Biomedical subjects

C Pratt

Publications and source records attributed to C Pratt.

At least 19 recordsLinked to original sources

PubMed2003

Effect of fragile X status categories and FMRP deficits on cognitive profiles estimated by robust pedigree analysis.

The effect of the fragile X pre-mutation and full mutation categories, and FMRP deficits in these categories, on neurocognitive status, have been assessed in fragile X individuals from 144 extended families, which included fragile X individuals, as well as their non-fragile X relatives. Neuropsychological status was assessed by the Wechsler summary and subtest test scores. A modification of the maximum likelihood estimators for pedigree data that is resistant to outliers was used to analyze the data. The results have demonstrated the effect of large expansions of CGG repeat in the FMR1 (fragile X mental retardation 1) gene (full mutation) in decreasing full scale IQ (FSIQ), as well as several FSIQ-adjusted subtest scores in the performance domain. Moreover, the results have demonstrated significant cognitive deficits in male individuals with pre-mutation. FMRP depletion correlates strongly with neurocognitive status in the full mutation subjects. Evidence for the effect of FMRP in smaller expansions (pre-mutation) in reducing FSIQ, Performance and Verbal scores, as well as subtest scores in males, has also been obtained. The results are also suggestive of factors other than FMRP deficit which may determine some specific cognitive deficits in fragile X pre-mutation carriers. Genetic variance estimated from the models accounts for less than half of the total variance in FSIQ, and it varies widely between individual Wechsler subtests.

Female↗

PubMed2003

Parotid neoplasms in children: experience of diagnosis and management in a district general hospital.

Parotid neoplasms are uncommon in children and the available literature is predominantly from specialized centres. This paper highlights our experience at a district general hospital, in the diagnosis and management of parotid neoplasms in children. The case records of all parotidectomies performed in a 26-year period between 1974-1999 were scrutinized and patients aged 18 years and below identified. The demographic data, histology, presentation, investigations, treatment, outcomes and complications were analysed. 545 parotidectomies were performed in 536 patients, in whom 569 neoplasms were diagnosed. Only 12 patients aged 18 and under were identified (2.2%). The relative frequency of individual tumours differed markedly from that in adults. 75% of the tumours were benign. Pleomorphic adenoma and mucoepidermoid carcinoma were the most common tumours. A painless mass was the most frequent clinical presentation and CT sialogram was the most common investigation. Parotidectomy with preservation of the facial nerve was performed in all cases, and adjuvant radiotherapy employed in the case of malignant tumours. All patients were alive and well at the time of last follow up. Transient facial nerve palsy and hypertrophic scars were the most common complications.

Adenoma, Pleomorphic↗

PubMed2001

The effect of oral vocabulary on reading visually novel words: a comparison of the dual-route-cascaded and triangle frameworks.

Dual-route-cascaded (DRC) (e.g. Coltheart & Rastle, Journal of Experimental Psychology: Human Perception and Performance 20 (1994) 1197) and triangle framework (e.g. Seidenberg & McClelland, Psychological Review 96 (1989) 523) predictions were tested regarding the effect of having a word in oral vocabulary prior to reading that same word. Over two sessions, at intervals of 2--3 days, 44 Grade 1 (6--7-year-old) children were aurally familiarized with the sound and meaning of ten novel words (semantic oral instantiation), and with just the sound of another ten novel words (non-semantic oral instantiation). Two to three days later non-word naming performance was significantly more accurate for aurally trained novel words compared to pseudohomophones, which were in turn advantaged over untrained non-words. The semantic manipulation had no effect. Experiment 2 manipulated articulation during (non-semantic) training. Forty Grade 1 children participated. Again, aurally trained items were named more accurately and quickly than equivalently trained pseudohomophones, which were in turn advantaged over untrained non-words. The articulation manipulation had no effect. The results suggest that word-specific phonological information is represented in the reading system independently of semantic or articulatory influences. The results are interpreted as being problematic for both the DRC and triangle frameworks, but more so for the latter.

Child↗

PubMed2001

Relations between the development of patterns of sleeping heart rate and body temperature in infants.

