Biomedical subjects
J Price
Publications and source records attributed to J Price.
A method for the assessment of the functional neuroanatomy of human sleep using FDG PET.
Although sleep is characterized by relative behavioral inactivity, cortical activity is known to cycle in well-defined periods across this state. Cognitive function during sleep has been difficult to define, although disturbances in sleep are known to result from, and to cause, various human pathologies, including neuropsychiatric disorders. Assessment of brain function in humans (related to cognitive operations) during sleep has been limited, until recently, to surface electrophysiologic recordings that limit analysis of regional function, particularly in deep structures. The current report describes one method of assessing human forebrain activation during sleep using the [18F]2-fluoro-2-deoxy-d-glucose ([18F]FDG) method and positron emission tomography (PET) measures of regional cerebral glucose utilization. In comparison with other functional brain imaging techniques (e.g., assessment of blood flow or functional magnetic resonance imaging), this method offers the advantage of a more naturalistic study of sleep since subjects do not have to sleep in a scanning device. This leads to a higher rate of successful completion of studies. The primary disadvantage of this method is the decreased temporal resolution necessitating assessments of global sleep states (e.g., REM or NREM) as opposed to assessing events within a sleep state (e.g., sleep spindles or rapid eye movements).
Prevention of central venous catheter associated thrombosis using minidose warfarin in patients with haematological malignancies.
Thrombosis is a well-recognized complication following insertion of central venous catheters and is associated with significant morbidity. In an attempt to reduce line-associated thrombosis, 108 consecutive patients with haematological malignancies were commenced on prophylactic 'minidose' warfarin, 1 mg/d, at the time of line insertion. This group of patients were compared with a historic group of 115 consecutive patients who had not received warfarin. Clinically-suspected venous thrombosis was confirmed by Doppler ultrasound or venography. Patients taking prophylactic warfarin had their prothrombin time measured three times per week with the aim of maintaining an INR <1.6. Five (5%) of the 108 patients who received minidose warfarin developed a thrombosis, at a median of 72 d (range 5-166) from the time of catheter insertion. In the 115 patients who were not anticoagulated 15 (13%) developed a catheter-associated thrombosis at a median of 16 d (range 1-35). There was a significant reduction in line-associated thrombosis in patients receiving warfarin (P=0.03). These data suggest that minidose warfarin reduces the incidence of central venous catheter related thrombosis in patients with haematological malignancies.
Axillary lymph node calcification due to metastatic papillary carcinoma.
A case is presented in which calcification in an axillary lymph node seen on a screening mammogram was the presenting feature of metastatic papillary carcinoma, presumed to be of thyroid origin. The differential diagnosis of axillary lymph node calcification seen on mammography is reviewed.
Focal organizing pneumonia mimicking small peripheral lung adenocarcinoma on CT scans.
The present report of four cases highlights the potential for focal organizing pneumonia (FOP) to masquerade as a small peripheral lung adenocarcinoma on CT scans. Both entities may present the CT appearance of a peripheral spiculated lung nodule, often with an air bronchogram. A history suggestive of an infectious aetiology and the presence of other foci of inflammatory change on CT scan may be helpful clues to the diagnosis of FOP. Because FOP is comparatively rare, surgical excision will usually be required to exclude malignancy. In some cases, however, particularly after a negative percutaneous biopsy, conservative management with a follow-up CT scan at 3-4 weeks may be an alternative to immediate surgical intervention.
Prospective evaluation of a teaching model to determine competency in performing flexible sigmoidoscopies.
OBJECTIVE: There are limited objective criteria for determining competency in performing flexible sigmoidoscopies. The authors developed a teaching model using eight objective criteria that measured both cognitive and technical skills in performing flexible sigmoidoscopies. The objective was to determine whether the teaching model was a valid method and then to compare it to a commonly used Overall Competence Score or independent observer method. METHODS: A total of 120 procedures with 10 residents were evaluated using the two methods. Eight objective parameters had been determined before validating the teaching model. Preset criteria determined competency on a single procedure, and competent performance on five procedures in a row determined certification to independently perform procedures. The teaching model was separately tested for validity and then compared with the independent observer method. RESULTS: A total of 120 procedures were graded using the teaching model method: 73 competent and 47 incompetent. Six of the seven objective parameters were associated with competency in the teaching model method. The eighth objective parameter was excluded because of lack of variation. Fifty of the 120 procedures were graded using the independent observer method: 36 competent and 14 incompetent. Two of the seven objective parameters were associated with competency in the independent observer method. Comparison of the two methods revealed seven discrepancies regarding competent and incompetent procedures. The correlation between the two methods was 0.71. CONCLUSION: The teaching model method offers objective criteria to evaluate skill in performing flexible sigmoidoscopies.
