DNA identification of species of the Anopheles maculipennis complex and first record of An. daciae in Belgium.

The present study aimed at identifying the members of the Anopheles maculipennis complex (Diptera: Culicidae) occurring in Belgium. Therefore, the second internal transcribed spacer of nuclear ribosomal DNA (ITS2) and the mitochondrial cytochrome oxidase subunit I (COI) loci were sequenced in 175 and 111 specimens, respectively, collected between 2007 and 2019. In parallel, the suitability of two species-diagnostic PCR-RFLP assays was tested. The identified specimens included: An. maculipennis s.s. (N = 105), An. daciae (N = 62), An. atroparvus (N = 6) and An. messeae (N = 2). Each species was characterized by unique ITS2 haplotypes, whereas COI only supported the monophyly of An. atroparvus, a historical malaria vector in Belgium. Species identification results were further supported by unique PCR-RFLP banding patterns. We report for the first time An. daciae in Belgium, where it was found to co-occur with An. maculipennis s.s. The latter was the most prevalent in the collection studied (60%) and appears to have the widest distribution in Belgium. As in other studies, An. daciae and An. messeae appeared the most closely related species, up to the point that their species status remains debatable, while their ecological differences, including vector competences, need further study.

Genetic structure and range expansion of Zeugodacus Cucurbitae (Diptera: Tephritidae) in Africa.

Hypotheses about the worldwide colonization routes of the melon fly, Zeugodacus cucurbitae (Diptera: Tephritidae), are mainly based on sparse historical records. Here we aim at reconstructing the colonization history of the African continent based on an improved description of the population structure of Z. cucurbitae and approximate Bayesian analyses. Individuals of Z. cucurbitae were sampled in 17 localities from East, West and Central Africa and genotyped at 19 microsatellite markers. Bayesian analyses showed intracontinental population structuring with populations from Uganda diverging from those of Tanzania and populations from Burundi and Kenya showing traces of admixture with West African samples. Approximate Bayesian Computation provided support to the hypothesis of a single introduction Z. cucurbitae into East Africa and subsequent expansion to West Africa, each colonization event was followed by a bottleneck that promoted population divergence within Africa. Parameter estimates suggested that these events are roughly compatible with the historical records of Z. cucurbitae presence in sub-Saharan Africa (viz. 1936 in East Africa and 1999 in West Africa) and allow excluding alternative hypotheses on older or multiple introductions of Z. cucurbitae.

An integrated diagnostic setup for the morphological and molecular identification of the Ceratitis FAR complex (C. anonae, C. fasciventris, C. rosa, C. quilicii, Diptera, Tephritidae).

The Ceratitis FAR complex (Diptera, Tephritidae) includes four economically important frugivorous flies (Ceratitis anonae, Ceratitis fasciventris, Ceratitis quilicii, Ceratitis rosa) whose immature stages and adult females cannot be properly resolved through morphological identification. In order to develop a simplified molecular tool for the identification of two of these species (C. rosa, C. quilicii), we selected a subset of six microsatellite markers out of a panel of 16 loci that were previously developed for the molecular differentiation of the taxa within the complex. These six markers were first tested in silico and then used for the actual genotyping of C. quilicii and C. rosa, resulting in the correct identification of all male reference specimens. Here, we propose an integrated morphological and molecular setup for the identification of the four species of the FAR complex. The decision map relies on preliminary DNA barcoding or morphological identification (when possible) to exclude species not belonging to the complex followed by (a) morphological identification of all adult male specimens and female C. anonae, (b) molecular identification via a panel of 16 microsatellite markers for immature stages, damaged vouchers and samples potentially including adult female C. fasciventris/C. quilicii/C. rosa and (c) molecular identification via a reduced panel of six microsatellite markers for samples including only C. quilicii and C. rosa. This simplified diagnostic setup was profitably implemented in the framework of the ERAfrica fruit fly project and will help correctly identify species within the FAR complex for their early detection and monitoring.

Outcome of hepatitis B and C virus-associated hepatocellular carcinoma occurring after renal transplantation.

