Acetylation polymorphism and leprosy

The sulfones are the drug of choice in the treatment of leprosy, with dapsone as the clear favorite. The major route for dapsone metabolism leading to its inactivation and excretion is via acetylation by hepaticN-acetyl transferase (NAT), as is the case with isoniazid (INH) and sulfamethazine (SMZ). The enzyme is known to exhibit genetic polymorphism. The object of the present study is mainly to determine the incidence of acetylator phenotype in a population of leprosy patients with a view to evaluating the degree of association, if any, between phenotype and the disease. Obviously a knowledge of the incidence of the phenotypes may provide a valuable contribution to the institution of more rational and successful therapy. In the normal or control subjects, as well as in the leprosy patients, the frequency distribution histograms of the percentage acetylsulfamethazine in urine and serum samples are bimodal, and this indicates the existence of a genetic polymorphism. Based on the bimodality, individuals were classified as either rapid or slow acetylators, and the incidence of the slow acetylator phenotype of about 51% was observed in the leprosy population. This gives a relatively high incidence of the allele controlling the slow acetylator (q=0.73). Although there is evidence that the mean percentage of SMZ acetylated in leprosy patients of the slow acetylator phenotype is significantly higher than that observed for the same phenotype in the controls (t=4.86,P<0.02), statistical analyses show that there is no association between the slow acetylator phenotype and the disease. Most of the individuals in the slow acetylator phenotype tend to show some adverse reactions when a total weekly dose of 600 mg is given. Such adverse reactions include heightened lepra reactions, blurring of vision, and headache. These reactions, we think, are due to accumulation of the drug in the subjects. This therefore brings into sharp focus the desirability of knowing the acetylator phenotype of an individual before the initiation of dapsone therapy.     

Assessment of the relationship between combinations of polymorphic variants of xenobiotic-metabolizing enzyme genes and predisposition to lung cancer

An imbalance between the phases of biotransformation systems, such as activation, detoxification, and release of toxic substances, is one of the causes of multifactor pathology. Therefore, it is important to examine the impact of the total contribution of the polymorphic variants of xenobiotic-metabolizing enzyme genes at all three phases on predisposition to lung cancer. The purposes of the present work were to study the relationship between polymorphic variants of xenobiotic-metabolizing enzyme genes and risk of lung cancer and to identify molecular genetic markers of predisposition to the disease. It was shown that GSTT1 null-genotype plays a dominant role in the development of lung cancer predisposition in the Belarusian population, while the polymorphic variants of other genes of xenobiotic-metabolizing enzymes render a modifying effect on predisposition to this disease. Combination 734AA CYP1A2/GSTT1(?)/GSTM1(+)/“slow” acetylator has the greatest risk significance, and combination GSTT1(?)/GSTM1(+)/“slow” acetylator exerts a protective effect.     

Comparative analysis of N-acetylation polymorphism in humans as determined by phenotyping and genotyping

The N-acetylation polymorphisms of volunteers from the Moscow population analyzed by phenotyping and genotyping have been compared. The ratios between the proportions of fast acetylators (FAs) and slow acetylators (SAs) estimated by phenotyping and genotyping do not differ significantly from each other (47 and 44%, respectively). The absolute acetylation rate widely varies in both FAs and SAs. The NAT2 genotype and allele frequencies in the population sample have been calculated. The most frequent alleles are NAT2*4 (a “fast” allele), NAT2*5, and NAT2*6 (“slow” alleles); the most frequent genotypes are NAT2*5/*5, NAT2*4/*6, and NAT2*4/*5. Comparative analysis of N-acetylation polymorphism estimated by phenotyping and genotyping in the same subjects has shown a complete concordance between the phenotype and genotype in only 62 out of 75 subjects (87%). Comparative characteristics and presumed applications of the two approaches (quantitative estimation of acetylation rate and qualitative determination of the acetylator genotype) to the identification of individual acetylation status are presented.     

