Biomedical subjects
Publications and source records attributed to D Miller.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Patient records in a central London genitourinary medicine (GUM) clinic relating to HIV testing were examined and compared for the 3 months immediately before and after World AIDS Day (WAD) in 1994, according to gender and sexual orientation, and the reasons given for testing. Additionally, patient-identified risk was compared with counsellor-identified risk in each case in 1994. Findings were compared with data from the initial HIV awareness campaign in 1986-87. In the 1994 study period, there were no significant differences in overall numbers attending or gender of test-seekers before and after WAD, or proportions of heterosexual, bisexual and gay test-seekers across the time periods. Within each of these groups, gay test seekers were significantly more likely to be HIV positive than heterosexuals, although there were no differences in numbers found positive in each group before and after WAD. Thirty-five per cent (n=268) reported a history of safer sex only, 32% (n=247) said 'sometimes', and 33% (n=249) said 'no'. Overall, the main reasons given for HIV test-seeking included having part of a sexual health screen, having episodes of unprotected sex and/or casual partners, concern over partner's status/monogamy, and intravenous drug user (IDU) contact. Reasons for testing in 1994 reflected greater awareness of HIV transmission compared to 1986-87, although only one-third of those tested reported a history of safer sex.
One approach to outcome measures for speech and language therapy is to display measures of the physical, acoustic, correlates of the perceptually salient features of the structure of speech. A difficulty with this approach is that there is no simple mapping of physical correlates onto speech percepts. In this workshop the physical measures of voice fundamental frequency and larynx contact quotient are explored in relation to the perception, analysis and treatment of aspects of voice quality in a speech and language therapy clinic. A fundamental principle is to analyse samples of continuous speech. The workshop will focus on clients with unilateral vocal fold paralysis.
Providing successful dental care is a daily challenge. Techniques to improve our own technical skills are of obvious value, however careful consideration of all the available facts help us to maximize the benefit of our technical skills. We are frequently limited by the conditions and attitudes that are attached to our patients. I suggest we need to recognize those limitations and convey them to those that we are caring for. Our formulation of an accurate treatment plan is the result of consideration of as many of the factors influencing the disease as can be discovered.
Parathyroid carcinoma is a rare endocrine malignancy characterized by the exaggerated metabolic effects of the parathyroid glands. The preoperative differential diagnosis between parathyroid carcinoma and primary hyperparathyroidism is often difficult because many of the signs and symptoms are very similar. Intraoperative differentiation is obscured by the strict anatomic and histologic criteria required for diagnosis of parathyroid carcinoma. We have encountered three patients with parathyroid carcinoma during the last 10 years and managed them successfully. Two of them presented with recurrence of hypercalcemia, one 11 years after and the other 3 years after the primary operation for hyperparathyroidism; both patients were eventually diagnosed with parathyroid carcinoma. The third case was suspected as primary hyperparathyroidism preoperatively but confirmed as carcinoma subsequent to histologic examination.
Explore the source record for details and available documents.
PURPOSE: We evaluated factors that influence MR signal changes during photic stimulation of the visual cortex. We also tested the hypothesis that functional MR imaging response corresponds to electroencephalographic (EEG) synchronization after photic stimulation. METHODS: Thirty-eight healthy subjects, 20 men and 18 women, underwent photic stimulation of the visual cortex. They were studied with a 1.5-T MR unit, and photic stimulation was induced via 8-Hz LED goggles. Seven subjects with and seven without detectable functional MR imaging response to photic stimulation underwent further studies with 16-channel EEG after 2- to 30-Hz stroboscopic stimulation. RESULTS: Thirteen men and 18 women had a significant increase in MR signal in the visual cortex; seven men showed no visual cortex activation during more than two repeated studies. Six of seven volunteers with increased functional MR imaging signal after photic stimulation also showed signs of EEG synchronization when an 8-Hz stroboscopic flash was used; six of seven subjects with no functional MR imaging lacked EEG synchronization at 8-Hz stimulation. CONCLUSIONS: Men were more likely than women to have undetectable MR signal changes after photic stimulation. This finding should be considered when interpreting results of functional MR imaging studies. EEG with stroboscopic examination is a good predictor of functional MR imaging sensitivity to changes in regional cerebral blood flow induced by sensory stimulation.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
PURPOSE: Accelerated protons were used in an attempt to limit treatment-related morbidity in children with tumors in or near the developing brain, by reducing the integral dose to adjacent normal tissues. METHODS AND MATERIALS: Children treated with protons at Loma Linda University Medical Center between August 1991 and December 1994 were analyzed retrospectively. Twenty-eight children, aged 1 to 18 years, were identified as at risk for brain injury from treatment. Medical records, physical examinations, and correspondence with patients, their parents, and referring physicians were analyzed. The investigators tabulated post-treatment changes in pre-treatment signs and symptoms and made judgments as to whether improvement, no change, or worsening related to disease or treatment had supervened. Magnetic resonance images were correlated with clinical findings and radiographic impressions were tabulated. RESULTS: Follow-up ranged from 7 to 49 months (median 25 months). Four instances of treatment-related morbidity were identified. Forty-one instances of site-specific, disease-related morbidity were identified: 15 improved or resolved and 26 remained unchanged after treatment. Four patients had radiographic evidence of local failure. Three of these patients, including two with high-grade glioma, have died. CONCLUSION: Early treatment-related morbidity associated with proton therapy is low. Tumor progression remains a problem when treating certain histologies such as high-grade glioma. Escalating the dose delivered to target volumes may benefit children with tumors associated with poor rates of local control. Long-term follow-up, including neurocognitive testing, is in progress to assess integral-dose effects on cognitive, behavioral and developmental outcomes in children with cranial tumors.