Kidney transplant recipients (KTR) are subjected to immunosuppressive therapy that can enhance hepatitis B and C virus replication, leading to cirrhosis and hepatocellular carcinoma (HCC). The aim of this study was to assess the prevalence and outcome of HCC in KTR. Case-control study. Patients with chronic HBV and/or HCV infection who underwent kidney transplantation between 1976 and 2011 and subsequently developed HCC were compared to a control group of patients with chronic HBV and/or HCV infection, matched for gender and age at HCC diagnosis, who did not receive kidney transplantation. Among 2944 KTR, 330 had hepatitis B and/or C. Fourteen developed HCC, a period prevalence of 4.2%. Age at HCC diagnosis was 52.6 ± 6.5 years (53.5 ± 5.7 in controls, P=.76). Time between transplantation and HCC diagnosis was 16.7 ± 2.7 years. Six HCCs were related to HBV, six to HCV and two to co-infection with HBV and HCV. Immunosuppressive therapy was comparable in HBV, HCV and HBV+HCV patients. At diagnosis, 71% of patients met Milan criteria (65% in the control group, P=.4). Alpha-fetoprotein levels, tumour characteristics and treatment modalities were comparable between both groups. Patient survival 2 years after HCC diagnosis was 28% in KTR, compared to 68% in controls (P=.024). Survival after HCC diagnosis is significantly worse in KTR compared to nontransplanted patients with HBV and/or HCV. Prevention is crucial and should be based on viral eradication/suppression before or after transplantation.

The potential distribution of Bactrocera dorsalis: considering phenology and irrigation patterns.

A species in the Bactrocera dorsalis (Hendel) complex was detected in Kenya during 2003 and classified as Bactrocera invadens Drew, Tsuruta & White. Having spread rapidly throughout Africa, it threatens agriculture due to crop damage and loss of market access. In a recent revision of the B. dorsalis complex, B. invadens was incorporated into the species B. dorsalis. The potential distribution of B. dorsalis has been previously modelled. However, previous models were based on presence data and did not incorporate information on the seasonal phenology of B. dorsalis, nor on the possible influence that irrigation may have on its distribution. Methyl eugenol-baited traps were used to collect B. dorsalis in Africa. Seasonal phenology data, measured as fly abundance throughout the year, was related to each location's climate to infer climatic growth response parameters. These functions were used along with African distribution records and development studies to fit the niche model for B. dorsalis, using independent global distribution records outside Africa for model validation. Areas at greatest risk of invasion by B. dorsalis are South and Central America, Mexico, southernmost USA, parts of the Mediterranean coast, parts of Southern and Eastern Australia and New Zealand's North Island. Under irrigation, most of Africa and Australia appear climatically suitable.

Seasonal Abundance of Mango Fruit Flies (Diptera: Tephritidae) and Ecological Implications for Their Management in Mango and Cashew Orchards in Benin (Centre & North).

We report the results of a large-scale (six orchards) and long-term (5-yr) study on seasonal population fluctuations of fruit flies (Diptera Tephritidae) in mango (2005-2009) and cashew (2007-2009) orchards in the Borgou Department, Benin.During the five consecutive years of mango fruit fly monitoring, 25 tephritid species were captured including three species of Bactrocera, 11 of Ceratitis, and 11 of Dacus, which is represented by 2,138,150 specimens in mango orchards. We observed significant differences in Bactrocera dorsalis (Hendel) counts between "high" and "low" mango production years from 2005 to 2008 but not in Ceratitis cosyra (Walker) counts. The native species, C. cosyra, the most abundant species during the dry season, peaked beginning of May, while the exotic species, B. dorsalis, the most abundant species during the rainy season, peaked in June. Preliminary results underlined the role of nine species of wild hosts and seven species of cultivated ones around mango orchards that played an important role in maintaining B. dorsalis in this Sudan zone all year round. The presence of C. cosyra stretched over 9 mo.During the first 14 wk of tephritid monitoring on cashew orchards situated near mango orchards, most flies (62%) were captured in traps positioned in cashew orchards, showing the strong interest of an early fly control on cashew before the mango season. According to these results, in the Sudan zone, effective and compatible control methods as proposed by the IPM package validated by the West African Fruit Fly Initiative project against mango fruit flies are proposed for a large regional tephritid control program in same zones of West Africa.

