Biomedical subjects

D C Miller

Publications and source records attributed to D C Miller.

At least 127 records · Page 7Linked to original sources

PubMed1996

Aortic dissection: percutaneous management of ischemic complications with endovascular stents and balloon fenestration.

PURPOSE: The purpose of this study was to evaluate endovascular stenting (EVS) and balloon fenestration (BF) of intimal flaps for the management of lower extremity, renal, and visceral ischemia in acute or chronic aortic dissection. METHODS: Twenty-two patients (16 male, 6 female) with a median age of 53 years (range 35 to 77 years) underwent percutaneous treatment for peripheral ischemic complications of 12 type A (five acute, seven chronic) and 10 type B (nine acute, one chronic) aortic dissections. RESULTS: Ten patients had leg ischemia, 13 had renal ischemia, and 6 had visceral ischemia. Sixteen patients were treated with EVS including 11 with renal, 6 with lower extremity, 2 with superior mesenteric artery, and 2 with aortic stents. Three patients had BF of the intimal flap, and three had BF in combination with EVS. Revascularization with clinical success was achieved in all 22 patients. Two patients died 3 days and 13.4 months after the procedure was performed, respectively. Of the remaining 20 patients, 1 is lost to follow-up, and 19 have persistent relief of clinical symptoms. Mean follow-up time is 13.7 months (range 1.1 to 46.5 months). One case was complicated by guidewire-induced perinephric hematoma. CONCLUSION: EVS and BF provide a safe and effective percutaneous method for managing peripheral ischemic complications of aortic dissection.

Acute Disease↗

PubMed1996

Guidelines for reporting morbidity and mortality after cardiac valvular operations.

At the request of the Councils of the Society of Thoracic Surgeons (STS) and the American Association of Thoracic Surgery (AATS) the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity reviewed the "Guidelines" published in September 1988 [3, 7, 8]. The purpose of the review was to update and clarify definitions within the guidelines and to consider recommendations made by other [2, 11]. The variety of cardiac valvular procedures has expanded since 1988; therefore, in this document the term "operated valve" indicates prosthetic and bioprosthetic heart valves of all types, operated or repaired native valves and allograft and autograft valves. The term "operated valve" includes any cardiac valve altered by a surgeon during an operation. Much morbidity and mortality is a direct consequence of the interaction between the patient and operated valve(s), although patient variables (e.g., age, degree of coronary arterial disease, follow-up care, etc.) may be more responsible for outcomes than an operated valve. However, no set of guidelines can identify all possible patient factors that may affect morbidity and mortality. General agreement regarding the following definitions of terms and suggestions for reporting data do not preclude more detailed analyses or constructive recommendations and investigators are encouraged to identify relevant patient factors in addition to factors related to operated valves. Purpose The purpose of these guidelines is to facilitate the analysis and reporting of results of operations on diseased cardiac valves. The definitions and recommendations that follow are guidelines, not standards, and are designed to facilitate comparisons between the experiences of different surgeons who treat different cohorts of patients at different times with different techniques and materials.

Data Collection↗

PubMed1996

Contrast-enhancing progressive multifocal leukoencephalopathy: radiological and pathological correlations: case report.

OBJECTIVE AND IMPORTANCE: Progressive multifocal leukoencephalopathy (PML), a demyelinating disease caused by the JC papovavirus, is an opportunistic infection afflicting patients with impaired cellular immunity. Although initially described in patients with hematological malignancies, PML has become associated with several other immunocompromised states, particularly human immunodeficiency virus (HIV) infection. There are numerous central nervous system manifestations in patients with acquired immunodeficiency syndrome. A major characteristic that distinguishes PML from other more common lesions, such as toxoplasmosis or non-Hodgkin's lymphoma, is the lack of contrast enhancement. We describe a case of PML that exhibits contrast enhancement, and we conclude that the diagnosis of PML must be considered in patients with HIV who have contrast-enhancing lesions. CLINICAL PRESENTATION: A 40-year-old woman presented with progressive hemiparesis, blurred vision, and ataxia. Magnetic resonance imaging revealed a contrast-enhancing lesion involving the left middle cerebellar peduncle, causing mild compression of the fourth ventricle. INTERVENTION: The patient underwent a stereotactic serial biopsy with the presumptive diagnosis of moderate- to high-grade glioma. Histological examination of the biopsy specimen revealed early PML. Subsequently, a test for HIV was obtained and the results were positive. CONCLUSION: We have reported another atypical radiographic characteristic of PML associated with HIV. We conclude that PML lesions can enhance after the administration of gadolinium. Therefore, the diagnosis of PML must be entertained in patients whose test results were positive for HIV with contrast-enhancing lesions and that a stereotactic serial biopsy may be necessary to provide a definitive diagnosis.

