated that, unlike RA, sustained blood levels of parent retinoid (RAG) can be achieved during at least 2 mo of daily administration. Another investigation to study the effects of RAG on the development and growth in nude mice of tumors derived from the human neuroblastoma cell line LA-N-5 showed that s.c. injection of RAG (30 micromol/kg BW) reduced tumor formation when the retinoid was first administered 3 d before tumor injection and continued daily for 30 d thereafter. In established tumors, RAG was shown to inhibit progressive tumor growth, the antitumor effects of RAG being comparable with RA. However, with RAG, as opposed to RA, there were no significant adverse physical side effects. Based on the results of these series of studies along with ample published reports over the last 15 y, we conclude that RAG may be a safe and effective alternative to RA and some other retinoids that are presently being utilized in the clinic.

In order to prove the hypothesis that humans and animals with adequate vitamin A status do not absorb and metabolize orally administered all-trans retinoyl beta-glucuronide, unlabeled retinoyl glucuronide (0.1 mmol) was orally dosed to fasting well-nourished young men. Neither retinoyl glucuronide nor retinoic acid, a possible metabolite, appeared in the blood within 12 h after ingestion. Next, radiolabeled all-trans 15-[14C]-retinoyl beta-glucuronide was chemically synthesized by a new procedure, and fed orally to rats of different vitamin A status. Analysis of blood and other tissues 5 or 24 h after the dose, showed the presence of radioactivity ( approximately 0.5%) in the blood of vitamin A deficient rats, but not in sufficient rats. Livers of all rats contained small, but detectable amounts (0.3 to 1.1% of the dose) of radioactivity. The accumulation of radioactivity in the liver was highest in deficient rats. Analysis of the retinoids showed that the radioactivity in serum and liver was due to retinoic acid formed from retinoyl glucuronide. Within 24 h after the dose, 31 to 40% of the administered radioactivity was excreted in the feces, and 2 to 4.7% of the dose was excreted in the urine. Results of the present studies show that oral administration of retinoyl beta-glucuronide did not give rise to detectable changes in blood retinoyl glucuronide and/or retinoic acid concentrations in humans or rats with adequate vitamin A status.

The aim of this study was to determine the bioavailability and bioconversion to vitamin A of a single oral dose in oil or an aqueous dispersion of labeled beta-carotene in rats of different vitamin A status. Weanling Sprague-Dawley rats were fed a vitamin A-deficient diet and supplemented for 4 wk with 0, 7, 21 and 63 micro g/(rat. d) of retinyl acetate. The rats, of different vitamin A status, were then given a single oral dose of 11,12-(3)H-beta-carotene (0.15 micro mol) dissolved in corn oil or dispersed in aqueous Tween 80. The rats were killed 4 or 24 h after the dose, and serum, liver, the entire digestive tract, other tissues, urine and feces were analyzed for carotenoids, retinoids and associated radioactivity. At 4 h after the dose, 85 +/- 9% of the administered radioactivity was recovered. Almost 50% of the dose was present as intact beta-carotene in the large intestine where further absorption and conversion was ruled out. The absorption of beta-carotene was very low, and < 5% of the radioactive dose was converted to retinoids. The absorption and conversion to vitamin A did not differ among rats of different vitamin A status. The results suggest that a single oral dose of beta-carotene might not be an effective way of raising vitamin A stores in the body.

SOME PROPERTIES OF A SEMI-SYMMETRIC METRIC CONNECTION IN A RIEMANNIAN MANIFOLD

The effects of single subcutaneous injections (sc) of graded doses (20, 40, 80, 160, 320, and 480 mumol/kg body weight (BW) of all-trans retinoic acid (RA) and all-trans retinoyl beta-glucuronide (RAG) on day 8.5 of gestation on the outcome of pregnancy in Sprague-Dawley rats was studied. At dose levels of 20, 40, and 80 mumol/kg BW, neither RA nor RAG showed any adverse maternal or fetal effects. However, at dose levels of 160, 320, and 480 mumol/kg, RA was found to be much more toxic than RAG to both mother and fetus. Fetuses of animals receiving a 160 mumol/ kg BW dose of RA were significantly reduced in weight and length, while animals receiving the same dose of RAG had fetuses of normal size. RA doses of 320 and 480 mumol/ kg BW resulted in symptoms of maternal toxicity and even death. In contrast, RAG at these high levels produced no signs of maternal toxicity. RAG doses of 320 and 480 mumol/ kg BW were also less toxic to fetuses. RA doses of 320 mumol/kg BW resulted in only 8% live births, while animals treated with an equivalent amount of RAG experienced 95% live births. Animals receiving a dose of 480 mumol/kg BW of RA had no live births, but similar doses of RAG resulted in 28% live births and pups of normal size.

