South American Origin Research Articles

Molecular Phylogenetics and Biogeography of the Caribbean-Centered Croton Subgenus Moacroton (Euphorbiaceae s.s.)

Initial molecular phylogenetic studies established the monophylly of the large genus Croton (Euphorbiaceae s.s.) and suggested that the group originated in the New World. A denser and more targeted sampling of Croton species points to a South American origin for the genus. The nuclear and chloroplast genomes indicate a different rooting for the phylogeny of Croton. Although we favor the rooting indicated by the chloroplast data our conclusions are also consistent with the topology inferred from the nuclear data. The satellite genera Cubacroton and Moacroton are embedded within Croton. These two genera are synonimized into Croton and a new subgenus, Croton subgenus Moacroton, is circumscribed to include them and their allied Croton species. Croton subgenus Moacroton is morphologically characterized by a primarily lepidote indumentum, bifid or simple styles, and pistillate flowers with sepals that are connate at the base. This newly circumscribed subgenus is found from North America to South America, and in contrast to the majority of Croton species most of its members are found in mesic habitats. The group is most diverse in the greater Caribbean basin. A molecular clock was calibrated to the phylogeny using the available Euphorbiaceae fossils. The timing and pattern of diversification of Croton is consistent with both the GAARlandia and Laurasian migration hypotheses. A single species, Croton poecilanthus from Puerto Rico, is placed incongruently by its nuclear and chloroplast genomes. The possibility of this species being of hybrid origin is discussed.

Studies in the genus Paspalum (Paniceae, Poaceae) in Europe — 2. The Quadrifaria group

Abstract Verloove, F. & Reynders, M.: Studies in the genus Paspalum (Paniceae, Poaceae) in Europe — 2. The Quadrifaria group. — Willdenowia 37: 423–430. — ISSN 0511-9618; © 2007 BGBM Berlin-Dahlem. doi:10.3372/wi.37.37203 (available via http://dx.doi.org/) The South American Paspalum quadrifarium has been reported as a naturalized xenophyte in Tuscany and Liguria, Italy, since at least the 1960s. In the present contribution the discovery of the closely related P. exaltatum, also of South American origin, in Liguria, Italy, is reported. These are the only known occurrences in Europe of both species, which are very similar to each other and likely to be confused. In the present paper their diagnostic features are discussed and original line drawings and SEM photographs for both taxa are presented. Their current distribution in Italy is shown and some ecological remarks are added.

Molecular analysis of the CLCN5 gene in Dent’s disease: first mutation identified in a patient from South America

Dent's disease is a rare renal tubular disorder characterized by low-molecular weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, rickets and eventual renal failure. The selective loss of low-molecular weight proteins points to a defect of the proximal tubule, where filtered proteins are normally reabsorbed by endocytosis. The disease tends to present in childhood or early adult life, and males are more severely affected than females. The disease is caused by mutations in CLCN5 or OCRL1, both on the X chromosome, which code for the chloride/proton exchange transporter ClC-5 and the phosphatidylinositol-4,5-biphosphate-5-phosphatase, respectively. Mutational analysis of CLCN5 gene from 4 unrelated patients diagnosed with Dent's disease and their relatives, 3 from Spain and 1 from Bolivia, was performed by PCR and automatic DNA sequencing. In the current study, we report the identification of 4 mutations in CLCN5 of 1 family from Bolivia and 3 families from Spain. Two of the mutations are novel and consist of 1 nonsense mutation, Y502X, and 1 missense mutation, L225P, affecting ClC-5alpha-helix F, one of the helices involved in formation of the chloride selectivity filter. Our results add to the expanding spectrum of mutations in CLCN5. This is the first report of a CLCN5 mutation in a Dent's disease patient of South American origin.

Mandibular morphology as an indicator of human subadult age: geometric morphometric approaches

Methods for skeletal identification have a long history in physical and forensic anthropology. Recent literature demonstrates that new methods are constantly being developed, concurrent with refinements to those already commonly employed. The present study concerns the application of geometric morphometrics to assess the potential of mandibular morphology as a developmental marker for estimating age at death in subadult human skeletal remains. The sample comprises 79 known age and sex subadult individuals of South African Bantu and African American origin; 38 bilateral three-dimensional landmarks were designed and acquired using a portable digitizer. Linear regression was used to predict age using the multivariate descriptors of mandible size and shape based on configurations of three-dimensional landmarks. Our results show that the mandible can be used to predict age in the subadult skeleton with accuracy comparable to standards based on the dentition (standard error rates are between +/-1.3 and +/-3.0 years). These results closely parallel our previous study using the linear measurement of ramus height, but suggest that geometric morphometrics may be slightly more accurate when adolescents are included in the sample.