Analysis of NAT2 point mutations with biological microchips

The NAT2 product, N-acetyltransferase 2, is involved in biotransformation and detoxification of several aromatic amines (in particular, 2-aminofluorene, 4-aminobiphenyl, and 4-naphthylamine), which are strongly mutagenic and carcinogenic, and acetylates some drugs, affecting their metabolism. A biological microchip was developed to detect 16 point mutations, which determine 36 alleles and 660 genotypes of NAT2. The genotypes can be divided into four groups according to the acetylator phenotype: groups with rapid (R/R), intermediate (R/S), or slow (S/S) acetylation and a group combining intermediate and slow alleles (“R/S or S/S”). The last group includes the alleles determined by combinations of seven mutations (191G/A, 282C/T, 341T/C, 481C/T, 590G/A, 803A/G, and 857G/A), whose cis or trans position is detectable by restriction enzyme analysis. The NAT2 genotype was unequivocally established for 37 out of 71 DNA specimens, while the other 34 specimens were characterized by more than two genotypes. By the acetylator phenotype, 16 out of the 34 genotypes were assigned to the group “R/S or S/S,” combining mutations 282C/T, 341T/C, 481C/T, 590G/A, and 803A/G. Thus, the biochip allows primary analysis of most NAT2 polymorphic substitutions, the acetylator genotype being important to know in predictive medicine and individualized therapy.     

Study of NAT2 genetic polymorphism in West African subjects: example of an healthy non-smoker Senegalese population

The NAT2 genetic polymorphism determines the individual acetylator status and, consequently, the capacity to metabolize, or not, drugs and xenobiotics which are substrates of NAT2. As the nature and frequency of the NAT2 polymorphisms vary remarkably between populations of different ethnic origins, genotyping strategies used to predict the acetylation phenotype need to be adapted for each particular population regarding their genetic backgrounds at this locus. As few data on the genetic polymorphism of NAT2 are available in the Senegalese population, we performed an extensive identification of NAT2 variants in 105 healthy non-smoker Senegalese subjects by direct PCR sequencing of the coding region. Eleven previously described SNPs were identified in this Senegalese population. Upon allele analysis, the four most frequent alleles were of the NAT2*5- (35.7?%), NAT2*6- (21.0?%), NAT2*12- (16.7?%) and NAT2*14- (10.0?%) type, the remaining alleles, including the wild-type NAT2*4, having each a frequency lower than 10?%. According to the observed genotypes, 51 and 50 subjects were predicted to be of the rapid (48.6?%) and slow (47.6?%) acetylator phenotype, respectively, while four individuals (3.8?%) were considered of unknown phenotype as they carry at least one allele with a yet unknown functional effect. These baseline data would be of particular interest to set up an efficient genotyping strategy to predict the acetylation status of Senegalese patients with tuberculosis and, thus, to optimize their isoniazid treatment.     

Effect of Rifampicin and Isoniazid on Liver Function

The effects of rifampicin and isoniazid on liver function have been studied in 63 patients with pulmonary tuberculosis; 29% showed abnormalities of serum aspartate aminotransferase (SGOT) and a similar percentage abnormalities of serum bilirubin. These usually occurred during the first 12 weeks of therapy. The average duration of the abnormalities was 14½ days, irrespective of whether treatment was interrupted or not.The relationship between raised SGOT and acetylator phenotype in a small number of patients suggests that those with raised SGOT are usually slow acetylator phenotypes. It seems that hepatic reactions in patients with previously normal liver function are usually mild and non-specific. However, patients who continue with rifampicin should be kept under close biochemical observation.     

Studies on the electrogenic action of acetylcholine with Torpedo marmorata electric organ: V. Qualitative correlation between pharmacological effects and equilibration processes of the cholinergic receptor protein as revealed by the structural probe quinacrine

When the differential fluorescence emission at 515 nm of receptor-rich membrane fragments from Torpedo marmorata labelled with quinacrine is followed by energy transfer, addition of a high concentration of an agonist such as 0.4 mm-carbamylcholine or 0.4 mm-phenyltrimethylammonium causes a fast (unresolved) increase of fluorescence intensity followed by a slow (minute range) decrease, which leads to a final stable level. On the other hand, a stepwise addition of agonist at low concentrations gives only a slow fluorescence increase. Antagonists, such as flaxedil and d-tubocurarine, at all the concentrations tested, bring about exclusively slow fluorescence increases. Decamethonium at 0.4 mm gives no slow reaction but only a fast (unresolved) increase without transient overshoot.Addition of a local anaesthetic reduces the amplitude of the fluorescence response to carbamylcholine. The α-toxin from Naja nigricollis does not cause any change of fluorescence intensity but blocks the effect of the cholinergic agonists and antagonists.Dissolution of the membrane fragments by a non-ionic detergent abolishes the fast transient reaction triggered by the agonists but preserves the slow ones observed in the presence of agonists or antagonists. The data are interpreted in terms of a three-state model, a revised version of the model of Katz & Thesleff (1957): the fast transient reaction brought about by the agonists being assigned to the “activation” of the receptor-ionophore complex and the slow one to its “desensitization”.     

