The Empirical Analysis of Cigarette Tax Avoidance and Illicit Trade in Vietnam, 1998-2010

Illicit trade carries the potential to magnify existing tobacco-related health care costs through increased availability of untaxed and inexpensive cigarettes. What is known with respect to the magnitude of illicit trade for Vietnam is produced primarily by the industry, and methodologies are typically opaque. Independent assessment of the illicit cigarette trade in Vietnam is vital to tobacco control policy. This paper measures the magnitude of illicit cigarette trade for Vietnam between 1998 and 2010 using two methods, discrepancies between legitimate domestic cigarette sales and domestic tobacco consumption estimated from surveys, and trade discrepancies as recorded by Vietnam and trade partners. The results indicate that Vietnam likely experienced net smuggling in during the period studied. With the inclusion of adjustments for survey respondent under-reporting, inward illicit trade likely occurred in three of the four years for which surveys were available. Discrepancies in trade records indicate that the value of smuggled cigarettes into Vietnam ranges from $100 million to $300 million between 2000 and 2010 and that these cigarettes primarily originate in Singapore, Hong Kong, Macao, Malaysia, and Australia. Notable differences in trends over time exist between the two methods, but by comparison, the industry estimates consistently place the magnitude of illicit trade at the upper bounds of what this study shows. The unavailability of annual, survey-based estimates of consumption may obscure the true, annual trend over time. Second, as surveys changed over time, estimates relying on them may be inconsistent with one another. Finally, these two methods measure different components of illicit trade, specifically consumption of illicit cigarettes regardless of origin and smuggling of cigarettes into a particular market. However, absent a gold standard, comparisons of different approaches to illicit trade measurement serve efforts to refine and improve measurement approaches and estimates.     

Diet of the Indochinese silvered langur (Trachypithecus germaini) in Kien Luong Karst area,Kien Giang Province

The Indochinese silvered langur (Trachypithecus germaini) is distributed to the west of Mekong River in Cambodia, Lao PDR, Thailand and Vietnam. During a two‐year study, from May 2014 to May 2016, we collected 320.44 hr of behavior, with 17,040 feeding bouts recorded (142 hr) for T. germaini on Chua Hang Karst Mountain, Kien Luong District, Kien Giang Province, Vietnam. Feeding accounted for 45% of the Indochinese silvered langurs’ activity budget. The plant diet of the Indochinese silvered langurs was principally composed of young leaves (58%), followed by mature leaves (9.5%), fruits (22.7%), flowers (4.7%), buds (3.3%), petioles (1.2%), and other (0.5%). A total of 58 plant species were fed on by the silvered langurs, and leaves of eight species (Phyllathus reticulatus, Ficus rumphii, Ficus tinctoria, Ficus microcarpa, Cayratia trifolia, Streblus ilicifolia, Combretum latifolium, and Streblus asper) were fed on throughout the year. P. reticulatus was most frequently eaten (13.9% feeding time, n = 1,733). Food selection differed significantly between months and seasons. The Indochinese silvered langurs ate 27 plant species in the wet season compared with 23 plant species in the dry season. Leaf chemical composition of two food categories, 16 eaten species (with 10 most frequently consumed species and six least consumed species), and four noneaten species, were analyzed. Feeding samples from eaten species in the Indochinese silvered langurs's diet contained lower amounts of condensed tannin, lignin, protein, ash, and lipids, but a higher amount of total sugar compared with samples from noneaten species. Furthermore, the most frequently consumed species contained lower amounts of lignin compared with the less frequently consumed species. Using a generalized linear model with five variables, including neutral detergent fiber (NDF), total sugar, lignin, lipid, and calcium (Ca) indicated that NDF positively correlated and lignin content negatively correlated with feeding records in the diet of these langur.     

l-Phenylalanyl-l-Glutamate-Stimulated, Chloride-Dependent Glutamate Binding Represents Glutamate Sequestration Mediated by an Exchange System

