51
|
Guzman R, Remonda L, Barth A. Angiographically undetected aneurysm in the neck remnant after endovascular coiling. Acta Neurochir (Wien) 2003; 145:815-6; discussion 816-7. [PMID: 14505113 DOI: 10.1007/s00701-003-0081-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
52
|
Kieffer EC, Willis SK, Arellano N, Guzman R. Perspectives of pregnant and postpartum latino women on diabetes, physical activity, and health. HEALTH EDUCATION & BEHAVIOR 2002; 29:542-56. [PMID: 12238699 DOI: 10.1177/109019802237023] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Impaired glucose tolerance and diabetes are prevalent among Latino women of childbearing age. Physical activity during and after pregnancy may contribute to weight control and improved metabolic status, but recommended activities may not be perceived as appropriate or feasible. To plan realistic and acceptable interventions, pregnant and postpartum Latino women in Detroit met in a focus group series to discuss their beliefs about diabetes and factors influencing their participation in regular physical activity during pregnancy and postpartum. Women believed that diabetes was primarily related to heredity and diet but not to physical activity. Exercise was believed to reduce stress and improve general health. Women suggested an organized group intervention, in a respected location, that offered safe physical activities within the context of a variety of activities for women and children. This strategy reduced concerns about safety and social acceptability while addressing their primary interest in social support.
Collapse
|
53
|
Gönner F, Lövblad KO, Heid O, Remonda L, Guzman R, Barth A, Schroth G. Magnetic resonance angiography with ultrashort echo times reduces the artefact of aneurysm clips. Neuroradiology 2002; 44:755-8. [PMID: 12221447 DOI: 10.1007/s00234-002-0825-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2001] [Accepted: 05/30/2002] [Indexed: 10/27/2022]
Abstract
We evaluated the ability of an ultrashort echo time (TE) three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) sequence to reduce the metal artefact of intracranial aneurysm clips and to display adjacent cerebral arteries. In five patients (aged 8-72 years) treated with Elgiloy or Phynox aneurysm clips we prospectively performed a conventional (TE 6.0 ms) and a new ultrashort TE (TE 2.4 ms) 3D TOF MRA. We compared the diameter of the clip-induced susceptibility artefact and the detectability of flow in adjacent vessels. The mean artefact diameter was 22.3+/-6.4 mm (range 14-38 mm) with the ultrashort TE and 27.7+/-6.4 mm (range 19-45 mm) with the conventional MRA ( P<0.0001). This corresponded to a diameter reduction of 19.5+/-9.2%. More parts of adjacent vessels were detected, but with less intense flow signal. The aneurysm dome and neck remained within the area of signal loss and were therefore not displayed. Ultrashort TE MRA is a noninvasive and fast method for improving detection of vessels adjacent to clipped intracranial aneurysms, by reducing clip-induced susceptibility artefact. The method cannot, however, be used to show remnants of the aneurysm neck or sac as a result of imperfect clipping.
Collapse
|
54
|
Guzman R, Morales J, Tirado JL. Chain Cluster Polymerization and Alkali Metal Intercalation into Niobium Ditelluride. Inorg Chem 2002. [DOI: 10.1021/ic00092a024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
55
|
Louridas G, Saadia R, Spelay J, Abdoh A, Weighell W, Arneja AS, Tanner J, Guzman R. The ArtAssist Device in chronic lower limb ischemia. A pilot study. INT ANGIOL 2002; 21:28-35. [PMID: 11941271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
BACKGROUND Patients with chronic critical limb ischemia following a failed bypass graft or with non-reconstructable distal disease diagnosed angiographically, have a very poor prognosis. This is a prospective pilot study to assess the influence of the ArtAssist Device on pedal blood flow and amputation rate. METHODS Thirty-three legs in 25 patients were evaluated. Ten legs presented with rest pain, and 23 legs with tissue loss. Nine legs had previously undergone bypass surgery. RESULTS At a mean follow-up of 3 months, 14 (42%) legs were amputated, and 19 (58%) were saved. Eleven of the amputated legs were in patients with chronic renal failure, a known risk factor. The amputation rate, excluding this group, was 13.6% (3/22). Toe pressures measured initially and after 3 months on the pump showed a significant improvement (p=0.03). Forty percent of patients presenting with rest pain improved, while 26% of foot ulcers healed on the pump. Mortality rate was 12%. CONCLUSIONS The results from this prospective study are encouraging but need to be validated in a larger prospective randomized study.