Defensive localism in white and black: a comparative history of European-American and African-American youth gangs

Despite the largely voluntary character of Nigerian immigration to the United States since 1970, it is not clear that their patterns of integration have emulated those of earlier immigrants who, over time, traded their specific national origins for “American” or “White” identities as they experienced upward mobility. This path may not be available to Nigerian immigrants. When they cease to be Nigerian, they may become black or African-American. In this paper, I use US Census data to trace patterns of identity in a Nigerian second-generation cohort as they advance from early school-age in 1990 to adulthood in 2014. The cohort shrinks inordinately across the period as its members cease to identify as Nigerian, and this pattern of ethnic attrition is most pronounced among the downwardly mobile – leaving us with a positively select Nigerian second generation and, perhaps, unduly optimistic assessments of Nigerian-American socioeconomic advancement.     

High frequency of the rapid isoniazid acetylator phenotype in Lagos (Nigeria)

The metabolism of isoniazid was investigated in 323 unrelated and healthy Nigerians in Lagos using a simple dosage and urinalysis procedure. The distribution was bimodal and the population frequency of rapid acetylators was 61.92%, a value higher than that for most Caucasian populations. Males and females were equally affected by the traits. Analysis of both the population and pedigree data showed that the slow acetylator phenotype is a recessive trait, and the gene frequency of the recessive allele as computed by maximum likelihood methods is 0.6175 +/- 0.022. The clinical implications of these findings are discussed.     

A new approach to species distributional indicators for the Marine Strategy Framework Directive (MSFD)

We propose alternative fish-populations spatial indicators for use in the Marine Strategy Framework Directive (MSFD). Following Commission Decision 2010/477, we have applied two different spatial indicators to three fish populations with “slow type” life-history traits, i.e. slow growing like Helicolenus dactylopterus, or large bodied like Merluccius merluccius and Lophius budegassa. We tested their efficiency separately and combined. One of these indicators, the presence/absence of the population in sampling squares, had already been applied during the initial assessment of the MSFD in Spain. Another indicator, the geographical spread, is proposed here as a new monitoring tool for the MSFD in Spanish waters. The results demonstrate for the three populations analyzed that neither indicator was sufficient alone to describe the population spatial pattern or its evolution. Thus, the approach to implementing the MSFD indicated in Commission Decision 2010/477 is not sufficient to provide integrated information about the spatial behavior of the fish populations analyzed. Although numerical targets or threshold values cannot be set, directional targets could be proposed, based on the results of both indicators, if evaluation of them is extended to more species and more geographical areas. The analysis could be extended to other “slow type” populations within the fish community and also to different ecoregions. We propose an approach including the estimation of two different indicators to monitoring both the area occupied and the geographical spread of fish populations within communities, interpreting them together to generate a more complete picture of the spatial patterns of those populations. In spite of the difficulties in fixing numerical targets or thresholds, or in distinguishing between environmentally and human driven changes in the population spatial distributions, this approach helps to summarize fish spatial behavior. It improves information from the indicators applied alone and reduces the requirement for a large number of maps (except for some particular event or population). The proposed indicators can be readily used by managers and politicians.     

Moral Publics: Human Trafficking,Video Films and the Responsibility of the Postcolonial Subject

This article analyzes the ways in which a Nigerian video film about human trafficking is received by Nigerian women who have themselves experienced trafficking in their migration to Italy. This contextualized case study is used as a methodological “lockpick” to open up new lines of enquiry into the relationship that southern Nigerian video films create with their audiences. The essay argues that, by virtue of their specific “addressivity,” the genre of Nigerian video films that focus on female migration and prostitution participates in the creation of moral publics that are concerned with the definition of the postcolonial subject’s responsibility in shaping his/her own destiny.     