Adult↗

PubMed1996

True lumen obliteration in complicated aortic dissection: endovascular treatment.

PURPOSE: To evaluate endovascular treatment of ischemic complications caused by true lumen obliteration in aortic dissection. MATERIALS AND METHODS: Endovascular techniques were used to treat true lumen obliteration in 11 patients with complicated aortic dissection. In all cases, the true lumen was compressed to a paper-thin sliver by the expanded false lumen. Two patients had Stanford type A (chronic) and nine had type B (six acute, three chronic) dissections. Obliteration of the true lumen was associated with branch vessel ischemia that included renal (n = 7), mesenteric (n = 6), and lower-extremity (n = 6) arterial compromise. Two patients were treated with aortic stents, four with balloon fenestration of the intimal flap, and three with both stent placement and fenestration. In two patients, ischemic complications caused by true lumen obliteration could not be treated with endovascular techniques. RESULTS: Revascularization was technically successful with relief of clinical symptoms in nine patients. Revascularization was unsuccessful in one patient in whom surgical revascularization of the superior mesenteric artery was necessary and in one in whom hypertension was managed medically. One patient developed thrombosis of a renal artery in which a stent had been placed. The 30-day mortality rate was 9%, and the mean follow-up was 10.1 months (range, 2 weeks to 39 months). CONCLUSION: True lumen obliteration can be safely and effectively treated with endovascular stent placement and balloon fenestration.

Aortic Dissection↗

PubMed1996

Left ventricular diastolic suction with zero left atrial pressure in open-chest dogs.

We investigated left ventricular (LV) diastolic volume changes (suction inflows) with left atrial pressure (LAP) clamped to ambient pressure in six open-chest, anesthetized dogs. The left atrium was cannulated and connected to a servo pump, and LAP was clamped to a set point near 0 mmHg for four beats by withdrawing blood. LAP averaged 5.88 +/- 1.44 mmHg before the clamp and fell to 0.74 +/- 0.61 mmHg (P < 0.0001) after the clamp. During the first clamped beat a transmitral pressure gradient of 1.0 +/- 0.6 mmHg was observed, resulting in LV filling of 2.6 +/- 1.8 ml. Subsequent beats developed suction-driven (mean negative LV pressure: -1.5 +/- 1.3 mmHg; P < 0.005 vs. zero) LV filling of 4.5 +/- 2.8 ml/beat with a peak transmitral pressure gradient of 1.7 +/- 0.6 mmHg. These data are consistent with the hypothesis that LV suction can be an important filling mechanism under condition in which LV end-systolic volume is reduced, e.g., reduced filling pressures, high heart rates, exercise, or increased inotropic drive.

Animals↗

PubMed1996

Pediatric brain tumors express multiple receptor tyrosine kinases including novel cell adhesion kinases.

We have used the polymerase chain reaction to clone and characterize growth factor receptor tyrosine kinases (RTKs) expressed in 3 pathologically distinct pediatric brain tumors, an anaplastic ependymoma, a glioblastoma multiforme and a primitive neuroectodermal tumor (PNET). These neoplasms are presumed to be derived from embryonic neuroepithelial precursor cells of the central nervous system. This cloning demonstrated expression of 24 distinct kinase genes: 16 receptor type kinases and 8 nonreceptor type kinases. The expression of 6 receptors, including Hek2, IRR, Ryk, FGFR3, and 2 members of the newly identified cell adhesion kinase receptor family, DDR and TKT, in such tumors has not been reported previously. Northern analysis of mRNA levels revealed DDR expression in 6 of 7 pediatric brain tumors including an ependymoma, PNET, glioblastoma and astrocytoma, and also in an adult pheochromocytoma. Thus, the DDR cell adhesion kinase may be widely expressed in pediatric brain tumors. Also, PCR cloning may be an effective procedure for characterizing RTKs in clinical tissue samples and revealing the expression of novel RTK species.