Collapse
|
56
|
Lövblad KO, el-Koussy M, Guzman R, Kiefer C, Remonda L, Taleb M, Reinert M, Wels T, Barth A, Schroth G, Seiler RW. Diffusion-weighted and perfusion-weighted MR of cerebral vasospasm. ACTA NEUROCHIRURGICA. SUPPLEMENT 2002; 77:121-6. [PMID: 11563268 DOI: 10.1007/978-3-7091-6232-3_26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
|
57
|
Colfax GN, Mansergh G, Guzman R, Vittinghoff E, Marks G, Rader M, Buchbinder S. Drug use and sexual risk behavior among gay and bisexual men who attend circuit parties: a venue-based comparison. J Acquir Immune Defic Syndr 2001; 28:373-9. [PMID: 11707675 DOI: 10.1097/00126334-200112010-00011] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
CONTEXT HIV risk behavior among urban gay/bisexual men has recently increased. High-risk sexual activity and drug use may be particularly high during circuit party (CP) weekends, during which gay/bisexual men congregate for social activities and dancing. OBJECTIVES To compare prevalence of risk behaviors during CP weekends with those during non-CP weekends. DESIGN Cross-sectional study. PARTICIPANTS 295 gay/bisexual men from the San Francisco Bay Area. MAIN OUTCOME MEASURES Drug use and sexual risk behavior during a San Francisco CP weekend, a CP weekend held in another geographic area (distant weekends), and two non-CP weekends. RESULTS During their most recent distant CP weekend, 80% of participants used methylenedioxymethamphetamine (ecstasy), 66% ketamine, 43% crystal methamphetamines, 29% gamma-hydroxybutyrate or gamma-butyrolactone (GHB/GBL), 14% sildenafil (Viagra), and 12% amyl nitrites (poppers); 53% used four or more drugs. Drug use prevalence was greater during CP than non-CP weekends ( p <.001). Unprotected anal sex with partners of unknown or opposite HIV serostatus was most prevalent during distant CP weekends, reported by 21% of HIV-positive and 9% of HIV-negative participants. In multivariate analysis, predictors of unprotected anal sex with opposite or unknown HIV serostatus partners included being HIV-positive (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4-7.5), and weekend use of crystal methamphetamines (OR 2.4; 95% CI, 1.1-4.9), sildenafil (OR, 3.8; 95% CI, 2.0-7.3), and amyl nitrites (OR, 2.2; 95% CI, 1.3-4.0). CONCLUSIONS Prevalence of high-risk activity during these weekends suggests significant potential for HIV transmission in this population. Public health programs in communities hosting CPs should aim to reduce rates of drug use and sexual risk behavior among CP participants, especially HIV-positive men.
Collapse
|
58
|
Lantz PM, Viruell-Fuentes E, Israel BA, Softley D, Guzman R. Can communities and academia work together on public health research? Evaluation results from a community-based participatory research partnership in Detroit. J Urban Health 2001; 78:495-507. [PMID: 11564852 PMCID: PMC3455911 DOI: 10.1093/jurban/78.3.495] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This article reports the results of a formative evaluation of the first 4 years of the Detroit Community-Academic Urban Research Center (URC), a community-based participatory research partnership that was founded in 1995 with core funding from the Centers for Disease Control and Prevention (CDC). Several organizations are members of this partnership, including a university, six community-based organizations, a city health department, a health care system, and CDC. The Detroit URC is a strong partnership that has accomplished many of its goals, including the receipt of over $11 million in funding for 12 community-based participatory research projects during its initial 4 years. Detroit URC Board members identified a number of facilitating factors for their growth and achievements, such as (1) developing a sound infrastructure and set of processes for making decisions and working together, (2) building trust among partners, (3) garnering committed and active leadership from community partners, and (4) receiving support from CDC. Board members also identified a number of ongoing challenges, including organizational constraints, time pressures, and balancing community interests in interventions and academic research needs. Overall, the Detroit URC represents a partnership approach to identifying community health concerns and implementing potential solutions.
