PubMed Health⌕ Search

Biomedical subjects

E J Schwartz

Publications and source records attributed to E J Schwartz.

7 recordsLinked to original sources
PubMed1999

Microinjection of morphine in the A7 catecholamine cell group produces opposing effects on nociception that are mediated by alpha1- and alpha2-adrenoceptors.

Stimulation of neurons in the ventromedial medulla produces antinociception in part by inhibiting nociceptive dorsal horn neurons. This antinociceptive effect is mediated in part by spinally projecting noradrenergic neurons located in the A7 catecholamine cell group. Methionine-enkephalin-immunoreactive neurons in the ventromedial medulla project to an area that includes the A7 cell group, and these enkephalin neurons may mediate part of the antinociception produced by stimulation of sites in the ventromedial medulla. This possibility was tested by determining the effects of microinjecting morphine near the A7 cell group on nociceptive foot and tail responses. Microinjection of a 3.75 nmol dose of morphine in the A7 region did not alter nociceptive responses, but a higher dose of 7.5 nmol facilitated these responses. In contrast, a higher dose of 15 nmol of morphine did not alter nociceptive responses. Selective alpha-adrenoceptor antagonists were injected intrathecally to determine whether the hyperalgesia produced by morphine is mediated by spinally projecting noradrenergic A7 neurons. Intrathecal injection of the alpha2-adrenoceptor antagonist yohimbine did not alter the hyperalgesic effect produced by the 7.5 nmol dose of morphine, but the alpha1 antagonist WB4101 reversed the hyperalgesia and produced antinociception that lasted for nearly 30 min. Although the 15 nmol dose of morphine did not alter nociceptive responses, intrathecal injection of yohimbine after the microinjection of morphine produced a significant facilitation of nociception, and intrathecal injection of WB401 produced a significant antinociceptive effect. Intrathecal injection of the antagonists alone did not consistently alter nociception. These findings, and those of published reports, suggest that morphine indirectly activates two populations of spinally projecting A7 noradrenergic neurons that have opposing effects on nociception. One of these populations facilitates nociception by an action mediated by alpha1-adrenoceptors in the spinal cord dorsal horn and the other population inhibits nociception by an action mediated by alpha2-adrenoceptors. These results suggest that some of the methionine-enkephalin neurons located in the ventromedial medulla that project to the A7 cell group can exert bidirectional control of nociceptive responses.

Analgesics, Opioid↗
PubMed1999

Radical retropubic prostatectomy reduces symptom scores and improves quality of life in men with moderate and severe lower urinary tract symptoms.

PURPOSE: We determine the impact of radical retropubic prostatectomy on lower urinary tract symptoms and quality of life due to urinary problems in men with clinically localized prostate cancer. MATERIALS AND METHODS: The American Urological Association (AUA) symptom index, a symptom problem index and a quality of life due to urinary problems question were administered to 104 men before and 12 months after radical prostatectomy. Urinary continence and satisfaction with the decision to undergo radical prostatectomy were also examined. RESULTS: In men with moderate or severe baseline urinary symptoms (AUA score 8 or greater) the total AUA symptom, symptom problem and quality of life question scores decreased by 51 (-6.39), 57 (-4.22) and 25% (-0.65), respectively, after radical prostatectomy. Except for nocturia statistically significant improvements were observed for all questions captured by the AUA symptom index. Radical prostatectomy did not significantly change mean AUA symptom score or symptom problem index in men with mild urinary symptoms (AUA score less than 8). In men with moderate or severe urinary symptoms radical prostatectomy significantly improved quality of life due to urinary problems. Although 10% of men exhibited some degree of clinically relevant stress incontinence, 98% were very satisfied or satisfied with the decision to undergo radical prostatectomy. CONCLUSIONS: In men with moderate or severe urinary symptoms radical prostatectomy improves lower urinary tract symptoms and quality of life due to urinary problems. The overall beneficial impact on voiding makes radical prostatectomy an attractive treatment option for clinically localized prostate cancer.

Adult↗
PubMed1998

Pathogenesis of human immunodeficiency virus (HIV)-associated nephropathy.

