COI haplotype groups in Mesocriconema (Nematoda: Criconematidae) and their morphospecies associations

Without applying an a priori bias for species boundaries, specimen identities in the plant-parasitic nematode genus Mesocriconema were evaluated by examining mitochondrial COI nucleotide sequences, morphology, and biogeography. A total of 242 specimens that morphologically conformed to the genus were individually photographed, measured, and amplified by a PCR primer set to preserve the linkage between specimen morphology and a specific DNA barcode sequence. Specimens were extracted from soil samples representing 45 locations across 23 ecoregions in North America. Dendrograms constructed by neighbor-joining, maximum likelihood, and Bayesian Inference using a 721-bp COI barcode were used to group COI haplotypes. Each tree-building approach resulted in 24 major haplotype groups within the dataset. The distinctiveness of these groups was evaluated by node support, genetic distance, absence of intermediates, and several measures of distinctiveness included in software used for the exploration of species boundaries. Five of the 24 COI haplotype groups corresponded to morphologically characterized, Linnaean species. Morphospecies conforming to M. discus, Discocriconemella inarata, M. rusticum, M. onoense, and M. kirjanovae were represented by groups composed of multiple closely related or identical COI haplotypes. In other cases, morphospecies names could be equally applied to multiple haplotype groups that were genetically distant from each other. Identification based on morphology alone resulted in M. curvatum and M. ornatum species designations applied to seven and three groups, respectively. Morphological characters typically used for species level identification were demonstrably variable within haplotype groups, suggesting caution in assigning species names based on published compendia that solely consider morphological characters. Morphospecies classified as M. xenoplax formed a monophyletic group composed of seven genetically distinct COI subgroups. The species Discocriconemella inarata is transferred to Mesocriconema inaratum based on its phylogenetic position on the COI tree as well as previous phylogenetic analyses using 18S, ITS1, and cytochrome b nucleotide sequences. This study indicates that some of the species considered cosmopolitan in their distribution are actually multispecies polyphyletic groupings and an accurate assessment of Mesocriconema species distributions will benefit from molecular determination of haplotype relationships. The groups revealed by COI analysis should provide a useful framework for the evaluation of additional Mesocriconema species and will improve the reliability of designating taxonomic units in studies of nematode biodiversity. 

Tropical nematode diversity: vertical stratification of nematode communities in a Costa Rican humid lowland rainforest

Comparisons of nematode communities among ecosystems have indicated that, unlike many organisms, nematode communities have less diversity in the tropics than in temperate ecosystems. There are, however, few studies of tropical nematode diversity on which to base conclusions of global patterns of diversity. This study reports an attempt to estimate nematode diversity in the lowland tropical rainforest of La Selva Biological Research Station in Costa Rica. We suggest one reason that previous estimates of tropical nematode diversity were low is because habitats above the mineral soil are seldom sampled. As much as 62% of the overall genetic diversity, measured by an 18S ribosomal barcode, existed in litter and understorey habitats and not in soil. A maximum-likelihood tree of barcodes from 360 individual nematodes indicated most major terrestrial nematode lineages were represented in the samples. Estimated 'species' richness ranged from 464 to 502 within the four 40 x 40 m plots. Directed sampling of insects and their associated nematodes produced a second set of barcodes that were not recovered by habitat sampling, yet may constitute a major class of tropical nematode diversity. While the generation of novel nematode barcodes proved relatively easy, their identity remains obscure due to deficiencies in existing taxonomic databases. Specimens of Criconematina, a monophyletic group of soil-dwelling plant-parasitic nematodes were examined in detail to assess the steps necessary for associating barcodes with nominal species. Our results highlight the difficulties associated with studying poorly understood organisms in an understudied ecosystem using a destructive (i.e. barcode) sampling method.

Vagus nerve stimulation: analysis of device parameters in 154 patients during the long-term XE5 study

PURPOSE

To determine the effect of changes in device settings and duty cycle (on and off times) on the efficacy of vagus nerve stimulation (VNS) for refractory epilepsy. In the long-term XE5 study of VNS for intractable epilepsy, the median reduction in seizure frequency improved significantly after 1 year of follow-up. A central question is whether device changes improve efficacy. We analyzed the effects of device parameter changes on seizure frequency in 154 subjects who completed the study and who had complete data for analysis.

METHODS

Retrospective analysis of device changes during the XE5 long-term study of VNS. During the XE5 long-term follow-up study, the subject's device settings were modified within a Food and Drug Administration (FDA)-approved range of output current, pulse duration, frequency, on time, and off time. Significant changes in device settings occurred after 3 months. We investigated the relationship between percentage reduction in seizures and changes in device parameters between the 3- and 12-month visits. Within-group comparisons were performed for those who continued on standard on/off cycle of 30 s on and 5 min off, and those with the most common off times of 3, 1.8, and < 1.1 min.

