Search PubMed⌕ Search

Biomedical subjects

Robert Miller

Publications and source records attributed to Robert Miller.

28 records · Page 2Linked to original sources
PubMed2004

Dihydropteroate synthase gene mutations in Pneumocystis and sulfa resistance.

Pneumocystis pneumonia (PCP) remains a major cause of illness and death in HIV-infected persons. Sulfa drugs, trimethoprim-sulfamethoxazole (TMP-SMX) and dapsone are mainstays of PCP treatment and prophylaxis. While prophylaxis has reduced the incidence of PCP, its use has raised concerns about development of resistant organisms. The inability to culture human Pneumocystis, Pneumocystis jirovecii, in a standardized culture system prevents routine susceptibility testing and detection of drug resistance. In other microorganisms, sulfa drug resistance has resulted from specific point mutations in the dihydropteroate synthase (DHPS) gene. Similar mutations have been observed in P. jirovecii. Studies have consistently demonstrated a significant association between the use of sulfa drugs for PCP prophylaxis and DHPS gene mutations. Whether these mutations confer resistance to TMP-SMX or dapsone plus trimethoprim for PCP treatment remains unclear. We review studies of DHPS mutations in P. jirovecii and summarize the evidence for resistance to sulfamethoxazole and dapsone.

Anti-Infective Agents↗
PubMed2003

Is aortic angiography necessary for accurate planning of endovascular aortic aneurysm stents?

UNLABELLED: Endovascular management of abdominal aortic aneurysms (AAA) relies upon accurate stent design. We hypothesized the length of the stent could be measured from computed tomogram (CT) generated 3D surface rendered images of the abdominal vessels, eliminating the need for digital subtraction angiography (DSA). METHODS: The CT scans from a consecutive series of 54 patients considered for endovascular AAA repair were reviewed. A TRIFAB Zenith (Cook) endovascular aortic stent was designed, using the manufacturer's sizing computer program. These hypothetical stents were compared to those that had been implanted, using measurements from both angiogram and CT (Spearman's test of correlation (p<0.05)). RESULTS: The stent body size and short limb extension (SLE) of stents in each group was similar (correlation coefficient 0.70(p<0.01) and 0.50 (p=0.014)), however, CT alone significantly underestimated the length of the long limb extension (LLE) (correlation coefficient 0.095). CONCLUSION: These data suggest that CT underestimates the tortuosity of iliac vessels. Aortic angiography is necessary for accurate AAA endovascular stent design.

Angiography, Digital Subtraction↗
PubMed2003

The number, size, and type of axons in rat subcortical white matter on left and right sides: a stereological, ultrastructural study.

Abundant evidence indicates important functional differences between the two cerebral hemispheres of humans, although the cellular basis of these differences is unknown. A recent hypothesis proposes that these functional differences depend on differences between sides in the "repertoire" of axonal conduction delays for cortico-cortical axons. In morphological terms this corresponds to differences in caliber, or proportion, of myelinated versus unmyelinated axons. Several behavioural studies have indicated that cerebral asymmetry occurs in rodents, in which rigorous morphological analysis is possible. The hypothesis was therefore tested for the first time in adult male Wistar rats, using transmission electron microscopy and stereological methods. Subcortical white matter was compared between left and right sides in three regions (frontal, parietal, and occipital). The average caliber and numerical density of unmyelinated and myelinated axons was compared between sides and between regions. All data were corrected for shrinkage. No significant differences between sides were found in the average caliber of either type of axon in any region. The numerical density of either type of axon also yielded no significant differences between sides in any region. Significant differences were evident between regions in both caliber and numerical density of the two axonal types, and these quantitative data are reported. The proportion of unmyelinated axons in the lateral white matter was also higher than in previous studies of hemispheric white matter that studied the corpus callosum. The present study provides no evidence supporting the hypothesis that functional hemispheric specialization is due to differences in axonal number, caliber or type.

Animals↗
PubMed2003

Rural interdisciplinary mental health team building via satellite: a demonstration project.

