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Biomedical subjects

J Masterson

Publications and source records attributed to J Masterson.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of the WHO/ISUP classification and cytokeratin 20 expression in predicting the behavior of low-grade papillary urothelial tumors. World/Health Organization/Internattional Society of Urologic Pathology.

It has not been possible to identify those low-grade papillary transitional cell bladder tumors that will recur based on conventional histopathologic assessment. Both the new World Health Organization/International Society of Urologic Pathology (WHO/ISUP) classification of transitional cell papillary neoplasms and the pattern of tumor cytokeratin 20 (CK20) immunostaining have been suggested as means of improving prognostication in low-grade transitional cell tumors. Forty-nine low-grade, noninvasive papillary transitional cell tumors were identified for the period between 1984 and 1993. The recently described WHO/ISUP classification was applied, and the tumors were classified histologically as papilloma, papillary neoplasm of low malignant potential (LMP) or low-grade papillary carcinoma. After CK20 immunostaining, the expression pattern in the tumor was classified as normal (superficial) or abnormal. Of 49 tumors, 20 were classified as papillary neoplasms of LMP and five of these patients (25%) experienced a recurrence. Of 29 tumors classified as low-grade papillary carcinoma, 14 (48.2%) recurred. In 46 of 49 cases, the CK20 immunostaining could be evaluated. Sixteen tumors showed normal (superficial) pattern of CK20 expression, and four (25%) of these patients experienced a recurrence. In contrast, of 30 patients with abnormal CK20 staining of their tumors, 15 (50%) patients had one or more recurrences. In this study, papillary neoplasms of LMP (as per the WHO/ISUP classification system) had a lower recurrence rate than low-grade papillary transitional cell carcinoma. Similarly low-grade urothelial tumors showing a normal CK20 expression pattern recurred less frequently than tumors with an abnormal pattern of CK20 staining. Neither of these differences was statistically significant, and recurrences were observed in 20% of patients whose tumors were both classified as papillary neoplasms of LMP and showed normal CK20 immunostaining; thus they do not allow a change in our current management of patients with low-grade papillary urothelial tumors, with close follow-up for all patients.

Adult↗
PubMed2000

The word-length effect and disyllabic words.

Three experiments compared immediate serial recall of disyllabic words that differed on spoken duration. Two sets of long- and short-duration words were selected, in each case maximizing duration differences but matching for frequency, familiarity, phonological similarity, and number of phonemes, and controlling for semantic associations. Serial recall measures were obtained using auditory and visual presentation and spoken and picture-pointing recall. In Experiments 1a and 1b, using the first set of items, long words were better recalled than short words. In Experiments 2a and 2b, using the second set of items, no difference was found between long and short disyllabic words. Experiment 3 confirmed the large advantage for short-duration words in the word set originally selected by Baddeley, Thomson, and Buchanan (1975). These findings suggest that there is no reliable advantage for short-duration disyllables in span tasks, and that previous accounts of a word-length effect in disyllables are based on accidental differences between list items. The failure to find an effect of word duration casts doubt on theories that propose that the capacity of memory span is determined by the duration of list items or the decay rate of phonological information in short-term memory.

Adult↗
PubMed1999

Posttraumatic stress disorder and traumatic brain injury: are they mutually exclusive?

It has been suggested that posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) must be mutually incompatible disorders. However, growing empirical evidence has begun to question this. Evidence suggests that although PTSD may be relatively rare among the TBI population, some TBI patients seem to develop PTSD. We suggest two theoretical routes through which PTSD might develop in TBI patients: through nonconscious processes in individuals who are subsequently amnesic, but who were conscious at the time of the traumatic episode and through subsequent appraisal processes in individuals who were unconscious during the traumatic episode.

Adaptation, Psychological↗
PubMed1999

Inferring sublexical correspondences from sight vocabulary: evidence from 6- and 7-year-olds.

We report an experiment designed to investigate 6-to-7-year-old children's ability to acquire knowledge of sublexical correspondences between print and sound from their reading experience. A computer database containing the printed word vocabulary of children taking part in the experiment was compiled and used to devise stimuli controlled for grapheme-phoneme correspondence (GPC) frequency and rime neighbourhood consistency according to the children's reading experience. Knowledge of GPC rules and rime units was compared by asking children to read aloud three types of nonword varying in regularity of GPC and consistency of rime pronunciation. Results supported the view that children can acquire knowledge of both GPC rules and rime units from their reading experience. GPC rule strength affects the likelihood of a GPC response; rime consistency affects the likelihood of a rime response.