The efficacy of all-trans-retinoic acid (tRA) and all-trans-retinoyl β-glucuronide (RAG), a water-soluble metabolite of vitamin A, in the topical treatment of acne is comparable. However, whereas 3.3 mM tRA shows side effects, 3.3 mM RAG does not. To assess the relative toxic and histologic effects (dermal and epidermal changes) of long-term (24-week) daily applications of tRA and RAG on the skin, separate skin patches were measured and marked dorsally on the skin of six 21-day-old, castrated male pigs. Each skin patch area was treated daily with a cream formulation containing either 3.3 mM RAG, 16.5 mM RAG, 33 mM RAG, 3.3 mM tRA, 16.5 mM tRA or blank cream. To serve as controls, one patch received no treatment, one patch received blank cream only and for 5.3 weeks one ‘washed’ patch was given daily application of 33 mM RAG with routine cleansing using a mild soap typical of skin care. The amount of cream used per square centimeter remained the same during the course of the study. Biopsy tissue was collected at –1, 0, 2, 4, 8, 12 and 24 weeks from 7 test patches. The ‘washed’ patch was biopsied once at the 5.3-week mark. Topically applied RAG cream (3.3 mM) resulted in significantly lower histologic scores when compared with scores from tissue treated with an equimolar concentration of tRA. The highest concentration of RAG tested (33.3 mM) resulted in a response comparable to that observed in the lowest tRA (3.3 mM) treated patch area. Daily cleansing of the test area receiving 33.3 mM RAG completely eliminated any clinical signs or negative histologic changes. In conclusion, long-term topical tRA treatment in young pigs, as in humans, showed dose-dependent adverse effects on the skin, whereas RAG treatment had significantly lower histologic changes and less irritation and/or inflammation.

Increased intake of fruits and vegetables is associated with reduced risk of cancer and other chronic diseases. Epoxycarotenoids are widely distributed in nature and constitute major dietary carotenoids in a number of fruits and vegetables. Previous studies have shown that beta-carotene 5,6-epoxide was absorbed well by humans, and was much more active than beta-carotene in inducing the differentiation of NB4 cells. Xanthophyll epoxides such as neoxanthin, violaxanthin and lutein 5,6-epoxide, are more abundant than epoxy-hydrocarbon carotenes in a number of vegetables and fruits that humans consume. To determine whether xanthophyll epoxides are also absorbed by humans, lutein 5,6-epoxide (taraxanthin) and zeaxanthin 5,6,5'6'-diepoxide (violaxanthin) were chemically prepared, dissolved in corn oil and orally administered to three human subjects. Analysis of plasma for carotenoids within 9 h after a single oral dose of either violaxanthin or taraxanthin failed to show any violaxanthin, taraxanthin or any of their metabolites.