Suprageneric phylogenetics of Myrteae, the generically richest tribe in Myrtaceae (Myrtales)

To clarify relationships within the predominantly Neotropical and exclusively fleshy‐fruited Myrteae (49 genera and c. 2,500 species), we provide a phylogenetic hypothesis for evolutionary relationships between 31 of these genera by analyzing nuclear ITS and ETS ribosomal DNA, and plastid psbA‐trnH and matK DNA sequences from 75 Myrteae species and 13 outgroup taxa using parsimony and Bayesian inference. Four morphological characters are epitomized on the resulting trees, and biogeographical analyses are also performed. Myrteae are monophyletic, comprising seven clades plus two isolated taxa of unclear relationships. Morphological characters exhibit homoplasy, although in combination are useful for clade diagnosis. Biogeographical analyses are inconclusive regarding the ancestral area of the tribe, but South American colonization before northern radiation via the Andes appears likely. The largest genera, Eugenia and Myrcia s.l., have western and southeastern South American origins, respectively.

Mandibular Morphology as an Indicator of Human Subadult Age: Interlandmark Approaches*

The dentition is widely recognized as the set of developmental markers that appear to show the least variability against chronological age; these markers are thus widely used in forensic anthropological investigations. As a possible alternative, we investigate here the potential of mandibular morphology as a developmental marker for estimating age at death in subadults. The sample analyzed comprises 79 known age and sex subadult individuals of South African Bantu and African American origin. Linear measurements of ramus height were obtained from the mathematical conversion of three-dimensional landmark data. A series of regression analyses were then performed to predict age by using the measurement of ramus height; results were cross-validated using a jackknife procedure. Our results show that ramus height can be used to predict age in the subadult skeleton with accuracy, closely approaching that of standards based on the dentition (standard error rates are between +/-1.1 years and +/-2.4 years).

Around the world in 10 million years: biogeography of the nearly cosmopolitan true toads (Anura: Bufonidae)

ABSTRACTAim The species‐rich family of true toads (Anura: Bufonidae) has been the focus of several earlier studies investigating the biogeography of geographically widespread taxa. Herein, we employ newly developed Bayesian divergence estimate methods to investigate the biogeographical history of this group. Resulting age estimates are used to test several key temporal hypotheses including that the origin of the bufonid clade pre‐dates Gondwanan vicariance (~105 million years ago, Ma). Area cladograms are also invoked to investigate the geographical origin of the family.Location Worldwide, except the Australia–New Guinea plate, Madagascar and the Antarctic.Methods A phylogenetic hypothesis of the relationships among true toads was derived from analysis of 2521 bp of DNA data including fragments from three mitochondrial (12S, tRNAval, 16S) and two nuclear (RAG‐1, CXCR‐4) genes. Analysis of multiple, unlinked loci with a Bayesian method for estimating divergence times allowed us to address the timing and biogeographical history of Bufonidae. Resulting divergence estimates permitted the investigation of alternative vicariance/dispersal scenarios that have been proposed for true toads.Results Our area cladogram resulting from phylogenetic analysis of DNA data supports a South American origin for Bufonidae. Divergence estimates indicate that the family originated earlier than had been suggested previously (78–99 Ma). The age of the enigmatic Caribbean clade was dated to the late Palaeocene–early Eocene. A return of bufonids to the New World in the Eocene was followed by rapid diversification and secondary expansion into South America by the early Oligocene (Rupelian).Main conclusions The South American origin of Bufonidae in the Upper Cretaceous was followed by relatively rapid expansion and radiation around the globe, ending with a return to the Americas via a Eurasian/North American land bridge in the Eocene. Though the exact route of this dispersal (Beringia or North Atlantic) remains unclear, an argument is made for the less frequently invoked North Atlantic connection. The origin of the enigmatic Caribbean lineage was found to be consistent with colonization following the bolide impact at the K/T boundary. These findings provide the first, firm foundation for understanding true toad divergence times and their truly remarkable and global radiation.

