Analysis of methanogen diversity in a hypereutrophic lake using PCR-RFLP analysis of mcr sequences

The incidence and diversity of methanogens in Priest Pot, a dynamic and active lake, were monitored by analysing mcrA gene sequences generated from total DNA samples obtained at different times of the year and amplified using the polymerase chain reaction. A number of mcrA clones were analysed by developing an RFLP-based protocol to generate a number of restriction patterns that were assigned to a number of classes. The RFLP patterns for each class were compared with published sequence information for mcrA from cultured methanogens as well as with those from other experimental studies. They could be used to assign tentative identification for some of the Priest Pot clones and also revealed the presence of a number of clones that could not be affiliated to any known methanogens. The limitations of using RFLP profiles of mcrA gene sequences for studying methanogen ecology are discussed.

Effects of levodopa on motor sequence learning in Parkinson's disease

BACKGROUND

Dopaminergic therapy with levodopa improves motor function in PD patients, but the effects of levodopa on cognition in PD remain uncertain.

OBJECTIVE

To use H(2)(15)O and PET to assess the effect of levodopa infusion on motor sequence learning in PD.

METHODS

Seven right-handed PD patients were scanned "on" and "off" levodopa while performing a sequence learning task. The changes in learning performance and regional brain activation that occurred during this intervention were assessed.

RESULTS

During PET imaging, levodopa infusion reduced learning performance as measured by subject report (p < 0.05). This behavioral change was accompanied by enhanced activation during treatment in the right premotor cortex and a decline in the ipsilateral occipital association area (p < 0.01). Levodopa-induced changes in learning-related activation responses in the occipital association cortex correlated with changes in learning indexes (p < 0.01).

CONCLUSIONS

Levodopa treatment appears to have subtle detrimental effects on cognitive function in nondemented PD patients. These effects may be mediated through an impairment in brain activation in occipital association cortex.

Associations between ST depression, four year mortality, and in-hospital revascularisation in unselected patients with non-ST elevation acute coronary syndromes

OBJECTIVE

To determine the associations between changes on the presenting ECG, in-hospital revascularisation, and four year mortality in patients with non-ST elevation acute coronary syndromes.

DESIGN

Prospective evaluation of all consecutive patients admitted in 1993 to the Green Lane Hospital coronary care unit, Auckland, New Zealand. Late follow up was undertaken at a median of 52 months. The ECGs were analysed after the hospital admission.

SETTING

Tertiary referral centre with direct local coronary care unit admissions.

INTERVENTIONS

Patients underwent physician recommended in-hospital revascularisation or initial conservative management.

RESULTS

The four year survival was 88% in the 115 patients who underwent revascularisation (65 (19%) percutaneous and 53 (16%) surgical revascularisation), compared with 75% in 316 patients managed conservatively (p = 0.024). Four year survival for patients undergoing revascularisation versus initial conservative management with respect to ECG groups was: no ECG changes (n = 101), 97% v 92% (p = 0.35); T wave inversion or 0.5 mm ST depression (n = 108), 89% v 78% (p = 0.18); ST depression > or = 1 mm (n = 122), 80% v 58% (p = 0.014); chi2 = 29, p < 0.001 for the linear trend across the groups. On multivariate analysis, independent predictors of four year mortality were: age (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01 to 1.08; p = 0.0046); ECG group (OR 1.88, 95% CI 1.21 to 2.95; p = 0.043); radiological pulmonary oedema (OR 2.81, 95% CI 1.18 to 7.05; p = 0.025); and revascularisation (OR 0.43, 95% CI 0.20 to 0.90; p = 0.023).

CONCLUSIONS

Among unselected patients with non-ST elevation acute coronary syndromes, in-hospital revascularisation is associated with decreased mortality at up to four years after admission. This association appears greater in patients with ST depression of > or = 1 mm on the presenting ECG.

Uterine evacuation with misoprostol during radiotherapy for cervical cancer in pregnancy

Radiotherapy as definitive treatment for invasive cervical cancer during pregnancy causes spontaneous abortion in most cases. Surgical evacuation of the uterus is indicated when abortion does not occur, exposing patients to additional morbidity. Two Latin American women, diagnosed with FIGO stage IB2 cervical cancer at approximately 15 weeks gestation, underwent radiotherapy with radiosensitizing chemotherapy. After intrauterine fetal demise was detected, both women underwent induction with misoprostol. Results included one complete abortion and one incomplete abortion without complications or delays in treatment. These cases demonstrate that induction with misoprostol appears to be a safe and effective alternative to surgical evacuation of the uterus when spontaneous abortion fails to occur during radiotherapy for locally advanced cervical cancer.