All-trans-retinoyl-beta-D-glucuronide (RAG) is an endogenous active metabolite of all-trans-retinoic acid (ATRA). In the present study, the pharmacokinetics of RAG was examined after the administration of a single intravenous does (5, 10, or 15 micromol/kg) and of multiple daily intravenous doses (5 micromol/kg) to rats for 8 days. The plasma concentrations of RAG and ATRA were measured by a reverse-phase HPLC method. A rapid distribution phase of approximately 1 h was observed in all of the rats after single or multiple doses. Thereafter, RAG was eliminated through a first-order process, in accord with a typical two-compartment first order pharmacokinetic profile. After single intravenous doses, the AUC of RAG increased proportionally with the dose and the clearance remained unchanged within the tested doses. There was no statistical significant difference in distribution rate constants from central compartment to peripheral compartment (K(12)) and from peripheral compartment to central compartment (K(21)) between different doses. However, as the dose increased from 5 micromol/kg to 10 micromol/kg, the volume of distribution at the steady state (V(ss)) and the volume of peripheral compartment (V(p)) decreased significantly (p0.05) from 1.290 +/- 0.269, 0.928 +/- 0.232. L/kg to 0.961 +/- 0.149, 0.647 +/- 0.107 L/kg, respectively. V(ss) and V(p) at a dose of 15 micromol/kg (0.924 +/- 0.187, 0.698 +/- 0.165 L/kg) were not significantly different from that at 10 micromol/kg. Thus, RAG might saturate the tissue-binding sites at higher doses. ATRA was detected as a metabolite of RAG at low levels (usually0.05 microM) only in the first 2 h after intravenous administration. RAG clearly was not extensively hydrolyzed to ATRA in our study. After multiple daily intravenous administration of RAG, the clearance (Cl) and the elimination rate constant (K(10)) remained unchanged (p0.05), indicating that long-term daily administration of RAG did not induce its accelerated metabolism. However, K(12), V(p), and V(ss) declined significantly (p0.05) from 1.67 +/- 0.54 h(-1), 0.928 +/- 0.232 L/kg, and 1.290 +/- 0.269 L/kg to 0.96 +/- 0.48 h(-1), 0.494 +/- 0.147 L/kg, and 0.818 +/- 0.187 L/kg, respectively. Therefore, long-term daily dosing of RAG seemed to decrease its distribution profile. Although the AUC of RAG did not change significantly after multiple dosing, the AUC of ATRA after RAG dosing significantly declined (p0.05) from 0.032 +/- 0.019 microM x h to 0.010 +/- 0.006 microM x h. The decline in the AUC of ATRA might reflect an increase in its uptake by tissue and/or in its metabolism. Because enhanced clearance is not associated with RAG after multiple administrations, RAG could be considered as an alternate to ATRA in appropriate clinical applications.

The work of Taguchi for determining the optimal settings of controllable factors through off-line experiments focuses on products with a single quality characteristic or response. However, most products have several quality characteristics or responses of interest. Taguchi's technique in itself optimizes a single response or performance characteristic yielding a set of process parameters. This particular setting may not give desired results for other characteristics of the product. In such cases, a need arises to obtain a single setting (optimal setting) of the process parameters, which can be used to produce the products with optimum or near optimum quality characteristics as a whole. Multi-characteristic response optimization may be the solution of the above problem. In the present paper a case study on V-processed castings of Al–7%Si alloy, utilizing a simplified multi-criterion methodology based on Taguchi's approach and utility concept, is discussed. Copyright © 2000 John Wiley & Sons, Ltd.

beta-Carotene might be converted oxidatively to vitamin A- active products in animals by the following three possible routes: 1) central cleavage, 2) sequential excentric cleavage or 3) random cleavage. Central cleavage is strongly favored by stoichiometric studies with tissue homogenates in vitro. To examine the relative importance of these pathways in rats in vivo, an oral dose (5.6 micromol) of all-trans beta-carotene in oil was given to vitamin A-deficient (-A) and to vitamin A-sufficient (+A) adult female Sprague-Dawley rats. Serum and several tissues were analyzed before and 3 h after dosing. The primary products of beta-carotene found in the intestine, serum and liver were retinol, retinyl esters and retinoic acid. Two minor oxidation products of beta-carotene, namely, 5,6-epoxy-beta-carotene and a partially characterized hydroxy-beta-carotene, were present in the stomach and its contents as well as in intestinal preparations. In the intestine, including its contents, of -A rats, very minor amounts of 5,6-epoxyretinyl palmitate and of beta-apocarotenals (8', 10', 12', 14') were identified. The total amount of the beta-apocarotenoids, however, was

An increased intake of fruits and vegetables has been shown to be associated with reduced risk of cancer. In epidemiological studies, supplements of β-carotene, which is abundant in fruits and vegetables, were not found to be beneficial in reducing the incidence of lung cancer in high-risk groups. Epoxycarotenoids are abundant in nature. 5,6-Epoxy-β-carotene was much more active than β-carotene in the induction of differentiation of NB4 cells [Duitsman, Becker, Barua and Olson (1996) FASEB J. 10, A732]. Epoxycarotenes may, therefore, have protective effects against cancer. In order to do this, however, epoxycarotenoids must be absorbed by the human body. There is no evidence that epoxycarotenoids, despite their abundance in dietary fruits and vegetables, are absorbed by humans. In this paper, it is demonstrated that orally administered dietary or synthetic epoxy-β-carotenes are absorbed by humans, as indicated by their appearance in the circulating blood.