Gastroesophageal Reflux Symptoms During and After Pregnancy: A Longitudinal Study

Prevalence of gastroesophageal reflux symptoms (GERS) increases during pregnancy, but there are no longitudinal studies on western populations examining their incidence in each trimester. Our aim was to describe the natural history of GERS in pregnancy and to ascertain whether pregnancy might be associated with a higher risk of developing GERS 1 yr postpartum. Pregnant women (<12 wk gestation) and age-matched controls were included. A telephone survey was conducted, covering pregnant women at 12, 24, and 36 wk of gestation and at 1 yr postpartum, using a validated questionnaire. Controls were interviewed at baseline and 21 months later. Data on 263 pregnant women were analyzed. Incidence of GERS was 25.8% (95% confidence interval [CI] 20.1-31.1%) in the first trimester, 24.3% (95% CI 18.1-30.6%) in the second, and 25.5% (95% CI 18.2-32.8%) in the third. Factors associated with developing GERS in the first trimester were South American origin (odds ratio [OR] 2.75, 95% CI 1.30-5.84) and prepregnancy occasional GERS (OR 3.00, 95% CI 1.35-6.66). Risk factors of GERS in the third trimester were cumulative weight gain during pregnancy (OR 1.18, 95% CI 1.04-1.32) and prepregnancy occasional GERS (OR 3.79, 95% CI 1.08-13.24). Incidence of frequent GERS at 1 yr postpartum was higher in pregnant versus control women (4.7%vs 1.3%, P < 0.05). Incidence of GERS is similar across the three trimesters of pregnancy. Accumulated weight gain during pregnancy is associated with a higher risk of GERS in the third trimester. Pregnancy might constitute a risk factor for developing GERS 1 yr postpartum.

Quality of US Soybean Meal Compared to the Quality of Soybean Meal from Other Origins

AbstractQuality of soybeans and soybean meals (SBM) from non‐US and US origins were compared. The US SBM was more consistent with higher digestibility (by KOH solubility), lower fiber and better quality of protein (by essential amino acid levels) than SBM of other major export origins (Argentina, Brazil and India). Protein quality carried through from whole soybeans to SBM, for a given origin. While the protein content was higher for the SBM from Brazil, the percentage of total digestible amino acids was highest for the SBM from the US and China. The US SBM had the highest content (total) of five essential amino acids for both poultry and swine feed uses, which when coupled with higher digestibility, would give US meal an advantage in rations balanced on amino acids. The mean particle size for all SBM from all origins was within the desirable range specified by nutritionists. The US soybeans were lower in protein than Brazilian soybeans, but higher than Argentine soybeans. The crude protein disadvantage of US soybeans was offset by higher concentrations of the essential amino acids in the lower protein soybeans. The US soybeans were lower in oil content than soybeans from either of the South American origins. Average protein and oil contents of US soybeans were consistent with the 2003 and 2004 annual soybean quality surveys. The US SBM held an advantage in digestibility and concentration of key amino acids in all three studies.

SUCCESSFUL LATINO COMMUNITY PARTNERSHIP PROGRAM FOR SMOKING CESSATION

A recent article by Lopez-Quintero et al.1 documented that US-based Latino smokers are less likely to receive smoking cessation advice than non-Latino White or African-American smokers. “Missed opportunities” in the primary-care setting for smoking cessation for Latinos include low acceptability of pharmacotherapies and counseling for smoking cessation.2–4 Innovative strategies, such as the use of community primary care–academic partnership models, are needed to overcome barriers to smoking treatment.1,5,6 In collaboration with the Rhode Island Department of Health and a community-based education and advocacy center, Progreso Latino, we implemented a smoking cessation program, iYa No Fumo! (“Right now, I am not smoking!”), using a community primary care–academic partnership model for 304 self-identified smokers of Central and South American origin. The program consisted of baseline intakes for assessment of nicotine dependence severity, medical and smoking histories, a group introductory workshop and motivational interviewing, and biweekly follow-up assessments—all conducted by bilingual tobacco treatment specialists. Recruitment—guided by focus groups and key informant interviews—was achieved through promotion at cultural events in the community, word of mouth, and statewide mass media campaigns. Nicotine replacement therapy (NRT; transdermal patches [21, 14, or 7 mg] or gum [2 or 4 mg]) was dispensed to all participants unless contraindicated (mean number of patches per participant = 34.3 [SD= 27.4]; patch strength = 21 [71.7%], 14 [27.8%], or 7 mg/day [0.6%]). Of those attending at least 1 follow-up session within 2 weeks of their target quit date (n = 96 [3 missing]), 45 (48.4%) reported abstinence from tobacco in the previous 7 days, 28 (30.1%) reported “cutting down” on their daily cigarette consumption, and the remaining 20 (21.5%) had relapsed. Using logistic regression, after controlling for nicotine dependence severity with a Spanish-translated, modified Horn-Russell scale,7 amount of patch received was found to significantly predict follow-up (B = 1.36; P < .001; n = 172) and self-reported abstinence status at follow-up (B = 1.08; P < .001). Abstinence rates were reported without biochemical verification. However, our observed abstinence rates were broadly consistent with published research performed in another study of NRT for Latino smokers.8 Findings suggest preliminarily that efforts to reduce disparities in smoking cessation counseling and treatment for Latino smokers may benefit from community primary care–academic partnership models—an approach that appears to maximize the acceptability and use of NRT.