Extracellular metabolites of 2-aminofluorene in cultures of rapid and slow acetylator rabbit hepatocytes as a model for urinary and biliary metabolism

N-acetylation is involved in determining species susceptibility to carcinogenicity by certain aromatic amines. In order to further investigate this relationship, the biotransformation of 2-aminofluorene (2-AF) by monolayer cultures of hepatocytes isolated from rapid and slow acetylator rabbits was studied. Analysis of biotransformation products liberated by cells was used as an indication of metabolites that would be excreted in the urine and bile. Hepatocytes from both acetylator phenotypes were found to extensively biotransform 2-AF. The overall rates of metabolism and the types of products formed were similar in the two phenotypes, although the quantity of several products differed. Hepatocyte cultures from rapid acetylators released a greater proportion of acetylated metabolites. Rapid acetylator hepatocytes released predominantly ring-hydroxylated-2-acetylaminofluorene (2-AAF) while the major product from the slow acetylator cultures was conjugated 2-AF. The amounts of extracellular N-hydroxy-2-acetylaminofluorene were similar in both phenotypes. No phenotype-dependent differences in extracellular metabolites were noted when hepatocytes were incubated with 2-AAF. These results indicate that hepatocytes from both phenotypes have similar capacities to excrete N-hydroxy-2-AAF and to detoxify the parent aromatic amine. These findings can be related to the carcinogenicity of 2-AF in either phenotype.     

Acetylation phenotypes in patients with bladder carcinoma

The present study was done to evaluate the possible association of bladder carcinoma with the slow acetylator phenotype in a portuguese population. 49 patients with bladder carcinoma were compared to a normal control group of 84 individuals. No statistically significant association was detected. But when subdividing the group of slow acetylators it is found that in the subgroup with 12-36% acetylation there is a higher percentage of patients, which is statistically significant. These results are in agreement with two other studies, using populations of similar ethnic origin.     

Analysis of the N-acetyltransferase 2 gene polymorphism in the patients with chronic obstructive pulmonary disease and in populations of the Volga-Ural region

Restriction fragment-length polymorphism of the gene coding for N-acetyltransferase 2 (NAT2) was typed in populations of the Volga-Ural region (Bashkirs, Tatars, Chuvashes, Udmurts, and Russians) as well as in patients with chronic obstructive pulmonary disease (COPD) and in healthy individuals. Rapid and slow acetylator phenotypes were determined based on the presence or absence of the KpnI, TaqI, and BamHI restriction endonuclease recognition sites. The proportion of slow acetylators in the populations examined varied from 40.00% in Bashkirs to 64.15% in Chuvashes with statistically significant difference between these two ethnic groups (chi 2 = 5.7; p = 0.02). Overall, in the Volga-Ural populations slow acetylators represented 56.25% of the subjects examined. This value was similar to those presented in other studies of Caucasoid populations. In the COPD patients a statistically significant decrease of the slow acetylator frequency to 48.28% compared to healthy individuals (62.18%) was observed (chi 2 = 4.60; p = 0.036). The data obtained suggest a possible association between the drug resistance in the COPD patients with the rapid acetylator phenotype, which can lead to the development of the chronic form of the disease.     

Selection never dominates drift (nor vice versa)

The probability that the fitter of two alleles will increase in frequency in a population goes up as the product of N (the effective population size) and s (the selection coefficient) increases. Discovering the distribution of values for this product across different alleles in different populations is a very important biological task. However, biologists often use the product Ns to define a different concept; they say that drift “dominates” selection or that drift is “stronger than” selection when Ns is much smaller than some threshold quantity (e.g., ½) and that the reverse is true when Ns is much larger than that threshold. We argue that the question of whether drift dominates selection for a single allele in a single population makes no sense. Selection and drift are causes of evolution, but there is no fact of the matter as to which cause is stronger in the evolution of any given allele.     

Distribution of acetylator phenotypes in the Moscow population

The data concerning distribution of acetylator phenotypes in Moscow city population are presented. 169 adults (96 women and 73 men) were tested by the Evans' method. The percentages of rapid and slow acetylators were 48 and 52%, respectively.     

Pharmacoanthropology: drug metabolism

This is a report of similarities and differences among various ethnically defined populations with respect to their capacities to metabolize the prototype drugs antipyrine, caffeine, and debrisoquine. There were equal levels of the three main metabolites of antipyrine in the urine of Caucasians and Orientals; differences in antipyrine clearance between English and Indian subjects appeared to have environmental causes. Exploration of various metabolite ratios of caffeine in the urine of Caucasians and Orientals living in Canada showed three patterns: 1) no interethnic difference occurred in the ratio thought to indicate xanthine oxidase activity; 2) products of 7-demethylation and of hydroxylation of paraxanthine , both probably produced by cytochrome P-450, showed different averages in the populations; 3) the new secondary metabolite acetylformyl -methyluracil proved to be a useful indicator of the genetically controlled acetylator status, thereby confirming the well-known population difference for acetylator gene frequency. Analysis of data on debriosquine hydroxylation suggested that interpretation of the standardized metabolic ratio may be appropriate for Caucasian and Oriental groups but is misleading for published data from Saudi Arabia, Nigeria, and Ghana; even these two closely related West African populations seem to differ in debrisoquine metabolism.     