Overnight patterns of rectal temperature and heart rate were recorded from 119 normal infants at weekly intervals from 7 to about 16 weeks of age. All data were collected in the infants' own homes. As previously reported, different infants developed an adult-like night time rectal temperature pattern abruptly at different ages. When heart rate data were collated by age, there was an apparently gradual fall in sleeping heart rate from 7 to about 14 weeks of age. This was, however, an artefact of data collation. Individual infants showed abrupt falls in heart rate at the time that the adult-like body temperature pattern appeared, but this occurred at different ages in different babies, so when data were collated cross sectionally, an apparently gradual fall resulted. The relation between the developmental changes in sleeping heart rate and rectal temperature was different in boys and girls, with girls showing a more abrupt and greater change in heart rate at the time of development of the adult-like body temperature pattern. Infants whose parents smoked had significantly lower heart rates once the adult-like body temperature pattern had appeared.

Aging↗

PubMed2001

A pilot safety trial of prolonged (48 h) infusion of the dual endothelin-receptor antagonist tezosentan in patients with advanced heart failure.

STUDY OBJECTIVES: Tezosentan, an IV dual endothelin-receptor antagonist, has demonstrated beneficial hemodynamic effects in patients with advanced heart failure. In addition, no notable differences in safety and tolerability variables were detected between tezosentan-treated and placebo-treated patients when infused over 4 to 6 h. The present study was conducted primarily to assess the safety and tolerability of tezosentan when administered over a prolonged, 48-h treatment period, and secondarily to investigate hemodynamic response. DESIGN: This randomized, double-blind, active-controlled study of continual IV administration of two dosages of tezosentan (20 mg/h and 50 mg/h; n = 6 each) or dobutamine (5 microg/kg/min; n = 2) over 48 h in patients with advanced heart failure was conducted to assess tolerability, safety, and hemodynamic variables (Doppler echocardiography). RESULTS: During tezosentan infusion, no episodes of hypotension requiring withdrawal of therapy occurred, and hemodynamic rebound was not observed after abrupt cessation of the infusion. There were no reports of worsening heart failure in tezosentan-treated patients up to 28 days following the infusion. The most common side effect during the infusion was headache (9 of 12 tezosentan-treated patients and both dobutamine-treated patients). Echocardiographic Doppler measurements suggested improvements in cardiac index, pulmonary capillary wedge pressure, and relaxation properties as well as in diastolic and systolic function in all treatment groups. CONCLUSIONS: Prolonged, 48-h IV dual endothelin-receptor antagonism with tezosentan was well tolerated with no new safety concerns emerging. These data further support the potential role of tezosentan in the treatment of patients with acute heart failure.

Acute Disease↗

PubMed2001

A phase I study of irinotecan in pediatric patients: a pediatric oncology group study.

A Phase I trial of irinotecan was performed to determine the maximum tolerated dose (MTD), the dose-limiting toxicities (DLTs), and the incidence and severity of other toxicities in children with refractory solid tumors. Thirty-five children received 146 courses of irinotecan administered as a 60-min i.v. infusion, daily for 5 days, every 21 days, after premedication with dexamethasone and ondansetron. Doses ranged from 30 mg/m2 to 65 mg/m2. An MTD was defined in heavily pretreated and less-heavily pretreated (i.e., two prior chemotherapy regimens, no prior bone marrow transplantation, and no radiation to the spine, skull, ribs, or pelvic bones) patients. Myelosuppression was the primary DLT in heavily pretreated patients, and diarrhea was the DLT in less-heavily pretreated patients. The MTD in the heavily pretreated patient group was 39 mg/m2, and the MTD in the less-heavily pretreated patients was 50 mg/m2. Non-dose-limiting diarrhea that was well controlled and of brief duration was observed in approximately 75% of patients. A partial response was observed in one patient with neuroblastoma, and in one patient with hepatocellular carcinoma. Stable disease (4-20 cycles) was observed in seven patients with a variety of malignancies including neuroblastoma, pineoblastoma, glioblastoma, brainstem glioma, osteosarcoma, hepatoblastoma, and a central nervous system rhabdoid tumor. In conclusion, the recommended Phase II dose of irinotecan administered as a 60-min i.v. infusion daily for 5 days, every 21 days, is 39 mg/m2 in heavily treated and 50 mg/m2 in less-heavily treated children with solid tumors.

