Modifying Hofstee standard setting for assessments that vary in difficulty, and to determine boundaries for different levels of achievement.

BACKGROUND: Fixed mark grade boundaries for non-linear assessment scales fail to account for variations in assessment difficulty. Where assessment difficulty varies more than ability of successive cohorts or the quality of the teaching, anchoring grade boundaries to median cohort performance should provide an effective method for setting standards. METHODS: This study investigated the use of a modified Hofstee (MH) method for setting unsatisfactory/satisfactory and satisfactory/excellent grade boundaries for multiple choice question-style assessments, adjusted using the cohort median to obviate the effect of subjective judgements and provision of grade quotas. RESULTS: Outcomes for the MH method were compared with formula scoring/correction for guessing (FS/CFG) for 11 assessments, indicating that there were no significant differences between MH and FS/CFG in either the effective unsatisfactory/satisfactory grade boundary or the proportion of unsatisfactory graded candidates (p > 0.05). However the boundary for excellent performance was significantly higher for MH (p < 0.01), and the proportion of candidates returned as excellent was significantly lower (p < 0.01). MH also generated performance profiles and pass marks that were not significantly different from those given by the Ebel method of criterion-referenced standard setting. CONCLUSIONS: This supports MH as an objective model for calculating variable grade boundaries, adjusted for test difficulty. Furthermore, it easily creates boundaries for unsatisfactory/satisfactory and satisfactory/excellent performance that are protected against grade inflation. It could be implemented as a stand-alone method of standard setting, or as part of the post-examination analysis of results for assessments for which pre-examination criterion-referenced standard setting is employed

Proteomic analysis of the Plasmodium male gamete reveals the key role for glycolysis in flagellar motility.

BACKGROUND: Gametogenesis and fertilization play crucial roles in malaria transmission. While male gametes are thought to be amongst the simplest eukaryotic cells and are proven targets of transmission blocking immunity, little is known about their molecular organization. For example, the pathway of energy metabolism that power motility, a feature that facilitates gamete encounter and fertilization, is unknown. METHODS: Plasmodium berghei microgametes were purified and analysed by whole-cell proteomic analysis for the first time. Data are available via ProteomeXchange with identifier PXD001163. RESULTS: 615 proteins were recovered, they included all male gamete proteins described thus far. Amongst them were the 11 enzymes of the glycolytic pathway. The hexose transporter was localized to the gamete plasma membrane and it was shown that microgamete motility can be suppressed effectively by inhibitors of this transporter and of the glycolytic pathway. CONCLUSIONS: This study describes the first whole-cell proteomic analysis of the malaria male gamete. It identifies glycolysis as the likely exclusive source of energy for flagellar beat, and provides new insights in original features of Plasmodium flagellar organization

Attentional control theory in childhood: enhanced attentional capture by non-emotional and emotional distractors in anxiety and depression

Attentional control theory (ACT) proposes that anxiety is associated with executive functioning deficits. The theory has been widely investigated in adults. The current study tested whether symptoms of childhood anxiety and depression were associated with experimentally measured attentional control in the context of non-emotional and emotional stimuli. Sixty-one children (mean age = 9.23 years, range = 8.39 - 10.41) reported their trait anxiety and depression symptoms and completed three visual search tasks. The tasks used a variant of an irrelevant singleton paradigm and measured attentional capture by task-irrelevant non-emotional (color) and emotional (facial expressions) distractors. Significant attentional capture by both non-emotional and emotional distractors was observed, and was significantly correlated with trait anxiety and symptoms of depression. The strength of relationship between attentional capture and the symptoms did not differ significantly for non-emotional and emotional distractors. The results suggest that symptoms of childhood anxiety and depression are associated with poorer attentional control both in the presence of emotional and non-emotional stimuli, supporting ACT in younger populations. This attentional deficit in the context of non-emotional information might be as central to childhood internalizing symptoms as attentional biases often observed on tasks investigating processing of emotional stimuli

PRIMO: an interactive homology modeling pipeline

The development of automated servers to predict the three-dimensional structure of proteins has seen much progress over the years. These servers make calculations simpler, but largely exclude users from the process. In this study, we present the PRotein Interactive MOdeling (PRIMO) pipeline for homology modeling of protein monomers. The pipeline eases the multi-step modeling process, and reduces the workload required by the user, while still allowing engagement from the user during every step. Default parameters are given for each step, which can either be modified or supplemented with additional external input. PRIMO has been designed for users of varying levels of experience with homology modeling. The pipeline incorporates a user-friendly interface that makes it easy to alter parameters used during modeling