Analysis of Variance↗
PubMed1998

A comparison of a non-ionic dimer, iodixanol with a non-ionic monomer, iohexol in low dose intravenous urography.

A prospective, double-blind study of 392 patients randomized into four groups was performed to establish whether diagnostic intravenous urograms could be obtained with a lower dose of iodine when using the dimeric, non-ionic contrast medium iodixanol compared with the monomeric, non-ionic iohexol. Patients received iodixanol or iohexol containing either 9 or 12 g of iodine (gI). The primary parameter was the diagnostic quality of the 6 min film, assessed in a blinded fashion, by consensus, by four radiologists. Iodixanol at both doses was diagnostic in over 90% of cases. Iohexol was only diagnostic in 74% (9 gI) and 81.8% (12 gI). Pairwise comparisons revealed that iodixanol 9 gI was significantly better than both iohexol 9 gI (p = 0.0005) and 12 gI (p = 0.014). No significant difference was present for different doses within the same contrast medium group. Iodixanol resulted in poorer bladder distension than iohexol. Iodixanol caused significantly less discomfort than iohexol.

Adult↗
PubMed1997

Evaluation of quantitative CT vertebral bone mineral density measurement and the Singh index in elderly females with hip fractures--a case control study.

This study aims to evaluate the ability of quantitative computed tomography (QCT) bone mineral density (BMD) measurement of vertebral bodies to predict risk of hip fracture. We also examine the predictive value of the radiographic Singh index and its relationship to the vertebral BMD. The vertebral BMD (using a QCT protocol) and radiographic Singh index were evaluated in 86 white females who had sustained a hip fracture after minor trauma. 86 age-matched female controls were also studied. All patients were post-menopausal, the age range was 52-95 years. BMD values were found to be low in both the study group and controls; there was no statistically significant difference between the groups. A low Singh index did not correlate with hip fracture, nor did it correlate with low vertebral BMD measurement. We conclude that vertebral BMD and radiographic Singh index are not reliable predictors of hip fracture in the elderly female.

Age Factors↗
PubMed1997

Comparison of an asymmetric screen-film combination with a conventional screen-film combination for chest radiography in 51 patients.

Comparison is made between a new asymmetric screen-film combination and a conventional screen-film combination for use in chest radiography. Seven anatomical features were assessed by three consultant radiologists in each of 51 film pairs. A preference was indicated if one system better demonstrated a particular feature. Alternatively, no preference was indicated if the feature was equally demonstrated by both systems or not demonstrated at all. Any pathology incidentally noted which remained unchanged between the two films was localized to lung, mediastinum or bone and marked in the same way. The asymmetric high contrast system scored higher than the conventional system for demonstration of anatomy in both mediastinum and lungs, but no difference emerged between the two systems in the demonstration of pathology. The asymmetric screen-film system showed improved mediastinal and, to a lesser degree, improved lung detail. Further assessment in necessary to define any associated improvement in diagnostic yield.

Decision Making↗
PubMed1996

Bone remodeling indices and secondary hyperparathyroidism in celiac disease.

OBJECTIVES: To determine the prevalence of hypovitaminosis D and secondary hyperparathyroidism (SHPT) and to assess bone turnover by using markers of bone formation and resorption in celiac disease (CD). METHODS: Forty-three patients with CD were investigated: group 1, newly diagnosed celiacs (n = 19); group 2, treated celiacs responding histologically to a gluten-free diet (n = 16); group 3, refractory celiacs, unresponsive to a gluten-free diet and immunosuppressive therapy (n = 8). Serum was drawn for intact parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D], ionized calcium (Cai), total alkaline phosphatase (AP), and biochemical markers of bone formation: procollagen I carboxyterminal propeptide (PICP) and osteocalcin (Oc). Urinary indices of bone resorption, deoxypyridinoline (DPD), pyridinoline (PyD), and hydroxyproline (OHP), were measured in a 2-h fasting urine. In 22 patients, computerized tomographic scan for bone mineral density (BMD) was performed. RESULTS: The prevalence in groups 1, 2, and 3, respectively, of hypovitaminosis D (< 50 nmol/L) was 58%, 25%, and 88%, and the prevalence of SHPT (> 5.4 pmol/L) was 25%, 19%, and 25%. Bone resorption markers were significantly elevated in all groups, and bone formation indices were elevated in the newly diagnosed celiacs compared with a group of healthy adults. Low BMD (T-score greater than -1 SD unit) was found in 68% of patients assessed; 36% of patients had a T-score greater than -2.5 SD units. CONCLUSIONS: Hypovitaminosis D and SHPT are common in newly diagnosed and refractory celiacs but are less common in those who respond to a gluten-free diet. Newly diagnosed patients have a high bone turnover state with elevation of both bone formation and resorption indices. Those with refractory disease demonstrate a remodeling imbalance with high bone resorption.