Adolescent↗

PubMed2000

'Now please wash your hands': the handwashing behaviour of final MBBS candidates.

The Handwashing Liaison Group has pointed out that "The failure of healthcare workers to decontaminate their hands reflects fundamentals of attitudes, beliefs and behaviours". Doctors are known to be poor at handwashing. This poor compliance may have its roots in a failure to learn this behaviour at medical college, where the influence of consultants and other role models may be critical. The handwashing behaviour of modern day medical students has not been previously studied. The Final MBBS Objective Structured Clinical Examination (OSCE) reflects learnt behaviours and attitudes of final year medical students 'absorbed' from role models within their training. We observed the handwashing behaviour of 187 candidates during the 1998 Final MBBS OSCE, at one clinical station, neurological examination of the lower limbs. Only 8.5% of candidates washed their hands after patient contact, although this figure rose to 18.3% with the aid of handwashing signs. These findings suggest that handwashing should become an educational priority. As student learning is highly focused by assessment (in-course or examination), we sug-gest that compliance with handwashing be built into undergraduate and Teaching Quality assessments with, for example, 'Hygiene marks' incorporated into OSCE or observed long case checklists. This study re-emphasizes the need for good clinical practice whenever teaching medical students.

Attitude of Health Personnel↗

PubMed2000

An evaluation of the impact of a self-care coping intervention on psychological and clinical outcomes in adolescents with newly diagnosed cancer.

The demands of cancer treatment are particularly challenging for newly diagnosed adolescents. If attempts to cope with these demands are unsuccessful, adolescents may not comply with or may refuse treatment. As a result, their chances of survival are decreased. The purpose of this study, guided by the Adolescent Self-Sustaining Model, was to determine the effects of a three-part educational intervention designed to facilitate copying on psychological (hopefulness, hopelessness, self-esteem, self-efficacy and symptom distress) and clinical outcomes (treatment toxicity) among adolescents newly diagnosed with cancer. This two-site study used a longitudinal experimental two-group design with adolescents randomly assigned to the intervention or control group. Four measurement points spanning the first 6 months of treatment were included in the design. Of 93 eligible adolescents, 78 (46 females and 32 males) agreed to participate. No statistically significant differences between the intervention and control groups, or between male and female participants, were detected at any measurement point. Differences in scores over time within groups were noted. Explanations for the lack of group differences are offered, as are recommendations for strengthening the intervention and design for future testing.

Journal Article↗

PubMed1999

Cardiovascular safety of fexofenadine HCl.

BACKGROUND: Certain first- and second-generation H1-receptor antagonists are associated with prolongation of the corrected QT interval (QTc) and, in rare instances, with ventricular dysrhythmias, including torsades de pointes ventricular tachycardia. OBJECTIVE: To assess the effect of fexofenadine HCl, a new non-sedating antihistamine, on QTc. METHODS: Dose-tolerance, safety, and drug-interaction studies with healthy volunteers; and clinical efficacy studies with seasonal allergic rhinitis patients were conducted. Twelve-lead ECG data were collected pre- and postdosing or serially throughout these studies. Outliers were defined as QTc >440 msec with a >/=10 msec increase from baseline. RESULTS: Fexofenadine HCl at single doses up to 800 mg q.d. (once daily) and multiple doses up to 690 mg b.d. for 28 days in healthy volunteers resulted in no increases in QTc (recommended dose range is 120-180 mg daily); QTc changes were similar to placebo. Compared with placebo, there were no statistically significant QTc increases in patients receiving fexofenadine HCl 80 mg b.d. for 3 months, 60 mg b. d. for 6 months, or 240 mg q.d. for 12 months. No statistically significant increases in QTc were detected when fexofenadine HCl 120 mg b.d. was administered in combination with erythromycin (500 mg t. d.) or ketoconazole (400 mg q.d.) after dosing to steady-state (6.5 days). In seasonal allergic rhinitis patients (n = 1160) treated with 40, 60, 120, or 240 mg b.d. fexofenadine HCl for 2 weeks, there were no dose-related increases in QTc and no significant increases in mean QTc compared with placebo. Frequency and magnitude of QTc outliers with fexofenadine HCl and placebo were similar in all studies. No case of fexofenadine-associated torsades de pointes has been observed in controlled trial experience with more than 6000 patients. CONCLUSION: Fexofenadine HCl has been investigated more extensively for possible electrophysiological effects than any other antihistamine. Fexofenadine HCl has no significant effect on QTc, even at doses much higher than those used in clinical practice.