Genetic characterization of Toxoplasma gondii isolates in dogs from Vietnam suggests their South American origin

Dogs are considered a potential risk for transmission of Toxoplasma gondii to humans because they can mechanically transmit oocysts to people and in certain parts of the world dog meat is consumed by humans. The prevalence of T. gondii in 42 dogs from rural Vietnam was determined. Antibodies to T. gondii were assayed by the modified agglutination test, and found in 21 (50%) of 42 dogs with titers of 1:20 in six, 1:40 in seven, 1:80 in two, 1:160 in two, 1:320 in two, 1:640 in one, and 1:1280 or higher in one. Hearts, tongues and brains of 21 seropositive dogs were bioassayed in cats, mice or both. Tissues from eight seropositive dogs were fed to eight T. gondii-free cats. Feces of cats were examined for oocysts. T. gondii was isolated from eight dogs by bioassay in cats. Genotyping of these eight T. gondii isolates using polymorphisms at 10 nuclear markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and a new SAG2, and an apicoplast marker Apico revealed two genotypes. Both genotypes were previously identified from the dog isolates in Colombia, suggesting their South America origin. However, they are different from the predominant Type I, II and III lineages that are widely spread in North America and Europe. This is the first report of isolation of viable T. gondii from any host in Vietnam.

Sexual dimorphism and population variation in the adult mandible

This article forms part of an ongoing series of investigations designed to apply three-dimensional (3D) technology to problems in forensic anthropology. We report here on new morphometric data examining sexual dimorphism and population variation in the adult human mandible. The material is sourced from dissection hall subjects of South African and American origin consequently the sex and a statement of age are known for each individual. Thirty-eight bilateral 3D landmarks were designed and acquired using a Microscribe G2X portable digitizer. The shape analysis software morphologika (www.york.ac.uk/res/fme) is used to analyze the 3D coordinates of the landmarks. A selection of multivariate statistics is applied to visualize the pattern, and assess the significance of, shape variation between the sexes and populations. The determination of sex and identification of population affinity are two important aspects of forensic investigation. Our results indicate that the adult mandible can be used to identify both sex and population affinity with increased sensitivity and objectivity compared to standard analytical techniques.

Sexual dimorphism and population variation in the adult mandible : Forensic applications of geometric morphometrics.

This article forms part of an ongoing series of investigations designed to apply three-dimensional (3D) technology to problems in forensic anthropology. We report here on new morphometric data examining sexual dimorphism and population variation in the adult human mandible. The material is sourced from dissection hall subjects of South African and American origin consequently the sex and a statement of age are known for each individual. Thirty-eight bilateral 3D landmarks were designed and acquired using a Microscribe G2X portable digitizer. The shape analysis software morphologika (www.york.ac.uk/res/fme) is used to analyze the 3D coordinates of the landmarks. A selection of multivariate statistics is applied to visualize the pattern, and assess the significance of, shape variation between the sexes and populations. The determination of sex and identification of population affinity are two important aspects of forensic investigation. Our results indicate that the adult mandible can be used to identify both sex and population affinity with increased sensitivity and objectivity compared to standard analytical techniques.