Collapse
|
59
|
Lövblad KO, Bassetti C, Schneider J, Guzman R, El-Koussy M, Remonda L, Schroth G. Diffusion-weighted mr in cerebral venous thrombosis. Cerebrovasc Dis 2001; 11:169-76. [PMID: 11306763 DOI: 10.1159/000047634] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The diagnosis of cerebral venous thrombosis is often difficult both clinically and radiologically and until now there is no method available to predict if brain lesions, detected clinically and using conventional brain imaging methods, may lead to full recovery, as expected in vasogenic edema or ischemic infarcts and even a hematoma. New fast neuroimaging techniques such as diffusion-weighted imaging (DWI) are sensitive to different reasons of changes in local tissular water concentration thus giving further insight into the pathophysiological mechanism as well as prognosis of cerebral venous thrombosis. We report the cases of 18 consecutive patients with a diagnosis of cerebral venous thrombosis based on clinical and imaging criteria. All patients underwent magnetic resonance imaging (MRI) of the brain, which comprised isotropic diffusion-weighted MR. Diffusion-weighted MRI showed positive findings in 17/18 cases. In 7 cases the clot could be directly visualized as an area of hyperintensity in the affected vein on DWI. In 7 cases DWI showed areas of signal loss corresponding to hematomas. In 6 cases DWI showed changes in signal intensity that were more subtle. In 4 cases of superficial venous thrombosis, there were areas of decreased ADC values (0.65-0.79 x 10(-3) mm(2)/s) whereas in 2 cases of deep venous thrombosis, increased DWI intensities could be found that corresponded to both an increase and a decrease in ADC, corresponding to a coexistence of cytotoxic and vasogenic edemas. Diffusion-weighted MRI can demonstrate directly the presence of an intravenous clot in a select number of patients. It can also demonstrate early ischemic changes, and can differentiate conventional T2-weighted MR areas of cytotoxic from vasogenic edema.
Collapse
|
60
|
Taleb M, Lövblad KO, El-Koussy M, Guzman R, Bassetti C, Arnold M, Oswald H, Remonda L, Schroth G. Reperfusion demonstrated by apparent diffusion coefficient mapping after local intra-arterial thrombolysis for ischaemic stroke. Neuroradiology 2001; 43:591-4. [PMID: 11512594 DOI: 10.1007/s002340100555] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Diffusion-weighted MRI (DWI) is becoming important for diagnosis and investigation of acute cerebral ischaemia. It has been reported that apparent diffusion coefficient (ADC) maps could be an indicator of reperfusion. Our aim was to use echo-planar technology to investigate this phenomenon. We report 19 patients treated by local intra-arterial thrombolysis for middle cerebral artery stroke within 6 h of the onset of symptoms, in whom we performed follow-up DWI. ADC were found to be higher in the patients with angiographically proven reperfusion.
Collapse
|
61
|
Mansergh G, Colfax GN, Marks G, Rader M, Guzman R, Buchbinder S. The Circuit Party Men's Health Survey: findings and implications for gay and bisexual men. Am J Public Health 2001; 91:953-8. [PMID: 11392940 PMCID: PMC1446474 DOI: 10.2105/ajph.91.6.953] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES This study examined characteristics of gay and bisexual men who attend circuit parties, frequency of and motivations for attending parties, drug use and sexual behavior during circuit party weekends, and use of risk reduction materials available at parties. METHODS A cross-sectional survey was conducted among 295 gay and bisexual men from the San Francisco Bay Area who had attended a circuit party in the previous year. RESULTS One fourth of the men reported a drug "overuse" incident in the previous year. Nearly all respondents reported use of drugs during circuit party weekends, including ecstasy (75%), ketamine (58%), crystal methamphetamine (36%), gamma hydroxybutyrate or gamma butyrolactone (25%), and Viagra (12%). Two thirds of the men reported having sex (oral or anal), 49% reported having anal sex, and 28% reported having unprotected anal sex during the 3-day period. An association was found between use of drugs and sexual risk behavior. Prevention materials were observed at party events by some men; however, relatively few men used the materials. Common motivations for attending the parties were "to listen to music and dance" and "to be with friends." CONCLUSIONS Intensive, targeted health promotion efforts are needed for gay and bisexual men who attend circuit parties.