Stimulation of glutamate binding by the dipeptide L-phenylalanyl-L-glutamate (Phe-Glu) was inhibited by the peptidase inhibitor bestatin, suggesting that the stimulation was caused by glutamate liberated from the dipeptide and not by the dipeptide itself. It further suggests that this form of glutamate binding should be reinterpreted as glutamate sequestration and that stimulation of binding both by dipeptides and after preincubation with high concentrations of glutamate is likely to be due to counterflow accumulation. Several other criteria indicate that most of glutamate binding stimulated by chloride represents glutamate sequestration: Binding is reduced when the osmolarity of the incubation medium is increased, when membranes incubated with [3H]glutamate are lysed before filtration, and when membranes are made permeable by transient exposure to saponin. Moreover, dissociation of bound glutamate after a 100-fold dilution of the incubation medium is accelerated about 50 times by the addition of glutamate to the dilution medium. This result would be anomalous if glutamate were bound to a receptor site; it suggests instead that glutamate is transported in and out of membrane vesicles by a transport system that preferentially mediates exchange between internal and external glutamate. Glutamate binding contains a component of glutamate sequestration even when measured in the absence of chloride. Sequestration is adequately abolished only after treating membranes with detergents; even extensive lysis, sonication, and freezing/thawing may be insufficient.     

Human esterase D gene: complete cDNA sequence,genomic structure,and application in the genetic diagnosis of human retinoblastoma

Summary The gene encoding human esterase D (EsD), a member of the nonspecific esterase family, is a useful genetic marker for retinoblastoma (RB) and Wilson's disease. Previously we identified a cDNA clone from this gene and determined its chromosomal location. In this report, we present the complete cDNA sequence of the human EsD gene. A long open reading frame encoded a predicted protein of 282 amino acids with molecular weight of 30 kD. A computer-assisted search of a protein sequence data base revealed homology with two other esterases, acetylcholinesterase of Torpedo and esterase-6 of Drosophila. Homologous region were centered around presumptive active sites, suggesting that the catalytic domains of the esterases are conserved during evolution. Three genomic clones of this gene were also isolated and characterized by restriction mapping. At least ten exons were distributed over a 35-kb (kilobase pair) region; each exon contained an average of 100 basepairs (bp). A polymorphic site for Apa I, located within an intron of the esterase D gene, can be used to identify chromosome 13 carrying defective RB alleles within retinoblastoma families.     

Specific binding of three neurotoxins with phospholipase A2 activity to synaptosomal membrane preparations from the guinea pig brain

Snake presynaptic toxins such as crotoxin, β-bungarotoxin and taipoxin block neuromuscular transmission through inhibiting the release of acetylcholine by their phospholipase A₂ activities. On the other hand, many other phospholipase A₂s show little neurotoxicity. It is likely that the difference lies in whether high affinity binding to nerve cell membranes exists or not. To test this idea, crotoxin, β-bungarotoxin and taipoxin were first radioactively labeled with Na(¹²⁵I) without loss of their neurotoxicity. Using the radioactive toxins we have found that each of the three showed specific binding to synaptosomal membranes from guinea pig brain. In contrast, we could not detect specific binding of a non-neurotoxic pancreatic phospholipase A₂. Crotoxin and taipoxin, but not β-bungarotoxin, also bound specifically to membrane preparation from other tissues. The binding of each toxin was not greatly affected by the other two toxins. The photoaffinity labeling technique has been used to obtain further information about the components which bind crotoxin. For this purpose, (¹²⁵I) crotoxin was derivatized with N-hydroxysuccinimidyl-4-azidobenzoate. Autoradiographic analysis of the membranes following photoirradiation in the presence of the modified crotoxin revealed that an 85K dalton component was preferentially covalently conjugated with the crotoxin analogue in a specific manner.     