RESULTS

Output current, pulse duration, frequency, and off time changed significantly between the 3- and 12-month long-term follow-ups. For the group as a whole, changes in device settings were not correlated with an improvement in efficacy. However, a significant improvement in efficacy occurred in a subgroup whose off time was reduced to < or = 1.1 min. In this group, the median reduction in seizures improved from 21% before the change in off time, to 39% after the change in off time (Wilcoxon Signed-Rank, p = 0.011). The responder rate (> 50% reduction in seizures) also significantly improved from 19 to 35% (McNemar's test, p = 0.046).

CONCLUSIONS

The data from this retrospective analysis indicate that device changes were not the primary determinant of increased efficacy at 12 months of long-term follow-up. In general, patients who remained on the original settings of 30 s on and 5 min off continued to respond or improve in their response over the 1-year period. However, some patients may benefit from reductions in off time (increases in duty cycle). In a subgroup initially resistant to VNS, a change in off time to < or = 1.1 min off did result in significant improvements in efficacy.

Increasing the impact of health plan report cards by addressing consumers' concerns

Most plan report cards that compare the performance of health plans have framed the decision about plan choice as an opportunity to get better-quality care. This study uses a controlled experimental design to examine the effect of reframing the health plan choice decision to one that emphasizes protecting oneself from possible risk. The findings show that framing the health plan decision using a risk message has a consistent and significant positive impact on how consumers comprehend, value, and weight comparative performance information.

Early clinical results of the use of radiofrequency lesioning in the treatment of plantar fasciitis

In this paper the authors discuss plantar fascial heel pain, including its etiology and treatment. The results of a retrospective study using radiofrequency lesioning on plantar fascial heel pain are presented and discussed. Thirty-nine patients were treated with radiofrequency lesioning, and 92% of the patients experienced complete resolution of symptoms following the procedure.

Vaginal birth after cesarean section in twin gestation

OBJECTIVE

We report a 10-year experience with vaginal birth after cesarean section in women with twins.

STUDY DESIGN

Data were gathered from labor and delivery records and maternal and neonatal hospital charts. Women with a vertical uterine scar, a previous uterine rupture, an unrepaired dehiscence, or obstetric contraindications to labor were excluded from a trial of labor. Full-thickness uterine defects requiring intervention were classified as ruptures; all others were classified as dehiscences.

RESULTS

Between Jan. 1, 1985, and Dec. 31, 1994, at Los Angeles County/University of Southern California Women's Hospital, 210 women with previous cesarean births were delivered of twins. One hundred eighteen (56%) underwent repeat cesarean delivery without a trial of labor. Ninety-two (44%) undertook a trial of labor with no uterine ruptures and no increase in maternal or perinatal morbidity or mortality.

CONCLUSIONS

In women with twins a trial of labor after a previous cesarean section is a safe and effective alternative to routine repeat cesarean delivery.

The effects of methadone maintenance with opioid takers. A review and some findings from one British city

Various benefits claimed for methadone maintenance in the treatment of opioid drug takers are reviewed. It is said to stop illicit drug use, maintain treatment contact, reduce morbidity, mortality and crime, and improve social adjustment. Little firm evidence is found to support these claims. Results are reported comparing 26 drug takers on methadone prescriptions with 16 illicit opioid takers. The measures used are Stimson's (1972) 'Patterns of Behaviour' questionnaire and direct behavioural measures of social functioning. The groups are found not to differ in terms of treatment contact, work status and involvement with other drug takers. There is some evidence that the methadone group is involved in less criminal activity. However, no association is found between amounts of drugs prescribed and numbers of local pharmacy thefts. It is concluded that the benefits of methadone maintenance have been exaggerated.

Total body washout for the treatment of endotoxin shock. An experimental study

In order to study the therapeutic effects of total body washout (TBW) in experimental endotoxin shock, we used the following procedure. Seventeen rabbits (controls) received Escherichia coli endotoxin (5 mg/kg) intravenously and were observed for 12 hours. Shock developed in 14 rabbits; they died in 5.2 +/- 1.0 (mean +/- SD) hours, with a survival rate of 18%. Seventeen rabbits were subjected to TBW only. Muscle temperature was lowered to 25 C with a pump oxygenator circuit and the animals were exsanguinated. After residual blood was flushed out with cold, lactated Ringer solution, the animals were rewarmed with another circuit that was primed with homologous blood. Fourteen animals survived (82%). Two hours after E. coli endotoxin was injected intravenously 17 animals were treated with TBW. The survival rate (53%) of this group was significantly higher than in the control group (18%) (P less than .005). Eight nonsurvivors showed hypotension and acidosis even after TBW treatment, thus indicating the irreversibility of their endotoxin shock. This study indicates that endotoxin shock may be reversed by TBW if it is instituted before irreversible cellular damage.