Dominance of an invasive fruit fly species, Bactrocera invadens, along an altitudinal transect in Morogoro, Eastern Central Tanzania.

Bactrocera invadens, a fruit fly from Asia, is an invasive pest species across Africa. It appears to continue spreading, not only in latitude but also in altitude. To assess its capacity to infest a large variety of hosts and its competition with other fruit fly species, a study along an altitudinal gradient was conducted. At low altitudes, the high abundance in the field and high infestation of B. invadens in different fruit species make it a serious pest. At high altitudes, colonization has started and B. invadens occurs in low numbers by reproducing successfully in high altitude fruits. Overall the abundance and infestation of B. invadens is influenced by its direct competitor Ceratitis rosa and the presence of its preferred host species. C. rosa is still the dominant species in temperate fruits grown at high altitude. Ceratitis cosyra, however, is negatively affected by B. invadens, this species seems to have shifted hosts to avoid competition. The broad host range and competitive potential of B. invadens increase the risk for further spread not only to higher areas, but also to subtropical regions.

Resolution of three cryptic agricultural pests (Ceratitis fasciventris, C. anonae, C. rosa, Diptera: Tephritidae) using cuticular hydrocarbon profiling.

Discrimination of particular species within the species complexes of tephritid fruit flies is a very challenging task. In this fruit-fly family, several complexes of cryptic species have been reported, including the African cryptic species complex (FAR complex). Cuticular hydrocarbons (CHCs) appear to be an excellent tool for chemotaxonomical discrimination of these cryptic species. In the present study, CHC profiles have been used to discriminate among three important agricultural pests from the FAR complex, Ceratitis fasciventris, Ceratitis anonae and Ceratitis rosa. Hexane body surface extracts of mature males and females were analyzed by two-dimensional gas chromatography with mass spectrometric detection and differences in CHC profiles between species and sexes tested through multivariate statistics and compared with species identification by means of microsatellite markers. Quantitative as well as qualitative CHC profile differences between sexes and species are reported. The CHC profiles consisted of a mixture of linear, internally methyl-branched and mono-, di- and tri-unsaturated alkanes. Twelve compounds were pinpointed as potential chemotaxonomical markers. The present study shows that presence or absence of particular CHCs might be used in the chemical diagnosis of the FAR complex. Moreover, our results represent an important first step in the development of a useful chemotaxonomic tool for cryptic species identification of these important agricultural pests.

Cryptic diversity and gene flow among three African agricultural pests: Ceratitis rosa, Ceratitis fasciventris and Ceratitis anonae (Diptera, Tephritidae).

The 'Ceratitis FAR complex' is a species complex of African fruit flies (Diptera, Tephritidae) including the major agricultural pest Ceratitis rosa and the morphologically similar Ceratitis fasciventris and Ceratitis anonae. To resolve their intra- and interspecific genetic relationships and to estimate gene flow within this complex, we surveyed allelic variation at 16 microsatellite loci in 27 African populations of the three morphospecies. Interpopulation genetic distances and individual Bayesian assignments distinguished five genotypic clusters: two involving C. rosa (R1, R2; that may occur in sympatry), two involving C. fasciventris (F1, F2; with parapatric distributions) and one involving C. anonae (A). Intra- and interspecific patterns of genetic differentiation were not hierarchically structured and genetic differentiation between conspecific clusters (F1-F2 and R1-R2) was higher or comparable with differentiation between heterospecific clusters (e.g. F1-A or R2-A). In some cases, gene flow estimates among morphospecies or among heterospecific genotypic clusters were significantly different from zero, showing the lack of reproductive isolation. Genetic differentiation between genotypic clusters was partly supported by morphological differences observed a posteriori in male secondary sexual characters. These results suggest important revisions to current models of ecological niche requirements and invasion risk of the major agricultural pest C. rosa and provide a basis for a taxonomic re-interpretation of the FAR complex.