This paper reports on the results of a demonstration project that examined the role of telehealth/telemedicine (hereafter referred to as telehealth) in providing interdisciplinary mental health training and support to health professionals in a rural region of Atlantic Canada. Special emphasis was placed on addressing the question of how training might affect interdisciplinary collaboration among the rural health professionals. Five urban mental health professionals from three disciplines provided training and support via video-satellite and internet, print and video resources to 34 rural health and community professionals. In order to assess the rural community's needs and the impact of the interventions, questionnaires were administered and on-site interviews were conducted before and after the project. Throughout the project, field notes were recorded and satisfaction ratings were obtained. Satisfaction with the video-satellite presentations was high and stable, with the exception of one session when signal quality was very poor. Rural participants were most satisfied with opportunities for interaction and least satisfied with the variable quality of the video transmission signal. High staff turnover among rural professionals resulted in insufficient power to permit statistical analysis. Positive reports of the project impact included expanded knowledge and heightened sensitivity to mental health issues, increased cross-disciplinary connections, and greater cohesion among professionals. The results suggest that, with some refinements, telehealth technology can be used to facilitate mental health training and promote interdisciplinary collaboration among professionals in a rural setting.

Counseling↗
PubMed2003

Sexual health experiences of adolescents in three Ghanaian towns.

CONTEXT: Ghanaian youth are greatly affected by widespread social change, and their reproductive health needs may differ by social group, age and gender. METHODS: In-person interviews on sexual health issues were conducted with 704 never-married youth aged 12-24 in three Ghanaian towns. The sample included youth who were in school, in apprenticeship programs or in neither school nor apprenticeship programs (unaffiliated). RESULTS: More than half of the respondents had ever had sexual intercourse (52%), with the adjusted odds for females being 1.6 times those for males and the odds for unaffiliated and apprenticed youth being 2.5-3.2 times those for in-school youth. The odds of having had sex in the previous month were elevated for females (2.0) and apprentices (2.7). Both sexes tended to accept violence towards women, with unaffiliated youth showing the highest level of acceptance and in-school youth the lowest. Nearly all respondents (99%) knew of condoms, but fewer than half (48%) could identify any of four elements of correct use; females and sexually inexperienced youth were the least informed. Two-thirds of respondents considered it unacceptable for males to carry condoms, and three-quarters considered it unacceptable for females. Twenty-five percent of males and 8% of females reported having had a sexually transmitted infection. One-third of sexually experienced females reported having ever been pregnant; of those, 70% reported having had or having attempted to have an abortion. CONCLUSIONS: Adolescent reproductive health programs should be targeted to the needs of specific groups.

Adolescent↗
PubMed2002

Enhanced diagnosis of narrow complex tachycardias with increased electrocardiograph speed.

The objective of this study was to determine if the addition of rapid speed (50 mm/s) electrocardiograms (EKGs) improves the clinician's diagnostic accuracy of narrow complex tachycardias when compared to standard speed (25 mm/s) EKGs. We conducted a prospective, comparative trial. Forty-five difficult narrow complex tachycardias (heart rate range: 150-250 beats per minute) were printed at both 25 mm/s and 50 mm/s. Eight board certified emergency physicians initially interpreted the standard speed EKG (standard group) and chose a therapy for the hypothetical patient. These eight participants later interpreted the same 45 EKGs by using both the standard and rapid speed EKGs (rapid group) and again chose a therapy. The gold standard for each EKG was based on the patient's clinical diagnosis and was independently confirmed in all cases by a board-certified cardiologist. The rhythm distribution was as follows: atrial flutter (17), atrial fibrillation (11), paroxysmal supraventricular tachycardia (15), and sinus tachycardia (2). Participants were masked to all clinical information and EKG ratios. Diagnostic accuracy was compared by using McNemar's chi(2) test. Correct diagnosis improved from 226/360 (63%), in the standard group to 257/360 (71%) in the rapid group (difference in means 8.6%, p = 0.002). The incorrect use of adenosine was decreased from 43/240 (18%) in the standard group to 32/240 (13%) in the rapid group (difference in means 4.5%, p = 0.06). In conclusion, correct diagnosis of difficult narrow complex tachycardias was improved when EKGs at both 25 mm/s and 50 mm/s were used for interpretation. It appears that the simple technique of increasing the EKG paper speed, and thus effectively spacing out the rhythm, enhances the diagnostic ability of the observer.

Adenosine↗