Collapse
|
62
|
Guzman R, Oswald H, Barth A, de Koning P, Remonda L, Lövblad K, Schroth G. Clinical validation of quantitative carotid MRA. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0531-5131(01)00166-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
63
|
Clements-Nolle K, Marx R, Guzman R, Katz M. HIV prevalence, risk behaviors, health care use, and mental health status of transgender persons: implications for public health intervention. Am J Public Health 2001; 91:915-21. [PMID: 11392934 PMCID: PMC1446468 DOI: 10.2105/ajph.91.6.915] [Citation(s) in RCA: 514] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES This study described HIV prevalence, risk behaviors, health care use, and mental health status of male-to-female and female-to-male transgender persons and determined factors associated with HIV. METHODS We recruited transgender persons through targeted sampling, respondent-driven sampling, and agency referrals; 392 male-to-female and 123 female-to-male transgender persons were interviewed and tested for HIV. RESULTS HIV prevalence among male-to-female transgender persons was 35%. African American race (adjusted odds ratio [OR] = 5.81; 95% confidence interval [CI] = 2.82, 11.96), a history of injection drug use (OR = 2.69; 95% CI = 1.56, 4.62), multiple sex partners (adjusted OR = 2.64; 95% CI = 1.50, 4.62), and low education (adjusted OR = 2.08; 95% CI = 1.17, 3.68) were independently associated with HIV. Among female-to-male transgender persons, HIV prevalence (2%) and risk behaviors were much lower. Most male-to-female (78%) and female-to-male (83%) transgender persons had seen a medical provider in the past 6 months. Sixty-two percent of the male-to-female and 55% of the female-to-male transgender persons were depressed; 32% of each population had attempted suicide. CONCLUSIONS High HIV prevalence suggests an urgent need for risk reduction interventions for male-to-female transgender persons. Recent contact with medical providers was observed, suggesting that medical providers could provide an important link to needed prevention, health, and social services.
Collapse
|
64
|
Lövblad KO, Ruoss K, Guzman R, Schroth G, Fusch C. Diffusion-weighted MRI of middle cerebral artery stroke in a newborn. Pediatr Radiol 2001; 31:374-6. [PMID: 11373930 DOI: 10.1007/s002470100442] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Diffusion-weighted MRI of the brain is becoming clinically available as a tool to investigate cerebral ischaemia. We report a newborn girl presenting with seizures in whom diffusion-weighted MRI showed a large hyperintensity in the area perfused by the left middle cerebral artery. Short-term neurological follow-up before discharge was uneventful and the patient was discharged without sequelae. On follow-up clinical examination, right-sided spastic signs were noted which disappeared with time.
Collapse
|
65
|
Yang J, Guzman R, Nandi S. Reconstituted normal human breast in nude mice: estrogen and progesterone receptors regulation. In Vivo 2001; 15:239-44. [PMID: 11491019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Actions of estrogen and progesterone on normal human breast are mediated by their respective receptors. Since receptor regulation studies in humans are difficult to perform, we have utilized our model system of reconstituted normal human breast in nude mice to determine expression of estrogen and progesterone receptors in response to exogenous estrogen and progesterone. In normal human breast in situ, only a subset of epithelial cells (about 10%) are positive for estrogen receptor. These cells which remain positive after transplantation into nude mice can be completely downregulated by administration of exogenous estrogen resulting in all transplanted human breast epithelial cells now being negative for estrogen receptor. Exogenous estrogen also upregulates the progesterone receptor in a subset of human breast epithelial cells rather than in all cells. Exogenous progesterone, alone or in combination with estrogen, did not affect the estrogen or progesterone receptors. Double immunofluorescent labelings for a proliferation marker and progesterone receptor in both surgical specimens and nude mice transplants demonstrate that proliferation and progesterone receptor expression do not take place in the same cell. Our in vivo model system enables studies on the biology of primary normal human breast epithelial cells which otherwise are difficult to perform in humans.