Dose-Response Relationship, Drug↗

PubMed1999

Characteristics of preschool and school-age children with imaginary companions.

The authors investigated the prevalence and characteristics of children who experience or who have experienced imaginary companions. For the study, a self-administered questionnaire that sought information regarding the characteristics of children with and without imaginary companions was completed by 478 parents of children within the age range of 3 to 9.5 years. A significantly larger number of children with imaginary companions were reported to be first-born children, to be very imaginative, to incorporate myth in their play, and to explain events as magical. Overall, these results are interpreted to indicate that birth order, combined with characteristics such as imaginativeness and a predisposition to engage in fantasy, characterizes children with imaginary companions.

Child↗

PubMed1999

Prognostic significance of apoptosis regulators in breast cancer.

Dysregulation of normal programmed cell death mechanisms plays an important role in the pathogenesis and progression of breast cancer, as well as in responses of tumors to therapeutic intervention. Overexpression of anti-apoptotic members of the Bcl-2 family such as Bcl-2 and Bcl-X(L) has been implicated in cancer chemoresistance, whereas high levels of pro-apoptotic proteins such as Bax promote apoptosis and sensitize tumor cells to various anticancer therapies. Though the mechanisms by which Bcl-2 family proteins regulate apoptosis are diverse, ultimately they govern decision steps that determine whether certain caspase family cell death proteases remain quiescent or become active. To date, approximately 17 cellular homologs of Bcl-2 and at least 15 caspases have been identified in mammals. Other types of proteins may also modulate apoptotic responses through effects on apoptosis-regulatory proteins, such as BAG-1-a heat shock protein 70 kDa (Hsp70/Hsc70)-binding protein that can modulate stress responses and alter the functions of a variety of proteins involved in cell death and division. In this report, we summarize our attempts thus far to explore the expression of several Bcl-2 family proteins, caspase-3, and BAG-1 in primary breast cancer specimens and breast cancer cell lines. Moreover, we describe some of our preliminary observations concerning the prognostic significance of these apoptosis regulatory proteins in breast cancer patients, contrasting results derived from women with localized disease (with or without node involvement) and metastatic cancer.

Antineoplastic Agents↗

PubMed1998

Conduct of phase I trials in children with cancer.

PURPOSE AND METHODS: Future progress in the care of children with cancer requires appropriate evaluations of promising new agents for pediatric indications, beginning with well-conducted phase I trials. This report summarizes current guidelines for the conduct of pediatric phase I trials and represents a consensus between American and European investigators. The primary objective of pediatric phase I trials is to define safe and appropriate doses and schedules of new agents that can subsequently be used in phase II trials to test for activity against specific childhood malignancies. Prioritization of agents for evaluation in children is critical, since many more investigational agents are evaluated in adult patients than can be systematically evaluated in children. Considerations used in prioritizing agents include activity in xenograft models, novel mechanism of action, favorable drug-resistance profile, and activity observed in adult trials of the agent. RESULTS AND CONCLUSION: Distinctive characteristics of pediatric phase I trials, in comparison to adult phase I trials, include the necessity for multiinstitutional participation and their higher starting dose (typically 80% of the adult maximum-tolerated dose [MTD]), both of which reflect the relative unavailability of appropriate patients. The application of uniform eligibility criteria and standard definitions for MTD and dose-limiting toxicity (DLT) help to assure that pediatric phase I trials are safely conducted and reliably identify appropriate doses and schedules of agents for phase II evaluation. Where possible, pediatric phase I trials also define the pharmacokinetic behavior of new agents in children.