Adrenal Gland Neoplasms↗

PubMed1996

Intramedullary spinal cord tumors in children under the age of 3 years.

Over a 13-year period extending from 1980 to 1993, 27 children less than 3 years of age underwent operation for removal of an intramedullary spinal cord tumor (IMSCT). The majority (18 of 27) of children had undergone surgery before being referred to New York University (NYU) Medical Center. The most common reasons for radiological investigation were pain (42%), motor regression (36%), gait abnormalities (27%), torticollis (27%), and progressive kyphoscoliosis (24%). Forty procedures were performed in 27 children. Nine children underwent two operations and two children underwent three procedures. A gross-total resection was achieved in 72% of the procedures. There was no surgical mortality. A comparison of the preoperative and 3-month postoperative functional grades for the first NYU procedure (NYU-1) yielded the following findings: 20 patients' conditions remained the same, five patients improved, and two patients deteriorated. The functional outcomes of a second operation (NYU-2) were similar. The majority of the children (24 of 27, 89%) had histologically determined low-grade lesions. There were 12 patients with low-grade astrocytomas (Grades I-III), eight with gangliogliomas, two with ganglioglioneurocytomas, one with a glioneurofibroma, and one child with a mixed astro/oligodendroglioma. Two children had anaplastic astrocytomas (Grades II-III) and one child had a glioblastoma multiforme. In a median follow-up review of 76 months, two patients died and two patients were lost to follow up. The 3- and 5-year progression-free survival (PFS) rates were 81.7% (standard error of the mean (SEM) 0.083) and 76.2% (SEM 0.094), respectively. Eight of 24 patients suffered a recurrence within a mean time of 45.4 +/- 28.9 months. All were treated with surgery (NYU-2). Lesions recurred in three of 12 children with low-grade astrocytomas, two of eight children with gangliogliomas, one child with an anaplastic astrocytoma, one child with a ganglioglioneurocytoma, and one child with a glioblastoma multiforme. At follow-up review, most of these children were doing well. Sixteen are in functional Grades I or II and 18 children attend a normal school system. The authors conclude that surgery for the removal of IMSCTs in children less than 3 years of age can be performed radically and safely. The postoperative functional performance is determined by the degree of the preoperative deficit. It is, therefore, of utmost importance to diagnose and treat these children as early as possible. Spinal cord tumors should be recognized as potentially excisable lesions on their initial presentation and when they recur. The optimum treatment for malignant lesions is still to be determined.

Child, Preschool↗

PubMed1996

Porcine valves: Hancock and Carpentier-Edwards aortic prostheses.

Hancock and Carpentier-Edwards porcine bioprostheses are the two most widely implanted biological valves and have become the standard by which the performance of newer tissue valves are measured. New guidelines for reporting valve-related complications have provided more comprehensive evaluations and meaningful comparison of the long-term results of valve substitutes. Clinical investigations directly comparing the Hancock and Carpentier-Edwards bioprostheses have shown no significant differences in the long-term performance of these two valves. The incidence of structural valve deterioration for porcine bioprostheses begins to increase 5 to 6 years after implantation. For patients undergoing aortic valve replacement, estimates of freedom from structural valve deterioration at 10 and 15 years range from 76% to 91% and 37% to 63%, respectively. The incidence of structural valve deterioration may be offset by the limited survival of older patients; thus, the durability of a bioprosthesis may be sufficient for the majority of these patients. The long-term results of the porcine bioprosthesis have been satisfactory, particularly in older patients and those undergoing aortic valve replacement. The performance of the Hancock modified orifice (MO) bioprosthesis is comparable with that of other bioprostheses despite its more complex fabrication process. Although it does not offer any distinct advantages in terms of durability, the Hancock MO valve is associated with lower pressure gradients and larger calculated valve areas compared with other porcine valves in the smaller sizes. Based on currently available data, there are no distinct differences in the performance of the second-generation porcine bioprostheses compared with the first-generation valves, and any purported advantages need to be confirmed with long-term evaluations.