All- trans retinoyl-β-glucuronide, a prominent water-soluble metabolite of all- trans retinoic acid (RA) in animals, is formed by the enzymic transfer of the glucuronyl moiety of uridine diphosphoglucuronic acid to RA. Uridine diphosphoglucuronic acid glucuronosyl transferases (UGTs) of microsomal preparations catalyze this reaction. In noninduced rat liver microsomes, maximal activity was observed in the physiologic range (pH 6.9–7.5) for all- trans -RA, 9- cis -RA, all- trans -4-oxo-RA, and the synthetic retinoid tetramethyl, tetrahydro-anthracenyl-benzoic acid. The activities toward 13- cis -RA and tetramethyl, tetrahydronaphthenyl-propenyl-benzoic acid were maximal between pH 5.4 and 6.9 and toward acitretin [9-(2′,3′,6′ trimethyl, 4′methoxybenzyl-1′) 3,7 dimethyl, nona-2,4,6,8 tetraenoic acid] at pH 8.4. Several organs catalyze this reaction, but the activities of noninduced microsomes from liver, kidney, and testes were higher than those from intestine and lung. Brain microsomes were inactive. During storage at –80°C, the stability of UGTs varied both with the tissue and the retinoid substrate. 3-Methylcholanthrene both induces UGTs and increases the permeability of microsomal preparations to its substrates. The rates of glucuronidation of the less biologically active retinoids all- trans -4-oxo RA and 13- cis -RA were increased relatively more (11-fold and 6-fold, respectively) than those of the natural ligands for nuclear transcription factors all- trans -RA and 9- cis -RA (threefold and twofold, respectively). We conclude that several microsomal UGTs, which are differentially regulated, act on retinoids.

The global consciousness for quality has motivated designers and manufacturing engineers to be engaged constantly in product and process development. The approach, quality by design, developed by Taguchi has produced a unique and powerful quality improvement discipline that differs from traditional practices. In the present paper, Taguchi's technique has been applied to obtain an optimal setting of V-process parameters. The results indicate that the sand grain fineness number and amplitude of vibration are the control factors. These factors affect both the mean and the variation of the bulk density of the V-process mould. The signal factor, that is the factor that affects only the mean value, is time of vibration. The insignificant factor is the degree of vacuum imposed. The optimum value of bulk density (1.588 gm/cm 3 ) at the optimal setting of these parameters has been obtained and confirmed by further experiments.

A method is presented for the quantitation of the glucuronide conjugates of 4-oxo-all-trans-, 4-oxo-13-cis-, 13-cis-, 9-cis- and all-trans-retinoic acids in rat urine utilizing solid-phase extraction and gradient reversed-phase HPLC. The range of the R.S.D. (relative standard deviation) for both the inter- and intra-assay precision was 1.45-11.60%. The recovery of all retinoyl-beta-glucuronides from rat urine ranged between 89 and 99%. The limit of detection was 0.01 microgram/ml using 5 ml of rat urine. This method was applied to quantitate the amount of retinoyl-beta-glucuronides produced in urine after the single and multiple oral administration of 13-cis-, 9-cis- and all-trans-retinoic acids to rats.

The synthesis and characterization of the novel glucuronide conjugates of 9-cis and 13-cis retinoic acid and of all-trans, 9-cis and 13-cis 4-oxoretinoic acid are described.

The complex of microsomal UDP-glucuronosyl transferases (UGT; EC 2,4.1.17) of rat liver catalyzes the formation of retinoyl β-glucuronide (RAG) from retinoic acid (RA) and retinyl β-glucuronide (ROG) from retinol (ROL) in the presence of UDP-glucuronic acid (UDPGA). The relative rates of formation of β-glucuronides in noninduced microsomes were: 9-cis RA > 13-cis RA > all-trans 4-oxo RA > TTNPB > all-trans RA > CD-367 > 13-cis ROL > 9-cis ROL > acetretin > all-trans ROL. Michaelis constant (KM) for all-trans RA, 13-cis ROL, TTNPB and UDPGA were 130 μM, 300 μM, 210 μM and 2.6 mM, respectively. Galacturonides of RA, but not detectably of ROL, were formed from UDP-galacturonic acid at 11–30% the rate of the β-glucuronides, whereas UDP derivatives of nonionized sugars did not serve as substrates. Pretreatment of rats with 3-methylcholanthrene markedly increased RAG formation in the absence of detergent (Triton X-100), but less so in its presence. Clofibrate pretreatment doubled the rate of RAG formation, whereas phenobarbital pretreatment showed little effect. N-Ethylmaleimide (5 mM) minimized cis-trans isomerization without significantly affecting glucuronidation. Rates of glucuronidation of retinoids clearly depend both on their isomeric states and on their chemical structures. Different UGT enzymes might well act on different geometric isomers of RA.