Implementing a seventh grade vaccination law: school factors associated with completion of required immunizations

OBJECTIVES

We investigated school factors associated with successful implementation of a seventh grade vaccination requirement.

METHODS

The proportion of students vaccinated with hepatitis B vaccine and measles containing vaccine was determined from records of schools in San Diego County, California. A school survey identified compliance strategies. Analysis identified factors associated with coverage.

RESULTS

In October 1999, 67.2% of 38,875 students had received the required vaccine doses. Of 315 schools, coverage was less than 40% in 60 schools and exceeded 80% in 111 schools. Factors associated with high coverage included private schools, early and frequent notice to parents, and, for public schools, higher overall socioeconomic status of students.

CONCLUSIONS

In preparation for a middle school vaccination requirement, early and frequent notification of parents improves coverage. Schools with a high percentage of low socioeconomic status students may require extra resources to support implementation.

Enhancement of brain activation during trial-and-error sequence learning in early PD

BACKGROUND

Although the pathophysiology remains unknown, most nondemented patients with PD have difficulty with frontal tasks, including trial-and-error sequence learning. If given time, they can perform cognitive tasks of moderate difficulty as well as controls. However, it is not known how brain function is altered during this time period to preserve higher cortical function in the face of PD pathology.

METHOD

To evaluate this phenomenon, the authors matched sequence learning between PD and control subjects for the last 30 seconds of a PET scan. Learning during the initial 50 seconds of PET was unconstrained.

RESULTS

Learning indices were equivalent between groups during the last 30 seconds of the scan, whereas rates of acquisition, correct movements, and forgetting differed in the first 30 seconds. In normal controls sequence learning was associated with activations in the right prefrontal, premotor, parietal, rostral supplementary motor area, and precuneus regions. To achieve equal performance, the PD group activated greater volume within these same regions, and also their left sided cortical homologs and the lateral cerebellum bilaterally.

CONCLUSIONS

Mildly affected patients with PD demonstrated only modest impairment of learning during the first 30 seconds of the task and performed equivalently with controls thereafter. However, the mechanism by which they achieved equiperformance involved considerable changes in brain function. The PD group had to activate four times as much neural tissue as the controls, including recruiting brain from homologous cortical regions and bilateral lateral cerebellum.

Cell-cell interactions influence resistance and survival of Salmonella serotype Typhimurium to environmental stress

AIMS

The aim of this work was to study the effects of prolonged nutrient stress on survival, cell interactions and resistance to inimical processes in Salmonella serotype Typhimurium.

METHODS AND RESULTS

Salmonella Typhimurium cells were subjected to prolonged incubation in the stationary phase of growth and the properties of starved cells (old) were investigated with reference to those of exponentially-growing cells (young). Competition experiments between old and young cells revealed cell-cell interactions that influenced stationary phase survival and response of the bacterium to heat stress. During prolonged incubation of cells, cycles of resistance and sensitivity to heat stress were identified. Competition experiments between old and young cells revealed that the resistance of young cells to heat increased to levels more like those of stationary phase cells than growing cells. The presence of old cells influenced the phenotype of young cells, possibly by means of cell-cell interactions. There was no evidence for the involvement of any extracellularly-produced factors in this phenomenon, but a requirement that the old competitor cells be viable could be demonstrated.

CONCLUSIONS

It is proposed that the complex interactions within stationary phase cultures of Salm. Typhimurium may be due to cycles of mutation in concert with an as yet undefined interaction between old cells and growing ones.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides evidence for active and diverse responses to nutrient stress within populations of Salm. Typhimurium that promote survival and that may be important for the success of this bacterium as a pathogen.

Parallel preparative high-performance liquid chromatography with on-line molecular mass characterization

High-throughput chemistry (HTC) is now an integral part of the lead discovery process in many pharmaceutical and related chemical companies. As this process becomes refined or improved, with the integration of systems with enhanced capabilities, and the requirement for quality compounds of high purity increases, purification is often considered a bottleneck. Although a wide range of purification techniques is available, high-performance liquid chromatography (HPLC) is usually the preferred method of purification to produce high-purity compounds. Parallel preparative HPLC with robust UV-guided fraction collection has been shown to reduce the bottleneck and complement the parallel synthesis systems. However, despite the success of this technique, post-purification analysis of fractions to identify the target compound adds an additional level of complexity. This paper describes the interfacing of the Biotage Parallex with the MUX interface on a single quadrupole mass spectrometer, thus combining robust UV-guided fractionation with on-line MS characterization.