Age Factors↗

PubMed1996

Improving methods of chordal sparing mitral valve replacement. Part I: A new, non-distorting isovolumic balloon preparation for the left ventricle with intact mitral subvalvular apparatus.

BACKGROUND AND AIMS OF THE STUDY: The conventional isovolumic preparation with a single balloon, although employed for many years, distorts the chordae tendineae of the intact mitral apparatus. MATERIAL AND METHODS: Anterior balloon (one balloon inserted via a slit in the anterior leaflet) and double balloon (two balloons through slits in both leaflets) methods were developed and compared to the conventional method and natural conditions (LV filled with saline, or 'gold standard') in six ex-vivo, non-beating porcine hearts. RESULTS: LV volumes measured by the double balloon, anterior balloon, and conventional techniques all correlated highly with natural conditions, but the conventional method had a lower correlation coefficient (r = 0.99, 0.98, p < 0.0001 and < 0.001; and 0.92 p < 0.01, respectively at a left ventricular (LV) pressure of 50 mmHg, while r = 1.00, 1.00, both p < 0.0001; and 0.92, p < 0.01, respectively at 70 mmHg). Epicardial echocardiography revealed that the double balloon technique filled the space behind the chordae while maintaining normal chordal geometry, but the anterior balloon alone did not (p < 0.001). Similarly, the conventional method did not fill the LV outflow tract (p < 0.001) and had a mitral annular shift toward the left atrium (p < 0.001). Photography of both leaflets showed that only the double balloon method maintained normal geometry as assessed by leaflet length ratio; the other methods produced distorted geometry compared to natural filling conditions. CONCLUSIONS: With an intact mitral valve, the double balloon method provides more precise LV pressure-volume measurements while preserving the normal geometry of the chordae tendineae and mitral annulus.

Animals↗

PubMed1996

Improving methods of chordal-sparing mitral valve replacement--Part II: Optimal tension for chordal resuspension.

BACKGROUND AND AIMS OF THE STUDY: Although chordal-sparing mitral valve replacement (MVR) is popular, the optimal tension for preserved or reattached chordae tendineae (CT) or for synthetic (ePTFE) CT is unknown. METHODS: Changes in left ventricular (LV) systolic and diastolic function in nine dogs with anterior CT preservation with different levels of end-diastolic chordal tension (0, 10, 20, 30, and 40 gm, measured by spring scale) were compared using an isovolumic double-balloon technique. RESULTS: LV function data at each level of tension were compared to control data using 0 gm of tension. Systolic function assessed as Emax (mmHg/ml) at 10, 20, 30, and 40 gm versus control was: 5.7 +/- 2.6/4.9 +/- 2.7, 4.7 +/- 2.2/4.7 +/- 2.7, 4.8 +/- 3.1/4.7 +/- 2.8, and 5.0 +/- 3.5/5.1 +/- 2.9; delta improvement from the control at 10 gm was larger than that at 20 gm (p < 0.05 by paired t-test). Diastolic function assessed as diastolic stiffness (Sd, mmHg/ml) at the same CT tensions versus control was: 0.56 +/- 0.23/0.56 +/- 0.34, 0.53 +/- 0.30/0.57 +/- 0.37, 0.56 +/- 0.39/0.52 +/- 0.38, and 0.60 +/- 0.36/0.58 +/- 0.39; delta Sd was smaller at 20 gm than at 30 gm (p = 0.05 by ANOVA). LV equilibrium volume (Veq, ml) was: 10.7 +/- 3.9/10.1 +/- 3.9, 9.6 +/- 3.4/9.9 +/- 3.8, 10.8 +/- 4.0/10.3 +/- 3.4, and 10.6 +/- 4.0/10.6 +/- 3.5; delta Veq was larger (i.e., more compliant chamber) at 10 gm than at 40 gm (p < 0.05 by rm-ANOVA). Arrhythmias precluding satisfactory measurements occurred in two dogs at 30 or 40 gm CT tension. CONCLUSIONS: With chordal tension exceeding 10 gm, which is barely palpable, there was no additional enhancement in LV systolic function compared to zero CT tension. Veq was largest at the lowest tension; LV diastolic function (assessed as Sd) deteriorated with tensions of 30 gm or higher. The optimal end-diastolic tension of preserved CT should enhance systolic LV performance without adversely affecting diastolic function; in this isovolumic model, minimal CT tension (10 gm) best met these goals. Excessive tension may negate the potential hemodynamic benefits of chordal preservation during mitral valve replacement.