All-trans-retinoyl β-glucuronide (RAG) was chemically synthesized in high yields (up to 79%) by a new procedure involving the reaction of the tetrabutylammonium salt of glucuronic acid with all-trans-retinoic acid (RA) via the imidazole or triazole derivative. When RAG was fed orally to vitamin A-deficient rats, RA was identified as the major metabolite in the serum within hours of administration of RAG. Very little or no RAG was detected in the serum. Thus RAG, which was not appreciably hydrolysed to RA in vitamin A-sufficient rats [Barua and Olson (1987) Biochem J. 263, 403–409], was rapidly converted into RA in vitamin A-deficient rats.

The purpose of these studies was to compare directly the percutaneous absorption, excretion and metabolism of all-trans-retinoyl Β-glucuronide (RAG), a nontoxic retinoid, with all-trans-retinoic acid (RA) in the rat. Previously, it was demonstrated that topical treatment of human acne with either RAG or RA in cream resulted in a significant reduction of lesions. Whereas 0.1 % RA showed adverse effects, concentrations of RAG up to 2.4% did not cause any adverse reactions. In the present studies, radiolabeled RAG or RA, dispersed in a water-based cream, was applied to the shaved dorsal skin of vitamin A-sufficient rats. Both RAG and RA were absorbed from the skin in a similar way. In both cases, radioactivity peaked in the plasma within 2-4 h and within the liver at 4-12 h. During a 7-day period, the overall excretion of radioactivity derived from RA and RAG in the feces and urine were similar, e.g. 17 and 12%, respectively. It is concluded that: (1)the transport, metabolism and excretion of topically applied radioactive RA and RAG are similar, although not identical, in the rat and (2) the toxic skin manifestations induced by RA but not by RAG cannot be attributed to major differences in their overall absorption, metabolism and excretion.

The purpose of this study was to evaluate the efficacy towards acne and the skin surface toxicity of all-trans-retinoyl β-glucuronide (RBG), a naturally occurring retinoid possessing low cytotoxicity and teratogenicity in animal and cell culture studies. In a double-blind study, 15 acne patients treated with 1.2% RBG cream for 16 weeks showed median reductions of 56%, 25% and 67% in total, inflammatory, and noninflammatory lesions, respectively, whereas the placebo group (14 patients) showed median reductions of 31%, 4% and 62%, respectively. The median reduction in total lesions was highly significant in the RBG group (P = 0.002) but not in the placebo group (P = 0.06). In a second initially double-blind study, ten acne patients treated topically for 26 weeks with 0.16–0.32% RBG cream and five patients with 0.1% all-trans-retinoic acid (Retin-A) showed similar responses, i.e. median reductions in total facial lesions of 70% (P = 0.001) and 75% (P = 0.01), respectively. Whereas all subjects treated topica...

A sensitive high-performance reversed-phase liquid chromatographic assay which utilizes isocratic elution and detection by two detectors has been developed to measure simultaneously several carotenoids, retinol, retinyl esters, and α- and γ-tocopherols in serum. Although 100 μl of serum or plasma is used routinely, as little as 10 μl can be analyzed. Typical lower limits of detection (5 : 1 signal/noise ratio) are 0.2 pmol for retinol, 6 pmol for α-tocopherol, 1 pmol for β-carotene, and 2 pmol for retinyl palmitate. Although lutein and zeaxanthin were only partially resolved from each other, all other major serum carotenoids including α-carotene from β-carotene and α-cryptoxanthin from β-cryptoxanthin were completely separated. Retinyl hexanoate and β-apo-8'-carotenyl decanoate are convenient, readily prepared internal standards for this assay. Relative retention indices, based on elution times of alkylphenone standards, proved useful both for characterization of compounds and for comparison between columns.