A quantitative comparison of frugivorous tephritids (Diptera: Tephritidae) in tropical forests and rural areas of the Democratic Republic of Congo.

Most of the current knowledge about African tephritids originates from studies performed in agricultural areas, while information about their distribution in pristine or moderately disturbed environments is extremely scarce. This study aims at (i) describing levels of spatial variability of frugivorous tephritids in tropical forests and small rural villages of the Congo River basin and (ii) verifying if human-mediated activities, such as small-scale agriculture and trade, can affect their distribution patterns. Four locations were sampled along a 250 km stretch of the Congo River. At each location, pristine and disturbed habitats (i.e. tropical forests and small rural villages, respectively) were sampled, with three replicate sites in each combination of habitat and location. Sampling with modified McPhail traps baited with four different attractants yielded 819 tephritid specimens of 29 species from seven genera (Bactrocera, Carpophthoromyia, Ceratitis, Dacus, Celidodacus, Perilampsis, Trirhithrum). The three most abundant species sampled (Dacus bivittatus, D. punctatifrons, Bactrocera invadens) showed significant variations in abundance across locations and sites and accounted for 98.29% of the overall dissimilarity between habitats. Assemblages differed among locations and sites while they showed significant differences between pristine and disturbed habitats in two out of the four locations. This study shows that frugivorous tephritids in central Congo have remarkably patchy distributions with differences among locations and sites representing the main source of variability. Our data show that, in rural villages of central Democratic Republic of Congo, human activities, such as small-scale agriculture and local commerce, are not always sufficient to promote differences between the tephritid assemblages of villages and those of the surrounding tropical forests.

Macrogeographic population structuring in the cosmopolitan agricultural pest Bactrocera cucurbitae (Diptera: Tephritidae).

The macrogeographic population structure of the agricultural pest Bactrocera cucurbitae (Diptera: Tephritidae) was investigated in order to identify the geographic origin of the species and reconstruct its range expansion. Individuals of B. cucurbitae were collected from 25 worldwide-distributed localities (n = 570) and genotyped at 13 microsatellite loci. The Bayesian clustering reveals that B. cucurbitae can be subdivided into five main groups corresponding to populations from (i) the African continent, (ii) La Réunion, (iii) Central Asia, (iv) East Asia and (v) Hawaii. The proportions of inter-regional assignments and the higher values of genetic diversity in populations from Pakistan, India and Bangladesh suggest that B. cucurbitae originated in Central Asia and expanded its range to East Asia and Hawaii on one hand and to Africa and the islands of the Indian Ocean on the other. A number of outliers (10-19 specimens according to different clustering algorithms) show high levels of admixture (Q > 0.70) with populations from different regions and reveal complex patterns of inter-regional gene flow. Anthropogenic transport is the most plausible promoter of this large-scale dispersal. The introduction of individuals from geographically distant sources did not have a relevant role in the most recent African invasions, which originated from the expansion of local populations. These results could provide a useful background to better evaluate invasion risks and establish priorities for the management of this cosmopolitan agricultural pest.

Ecological niche and potential geographic distribution of the invasive fruit fly Bactrocera invadens (Diptera, Tephritidae).

Two correlative approaches to the challenge of ecological niche modeling (genetic algorithm, maximum entropy) were used to estimate the potential global distribution of the invasive fruit fly, Bactrocera invadens, based on associations between known occurrence records and a set of environmental predictor variables. The two models yielded similar estimates, largely corresponding to Equatorial climate classes with high levels of precipitation. The maximum entropy approach was somewhat more conservative in its evaluation of suitability, depending on thresholds for presence/absence that are selected, largely excluding areas with distinct dry seasons; the genetic algorithm models, in contrast, indicate that climate class as partly suitable. Predictive tests based on independent distributional data indicate that model predictions are quite robust. Field observations in Benin and Tanzania confirm relationships between seasonal occurrences of this species and humidity and temperature.

Uncovering the tracks of a recent and rapid invasion: the case of the fruit fly pest Bactrocera invadens (Diptera: Tephritidae) in Africa.