Human immunodeficiency virus-associated nephropathy (HIVAN) is the third leading cause of end-stage renal failure in Blacks between the ages of 20 and 64. Because the incidence of HIV infection has continued to increase in Blacks as survival has improved, the pool of patients alive and at risk for developing HIVAN has vastly expanded. This suggests that HIVAN will continue to increase in importance to the end-stage renal disease program. The racial predilection for the disease in Blacks implies that genetic or environmental cofactors are involved. Evidence in human and animal models has shown that proliferation of renal epithelial cells is the predominant feature of the disease and that apoptosis occurs. The prospect that renal infection is necessary to stimulate cells to proliferate remains a possibility but is not yet proven. Cytokine dysregulation may also be involved in disease progression, but evidence is lacking that altered cytokine production is the proximate cause of HIVAN. Many issues remain to be resolved including the potential for renal infection in vivo, the mechanisms responsible for proliferation and apoptosis, and factors that provide racial susceptibility to HIVAN. Advances in our understanding of pathogenesis will be required to control the growth of HIV-related renal diseases in the ESRD population.

AIDS-Associated Nephropathy↗
PubMed1995

The human blood-brain barrier glucose transporter (GLUT1) is a glucose transporter of gray matter astrocytes.

Human and monkey brain sections were examined by immunohistochemical light and electron microscopy to determine the distribution of GLUT1, a glucose transporter isoform associated with erythrocytes and endothelial cells of the human blood-brain barrier. Protein immunoblotting of fractionated human brain membranes was performed to determine the distribution of molecular forms of the transporter. GLUT1 staining was abundant in erythrocytes and cerebral endothelium of gray and white matter but was also present diffusely in gray matter neuropil when viewed by light microscopy. Immunoelectron microscopy confirmed the gray matter and vascular localization of GLUT1, with specific GLUT1 staining seen in erythrocytes, gray and white matter endothelial cells, astrocyte foot processes surrounding gray matter blood vessels, and in astrocyte processes adjacent to synaptic contacts. No astrocytic staining was identified in white matter. Astrocyte GLUT1 staining was identified only in mature gray matter regions; undifferentiated regions of preterm (22-23 weeks gestation) cortex had GLUT1 staining only in blood vessels and erythrocytes, as did germinal matrix. Immunoblots of adult human frontal cortex revealed that two forms of GLUT1 (45 and 52 kDa) were present in unfractionated brain homogenates. Immunoblots of vessel-depleted frontal lobe revealed only the 45 kDa form in gray matter fractions, and depleted in membranes prepared from white matter regions. We conclude that the GLUT1 isoform of glucose transporter is present both in endothelium of the blood-brain barrier and in astrocytes surrounding gray matter blood vessels and synapses. Furthermore, the form present in astrocytes is likely to have a lower molecular weight than the form found in cerebral endothelium. The GLUT1 transporter may play an important role not only in astrocyte metabolism, but also in astrocyte-associated pathways supporting neuronal energy metabolism.

Animals↗
PubMedDate not supplied

Forecasting the future of HIV epidemics: the impact of antiretroviral therapies & imperfect vaccines.

Mathematical models can be used as health policy tools and predictive tools. Here we review how mathematical models have been used both to predict the consequences of specific epidemic control strategies and to design epidemic control strategies. We review how models have been used to evaluate the potential impact on HIV epidemics of (i) combination antiretroviral therapies (ART) and (ii) imperfect vaccines. In particular, we discuss how models have been used to predict the potential effect of ART on incidence rates, and to predict the evolution of an epidemic of drug-resistant HIV. We also discuss, in detail, how mathematical models have been used to evaluate the potential impact of prophylactic, live-attenuated and therapeutic HIV vaccines. We show how HIV vaccine models can be used to evaluate the epidemic-level impact of vaccine efficacy, waning in vaccine-induced immunity, vaccination coverage level, and changes (increases or decreases) in risky behavior. We also discuss how mathematical models can be used to determine the levels of cross-immunity that vaccines will need to attain if they are to be used to control HIV epidemics in countries where more than one subtype is being transmitted.

AIDS Vaccines↗