High-throughput purification of combinatorial arrays

Performance and reproducibility of the Biotage Parallex, a high-throughput purification system, was evaluated using known standards. The results indicate that parallel purification is a robust technique for purifying large numbers of compounds. Results from one of the first libraries to be purified on the Biotage Parallex are presented and discussed. Since fractionation by UV can often result in a large number of fractions, threshold trigger versus yield and number of fractions was also investigated. This approach was used to purify an array of 4320 compounds, produced by an 11-step solid-phase synthesis in Irori MicroKans. Ninety-three percent of the compounds were successfully processed, with >90% having purity >95%.

Primary dystonia: is abnormal functional brain architecture linked to genotype?

The DYT1 dystonia mutation is associated with an abnormal metabolic brain network characterized by hypermetabolism of the basal ganglia, supplementary motor area, and the cerebellum. In this study, we quantified the activity of this network in carriers of other dystonia mutations to determine whether this functional abnormality is linked to genotype. The findings suggest that the DYT1 metabolic topography is not genotype specific and may be present in carriers of other dystonia mutations.

MOET: Bangladesh--an initial experience

OBJECTIVES

To summarize the quantitative and qualitative immediate assessments of the Managing Obstetric Emergencies and Trauma (MOET) course and to examine the individual changes in score obtained for each of the scenarios.

METHODS

Students' knowledge before and after the course was evaluated with a standardized comprehensive questionnaire.

RESULTS

All candidates showed an improvement in postcourse, compared to precourse, scores. In the individual score analysis only one scenario showed a non-significant change. The majority of other scenarios showed highly significant improvement between the two scores.

CONCLUSION

This paper summarises the development of the first MOET course to be run outside the UK. It demonstrates the reliability of the model-based scenario foundation with a highly significant improvement in knowledge about obstetric emergency management. Further evaluation of longer term practice changes is now required.

Randomised controlled study of sleep after nefazodone or paroxetine treatment in out-patients with depression

BACKGROUND

Sleep effects of antidepressants are important clinically and for elucidating mechanism of action: selective serotonin reuptake inhibitors disturb sleep and 5-HT(2) receptor-blocking compounds may enhance sleep quality.

AIMS

To compare the objective and subjective effects on sleep of paroxetine and nefazodone in patients with moderate to severe depression.

METHOD

Forty patients with depression were randomised to take paroxetine 20-40 mg/day or nefazodone 400-600 mg/day for 8 weeks. Objective and subjective quality of sleep and depression measures were assessed throughout.

RESULTS

Nefazodone significantly increased objective sleep efficiency and total sleep time, and improved subjective sleep on days 3 and 10. Paroxetine decreased sleep efficiency early in treatment and some sleep disruption remained at week 8. Paroxetine but not nefazodone produced marked suppression of rapid eye movement (REM) sleep.

CONCLUSIONS

Nefazodone improves sleep in early treatment compared with paroxetine in patients with moderate to severe depression. These effects are seen within the first 2 weeks of treatment and diminish thereafter.

Relationships among the metabolic patterns that correlate with mnemonic, visuospatial, and mood symptoms in Parkinson's disease

OBJECTIVE

A multivariate analysis of baseline brain metabolism was used to investigate the relationships among pathophysiological mechanisms responsible for cognitive dysfunction and dysphoria in nondemented patients with Parkinson's disease.

METHOD

Using [(18)F]fluorodeoxyglucose positron emission tomography and neuropsychological tests, the authors studied 15 nondemented patients who had Parkinson's disease without major depression (DSM-III-R). Their mean age was 59.2 years (SD=9.2), the mean rating of Parkinson's disease stage (Hoehn and Yahr scale) was 3.3 (SD=0.9), and all had Mini-Mental State Examination scores of 24 or higher. To identify specific regional patterns of brain metabolism associated with abnormal cognitive and mood functioning, the data were analyzed by using brain-behavior partial least squares. This multivariate voxel-based analysis allowed detection of significant topographic patterns of metabolic activity and quantification of the extent to which each topographic pattern correlated with scores on mnemonic, visuospatial, and dysphoric tests.

RESULTS

Two significant, independent topographic patterns were identified. Pattern 1 included parieto-occipito-temporal and medial temporal brain regions, and pattern 2 included the lateral frontal and anterior limbic cortex. Patterns 1 and 2 exhibited a double dissociation in their behavioral correlates: pattern 1 correlated with both visuospatial and mnemonic functioning but not with dysphoria; pattern 2 correlated with dysphoria but not with the cognitive measures.

CONCLUSIONS

The authors used the independence of topographic patterns and the size of correlations between topographic patterns and behavior to infer relationships among the pathophysiological processes responsible for the correlations. The finding that mildly abnormal mnemonic and visuospatial functioning correlated with the same topographic pattern suggests that a common pathophysiology underlies this marker of cognition in Parkinson's disease. By contrast, the independence of the two topographic patterns supports the notion that different mechanisms underlie cognitive and dysphoric symptoms in nondemented patients with Parkinson's disease.