Phytophagous insects of the genus Bactrocera are among the most economically important invasive fruit fly pests. In 2003, an unknown Bactrocera species was found in Kenya. First identified as an 'aberrant form' of the Asian B. dorsalis complex, it was later recognized as a new species, Bactrocera invadens. Within 2 years of its discovery, the species was recorded in several African countries, becoming an important quarantine pest. As this invasive fly was discovered only recently, no data are available on its invasion pattern in Africa. This pilot study attempts to infer from genetic data the dynamic aspects of the African invasion of this pest. Using microsatellite markers, we evaluated the level of genetic diversity and the extent of common ancestry among several African populations collected across the invaded areas. A sample from the Asian Sri Lankan population was analysed to confirm the Asian origin of this pest. Genetic data cast no doubt that Sri Lanka belongs to the native range, but only a small percentage of its genotypes can be found in Africa. African populations display relatively high levels of genetic diversity associated with limited geographical structure and no genetic footprints of bottlenecks. These features are indicative of processes of rapid population growth and expansion with possible multiple introductions. In the span of relatively few years, the African invasion registered the presence of at least two uncorrelated outbreaks, both starting from the East. The results of the analyses support that invasion started in East Africa, where B. invadens was initially isolated.

African Dacus (Diptera: Tephritidae: molecular data and host plant associations do not corroborate morphology based classifications.

The genus Dacus Fabricius includes economically important pest fruit flies distributed in the Afrotropical and Indo-Australian regions. Two recent revisions based on morphological characters proposed new and partially discordant classifications synonymizing/revalidating several subgeneric names and forming species groups. Regardless these efforts, the phylogenetic relationships among Dacus species remained largely unresolved mainly because of the difficulties in assigning homologous character states. Therefore we investigated the phylogeny of African Dacus by sequencing 71 representatives of 32 species at two mitochondrial (COI, 16S) and one nuclear (period) gene fragments. Phylogenetic relationships were inferred through Bayesian and Maximum Parsimony methods and hypotheses about the monophyly of Dacus subgenera were tested by Shimodaira-Hasegawa tests. The congruence tests and the analyses of the single gene fragments revealed that the nuclear gene supports similar conclusions as the two mitochondrial genes. Levels of intra- and inter-specific differentiation of Dacus species were highly variable and, in some cases, largely overlapping. The analyses of the concatenated dataset resolved two major bootstrap-supported groups as well as a number of well-supported clades and subclades that often comprised representatives of different subgenera. Additionally, specimens of Dacus humeralis from Eastern and Western African localities formed separate clades, suggesting cryptic differentiation within this taxon. The comparisons between the molecular phylogeny and the morphological classification revealed a number of discrepancies and, in the vast majority of cases, the molecular data were not compatible with the monophyly of the currently recognised subgenera. Conversely, the molecular data showed that Apocynaceae feeders are a monophyletic sister group of species feeding on both Cucurbitaceae and Passifloraceae (these latter being also monophyletic). These results show a clear association between the molecular phylogeny of African Dacus and the evolution of host plant choice and provide a basis towards a more congruent taxonomy of this genus.

Host range and distribution of fruit-infesting pestiferous fruit flies (Diptera, Tephritidae) in selected areas of Central Tanzania.

The host range of major fruit fly pests in Central Tanzania was evaluated from October 2004 to October 2006. Samples of 48 potential hosts were collected and incubated for fruit fly emergence. Bactrocera invadens was the dominant species in incidence expressed as the ratio of infested to total number samples collected, as well as infestation rate, expressed as number of flies emerging per unit weight. Eight new host fruits are reported. Infestation by native pests, such as Ceratitis capitata and C. cosyra, was minor compared to B. invadens. Ceratitis rosa was the dominant species in temperate fruits, and Cucurbitaceae were mainly infested by Bactrocera cucurbitae, a specialized cucurbit feeder. Among commercial fruits, high infestation incidences were observed in mango and guava, but they decreased throughout the fruiting season. Low infestation rates were observed in all Citrus species and in avocado, indicating these fruits as poor hosts for the studied fruit fly pests in this region. Widespread availability and abundance of fruit species studied here ensures year-round breeding of B. invadens. Seasonal infestation differs, with mango being the most important host in October to January, while guava being important from February to August. Tropical almond showed very high incidence and infestation rate for B. invadens and might act as an important reservoir host, bridging the fruiting seasons of mango and guava. Soursop acts as an important host for C. cosyra after the mango season. Ceratitis capitata is a pest of minor importance of the commercial fruits studied in this region.