Antineoplastic Agents↗

PubMed1998

Phase I trial of 9-aminocamptothecin in children with refractory solid tumors: a Pediatric Oncology Group study.

PURPOSE: A phase I trial of 9-aminocamptothecin (9-AC) was performed in children with solid tumors to establish the dose-limiting toxicity (DLT), maximum-tolerated dose (MTD), and the pharmacokinetic profile in children and to document any evidence of activity. PATIENTS AND METHODS: A 72-hour infusion of 9-AC dimethylacetamide formulation was administered every 21 days to 23 patients younger than 21 years of age with malignant tumors refractory to conventional therapy. Doses ranged from 36 to 62 microg/m2 per hour. Pharmacokinetics were to be performed in at least three patients per dose level. The first course was used to determine the DLT and MTD. RESULTS: Nineteen patients on four dose levels were assessable for toxicities. At 62 microg/m2 per hour, three patients experienced dose-limiting neutropenia and one patient experienced dose-limiting thrombocytopenia. Pharmacokinetics were performed on 15 patients (nine patients had complete sets of plasma sampling performed). The pharmacokinetics of both lactone and total 9-AC were highly variable. The percentage of 9-AC lactone at steady-state was 10.8% +/- 3.6%. Total 9-AC and its lactone form had a terminal half-life of 8.1 +/- 3.8 and 7.1 +/- 3.9 hours, respectively, and a volume of distribution at steady-state (Vdss) of 21.2 +/- 13.3 L/m2 and 135.3 +/- 52.5 L/m2, respectively. Hepatic metabolism and biliary transport had an important role in 9-AC disposition. CONCLUSION: The recommended phase II dose of 9-AC administered as a 72-hour infusion every 21 days to children with solid tumors is 52 microg/m2 per hour. Neutropenia and thrombocytopenia were dose limiting.

Adolescent↗

PubMed1998

Utilizing parent report to investigate young children's fears: a modification of the Fear Survey Schedule for Children--II: A research note.

The Fear Survey Schedule for Children-II (FSSC-II) (Gullone & King, 1992) was modified for parent report and a younger age group. The modified instrument (FSSC-IIP) was completed by 753 parents of children within the age range 3.0 to 8.9 years. Results revealed a stable eight-factor solution that was sensitive to age and gender differences. Parents reported a higher overall level of fear for school children compared to preschool children, and a higher overall level of fearfulness for girls compared to boys. The most common fears reported were getting lost in a crowd and in a strange place.

Child↗

PubMed1998

Belief term development in children with autism, Asperger syndrome, specific language impairment, and normal development: links to theory of mind development.

This study examined the relationship between the development of theory of mind and the development of the belief terms think, know, and guess. Children with autism and Asperger syndrome, matched to children with specific language impairment and normal development, completed false belief, belief term comprehension, and belief term expression tasks. The autistic group's performance on the false belief, belief term comprehension, and belief term expression tasks was significantly poorer than that of the Asperger, language impaired, and normal groups. Across groups an association was found between false belief and belief term performance. Results support a growing body of literature demonstrating links between the development of theory of mind and communicative competence.

Autistic Disorder↗

PubMed1997

Asymptomatic Cardiac Ischemia Pilot (ACIP) study two-year follow-up: outcomes of patients randomized to initial strategies of medical therapy versus revascularization.