Collapse
|
66
|
Popnikolov N, Yang J, Liu A, Guzman R, Nandi S. Reconstituted normal human breast in nude mice: effect of host pregnancy environment and human chorionic gonadotropin on proliferation. J Endocrinol 2001; 168:487-96. [PMID: 11241180 DOI: 10.1677/joe.0.1680487] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The proliferation of normal human breast epithelial cells in women is highest during the first trimester of pregnancy. In an attempt to analyze this hormonal environment in a model system, the effect of host mouse pregnancy and the administration of human chorionic gonadotropin (hCG) were assessed in normal human breast epithelial cells transplanted into athymic nude mice. Human breast epithelial cells, dissociated from reduction mammoplasty specimens and embedded inside the extracellular matrices comprised of collagen gel and Matrigel, were transplanted into nude mice. Proliferation was measured in vivo by BrdU labeling followed by immunostaining of sections from recovered gels in response to an altered hormonal environment of the host animal. The host animal was mated to undergo pregnancy and the complex hormonal environment of the host animal pregnancy stimulated growth of transplanted human cells. This effect increased with progression of pregnancy and reached the maximum during late pregnancy prior to parturition. In order to determine whether additional stimulation could be achieved, the transplanted human cells were exposed to a second cycle of host mouse pregnancy by immediately mating the animal after parturition. This additional exposure of host mouse pregnancy did not result in further increase of proliferation. The effect of hCG administration on transplanted human cells was also tested, since hCG level is highest during the first trimester of human pregnancy and coincides with the maximal breast cell proliferation. Administration of hCG alone stimulated proliferation of human cells in a dose-dependent manner, and could further enhance stimulation achieved with estrogen. The host mouse mammary gland also responded to hCG treatment resulting in increased branching and lobulo-alveolar development. However, the hCG effect on both human and mouse cells was dependent on intact ovary since the stimulation did not occur in ovariectomized animals. Although hCG receptor transcripts were detected in human breast epithelial cells, raising the possibility of a direct mitogenic action, the hCG effect observed in this study may have been mediated via the ovary by increased secretion of ovarian steroids. In summary, using our in vivo nude mice system, the proliferation of normal human breast epithelial cells could be stimulated by host mouse pregnancy and by administration of hCG.
Collapse
|
67
|
Schwerzmann M, Seiler C, Lipp E, Guzman R, Lövblad KO, Kraus M, Kucher N. Relation between directly detected patent foramen ovale and ischemic brain lesions in sport divers. Ann Intern Med 2001; 134:21-4. [PMID: 11187416 DOI: 10.7326/0003-4819-134-1-200101020-00009] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND In divers, the significance of a patent foramen ovale and its potential relation to paradoxical gas emboli remain uncertain. OBJECTIVE To assess the prevalence of symptoms of decompression illness and ischemic brain lesions in divers with regard to the presence of a patent foramen ovale. DESIGN Retrospective cohort study. SETTING University hospital and three diving clubs in Switzerland. PARTICIPANTS 52 sport divers and 52 nondiving controls. MEASUREMENTS Prevalence of self-reported decompression events, patent foramen ovale on contrast transesophageal echocardiography, and ischemic brain lesions on magnetic resonance imaging. RESULTS The risk for decompression illness events was 4.5-fold greater in divers with patent foramen ovale than in divers without patent foramen ovale (risk ratio, 4.5 [95% CI, 1.2 to 18.0]; P = 0.03). Among divers, 1.23 +/- 2.0 and 0.64 +/- 1.22 ischemic brain lesions per person (mean +/- SD) were detected in those with and those without patent foramen ovale, respectively. Among controls, 0.22 +/- 0.44 and 0.12 +/- 0.63 lesion per person were detected (P < 0.001 for all groups). CONCLUSIONS Regardless of whether a diver has a patent foramen ovale, diving is associated with ischemic brain lesions.
Collapse
|
68
|
El-Koussy M, Guzman R, Bassetti C, Stepper F, Barth A, Lövblad KO, Schroth G. CT and MRI in acute hemorrhagic stroke. Cerebrovasc Dis 2000; 10:480-2. [PMID: 11070382 DOI: 10.1159/000016113] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report the case of a woman presenting with an acute onset of hemiplegia. MRI was performed and showed a hyperintense mass on diffusion-weighted imaging, with areas of high signal intensity on T2* imaging and T2/PD imaging. T1-weighted imaging showed a more inhomogeneous lesion with a central isointense part corresponding to the acute clot, as well as a peripheral crescent of hypointense plasma; since another mass lesion could not be acutely excluded, computed tomography was performed immediately afterwards, showing a hyperdense hematoma. The patient was taken to the neurosurgical operating theater, where she underwent decompressive craniotomy and evacuation of the hematoma.