High suspicion of bacillary angiomatosis in a kidney transplant recipient: a difficult way to diagnose--case report.

Bacillary angiomatosis is an infection caused by Bartonella, which has first been described in human immunodeficiency virus (HIV)-infected patients. We report an unusually located lesion, in a totally asymptomatic kidney transplant recipient. The diagnosis was strongly suggested based on the iconography and our histological analysis, but was not confirmed using polymerase chain reaction (PCR) and immunohistochemical studies. We illustrate our difficult way to the diagnosis as well as the course of the disease and our therapeutic strategy.

Impact of Acute Infection Requiring Hospitalization on Tacrolimus Blood Levels in Kidney Transplant Recipients.

BACKGROUND: Tacrolimus is metabolized by members of the cytochrome p450 3A subfamily, and its bioavailability depends also on P-glycoprotein. We have observed that some patients admitted for infection presented with increased tacrolimus trough levels (TLs). The aim of the study was to assess the impact of infection on tacrolimus TLs and to determine the factors involved in TL fluctuations. METHODS: This retrospective cohort study included patients transplanted with a kidney between 2009 and 2011 who were hospitalized for an acute infection. Tacrolimus TLs and dosages were recorded before hospitalization, at admission, and 1 month after discharge. Increased levels of tacolimus were defined as TL 25% higher on admission than those recorded at the last visit before hospitalization. RESULTS: Seventy-seven patients were hospitalized 138 times for infection. More than two thirds of first hospitalizations occurred during the first post-transplant year. Causes of hospitalization were urinary (33%), cytomegalovirus (27%), digestive (15%), and pulmonary (12%) infections. Thirty-five percent of kidney transplant recipients had increased tacrolimus TLs (27/77 patients) in 24% of the hospitalizations (34/138). In 34 hospitalizations occurring in 27 patients, TL at admission was ≥25% compared with the last visit before admission. Comparing these 34 hospitalizations with the other 104, no significant differences were noted, except for a greater fraction of digestive infections in the group with elevated tacrolimus TLs, independent of diarrhea occurrence. CONCLUSIONS: Up to 35% of kidney transplant recipients admitted for acute infection present with high tacrolimus TLs, requiring a dose reduction. How acute infection precisely affects metabolism and bioavailability of tacrolimus remains to be investigated.

Immunotherapy of established tumors in mice by intratumoral injection of an adenovirus vector harboring the human IL-2 cDNA: induction of CD8(+) T-cell immunity and NK activity.