Optically pure (> 99.5%) enantiomers of insect juvenile hormones (JH) I, II, and III were obtained by injection of racemic mixtures onto a chiral HPLC column using hexane:2-propanol (99.5:0.5) as the mobile phase. The enantiomers of JH III were the best resolved (R = 4.26), followed by those of JH II (R = 2.29) and JH I (R = 1.47). These purified natural and unnatural enantiomers were used to further characterize an antiserum (444) developed for JH radioimmunoassays (RIAs). Based on ED50 values generated using optically pure [methyl-3H]-10R,11S-JH II as a tracer, the natural isomers of JH I, JH II, and JH III were 30, 87, and 36 times more immunoreactive, respectively, than the unnatural isomers. When compared with the racemates, the natural isomers were approximately twice as immunoreactive. In competitive displacement studies where the natural enantiomers of the three JHs were compared, immunoreactivities were in the order JH II > JH I > JH III (ED50 = 109, 198, and 300, respectively). Availability of pure natural enantiomers of JH, both as tracers and competitors, should improve the sensitivity and accuracy of JH titer determinations made by RIA and facilitate various enzyme, binding protein, and receptor studies.
Malignant catarrhal fever (MCF) is traditionally regarded as a disease with a short clinical course, low morbidity and high case fatality rate. Owing to the limitations of the assays used for laboratory diagnosis. It was difficult in characterise the clinical spectrum of sheep-associated MCF, particularly when the cattle recovered from an MCF-like clinical syndrome. Over a period of three years, 11 cattle that survived MCF for up to two-and-a-half years were identified on four premises. A clinical diagnosis of MCF was confirmed by the detection of ovine herpesvirus-2 DNA in peripheral blood leucocytes using a polymerase chain reaction (PCR) assay that detects a specific 238 base-pair fragment of viral genomic DNA. Of the 11 cattle examined, six recovered clinically with the exception of bilateral corneal oedema with stromal keratitis (four animals) and unilateral perforating keratitis (one animal). The 10 animals available for postmortem examination had disseminated subacute to chronic arteriopathy. Recovery was associated with the resolution of the acute lymphoid panarteritis that characterises the acute phase of MCF, and with the development of generalised chronic obliterative arteriosclerosis. Bilateral leucomata were due in part to the focal destruction of corneal endothelium secondary to acute endothelialitis. Formalin-fixed tissues and/or unfixed lymphoid cells from all 11 cattle were positive for sheep-associated MCF by PCR. These observations indicate that recovery and chronic disease are a significant part of the clinical spectrum of MCF and that such cases occur with some frequency in the area studied. The affected cattle remain persistently infected by the putative sheep-associated MCF gammaherpesvirus.
The purpose of the present study was to evaluate the differential activation of the motor cortex during finger tapping in patients with schizophrenia using the newly available imaging method of functional magnetic resonance imaging (fMRI). Nine patients with DSMIII-R schizophrenia and 9 well-matched healthy volunteer subjects underwent fMRI examination on a conventional MR unit; activation of the primary motor cortex was evaluated during performance of a finger motion task. Localized activation of the motor cortex was observed in 17 of 18 subjects during fMRI. Patients and controls were, however, indistinguishable with respect to signal intensity or area thereof within the motor cortex. fMRI did not reveal motor cortical dysfunction in schizophrenia. Despite its infancy, fMRI holds considerable promise to advance understanding of the neurodynamics of psychiatric disorders, particularly schizophrenia.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
OBJECTIVE: To examine the neuroanatomical correlates of late-life minor depression using magnetic resonance imaging. DESIGN: Cross-sectional quantitative magnetic resonance imaging study of elderly patients with minor depression and age-matched controls. SETTING: Patients and controls were recruited from the community through advertisements to the Section of Geriatric Psychiatry, University of Pennsylvania, Philadelphia. PARTICIPANTS: Our sample included 18 subjects diagnosed as having minor depression using the modified Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, research criteria and 31 controls without depression. Patients were free of other central nervous system disease and both groups had comparable degrees of medical comorbidity. MAIN OUTCOME MEASURES: All images were acquired on a 1.5-T scanner and absolute and normalized quantitative measures of global and focal brain and cerebrospinal fluid volumes were compared between groups. RESULTS: Prefrontal lobe volume was significantly smaller in the group with minor depression (P = .002) compared with controls after controlling for age, sex, and age by sex interactions. More global measures of brain and cerebrospinal fluid volumes were comparable in both groups. CONCLUSIONS: These data suggest that focal prefrontal atrophy may provide an important neuroanatomical substrate in late-life minor depression.
Educational researchers assess self-efficacy by asking students to rate their capability of succeeding at specific target tasks (e.g., math test items) and then testing their performance to actually solve similar test items. Pajares and colleagues (Pajares & Kranzler, 1995; Pajares & Miller, 1994, 1995, in press) argued for the use of identical items to assess self-efficacy and performance in order to maximize self-efficacy's predictive power. In two studies, structural equation models (SEM) demonstrated that this variation led to positively biased estimates of paths from self-efficacy to performance and negatively biased estimates of paths from self-concept to performance. Whereas corrections for this bias did not substantially alter the size of effects or substantive interpretations, results from both studies were consistent with a priori predictions about the nature of this bias. Researchers are encouraged to use similar but not identical items to assess self-efficacy and performance, a construct validity approach to interrogate their interpretations, more diverse outcome measures, and SEM approaches like those demonstrated here.