Neurophysiology of geniculate ganglion (facial nerve) taste systems: species comparisons

On the basis of various measures taken from geniculate gangliontaste neurons in four species, it was concluded that withineach species the neurons could be subdivided into distinct functionalgroups. In this report, the neural groups of different specieswere directly compared. Units from all four species were studiedwith a common test series of solutions in addition to otherstimuli. Since these stimuli were presented at the same concentrationsto all species, direct quantitative comparisons across specieswere possible for a wide range of chemical compounds. In addition,the neural groups were compared with respect to spontaneousand evoked activity measures, latency to electrical stimulation,and receptive field characteristics. These neurophysiologicaldata suggest a basic model of four distinct subgroups: acidunits, salt units, amino acid units, and X units.     

Comparative antioxidant enzyme study in freshwater fishes. II. Distribution of antioxidant enzymes and lipid peroxidation in omnivorous fish organs

Comparative studies were performed on the activities of superoxide dismutases, catalase and glutathione peroxidase in organ homogenates from three omnivorous fishes, the barbel, crucian carp and common carp. The lipid peroxidation and protein contents of organ homogenates were also compared. These comparative measurements primarily provide control values for subsequent toxicological examinations. The highest total superoxide dismutase activities were found in the liver or roe, kidney, heart and spleen in every cases. The antioxidant enzyme activities and other studied parameters of the organ homogenates partly appear to depend on the feeding mode, but are rather characteristic of the fish variety.     

ATP sulfurylase from Penicillium chrysogenum: measurements of the true specific activity of an enzyme subject to potent product inhibition and a reassessment of the kinetic mechanism

Homogeneous ATP sulfurylase from Penicillium chrysogenum has been reported to have an extremely low activity toward its physiological inorganic substrate, sulfate. This low activity is an artifact resulting from potent product inhibition by 5'-adenylylsulfate (APS) (Ki less than 0.25 microM). Assays based on 35S incorporation from 35SO4(2-) into charcoal-adsorbable [35S]APS are nonlinear with time, even in the presence of a large excess of inorganic pyrophosphatase. However, in the presence of excess APS kinase (along with excess pyrophosphatase), the ATP sulfurylase reaction is linear with time and the enzyme has a specific activity (Vmax) of 6 to 7 units mg protein-1 corresponding to an active site turnover number of at least 400 min-1. Monovalent oxyanions such as NO3-, ClO3-, ClO4-, and FSO3- are competitive with sulfate (or molybdate) and essentially uncompetitive with respect to MgATP. However, thiosulfate (SSO3(2-)), a true sulfate analog and dead-end inhibitor of the enzyme (competitive with sulfate or molybdate), exhibited clear noncompetitive inhibition against MgATP. Furthermore, APS was competitive with both MgATP and molybdate in the molybdolysis assay. These results suggest (a) that the mechanism of the normal forward reaction may be random rather than ordered and (b) that the monovalent oxyanions have a much greater affinity for the E X MgATP complex than for free E. In this respect, FSO3-, ClO4-, etc., are not true sulfate analogs although they might mimic an enzyme-bound species formed when MgATP is at the active site. The nonlinear ATP sulfurylase reaction progress curves (with APS accumulating in the presence of excess pyrophosphatase or PPi accumulating in the presence of excess APS kinase) were analyzed by means of "average velocity" plots based on an integrated rate equation. This new approach is useful for enzymes subject to potent product inhibition over a reaction time course in which the substrate concentrations do not change significantly. The analysis showed that ATP sulfurylase has an intrinsic specific activity of 6 to 7 units mg protein-1. Thus, the apparent stimulation of sulfurylase activity by APS kinase results from the continual removal of inhibitory APS rather than from an association of the two sulfate-activating enzymes to form a "3'-phospho-5'-adenylylsulfate synthetase" complex in which the sulfurylase has an increased catalytic activity. The progress curve analyses suggest that APS is competitive with both MgATP and sulfate, while MgPPi is a mixed-type inhibitor with respect to both substrates. The cumulative data point to a random sequence for the forward reaction with APS release being partially rate limiting.