Animals↗

PubMed1996

Improving methods of chordal-sparing mitral valve replacement--Part III: Optimal direction for artificial chordae.

BACKGROUND AND AIMS OF THE STUDY: The optimal direction to preserve artificial chordae tendineae (CT) during mitral valve replacement (MVR) is not known, especially in regard to the response to inotropic stimulation which simulates exercise conditions. METHODS: Using a non-distorting isovolumic balloon technique, we compared left ventricular (LV) systolic and diastolic mechanics in 11 dogs in a control state (no chordal sparing) and with four different methods of chordal preservation: posterior, anterior, oblique (anterior papillary muscle chordae directed anteriorly and others posteriorly, the direction which theoretically augments LV systolic twist), and counter-oblique (counter, chordae preserved in directions opposite to oblique). RESULTS: Before dobutamine, delta Emax from the control was: 0.32 +/- 0.82, 0.10 +/- 0.43, 0.64 +/- 1.07, and 0.51 +/- 0.78 (anterior, posterior, oblique, and counter method, respectively). With dobutamine (3 mg/kg/min), delta Emax (mmHg/ml) was: 0.41 +/- 1.21, -0.13 +/- 0.75, 0.59 +/- 0.82*, and -0.34 +/- 0.71. Before dobutamine, delta LV stiffness (Sd, mmHg/ml) was -0.01 +/- 0.09, -0.02 +/- 0.12, 0.02 +/- 0.10, and 0.01 +/- 0.12; with dobutamine it was 0.01 +/- 0.09, 0.00 +/- 0.15, 0.03 +/- 0.15, and -0.06 +/- 0.11. Similarly, before dobutamine delta LV equilibrium volume (Veq) was -1.2 +/- 3.8, -0.3 +/- 3.0, -0.7 +/- 2.7, and -0.2 +/- 3.5, whereas with dobutamine zeta eq was -0.1 +/- 1.1, -0.4 +/- 0.8, 0.6 +/- 1.7, and -0.4 +/- 1.1. (Mean +/- S.D.; *p = 0.005 posterior and counter by ANOVA; p = NS (< 0.06) versus counter and posterior by ANOVA). CONCLUSIONS: The oblique method enhanced systolic LV function both with and without dobutamine, while a tendency towards better diastolic LV function (Veq) was observed with dobutamine. The anterior method was next best in preserving systolic function, both with and without dobutamine. LV diastolic function tended to deteriorate with dobutamine in the posterior group. Systolic function with the counter method deteriorated with dobutamine. These results warrant further study in an ejecting model to investigate LV systolic and diastolic mechanics with the oblique method of CT preservation, including interactions with LV systolic twist and diastolic recoil.

Animals↗

PubMed1995

Surgical management of aortic dissection during a 30-year period.