The adaptive function of mood change.
It is useful to imagine an 'agonistic strategy set', containing the two alternative and mutually incompatible strategies of escalation and de-escalation. The strategy set is accessed by loss, threat or some other form of 'ranking stress'. It is further suggested that ranking stress is dealt with relatively independently at three levels of the brain/mind, so that an agonistic strategy set is deployed at each of the three levels. Normally, all three levels escalate or de-escalate in unison, but sometimes lower level de-escalation is associated with middle or higher level escalation, and then the resolution of agonistic situations is delayed and psychopathology may be recognized.
Changes in medical student attitudes as they progress through a medical course.
OBJECTIVES: To explore the way ethical principles develop during a medical education course for three groups of medical students--in their first year, at the beginning of their penultimate (fifth) year and towards the end of their final (sixth) year. DESIGN: Survey questionnaire administered to medical students in their first, fifth and final (sixth) year. SETTING: A large medical school in Queensland, Australia. SURVEY SAMPLE: Approximately half the students in each of three years (first, fifth and sixth) provided data on a voluntary basis, a total of 385 students. RESULTS: At the point of entry, minor differences were found between medical students and first year law and psychology students. More striking were differences between male and female medical students, suggesting early socialization had a substantial impact here. CONCLUSIONS: Results indicate that substantial changes in attitude have developed by the beginning of fifth year with little change thereafter. Gender difference persisted. Some difference in ethical attitudes were found when groups of different ethnic backgrounds were compared. The impact of a move to a graduate medical course, which gives high priority to ethics within a professional development domain, can now be evaluated.
Dorothy Wordsworth's mental illness.
Explore the source record for details and available documents.
Targeted intervention research studies on sexually transmitted diseases (STD): methodology, selected findings and implications for STD service delivery and communications.
OBJECTIVE: To report the findings of qualitative studies designed for use in improving sexually transmitted disease (STD) programs. The studies explore illness conceptions and treatment behaviors for STD in five African countries. These targeted intervention research (TIR) studies were performed on clinic-based and community-based samples in representative communities and utilized a variety of qualitative research methods (e.g. in-depth and key informant interviews, focus group discussions). FINDINGS: Study findings revealed that community members' explanations of symptoms, classification of illnesses, and perceptions of whether symptoms are pathological or serious influence individual health-care-seeking behaviors. Data also showed that local terms for STD are often disparaging and do not fit into biomedical designations. STD patient care-seeking frequently reflects an ordered, albeit loosely constructed, process of elimination in pursuit of symptom relief, wherein alternative treatments are tried and proven effective or abandoned. CONCLUSIONS: The TIR studies highlight the importance of community-specific strategies aimed at increasing prompt care seeking at qualified biomedical facilities. Information from study data should lead programs to sensitize health professionals to community understanding about STD and to design services and communication programs that are meaningful and appropriate to local contexts.
Systematic screening of the LDL-PLA2 gene for polymorphic variants and case-control analysis in schizophrenia.
Systematic scans of the genome using microsatellite markers have identified chromosome 6p21.1 as a putative locus for schizophrenia in multiply affected families. There is also evidence from a series of studies for a role of abnormal phospholipid metabolism in schizophrenia. In light of these findings, and the role of platelet activating factor in neurotransmission and neurodevelopment, we have examined the LDL-PLA2 (plasma PAF acetylhydrolase, PAF-AH) gene, a serine dependent phospholipase that has been mapped by hybrid mapping to chromosome 6p21.1, as a positional candidate gene for schizophrenia. The gene was systematically screened using SSCP/HD analysis for polymorphisms associated with the disease. Four polymorphic variants were found within the gene and studied in a group of 200 schizophrenic patients and 100 controls. The variant in exon 7 (Iso195Thr) was found to be weakly associated with schizophrenia (p = 0.04) and the variant in exon 11 (Val379Ala) almost reached significance (p = 0.057). After correcting for multiple testing no significant associations were detected. Haplotype analysis combining pairs of polymorphisms also provided no evidence for association of this gene with schizophrenia in our sample of patients.