BACKGROUND: Patients with ischemia during stress testing and ambulatory ECG monitoring have an increased risk of cardiac events, but it is not known whether their prognosis is improved by more aggressive treatment with anti-ischemic drugs or revascularization. METHODS AND RESULTS: The Asymptomatic Cardiac Ischemia Pilot study randomized 558 such patients who had coronary anatomy suitable for revascularization to three treatment strategies: angina-guided drug therapy (n=183), angina plus ischemia-guided drug therapy (n=183), or revascularization by angioplasty or bypass surgery (n=192). Two years after randomization, the total mortality was 6.6% in the angina-guided strategy, 4.4% in the ischemia-guided strategy, and 1.1% in the revascularization strategy (P<.02). The rate of death or myocardial infarction was 12.1% in the angina-guided strategy, 8.8% in the ischemia-guided strategy, and 4.7% in the revascularization strategy (P<.04). The rate of death, myocardial infarction, or recurrent cardiac hospitalization was 41.8% in the angina-guided strategy, 38.5% in the ischemia-guided strategy, and 23.1% in the revascularization strategy (P<.001). Pairwise testing revealed significant differences between the revascularization and angina-guided strategies for each comparison. CONCLUSIONS: A strategy of initial revascularization appears to improve the prognosis of this population compared with angina-guided medical therapy. A larger long-term study is needed to confirm this benefit and to adequately test the potential of more aggressive drug therapy.

Adrenergic beta-Antagonists↗

PubMed1997

Outcome of treatment for pediatric sarcoma of the foot: a retrospective review over a 20-year period.

Soft tissue sarcomas (STS) arising in the foot are rare in children. From 1975 to 1994, 18 children (median age, 13.5 years) were treated at St Jude Children's Research Hospital for STS of the foot. Five children had rhabdomyosarcoma (RMS), with alveolar histology in four cases. All of these patients presented with metastatic disease, which proved fatal within 9 to 24 months despite combined modality treatment with chemotherapy, radiation, and surgery. Thirteen patients had nonrhabdomyosarcoma soft tissue sarcoma (NRSTS). The most common histological variant was synovial sarcoma (7 patients). Of the 10 who presented with localized disease, seven survived 1 to 12 years (median, 7 years). Surgical treatment for these consisted of local excision (n = 2), wide local excision (n = 3), below knee amputation (n = 1 ), ray amputation (n = 1). Three received supplemental radiation, and one was also treated with chemotherapy. Local or distant recurrence proved fatal in the three other children who had localized disease. Three children who presented with metastatic NRSTS died 8 to 14 months after diagnosis. All surviving patients are without significant functional disability. In our experience, pediatric RMS of the foot has a poor outcome, attributable to both alveolar histology and presence of metastatic disease at diagnosis. In contrast, NRSTS of the foot is more often localized, and limited surgery with adjuvant radiation in the absence of clear margins should be the treatment of choice.

Adolescent↗

PubMed1996

Asymptomatic Cardiac Ischemia Pilot (ACIP) Study. Relationship between exercise-induced and ambulatory ischemia in patients with stable coronary disease.

BACKGROUND: We investigated whether the presence and frequency of asymptomatic ischemic episodes recorded during ambulatory ECG (AECG) monitoring could be predicted on the basis of clinical characteristics or exercise treadmill test (ETT) performance in patients with stable coronary disease and whether the estimate of ischemia severity was similar between the AECG and ETT. METHODS AND RESULTS: Patients screened for the Asymptomatic Cardiac Ischemia Pilot (ACIP) study were selected for the current analysis if data were available from 48-hour AECG monitoring as well as from an ETT during which the patient developed > or = 1-mm ST-segment depression. Exercise ECG data were available for 143 of the 910 patients without ischemic episodes and for 659 of the 910 patients with ischemic episodes during AECG monitoring. Angina was more frequent among patients with ambulatory ischemic episodes than among patients without such ischemia (P < .001). Patients with AECG ischemia had a consistently more marked ischemic response on the ETT than patients without AECG ischemia; patients likely to have AECG ischemia could be predicted on the basis of ETT performance characteristics. However, the correlation coefficients between the severity of ischemia estimated by ETT and by AECG were small. CONCLUSIONS: There are significant relations between ischemia detected by AECG monitoring and by ETT, but the relations are limited, indicating that the two tests are not redundant to characterize coronary patients. A larger study investigating the prognostic significance of the ischemia identified by each modality, with follow-up for clinical events, will be necessary to determine the most appropriate methods to evaluate patients with stable coronary disease.

Coronary Disease↗