BACKGROUND: Certain recent studies have demonstrated improved surgical outcome in patients with aortic dissection. We analyzed the surgical survival rates of patients with acute aortic dissections and the late prognosis of those with aortic dissection during a 30-year period. METHODS AND RESULTS: Between 1963 and 1992, 360 patients (256 men and 104 women; mean +/- 1 SD age, 57 +/- 14 years) underwent surgery for aortic dissection: 174 patients had an acute type A (AcA), 46 an acute type B (AcB), 106 a chronic type A (ChA), and 34 a chronic type B (ChB) aortic dissection. The overall operative mortality rate was 24 +/- 8% (26 +/- 3% for AcA, 39 +/- 8% for AcB, 17 +/- 4% for ChA, and 15 +/- 6% for ChB, [+/- 70% confidence limit]). The operative mortality rates for patients with acute aortic dissection (AcA or AcB) were assessed for five time "windows": 1963 to 1972 (42 +/- 8%), 1973 to 1977 (37 +/- 8%), 1978 to 1982 (15 +/- 6%), 1983 to 1987 (27 +/- 6%), and 1988 to 1992 (26 +/- 6%). Logistic regression analysis suggested that the low operative mortality rate during the 1978-to-1982 interval occurred by chance. Multivariate analysis showed earlier operative year, hypertension, cardiac tamponade, renal dysfunction, and older age were independent determinants of operative death. Actuarial survival rates (including early deaths) after 5, 10, and 15 years for AcA patients were 55%, 37%, and 24%; for AcB, 48%, 29%, and 11%; for ChA, 65%, 45%, and 27%; and for ChB, 59%, 45%, and 27%. Multivariate analysis revealed that older age and previous operation were significant predictors for late death. Freedom from reoperation for all patients was 84%, 67%, and 57% at 5, 10, and 15 years, respectively. CONCLUSIONS: Although the operative mortality rate decreased over time for patients with aortic dissection, the risk for those with acute aortic dissection during the last 10 years (1983 to 1992) is probably more realistic than that observed in the preceding 5-year interval (1978 to 1982). The operative mortality rates for patients with chronic aortic dissection have remained relatively static. Earlier diagnosis of acute aortic dissection before development of cardiac tamponade and renal impairment is critical to improve the operative salvage rate. Long-term outcome still is not optimal, which emphasizes the need for better serial postoperative aortic imaging surveillance and medical follow-up and blood pressure control.

Adult↗

PubMed1995

Left ventricular function, twist, and recoil after mitral valve replacement.

BACKGROUND: Preservation of the mitral subvalvular apparatus during mitral valve replacement (MVR) has become more popular, in part because of the clinically and experimentally demonstrated more optimal left ventricular (LV) performance after surgery; the mechanisms responsible for this beneficial influence, however, have not been clearly elucidated. METHODS AND RESULTS: Fourteen dogs underwent placement of 26 myocardial markers into the LV and septum. One week later, the animals were studied while awake, sedated, and atrially paced (120 beats per minute) both under baseline conditions and after inotropic stimulation (calcium). The animals then underwent MVR and were randomized into either chord-sparing (MVR-Intact) or chord-severing (MVR-Cut) techniques. Two weeks later, the animals were studied under the same conditions. LV systolic function was assessed by the slope of the end-systolic pressure-volume relation (Ees); early LV diastolic filling was analyzed by the pressure-time constant of relaxation (tau). The instantaneous longitudinal gradient of torsional deformation for the LV (twist) was also calculated, as were the changes in twist with respect to time during systole and early diastole (LV recoil). Intergroup comparison showed a trend toward increased contractility (Ees, P = .061, before versus after MVR), as well as faster relaxation for the MVR-Intact group. Concurrent analysis of LV systolic function and the rate of systolic twist revealed a significant inverse relation, which disappeared after MVR when the chordae were severed. CONCLUSIONS: These observations suggest that the mitral subvalvular apparatus acts as a modulator of LV systolic torsional deformation into LV pump (or ejection) performance.

Animals↗

PubMed1995

Post-polio syndrome spinal cord pathology. Case report with immunopathology.

Post-polio syndrome (PPS) describes the clinical onset of progressive muscular weakness many years after survival of acute paralytic poliomyelitis, often in muscle groups clinically unaffected by the original disease process. Prior pathologic descriptions of this often disabling, but not usually fatal, syndrome have been scanty. These have emphasized the presence of persistent or new inflammation in the meninges, spinal cord, and muscles of affected patients. The inflammation suggests several pathogenetic hypotheses, including persistent active poliovirus infection, autoimmune attack on central and peripheral nervous system elements, or increased vulnerability of poliovirus-damaged tissue to new infections. We have recently examined the central nervous system from a PPS patient. The cord showed focal perivascular intraparenchymal chronic inflammatory infiltrates. Immunoperoxidase staining demonstrated that the infiltrates were virtually pure populations of B lymphocytes (immunopositive with antibody L26, and immunonegative with the T cell marker UCHL1 as well as the macrophage marker HAM56). There were rare macrophages (HAM56 immunopositive) and no T cells. The character of the infiltrates suggests that PPS could be an autoimmune disorder mediated by antibodies produced in situ, and not by a cell-mediated process. Additional important pathological features were the presence in the anterior horns of axonal spheroids and of moderate Wallerian degeneration in the lateral columns. The brain was entirely unremarkable, with no detectable cell loss of gliosis in the internal capsules or precentral gyri.