Collapse
|
69
|
Yang J, Guzman R, Nandi S. Histomorphologically intact primary human breast lesions and cancers can be propagated in nude mice. Cancer Lett 2000; 159:205-10. [PMID: 10996733 DOI: 10.1016/s0304-3835(00)00556-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The natural history of various human breast lesions and cancer in patient is difficult to study since diagnosis is established only after surgical ablation and therefore the clinical course of the undisturbed lesion in vivo can no longer be followed. Development of an experimental system which can propagate and maintain human breast lesions and cancer, similar to those seen in surgical breast specimens, may be a first step in the analyses of these various entities. We report that histomorphologically intact human breast lesions and cancer can be recreated in an experimental system using athymic nude mice. When the dissociated cells from surgical breast cancer specimens are embedded in extracellular matrices (collagen gel, Matrigel, or a mixture of the two) and then transplanted into athymic nude mice, the transplanted cells undergo morphogenesis to reflect their original phenotype. A mixture of the two matrices most closely mirrored the breast tissue in situ when stained with Alcian blue-PAS which stains for mucins. In this mixture, not only is the histomorphology recreated, but well-established clinical molecular markers including the estrogen receptor, c-erbB-2 (HER-2/neu), and aberrant cell proliferation are maintained. With the use of an appropriate extracellular matrices, surgical specimens of human breast lesions and cancer can be analyzed in an in vivo experimental system.
Collapse
MESH Headings
- Actins/analysis
- Adult
- Aged
- Animals
- Breast/chemistry
- Breast/pathology
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Carcinoma, Ductal, Breast/metabolism
- Carcinoma, Ductal, Breast/pathology
- Collagen/pharmacology
- Drug Combinations
- Female
- Gels
- Humans
- Immunohistochemistry
- Laminin/pharmacology
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Mice
- Mice, Nude
- Middle Aged
- Neoplasm Transplantation
- Proliferating Cell Nuclear Antigen/analysis
- Proteoglycans/pharmacology
- Receptor, ErbB-2/analysis
- Receptors, Estrogen/analysis
- Tumor Cells, Cultured/cytology
- Tumor Cells, Cultured/drug effects
Collapse
|
70
|
Yang J, Liu A, Guzman R, Nandi S. Estrogen receptor variants in epithelial compartment of normal human breast. Endocrine 2000; 12:243-7. [PMID: 10963044 DOI: 10.1385/endo:12:3:243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/1999] [Revised: 01/06/2000] [Accepted: 01/07/2000] [Indexed: 11/11/2022]
Abstract
Estrogen receptor (ER) splice variants have previously been identified in normal human breast. Normal breast, however, comprises many cell types including fat cells, fibroblasts, endothelial cells, and a variety of inflammatory cells besides breast epithelial cells. The objective of our study was to demonstrate the existence of several variants in the epithelial compartment of the normal human breast. To this end, highly enriched breast epithelial cells from reduction mammoplasty specimens were isolated using Percoll gradient centrifugation. We analyzed the presence of both wild-type (WT) and variant receptors in human breast epithelial cells using the seminested polymerase chain reaction and direct automated sequencing of the amplified products. We demonstrated that a number of spliced variants of the ER coexist with the WT receptor. Variants lacking exons 2, 4, 5, and 7 are detected in the breast epithelial compartment of the normal human breast.
Collapse
|
71
|
Guzman R, Remonda L, Lövblad K, Barth A, Schroth G. Iatrogenic Rupture of a Cerebral Aneurysm on the Feeding Artery of an Arteriovenous Malformation. Interv Neuroradiol 2000; 6:141-5. [DOI: 10.1177/159101990000600210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2000] [Accepted: 03/30/2000] [Indexed: 11/17/2022] Open
Abstract
We present the case of a patient with acute onset of headache who showed a flow-related acutely ruptured aneurysm on the feeding artery of an AVM in the angiogram. Rerupture of the aneurysm occurred during angiography after endovascular treatment with a Guglielmi detachable coil. The possible mechanisms leading to rupture of the aneurysm are discussed.
Collapse
|
72
|
Yang J, Liu A, Dougherty C, Chen X, Guzman R, Nandi S. Beware of contaminating mouse cells in human xenografts from nude mice. Anticancer Res 2000; 20:1635-9. [PMID: 10928083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Human tumor xenografts in nude mice are widely utilized model system for the transplantation of human surgical specimens and human established cell lines. Gene expression studies are often carried out in these model systems. With an increasing use of PCR based analyses, the extreme sensitivity of this technique poses a serious challenge with regards to the extent of contaminating host mouse cells in the human tumor xenografts. These xenografts are never free of host cell contamination. We detected mouse estrogen receptor expression in several human tumor xenografts using RT-PCR demonstrating that precaution is necessary when utilizing PCR based analyses in human tumor xenografts. A cytologically based methodology which distinguishes human versus mouse cells will be more suitable for ER expression studies using human xenograft models. Both (1) in situ hybridization using human probe and (2) immunocytochemistry using a monoclonal antibody directed against human cytokeratin have been used successfully to distinguish human cells versus host mouse cells in human xenografts in nude mice. Immunostaining of ER can then be utilized to determine the expression pattern of ER in the transplanted human cells.