Pendular activity of human upper limbs during slow and normal walking

When walking at normal and fast speeds, humans swing their upper limbs in alternation, each upper limb swinging in phase with the contralateral lower limb. However, at slow and very slow speeds, the upper limbs swing forward and back in unison, at twice the stride frequency of the lower limbs. The change from “single swinging” (in alternation) to “double swinging” (in unison) occurs consistently at a certain stride frequency for agiven individual, though different individuals may change at different stride frequencies. To explain this change in the way we use our upper limbs and individual variations in the occurrence of the change, the upper limb is modelled as a compound pendulum. Based on the kinematic properties of pendulums, we hypothesize that the stride frequency at which the change from “single swinging” to “double swinging” occurs will be at or slightly below the natural pendular frequency (NPF) of the upper limbs. Twenty-seven subjects were measured and then filmed while walking at various speeds. The mathematically derived NPF of each subject's upper limbs was compared to the stride frequency at which the subject changed from “single swinging” to “double swinging.” The results of the study conform very closely to the hypothesis, even when the NPF is artificially altered by adding weights to the subjects' hands. These results indicate that the pendulum model of the upper limb will be useful in further investigations of the function of the upper limbs in human walking. © 1994 Wiley-Liss, Inc.     

Time to Normalization and Sustainable Normal Serum Thyrotropin Concentrations in Patients with Hyperthyroidism: Comparison of Methimazole and Radioactive Iodine Treatments

ObjectiveThe aim of this study was to compare the “time to euthyroidism” and “time spent in euthyroidism” following methimazole (MMI) and radioactive iodine (RAI) treatments.MethodsThree hundred fifty-eight patients with hyperthyroidism, 178 who underwent long-term MMI treatment and 180 patients who underwent RAI treatment, were analyzed. The time to normalization of increased serum values of free thyroxine and triiodothyronine and suppressed serum thyroid-stimulating hormone (TSH) values as well as the percentage of time that the thyroid hormone levels remained within normal ranges during a mean follow-up time of 12 years were compared.ResultsThe mean time to euthyroidism was 4.59 ± 2.63 months (range, 2-16 months) in the MMI group and 15.39 ± 12.11 months (range, 2-61 months) in the RAI group (P < .001). During follow-up, the percentage of time spent in euthyroidism was 94.5% ± 7.3% and 82.5% + 11.0% in the MMI and RAI groups, respectively (P < .001). Serum TSH values above and below the normal range were observed in 5.3% and 0.2% of patients, respectively, in the MMI group and 9.8% and 7.7% of patients, respectively, in the RAI group (P < .001). The time to euthyroidism and the percentage of time spent in euthyroidism in 40 RAI-treated patients with euthyroidism were similar to those in the MMI group and significantly shorter than those in the RAI-treated hypothyroid and relapsed subgroups. In patients who continued MMI therapy for >10 years, the percentage of time spent in euthyroidism was >99%.ConclusionIn our cohort of selected patients, MMI therapy was accompanied by faster achievement of the euthyroid state and more sustained normal serum TSH levels during long-term follow-up compared with RAI therapy.     

A new semi-automated instrument to improve the fine needle aspiration procedure during breast lesion cell sampling

A large and increasing number of women in the western world will at some point during their life be investigated morphologically for some type of breast lesion. Fine Needle Aspiration (FNA) is one morphological method which is considered to be the fastest, cheapest and the most patient-friendly approach. However, the frequency of conclusive samples using this method varies and is often too low, especially when performed by unexperienced operators. In this study we have developed and tested a new semi-automated instrument (“CytoTest”) designed for FNA which is intended to improve the efficacy of the technique by increasing the percentage of conclusive samples. A total of 443 consecutive aspiration procedures on palpable breast lesions were performed to compare this new “CytoTest” equipment with the standard protocol using the same type of needles. We conclude that by increasing the extent and frequency of the reciprocatory motions used by an experienced sampling operator as well as enhancing the ejection pressure, the cellular yield can be increased almost three folded compared to the standard protocol. For cases with high amounts of non-diagnostic material (such as blood or cystic fluid) which were discarded, up to four times more sample could be obtained. Furthermore, the frequency of sparse samples under 1 mg was halved with use of the “CytoTest”.