Adult↗
PubMed1995

Three cases of pulmonary aspergilloma in adult patients with cystic fibrosis.

Pulmonary aspergillomas usually occur when Aspergillus fungi colonise lung tissue previously damaged by disease. Pulmonary aspergillomas in three adult patients with cystic fibrosis are reported--an association not previously described. At the time of diagnosis all three patients had previous long term colonisation with Aspergillus fumigatus and severe advanced destructive lung disease with lung function less than 25% of the predicted normal values. It is likely that, with increasing survival in cystic fibrosis, more adult patients will develop aspergillomas during the protracted phase of end stage lung disease that characterises the terminal years of this condition.

Adult↗
PubMed1994

The utility of nasal bone radiographs in nasal trauma.

A prospective study was performed to assess the value of nasal bone radiographs taken in the accident and emergency department. The study population consisted of 100 consecutive patients who had nasal bone radiographs in our accident and emergency (A&E) department following trauma. We looked at the casualty officers', radiologists' and ENT surgeons' assessment of the cases. Thirty months later we reviewed the patients' notes to identify the number who sought medico-legal reports on their injury in that interval. We found sporting injuries to be the commonest mechanism of injury, followed closely by accidental falls. The remaining third was made up predominantly of cases of personal assault and road traffic accidents. Only two patients had a naso-pharyngeal history recorded on their visit to A&E. Thirty-five patients were referred to ENT out-patients, only 24 kept their appointment. Thirty-one of the 35 ENT referrals were felt to have a fracture demonstrated on their radiographs. However, 19 of those discharged were also thought to have an X-ray-proven fracture. Thirty months later only two patients had requested a medico-legal report. We demonstrate that the decisions regarding treatment of nasal trauma are based on clinical findings and that nasal bone radiography has no place in the decision making process and should therefore be abandoned.

Adolescent↗
PubMed1994

Iodixanol in intravenous urography: a comparison of iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iopamidol 300 mgI/ml (NIOPAM).

The first European trial of iodixanol (Nycomed Imaging AS) in adult intravenous urography is reported. Iodixanol is a new non-ionic, dimeric contrast medium of low osmolality. A double-blind, randomized, three group parallel study comparing iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iopamidol 300 mgI/ml (Niopam) was undertaken. A total of 173 of 180 patients entered completed the trial. Efficacy was evaluated with regard to overall diagnostic information and pyelographic density 5 min after contrast medium administration. Efficacy was found to increase with increasing iodine concentration, with no significant difference between the three contrast media. The incidence of adverse events was low, with no significant difference between the groups. Discomfort occurred less frequently with iodixanol than with iopamidol. We conclude that iodixanol is a safe and efficacious contrast medium for use in intravenous urography.

Adult↗
PubMed1994

Identification of inappropriate radiological referrals with suspected gallstones: a prospective audit.

The objective of this study was to derive and test clinical scoring system in order to predict the presence of gallstones and to identify inappropriate referrals. The design of this scoring system comprised a prospective audit of all referrals with suspected gallstones and a prospective validation of the system on new patients. The subjects used in the study consisted of 300 inpatient, outpatient and general practitioner referrals to a radiology department with suspected gallstones during the period 1984-1986 (1st cohort) and 200 similar referrals from 1987 to 1988 (2nd cohort). The main outcome measures were gallstones as determined by oral cholecystogram and/or ultrasound of the gallbladder. 32.7% and 24.0% of referrals in the first and second cohorts, respectively, had gallstones. A scoring system to predict gallstones was derived on the first cohort based on age, Murphy's sign, duration and type of pain, presence or absence of flatulence, and source of referral. This scoring system discriminated well between those with and without stones in both cohorts. Low risk groups, comprising about 15% of the referrals in each cohort, were identified with a prevalence of gallstones of 4.5% (1st cohort) and 3.0% (2nd cohort). If these patients had not been referred the radiological workload would have dropped by 15%, with a very small reduction in diagnostic yield. We conclude that prior to radiological assessment it is possible, on the basis of source of referral and symptoms, to identify a group of patients with a low prevalence of gallstones. These cases, with a low diagnostic yield, contribute substantially to the workload of a radiological department.

Adult↗
PubMed1994

Comparison of a new dual characteristic film-screen system (insight) with a standard film-screen system for chest radiology.