Collapse
MESH Headings
- Animals
- Base Sequence
- DNA Probes
- DNA, Complementary/analysis
- Genome, Human
- Humans
- Immunohistochemistry
- In Situ Hybridization
- Keratins/analysis
- Keratins/genetics
- Mice
- Mice, Nude
- Molecular Sequence Data
- Neoplasm Transplantation
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Receptors, Estrogen/analysis
- Receptors, Estrogen/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Species Specificity
- Transplantation, Heterologous/pathology
- Tumor Cells, Cultured
Collapse
|
73
|
Solter P, Liu Z, Guzman R. Decreased hepatic ALT synthesis is an outcome of subchronic microcystin-LR toxicity. Toxicol Appl Pharmacol 2000; 164:216-20. [PMID: 10764635 DOI: 10.1006/taap.2000.8895] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Alanine aminotransferase (ALT; EC 2.6.1.2) is important for the transamination of amino acids and is also an important serum marker of hepatic damage. However, we had previously shown that hepatic ALT activity decreases with subchronic exposure to the hepatotoxin, microcystin-LR (MCLR), a potent inhibitor of serine/threonine protein phosphatases types 1 and 2A. These previous findings suggest that one outcome of subchronic MCLR toxicosis is decreased ALT synthesis by hepatocytes. This could affect the diagnostic sensitivity of serum ALT activity and metabolic processes within the cell. This study was done to investigate the mechanism by which ALT activity decreases following prolonged MCLR exposure. Immunoblots were first performed on liver tissue from 12 Harlan-Sprague-Dawley rats that had been treated with 0, 16, 32, or 48 microg/kg of microcystin-LR per day by continuous intraperitoneal infusion for 28 days. These revealed a dose-dependent decrease in ALT protein concentrations that correlated directly with hepatic ALT activity (r = 0.8132; P = 0.0013). Sixteen additional rats, treated with the same doses of MCLR showed a dose-dependent decrease in hepatic ALT activity to approximately 19% of values in saline-treated controls. Northern blot analysis revealed a decrease in hepatic ALT mRNA that correlated directly to hepatic ALT activity (r = 0.7909; P = 0.0004). It was concluded that subchronic MCLR exposure causes decreased hepatic ALT protein and mRNA concentrations. These findings suggest that one sequela of MCLR toxicosis is decreased hepatic ALT synthesis.
Collapse
|
74
|
Guzman R, Lövblad KO, Meyer M, Spenger C, Schroth G, Widmer HR. Imaging the rat brain on a 1.5 T clinical MR-scanner. J Neurosci Methods 2000; 97:77-85. [PMID: 10771078 DOI: 10.1016/s0165-0270(00)00172-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetic resonance imaging (MRI) offers a noninvasive technique for studying neurodegenerative events in the rat brain, however, most of the studies are performed on small bore purpose dedicated MR scanners of limited availability and at high cost. The present study explored the feasibility of using a clinical whole body MR-scanner to perform imaging in rat brain and specifically in models of Parkinson's (PD) and Huntington's disease (HD). For that purpose rats were placed into a specially designed PVC device equipped with a flexible surface coil-and T2-weighted spin echo sequences were acquired on a Siemens Magnetom Vision at 1.5 T. In the experimental protocols of PD and HD, animals underwent 6-hydroxydopamine (6-OHDA) and quinolinic acid (QA) injections, respectively and were subsequently grafted with fetal tissue. T2-weighted images showed a small hyperintense area at the 6-OHDA lesion site and a diffuse hyperintensity in the striata with QA lesions. Transplants were seen as a hypointense area surrounded by a hyperintense rim on T1-weighted images. Moreover, disturbances of the blood-brain-barrier and its time of restoration could be monitored. In conclusion, high-resolution in vivo imaging of small animals is feasible with clinical MR-scanners and hence allows the study of various experimental protocols.
Collapse
|
75
|
Foga MM, McGinn GJ, Kroeker MA, Guzman R. Sepsis due to Clostridium septicum: case report. Can Assoc Radiol J 2000; 51:85-9. [PMID: 10786915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
|