Anterior Horn Cells↗

PubMed1995

Tenascin expression in astrocytomas correlates with angiogenesis.

We investigated the expression and distribution of the extracellular matrix protein tenascin (TN) in 59 astrocytomas and 11 samples of normal brain by Western blot analysis and immunohistochemistry using antibodies against human TN. The tumors included 14 juvenile pilocytic astrocytomas (grade 1), 13 low grade fibrillary astrocytomas (grade II), 8 anaplastic astrocytomas (grade III), and 24 glioblastomas multiforme (grade IV). Proliferation indices were calculated by computer-based image analysis after immunostaining with the MIB-1 antibody against the Ki-67 proliferation-associated antigen. Western blot analysis for TN on fresh frozen tumor tissue from 23 of the 59 astrocytomas indicated up to 4-fold higher TN expression in glioblastomas multiforme than in nontumorous control tissues. Enhanced intercellular expression of TN was observed by immunohistochemistry in glioblastomas multiforme. More-over, TN immunostaining was consistently greater within and around the walls of hyperplastic blood vessels than nonhyperplastic vessels of both high grade tumors and juvenile pilocytic astrocytomas. Juvenile pilocytic astrocytomas with increased TN expression by Western blot analysis had vascular hyperplasia by light microscopy. Proliferation indices moderately correlated with tumor grade. Enhanced immunohistochemical expression of TN was associated with higher tumor grade with higher proliferation indices. The strong association of TN and vascular hyperplasia, regardless of tumor grade, suggests that TN may play a crucial role in angiogenesis.

Astrocytoma↗

PubMed1995

Binswanger's disease presenting as levodopa-responsive parkinsonism: clinicopathologic study of three cases.

We report three cases of autopsy-proven Binswanger's disease (subcortical arteriosclerotic encephalopathy) with unusual clinical features. Two patients had supranuclear gaze disturbances, early gait dysfunction, and speech disorders suggestive of progressive supranuclear palsy. One of these patients was not demented at the time of death. The third patient had features typical of Parkinson's disease. All three patients were responsive to treatment with levodopa. The clinical spectrum of Binswanger's disease should be expanded to include levodopa-responsive parkinsonism.

Aged↗

PubMed1995

Aortic dissection.

Explore the source record for details and available documents.

Aortic Dissection↗

PubMed1995

Durability of the Hancock MO bioprosthesis compared with standard aortic valve bioprostheses.

To compare the durability of the Hancock modified orifice (Hancock MO, model 250 [H-MO]) valve with two other commonly used standard aortic valve bioprostheses, a cohort of 1,602 patients undergoing aortic valve replacement using porcine valves between 1971 and 1990 (excluding simultaneous mitral valve replacement) was analyzed retrospectively using Cox model multivariate techniques. Five hundred sixty-one patients received a composite H-MO valve, 652 received a standard Hancock model 242 (H) valve, and 389 received a Carpentier-Edwards model 2625 (C-E) valve. Mean age was 60 +/- 15 years (+/- 1 standard deviation) (71% male). Follow-up (10,247 patient-years) extended to 15 years and was 97% complete. The main focus of this study was bioprosthetic durability, using The American Association for Thoracic Surgery/The Society of Thoracic Surgeons guidelines to define structural valve deterioration (SVD). Multivariate analysis revealed that (younger) age (p < 10(-5), liver disease (p = 0.02), and 1981 to 1985 operative period (p = 0.012) were the only significant, independent predictors of SVD. In concordance with previous reports, the SVD freedom estimate was greater than 90% at 15 years for patients older than 70 years of age. Hepatic dysfunction had an adverse effect on SVD (estimated freedom from event at 10 years was 34 +/- 17% [standard error of mean] versus 78 +/- 2% for those without liver disease), but this affected only 3% of patients. Interestingly, one operative period (1981 to 1985) was associated with a slightly higher risk of SVD compared to the three other 5-year time windows. Valve type did not emerge as a significant risk factor for SVD.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