A Phylogenetic Study of &lt;I&gt;Cuphea&lt;/I&gt; (Lythraceae) Based on Morphology and Nuclear rDNA ITS Sequences

Cuphea is an endemic genus of the New World and the most speciose member of the Lythraceae with ca. 260 species classified in two subgenera and 13 sections. As a first attempt to construct a phylogenetic framework for the genus, data from morphology and nuclear ITS sequences for 53 species and four outgroup taxa were analyzed. Independent results employing morphological and molecular datasets confirmed Cuphea as monophyletic with Pleurophora as sister. The morphological strict consensus tree was substantially unresolved. The ITS parsimony and maximum likelihood phylogenies indicated South America as the initial center of diversification and identified a deep trichotomy, one branch of which was equivalent to subg. Cuphea. The ITS analyses also recognized seven well-supported clades, each composed of members from two to four taxonomic sections. Species of section Melvilla appear in five of the seven clades, supporting the hypothesis that the large, intensely-colored, bird-pollinated floral tubes that define the section are convergent, having evolved from smaller, more promiscuously-pollinated, green-tubed flowers. Sixteen endemic North American species have a single South American origin and form the core of a secondary center of Cuphea diversification in Mexico. The ITS analyses provide initial phylogenetic hypotheses for the genus that clarify relationships previously obscured by the highly homoplastic nature of the morphological taxonomic characters.

PHYLOGENETIC ANALYSIS OF THE CARDINI GROUP OF DROSOPHILA WITH RESPECT TO CHANGES IN PIGMENTATION

Phenotypic variability is the engine that drives future diversification with the expectation that polymorphic ancestors give rise to descendants harboring a subset of the ancestral variation. Here we examine evolutionary transitions from polymorphism to monomorphism in a visually striking New World radiation of fruit flies, the Drosophila cardini group. This group is distributed across the Americas and the Caribbean islands and exhibits a wide spectrum of abdominal pigmentation variation. Specifically, the D. dunni subgroup consists of Caribbean island endemics, each of which is monomorphic for its pigmentation pattern, with an interspecific cline of pigmentation across the islands. The D. cardini subgroup consists of American continental species with wide-ranging distributions and intraspecifically variable abdominal pigmentation. We determined the phylogeny of 18 species and subspecies using three nuclear and three mitochondrial regions analyzed with maximum parsimony, maximum likelihood, and Bayesian methods. The topology produced from a combined dataset exhibited high support values at all nodes, and differed from earlier phylogenetic hypotheses based on polytene chromosome inversion patterns and isozyme data. We find that the D. dunni subgroup species, with the exception of D. belladunni, are derived from a single source not of direct South American origin and their dispersal across the islands of the Caribbean does not follow a simple stepping-stone model. Morphological changes in pigmentation across the island species are incongruent with the colonization history of the group indicating that natural selection may have played a role in the determination of this character. Finally, we demonstrate that monomorphic species have arisen independently from polymorphic ancestors two to three times.

The biogeography of the austral, subalpine genus Ourisia (Plantaginaceae) based on molecular phylogenetic evidence: South American origin and dispersal to New Zealand and Tasmania

Molecular phylogenetic analyses of 26 of the 28 species of Ourisia, including eight of ten subspecies and two purported natural hybrids, are presented and used to examine the biogeography of the genus, which is distributed in subalpine to alpine habitats of South America, New Zealand and Tasmania. Gondwanan vicariance, often cited as the cause of this classic austral biogeographical pattern, was rejected by parametric bootstrapping of our combined dataset. Alternatively, various lines of evidence are presented in favour of a South American origin of Ourisia and subsequent dispersal to Australasia. Specifically, the genus likely arose in the Andes of central Chile and spread to southern Chile and Argentina, to the north-central Andes, and finally to Tasmania and New Zealand. The ancestor of the New Zealand species probably first arrived on the South Island, where the New Zealand species of Ourisia are most diverse, and migrated to the North and Stewart Islands. Because the Tasmanian and New Zealand species are sister to one another, the direction of dispersal between these two areas is equivocal. These results agree with other molecular phylogenetic studies that show that past dispersal between southern hemisphere continents has played an important role in the evolutionary history of many high-elevation austral plants. Our data also show that within South America, many of the geographical barriers (with the exception of the Atacama Desert) that have played a role in the evolution of other plant groups have not affected Ourisia species. Within New Zealand, the phylogeny and biogeography of species of Ourisia coincide with the geological history of the country and patterns of other alpine plants. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 87, 479–513.

The chrondoprotective actions of a natural product are associated with the activation of IGF-1 production by human chondrocytes despite the presence of IL-1beta.