A new dual image receptor screen-film combination has been developed by Kodak with the objective of improving mediastinal and retro-cardiac detail whilst retaining good contrast and detail in the lung fields. This system was compared with our standard chest system. The study population was 36 patients with sarcoidosis. A postero-anterior (PA) chest film using our standard system was followed by a PA chest film using the new system--both using high kVp technique. The pairs of radiographs were assessed for (1) presence or absence of lymphadenopathy; (2) visibility of anterior and posterior mediastinal and azygo-esophageal lines; (3) visibility of vessels in the outer and inner thirds of the lungs and (4) visibility of infiltrates, if present. The new film-screen combination was judged to show the mediastinal structures better in almost all instances. However, our standard combination was preferred for lung detail visualization in most cases. No significant difference was found between the two systems in their ability to demonstrate lymphadenopathy. The results were almost unchanged when the observers were given the option to score the criteria as equally well demonstrated on both films as opposed to not having this option available. We feel the advantages of the Insight system do not compensate for the significant loss of parenchymal detail resulting from the use of this system.

Adult↗
PubMed1993

An open-label dose-escalation trial of oral dehydroepiandrosterone tolerance and pharmacokinetics in patients with HIV disease.

Dehydroepiandrosterone (DHEA) is a naturally occurring adrenal steroid reported to have immunomodulatory and antiviral activity in cellular and animal models as well as modest in vitro antiretroviral activity against human immunodeficiency virus (HIV). A phase I dose-escalation study was performed to evaluate the safety and pharmacokinetics of DHEA in subjects with symptomatic HIV disease and an absolute CD4 lymphocyte count between 250 and 600 cells/microliters. Thirty-one subjects were evaluated and monitored for safety and tolerance. The oral drug was administered three times daily in doses ranging from 750 mg/day to 2,250 mg/day for 16 weeks. Some immunological and virological parameters were monitored as well. The drug was well tolerated and no dose-limiting side effects were noted. Dose proportionality was evidenced neither by the serum DHEA nor by DHEA-S time-concentration curves for the three dosing groups. However, the study cohort appeared to consist of two subpopulations with markedly different bioavailability for a given DHEA dose. No sustained improvements in CD4 counts nor decreases in serum p24 antigen or beta-2 microglobulin levels were observed. However, serum neopterin levels decreased transiently by 23-40% at week 8 compared with baseline in all dosing groups. DHEA was well tolerated by patients with mild symptomatic HIV disease; evaluation of this agent for efficacy in HIV disease would require randomized, controlled trials.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Normal bone density in Irish women: is American normative data suitable for use in Ireland?

The objective of the study was to determine whether or not U.S. normal data for female Vertebral Bone Mineral Density is suitable for use in an Irish population. One hundred and fifty-six healthy Caucasian women of permanent Irish domicile had bone densitometry performed using single energy quantitative computed tomography of L2, L3 and L4 vertebrae. We found that comparison of our results to normal American data shows a slight and progressive increase in bone mineral content of postmenopausal American women with age relative to the Irish population. This difference is small and not sufficient to justify development of separate normal values for Irish women. We conclude that this discrepancy may be due to a combination of environmental and racial factors or to the more rigorous exclusion criteria applied in our study.

Adult↗
PubMed1992

Nonword naming: further exploration of the pseudohomophone effect in terms of orthographic neighborhood size, graphemic changes, spelling-sound consistency, and reader accuracy.

Five experiments examined nonword pronunciation. As reported by McCann and Besner (1987), accurate, regular pronunciations increased as the number of orthographic neighbors (N) increased. Adults read pseudohomophones (nonwords that sound like a word) more accurately than other nonwords only when the nonwords were low n, shared the consonants with the words on which they were based, and overall accuracy was lower. Children showed a pseudohomophone advantage even when N was high. Adults pronounced nonwords comprised of inconsistent endings (with existing regular and irregular pronunciations) in an irregular fashion when this resulted in a word; this applied to relatively high-N items.

Adult↗
PubMed1992

Beginning reading with phonology.

Seymour & Elder (1986) investigated the reading of children in the first year of school and suggested that the first stage of learning to read shows little involvement of assembled phonology. The present study examines processes involved in the reading-aloud and printed-word comprehension of children in the second year of school. Use of assembled phonology was evident in the children's reading-aloud responses, and proficiency in its use was related to reading ability. Printed-word comprehension appeared to involve prior retrieval of a phonological code for less frequent words. Similarities between the processing systems for reading used by these children and by skilled readers were discussed, and related to the computational model of reading development proposed by Seidenberg & McClelland (1989).

Child↗