Developmental changes in integrin beta-subunits in rat cerebral cortex.
The present study was carried out to characterize the developmental expression of beta 1-, beta 5- and beta 6-integrin subunits in rat cerebral cortex. Using reverse transcriptase-polymerase chain reaction, mRNA of the three beta-subunits were shown to be present at all developmental stages. Based on immunoblots, beta 1-subunit expression was decreased during cortical development from embryonic stages to adults. beta 6-subunit expression appeared only in adult cortex. beta 5-subunit expression did not change during development. These beta-subunits were expressed in cortical embryonic cells as revealed by immunological studies in vitro. beta 5 and beta 6 were also present in neuronal cells and in oligodendrocytes in adult cortex. Altogether, these results demonstrate that rat cerebral cortex expresses distinct integrin beta-subunits with different developmental profiles. This switch of beta-subunits may be an important mechanism for the regulation of cell behaviour during development.
A selection test for Australian graduate-entry medical schools.
One of the selection criteria for the three Australian medical schools with graduate-entry programs is performance in a common entry test, the Graduate Australian Medical School Admissions Test (GAMSAT). We found that scores for GAMSAT in 1996 (its second year) varied significantly with candidate sex, age, highest degree level and main subject in first degree. Mean scores were highest for men, younger candidates, honours graduates and those with a physical sciences background. However, arts and social sciences graduates (9.8% of applicants) comprised 11.4% of the 200 top-scoring candidates.
Development of the neonatal rabbit retina in organ culture. 1. Comparison with histogenesis in vivo, and the effect of a gliotoxin (alpha-aminoadipic acid).
Organ cultures from neonatal rabbit retinae grew well over periods of up to 2 weeks in vitro. Proliferation in vitro declined in parallel with the decline seen in vivo, although the rate of proliferation in the explants was slightly reduced. The proliferation of progenitor cells in vitro produced the same cell types produced postnatally in vivo. Postnatally generated cell clones, labeled by means of a retroviral vector, consisted mainly of rods and Müller cells. The layers of the retinae developed as in vivo; an outer plexiform layer occurred after the first 2 days in vitro. Ultrastructurally, ribbon synapses (outer and inner plexiform layer) and conventional synapses (inner plexiform layer) were observed. The photoreceptor cells grew well-developed inner segments and cilia but no mature outer segments. The cultured retinae contained a well-developed, regular lattice of Müller cells expressing vimentin as in vivo. The neuron-to-Müller cell-ratios were essentially the same as in vivo, viz. about 15 to 16 neurons, among them about 10 to 11 (rod) photoreceptor cells per Müller cell. When the glia cell-specific toxin alpha-aminoadipic acid (alpha AAA) was applied, the pattern of vimentin-positive Müller cells became irregular, or even locally missing. In such cases, the tissue became disorganized as indicated by a local disappearance of the regular layering, and development of many rosettes. It is concluded that an intact lattice of Müller cells is necessary for the migration of young neurons, and for correct formation of retinal layers.
Screening for major deep vein thrombosis in seriously injured patients: a prospective study.
The purpose of the study is to determine the prevalence of acute deep venous thrombosis (DVT) in severely injured trauma patients, to investigate the cost effectiveness of a noninvasive surveillance program, and to assess the merit of current methods of prophylaxis against DVT. One hundred and forty-eight patients (295 limbs) with a mean age of 36.5 years, mean trauma score of 13.3, mean injury severity score of 22.4 with predominantly blunt injuries (88.5%), were part of the study. The mean length of stay was 17.6 days. Venous duplex scans (VDS) were performed on inpatients on days 2-5, day 11, and day 30 following admission. Sequential compression device and/or subcutaneous heparin was used in 99% of patients with compliance being monitored by trauma nurse clinicians. A total of 272 VDS were performed with total charges of $111,520. DVT was found by VDS or venography in eight limbs (2.7%) of six patients (4%), our of the limbs being symptomatic. Two additional patients had pulmonary embolism, both with normal VDS. Routine serial VDS in severely injured patients who undergo aggressive prophylaxis against DVT is not cost effective and therefore not justified.