An expanded evaluation of protein function prediction methods shows an improvement in accuracy

Background: A major bottleneck in our understanding of the molecular underpinnings of life is the assignment of function to proteins. While molecular experiments provide the most reliable annotation of proteins, their relatively low throughput and restricted purview have led to an increasing role for computational function prediction. However, assessing methods for protein function prediction and tracking progress in the field remain challenging.Results: We conducted the second critical assessment of functional annotation (CAFA), a timed challenge to assess computational methods that automatically assign protein function. We evaluated 126 methods from 56 research groups for their ability to predict biological functions using Gene Ontology and gene-disease associations using Human Phenotype Ontology on a set of 3681 proteins from 18 species. CAFA2 featured expanded analysis compared with CAFA1, with regards to data set size, variety, and assessment metrics. To review progress in the field, the analysis compared the best methods from CAFA1 to those of CAFA2.Conclusions: The top-performing methods in CAFA2 outperformed those from CAFA1. This increased accuracy can be attributed to a combination of the growing number of experimental annotations and improved methods for function prediction. The assessment also revealed that the definition of top-performing algorithms is ontology specific, that different performance metrics can be used to probe the nature of accurate predictions, and the relative diversity of predictions in the biological process and human phenotype ontologies. While there was methodological improvement between CAFA1 and CAFA2, the interpretation of results and usefulness of individual methods remain context-dependent

The effect of the menopause on prolactin levels in patients with hyperprolactinaemia.

OBJECTIVE: Microprolactinomas have been reported to resolve spontaneously after pregnancy and there have been suggestions that oestrogen therapy increases the size of microprolactinomas. Little is known, however, about the effect of the menopause in patients previously known to be hyperprolactinaemic. The aim of this study was to find out if pregnancy or the menopause leads to an alteration in prolactin levels. DESIGN: We conducted a retrospective study of 148 case notes of patients with hyperprolactinaemia and microprolactinomas treated at the Radcliffe Infirmary during the period 1976-96. Sixty-nine female patients who had not had pituitary surgery as treatment for microprolactinoma were used as a control group. None of this group became pregnant or reached the menopause. They were compared with 25 female patients who became pregnant, 11 who became menopausal and 11 who were male. Subjects were excluded from the analysis if there were no follow-up data off dopamine agonist treatment or if they were surgically cured. Data were gathered on demographic parameters, treatment given, scan abnormalities, prolactin levels at diagnosis and last follow up, prolactin levels pre- and postpregnancy as well as pre- and postmenopause. The pregnancy, postmenopausal and male patient groups were compared with the control group and each other to see if they had a higher frequency of normalization of their prolactin levels during follow up. Various factors were examined as possible variables for the normalization of prolactin, including the detection of scan abnormalities at diagnosis, prolactin levels at diagnosis as well as treatment with dopamine agonists and duration of follow up. RESULTS: Forty-five percent of the menopausal group, 24% of the pregnancy group and 18% of the male group subsequently normalized their prolactin levels during the period of the study in comparison with 7% of the control group. The menopausal groups had a significantly higher chance of normalizing their prolactin compared to the control group (P &lt; 0.005), whilst the pregnancy group showed a non-significant trend towards normalizing their prolactin (P = 0.06). The detection of scan abnormalities, treatment with dopamine agonist therapy and duration of follow up were not associated with normalization of prolactin levels. CONCLUSION: Female patients with hyperprolactinaemia who pass through the menopause have a significant chance of normalizing their prolactin levels. Females who pass through pregnancy may have a higher chance of normalizing their prolactin levels. The menopause is an indication for reassessment of the need to continue to treat hyperprolactinaemia and microprolactinoma

An account of the quality of life of patients after treatment for non-functioning pituitary tumours.