When single large equimolar doses (0.38-0.41 mmol/kg BW) of all-trans retinoic acid (RA), all-trans retinoyl beta-glucose (RBGL), and all-trans retinoyl beta-glucuronide (RBG) are administered orally in oil on day 8.5 of pregnancy to Sprague-Dawley rats, RA and RBGL proved highly teratogenic, whereas RBG was not. Indeed, fetuses from RBG-treated dams were 16% heavier (P < 0.01) than control fetuses. After dosing with RA and RBGL, RA appeared in large amounts within 0.5 h in the maternal plasma and within 1.0 h in the embryo. In contrast, orally administered RBG seemed to be absorbed much more slowly, to be converted very slowly to RA, and not to accumulate either as RBG or as RA in the embryo. When incubated in vitro with embryos and attached membranes, however, both all-trans RBG and all-trans RA were partially converted to 13-cis RA. The nonteratogenicity of RBG, in contrast to RA, seems to be due to a much slower rate of GI absorption, a slow rate of hydrolysis to RA, a limited passage from the maternal circulation into the embryo, and a lower inherent toxicity.

The synthesis and characterization of the novel glucuronide conjugates of 9-cis and 13-cis retinoic acid and of all-trans, 9-cis and 13-cis 4-oxoretinoic acid are described.

Retinoids are unstable compounds being readily oxidized and/or isomerized to altered compounds, especially in the presence of oxidants including air, light, and excessive heat. They are labile toward strong acids and solvents that have dissolved oxygen or peroxides. In this review, procedures for handling and storage of retinoids and biological samples containing them have been described. The physical and chemical properties of retinoids have been reported. Simplified procedures for derivatizations and purification, and methods for quantitation of retinoids have been presented.

Soon after [11-3H]retinoic acid (RA) (1.1 x 10(8) d.p.m.) was administered orally to rats either as a large dose (115 micrograms = 0.38 mumol/rat) or mixed with unlabelled RA as a huge dose (22 mg = 73.33 mumol/rat), retinoyl beta-glucuronide (RAG) was identified and characterized as a significant metabolite in the serum and small intestine. Of the administered dose, 70% remained unchanged as retinoic acid in the stomach up to 1 h. Significant amounts of 5,6-epoxyretinoic acid, 4-hydroxyretinoic acid, esters of retinoic acid and several polar retinoids, including 4-oxoretinoic acid, were also detected in the stomach. No significant difference was observed in the nature of the retinoids found after a large or a huge dose; however, the ratio of RAG/RA was higher after a huge dose than after a large dose. Thus RAG, which is biologically active in vivo and in vitro, is formed quickly in significant amounts in tissues after a dose of RA.

Retinoyl beta-glucuronide (RAG) and retinyl beta-glucuronide (ROG) inhibit prolactin-induced morphological developments in cultured mouse mammary gland, and are equally effective in depressing prolactin and steroid hormone-induced DNA synthesis in the same tissue. Retinol is essentially inactive by both assay methods. Although RAG and ROG show little or no toxicity in several cell and animal models, some possibly toxic manifestations were seen at higher concentrations in cultured mammary tissue. Nonetheless, because of the strong correlation between the actions of chemopreventive agents in culture mouse mammary glands and their effectiveness in vivo, the retinoid glucuronides may well prove to be useful cancer chemopreventive agents.

A simple method of sample preparation for LC analysis of retinoic acid (RA) and retinoyl β-glucuronide (RAG) in creams has been developed. Water-based cream of all trans -RAG, devoid of side effects but efficacious in the treatment of acne vulgaris, was found to be hydrolyzed to RA in a temperature dependant manner. The potential benefits of water-based RAG cream stored at room temperature for the treatment of acne and wrinkle is discussed.

The purpose of this study was to examine the pharmacokinetics of a single dose (6.3 mumol, 3 mg) of all-trans retinoyl beta-glucuronide (RAG), when given either orally in corn oil or by intraperitoneal (IP) injection in dimethylsulfoxide (DMSO) to adult Sprague-Dawley rats. Following dosing, serial blood samples were collected at various times up to 48 hours from each rat via saphenous vein puncture. Retinoids were extracted from plasma samples and analyzed by high-performance liquid chromatography. In the plasma of IP-dosed rats (n = 6), a derivative of RAG, tentatively identified as the lactone of RAG (RAGL), was the major product found. RAGL persisted in the plasma for up to 48 hours. Much smaller concentrations of RAG and of retinoic acid (RA) were also present in the plasma at two to four hours, but generally not thereafter. In orally dosed rats (n = 6), neither RAG nor its products, except for occasional traces of the lactone, were detected. Plasma retinol levels decreased in both IP-injected and orally treated rats, the decrease being significant in orally dosed rats.