Intratumoral (i.t.) injections of an adenovirus encoding the human interleukin-2 (IL-2) under the control of the RSV (Ad-pRSV-IL-2) or CMV (Ad-pCMV-IL-2) promoter were performed in established mastocytoma P815 tumors in B6D2 mice. Both early and long-term survival were found increased in mice treated with Ad-pCMV-IL-2 as compared with those obtained with Ad-pRSV-IL-2: tumor regression was observed in 30--50% of mice for the former and 5--15% for the latter. Difference in efficacy between the two vectors was directly correlated to the amount of IL-2 produced i.t. between 24 and 48 hours postinjection, which reached 10--20 ng/tumor for Ad-pCMV-IL-2 and 0.3--0.5 ng/tumor for Ad-pRSV-IL-2. In both cases, expression in the tumor was clearly detectable for a period of 7--10 days postinjection. Serum IL-2 was not detectable in mice treated with Ad-pRSV-IL-2, whereas expression peaked at a total of 1--2 ng at 24 hours but declined very rapidly in the Ad-pCMV-IL-2-treated group. Constant production of IL-2 inside the tumor was necessary for successful therapy because i.t. injections of recombinant IL-2 at levels up to 1 microg for five consecutive days did not lead to antitumoral activity. Evidence of induced systemic immunity following Ad-pCMV-IL-2 injections was obtained from rechallenge experiments in which tumor-free mice after treatment rejected a subsequent contralateral injection of a lethal dose of P815 tumor cells and from the observation that regression of nontreated tumors occurred in animals bearing bilateral tumors that were treated i.t. in a single tumor with Ad-pCMV-IL-2. P815-specific cytotoxic T lymphocytes (CTL) were found specifically in spleen cells from cured mice or rechallenged mice but not in control mice. Interestingly, limiting dilution analysis of anti-P815 CTL precursor (CTLp) frequency revealed a significant increase in mice cured of their tumor as compared to that obtained in naive mice or control mice treated or not with Ad-IL-2 but whose tumor was growing. In vivo depletion of T-cell subsets, as well as natural killer cells at the time of i.t. injections with Ad-pCMV-IL-2, demonstrated that both CD8(+) T cells and natural killer cells, but not CD4(+) T cells, were required for successful therapy. Finally, mice preimmunized with Ad-null viruses were severely compromised in their capacity to eradicate established P815 tumors after Ad-pCMV-IL-2 therapy, at least when neutralizing antibody titers reached a critical level.

Treatment of renal graft artery stenosis. Comparison between surgical bypass and percutaneous transluminal angioplasty.

In order to compare saphenous bypass (SB) and percutaneous transluminal angioplasty (PTA) as treatment of renal graft artery stenosis (GAS), we have reviewed the results of both procedures in 33 patients treated consecutively by either SB (n = 16) or PTA (n = 17). All patients had become hypertensive within the first year after transplantation despite triple hypotensive drug therapy. SB was performed 17 (range 3-55) and PTA 19 (range 2-96) months after transplantation. SB failed in only 1 patient as a result of vascular thrombosis with graft loss. PTA was technically unsuccessful in 3 patients and was complicated by vascular branch thrombosis in 1 patient. Blood pressure decrease was similar in both groups: from 179/114 before SB to 147/90 (n = 15, P less than .001) at 6 months and 150/93 (n = 14, P less than .005) at 12 months after SB and from 177/110 before PTA to 149/93 (n = 13, P less than .01) at 6 months and 150/95 (n = 10, P less than .02) at 12 months. At 1 year, control of BP was improved in 85% of SB group patients and 74% of PTA group patients. Recurrent stenosis was documented in 3 PTA group patients: subsequently 1 had a successful SB and the 2 others a repeated PTA--successful in 1, unsuccessful in the other. We conclude that both methods are equally effective for BP control but that PTA entails a higher rate of initial failure and a significant rate of restenosis. However, because of technical ease and better tolerance, PTA emerges as the first-choice treatment of GAS, SB remaining indicated when PTA is not feasible or has failed.

Simultaneous determination of endogenous and 13C-labelled thyroid hormones in plasma by stable isotope dilution mass spectrometry.

This study describes a capillary gas chromatography-mass spectrometry (GC-MS) method for the simultaneous determination of endogenous thyroid hormone (thyroxine, T4) and its 13C-labelled analogue (13C6-thyroxine) in plasma. 13C9-thyroxine was used as analytical internal standard. A double derivatization (CH3OH/HCl and HFBA) inducing good GC mobility was used for the GC-MS analysis of the thyroid hormones. Quantification was carried out by selected ion monitoring (SIM) of specific ions of the fragment ions (m/z 970/976/979). The detection limit of the present GC-MS-SIM method was found to be 100 pg per injection for thyroxine (S/N=3.0). A first implementation in in vivo tests of 13C6-T4 like metabolic tracer was carried out under veterinary control on one cat and one rabbit. The thyroxine follow-up was done by GC-MS and based on double isotopic dilution with two different regio-selective 13C-labelled molecules of the same hormone. The present paper discusses the possibilities and limitations of this methodology. The in vivo experiment demonstrated that the use of stable isotopes and mass spectrometry provide a reliable methodology for hormonal monitoring.