OBJECTIVE: Studies assessing quality of life in GH-deficient adults have shown varying results. This may be due to a number of factors including varying causes of GH deficiency, the use of radiotherapy in treatment and patient selection. We aimed to assess whether anterior pituitary hormone deficiency or external pituitary radiotherapy influenced the quality of life of patients with non-functioning pituitary tumours. PATIENTS: We studied 48 patients treated and under follow-up for non-functioning pituitary tumours on standard hormone replacement therapy excluding GH. There were 21 females and 27 males with a mean age of 59 +/- 12 years. We also studied 42 control patients who had undergone mastoid surgery and were followed at least annually. There were 17 females and 25 males with a mean age of 61 +/- 14 years. DESIGN: All patients attended a research clinic and completed the Short Form 36 (SF36) and General Well Being Schedule (GWBS) to assess quality of life. Thyroid function tests, IGF1 and IGFBP3 were measured on all patients. Gonadotrophin and cortisol measurements were made on the patients with pituitary disease where appropriate. RESULTS: IGF1 and IGFBP3 levels were lower in the pituitary patients compared with controls: 104 +/- 98 vs 143 +/- 37 micrograms.l (P &lt; 0.0001) and 2.9 +/- 0.75 vs 3.3 +/- 0.52 mg/l (P &lt; 0.004). There were no significant differences in the quality of life scores between the pituitary patients and the control subjects. There was also no difference in quality of life between pituitary patients with two or more hormone deficiencies (n = 29) compared with controls. Patients who had received radiotherapy (n = 18), when compared with controls, had a decreased mental health score using the SF36 71 +/- 21 vs 81 +/- 17 (P &lt; 0.05) and decreased total GWBS score 70 +/- 20 vs 82 +/- 17 (P &lt; 0.05). Subscore analysis of GWBS showed this to be due to depression and decreased control of emotions. CONCLUSIONS: We found that the quality of life of patients treated and under follow up for non-functioning pituitary tumours was similar to that of patients treated by mastoid surgery and under similar follow up. The pituitary patients deficient in two hormones and thus most likely to be GH deficient were also similar to the controls. These results suggest that adding GH replacement in this patient group may not be routinely indicated for improvement in quality of life and needs careful assessment. Patients who had received radiotherapy were more depressed and anxious than controls. Further investigation into the psychological and psychomotor effects of radiotherapy in this group of patients is required

Outcome of transphenoidal surgery for acromegaly and its relationship to surgical experience.

BACKGROUND: A number of surgical series have been reported on the treatment of acromegaly and their results vary widely. The acceptable definition of remission has changed in recent years and it is known, though in a small series, that growth hormone levels of &gt; 5 mU/l are still associated with an increased mortality from the condition. We have analysed data at this centre and examined the outcome of transphenoidal surgery for acromegaly, compared our results with recently published series from other centres and also assessed factors which might effect outcome including whether there is any demonstrable effect of the experience of the surgeon on outcome. PATIENTS AND METHODS: We have analysed data from all of our 139 patients in whom follow up data are available who have undergone initial transphenoidal surgery for acromegaly by one surgeon at this centre, between 1974 and 1995. Follow up was for a median of 5 years (range 1 month to 17 years). RESULTS: 67% of patients achieved the criterion for remission (mean GH &lt; 5 mU/l). Success was related to tumour size and preoperative growth hormone values. Thus 91% of patients with microadenomas were in remission postoperatively compared to 46% of patients with macroadenomas. Analysis of the results according to the year of operation showed an improvement in success rates with time. More than 15 years ago, the success rate according to the growth hormone criteria set was 48% and the failure rate 52%. In contrast in the last 5 years analysed, the overall success rate was 74% with a failure rate of 26% (P &lt; 0.04). The success rate for microadenomas was 50% initially, then remained 100%. The case mix was analysed and no change was found. We have also demonstrated an improvement in pituitary function (including normalization of preoperative elevated prolactin) with time so that pre 1981 16% of patients' pituitary function improved perioperatively but 10 years later this figure had risen to 34% (P &lt; 0.03). There was no change over time in the development of pituitary hypofunction, complication rate or recurrence rate. CONCLUSION: Surgical treatment is a safe and effective treatment for acromegaly and remains the first choice of treatment for most acromegalic patients. The results of this centre compare favourably with series from other centres. We have demonstrated improved results, both in terms of post operative growth hormone values and pituitary function tests with time and increasing neurosurgical experience. We conclude that outcome for the surgical treatment for acromegaly is best achieved with one surgeon specialising in pituitary surgery. Improved operative outcome thus achieved has major cost implications and avoids the necessity for consideration of postoperative radiotherapy and the use of expensive growth hormone suppressing drugs in the postoperative period