The efficacy of all-trans-retinoic acid (tRA) and all-trans-retinoyl beta-glucuronide (RAG), a water-soluble metabolite of vitamin A, in the topical treatment of acne is comparable. However, whereas 3.3 mM tRA shows side effects, 3.3 mM RAG does not. To assess the relative toxic and histologic effects (dermal and epidermal changes) of long-term (24-week) daily applications of tRA and RAG on the skin, separate skin patches were measured and marked dorsally on the skin of six 21-day-old, castrated male pigs. Each skin patch area was treated daily with a cream formulation containing either 3.3 mM RAG, 16.5 mM RAG, 33 mM RAG, 3.3 mM tRA, 16.5 mM tRA or blank cream. To serve as controls, one patch received no treatment, one patch received blank cream only and for 5.3 weeks one 'washed' patch was given daily application of 33 mM RAG with routine cleansing using a mild soap typical of skin care. The amount of cream used per square centimeter remained the same during the course of the study. Biopsy tissue was collected at -1, 0, 2, 4, 8, 12 and 24 weeks from 7 test patches. The 'washed' patch was biopsied once at the 5.3-week mark. Topically applied RAG cream (3.3 mM) resulted in significantly lower histologic scores when compared with scores from tissue treated with an equimolar concentration of tRA. The highest concentration of RAG tested (33.3 mM) resulted in a response comparable to that observed in the lowest tRA (3.3 mM) treated patch area. Daily cleansing of the test area receiving 33.3 mM RAG completely eliminated any clinical signs or negative histologic changes. In conclusion, long-term topical tRA treatment in young pigs, as in humans, showed dose-dependent adverse effects on the skin, whereas RAG treatment had significantly lower histologic changes and less irritation and/or inflammation.

All-trans-retinoyl beta-D-glucuronide, a water-soluble glucuronic acid conjugate of all-trans-retinoic acid, has demonstrated high biological activity and low toxicity in most in vitro and in vivo models. Since the reparative effects of retinoids on epithelium are well-known, our aim was to study the effect(s) of intravenously-administered all-trans-retinoyl beta-D-glucuronide in lambs with chronic bacterial bronchopneumonia.Two groups of lambs were inoculated intrabronchially with either pyrogen-free saline or Mannheimia haemolytica. Thirty-three days later, lambs were injected four times at five-day intervals with 2 mL of 116 mM all-trans-retinoyl beta-D-glucuronide (6.0-9.3 mmol/kg or 2.86-4.42 mg/kg animal body weight) in dimethyl sulfoxide, or dimethyl sulfoxide alone. Animal behavior and signs of clinical illness were logged daily. Lung and liver samples were assessed for histopathology, while serum and liver samples were extracted for retinoids and analyzed by reversed-phase gradient high-performance liquid chromatography.Repeated injections of highly concentrated all-trans-retinoyl beta-D-glucuronide did not cause changes in appetite, activity or other behaviors nor did it cause histologic lesions in liver and lung. However, it had no effect on resolution of lung lesions resultant of chronic Mannheimia haemolytica bronchopneumonia.Repeated intravenous administration of high amounts of all-trans-retinoyl beta-D-glucuronide to lambs did not elicit signs of gross or microscopic toxicity. However, administering all-trans-retinoyl beta-D-glucuronide too late in the progression of bacterial pneumonia is thought to be the main reason for its lack of effect in this model. A retinoid lactone derivative was detected in sheep serum and liver several days after treatment.

Two high-performance liquid chromatography (HPLC) procedures, a rapid normal-phase isocratic method for the analysis primarily of retinol and retinoic acid on a 3 mu silica column, and a reversed-phase gradient method for the simultaneous analysis of retinoids and very polar to nonpolar carotenoids on a 3 mu C18 column, are described. The normal-phase isocratic HPLC procedure is rapid (12 min), requires a sample size of 100 microl or less of serum, and is suitable for routine analysis of retinol in any serum, and of retinol and retinoic acid in serum after administration of retinoic acid. The reversed-phase gradient method is suitable for the simultaneous analysis of very polar to nonpolar carotenoids such as epoxy-xanthophylls and xanthophyll esters, along with other carotenoids and retinoids that occur normally in human serum and other plant and animal tissues. A run time of 30-70 min is necessary, depending on the presence or absence of xanthophyll esters in the sample.