BackgroundCartilage loss is a hallmark of arthritis and follows activation of catabolic processes concomitant with a disruption of anabolic pathways like insulin-like growth factor 1 (IGF-1). We hypothesized that two natural products of South American origin, would limit cartilage degradation by respectively suppressing catabolism and activating local IGF-1 anabolic pathways. One extract, derived from cat's claw (Uncaria guianensis, vincaria®), is a well-described inhibitor of NF-κB. The other extract, derived from the vegetable Lepidium meyenii (RNI 249), possessed an uncertain mechanism of action but with defined ethnomedical applications for fertility and vitality.MethodsHuman cartilage samples were procured from surgical specimens with consent, and were evaluated either as explants or as primary chondrocytes prepared after enzymatic digestion of cartilage matrix. Assessments included IGF-1 gene expression, IGF-1 production (ELISA), cartilage matrix degradation and nitric oxide (NO) production, under basal conditions and in the presence of IL-1β.ResultsRNI 249 enhanced basal IGF-1 mRNA levels in human chondrocytes by 2.7 fold, an effect that was further enhanced to 3.8 fold by co-administration with vincaria. Enhanced basal IGF-1 production by RNI 249 alone and together with vincaria, was confirmed in both explants and in primary chondrocytes (P <0.05). As expected, IL-1β exposure completely silenced IGF-1 production by chondrocytes. However, in the presence of IL-1β both RNI 249 and vincaria protected IGF-1 production in an additive manner (P <0.01) with the combination restoring chondrocyte IGF-1 production to normal levels. Cartilage NO production was dramatically enhanced by IL-1β. Both vincaria and RNI 249 partially attenuated NO production in an additive manner (p < 0.05). IL-1β – induced degradation of cartilage matrix was quantified as glycosaminoglycan release. Individually RNI 249 or vincaria, prevented this catabolic action of IL-1β.ConclusionThe identification of agents that activate the autocrine production of IGF-1 in cartilage, even in the face of suppressive pro-inflammatory, catabolic cytokines like IL-1β, represents a novel therapeutic approach to cartilage biology. Chondroprotection associated with prevention of the catabolic events and the potential for sustained anabolic activity with this natural product suggests that it holds significant promise in the treatment of debilitating joint diseases.

Tecia solanivora

<i>Tecia solanivora</i>

Reconstructing the Origins and Dispersal of the Polynesian Bottle Gourd (Lagenaria siceraria)

The origin of the Polynesian bottle gourd (Lagenaria siceraria), an important crop species in prehistoric Polynesia, has remained elusive. Most recently, a South American origin has been favored as the bottle gourd could have been introduced from this continent with the sweet potato by Polynesian voyagers around A.D. 1,000. To test the hypothesis of an American origin for the Polynesian bottle gourd, we developed seven markers specific to bottle gourd (two chloroplast and five nuclear). The nuclear markers were developed using a new technique where polymorphic inter simple sequence repeat (ISSR) markers are converted into single-locus polymerase chain reaction and sequencing markers--an approach that will be useful for developing markers in other taxa. All seven markers were sequenced in 36 cultivars of bottle gourd from Asia, the Americas, and Polynesia. The results support a dual origin for the Polynesian bottle gourd: the chloroplast markers are exclusively of Asian origin, but the nuclear markers show alleles originating in both the Americas and Asia. Because hybridization of Polynesian bottle gourds with post-European introductions cannot be excluded, ancient DNA from archaeological material will be useful for further elucidating the prehistoric movements of this species in Polynesia. This work has implications not only for the dispersal of the Polynesian bottle gourd but also for the domestication and dispersal of the species as a whole.

Dexamethasone in the treatment of obstetric cholestasis: A case series

SummaryTwelve women with obstetric cholestasis were given dexamethasone after failure to respond to ursodeoxycholic acid. Clinical improvement was achieved in eight cases, without complete resolution of symptoms. Biochemical response was achieved in seven cases. All but two cases had good correlation between clinical and biochemical response. Women of Asian and South American origin were more likely to respond to dexamethasone than Caucasians. There were no reported maternal or fetal side-effects. However, the subsequent consequences of dexamethasone treatment for the mother and fetus have not been thoroughly evaluated. Therefore, even in Asian and South American women, larger studies of dexamethasone are required before this treatment can be recommended as a universally safe and effective treatment for obstetric cholestasis.