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Siegel A, Frommelt L, Runde W. [Therapy of bacterial knee joint infection by radical synovectomy and implantation of a cemented stabilized knee joint endoprosthesis]. Chirurg 2000; 71:1385-91. [PMID: 11132327 DOI: 10.1007/s001040051231] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
INTRODUCTION The report presents an alternative to the treatment of joint destruction in cases of knee joint empyema by resection or arthrodesis: implantation of a stabilised knee prosthesis using antibiotic-loaded bone cement for fixation. METHOD From 1985 to 1997 a total of 33 knees in 32 patients (21 female, 12 male) were treated for knee empyema by radical synovectomy and implantation of a stabilised knee prosthesis fixed in position with antibiotic-loaded bone cement. The antibiotics were chosen according to the antibiogram of the pathogen. In all these cases the infections had not responded to previous treatment. The criterion for success was the elimination of infection. The follow-up period ranged from 2 to 15 years. RESULTS Of 33 infected knees 31 (93.9%) were followed up. In 22 cases (71.0%) the infection was eliminated by primary surgery. In five cases (16.1%) further exchange operations were necessary to eliminate the infection. In four cases (12.9%) preservation of the joint was not possible. CONCLUSION Uncontrolled infection in cases of knee empyema and destruction of the joint can be treated by radical synovectomy and implantation of a stabilised knee prosthesis using antibiotic-loaded bone cement for fixation. The success rate corresponds to the results of one-stage exchange arthroplasty to treat periprosthetic infection of knee prostheses. This therapy should be performed only in specialised centres which have the facilities and personnel essential for accurate bacteriological diagnosis and recommendation.
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Zourabian A, Siegel A, Chance B, Ramanujan N, Rode M, Boas DA. Trans-abdominal monitoring of fetal arterial blood oxygenation using pulse oximetry. JOURNAL OF BIOMEDICAL OPTICS 2000; 5:391-405. [PMID: 11092427 DOI: 10.1117/1.1289359] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/1999] [Revised: 04/13/2000] [Accepted: 06/26/2000] [Indexed: 05/23/2023]
Abstract
Pulse oximetry (oxygen saturation monitoring) has markedly improved medical care in many fields, including anesthesiology, intensive care, and newborn intensive care. In obstetrics, fetal heart rate monitoring remains the standard for intrapartum assessment of fetal well being. Fetal oxygen saturation monitoring is a new technique currently under development. It is potentially superior to electronic fetal heart rate monitoring (cardiotocography) because it allows direct assessment of both the fetal oxygen status and fetal tissue perfusion. Here we present the analysis for determining the most optimal wavelength selection for pulse oximetry. The wavelengths we chose as the most optimal are the first in the range of 670-720 nm and the second in the range of 825-925 nm. Further, we discuss the possible systematic errors during our measurements and their contribution to the obtained saturation results. We present feasibility studies for fetal pulse oximetry, monitored noninvasively through the maternal abdomen. Our preliminary experiments show that the fetal pulse can be discriminated from the maternal pulse and thus, in principle, the fetal arterial oxygen saturation can be obtained. We present the methodology for obtaining these data, and discuss the dependence of our measurements on the fetal position with respect to the optode assembly.
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Sitthisomwong P, Weiner S, Levin L, Reisman S, Siegel A. The effect of a cholecystokinin agonist on masseter muscle activity in the cat. J Dent Res 2000; 79:1823-8. [PMID: 11078001 DOI: 10.1177/00220345000790101501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The CCK(B) agonist, pentagastrin, has been shown to induce anxiety in human subjects. Similarly, in the cat model, pentagastrin facilitates the expression of hypothalamically activated emotional behavior. Because hypothalamically mediated emotional behavior is also accompanied by increased EMG activity in the jaw muscles, these experiments were designed to examine the combined effects of administration of pentagastrin with activation of hypothalamically mediated emotional behavior upon jaw muscle EMG activity. Electrodes were carefully lowered through previously placed guide tubes overlying the hypothalamus until a behavioral site was identified. Following the establishment of a stable threshold current for eliciting an emotional behavioral response, the skin overlying the ipsilateral masseter muscle was shaved and cleaned with alcohol, and surface electrodes were attached. The EMG was recorded, amplified, digitized, and stored in a microcomputer for analysis. Mean power frequencies (MPF) and latencies for behavior were calculated for baseline prior to infusion of all drugs. Following this, the effects of intravenous administration of pentagastrin and the CCK(B) antagonist LY288513 on the MPF were determined. The infusion of the CCK(B) agonist, pentagastrin (0.77, 1.92, and 3.84 microg/kg), decreased MPF in a time-related manner. The effects of pentagastrin 1.92 microg/kg were blocked by the CCK(B) antagonist, LY288513 (6.54 microg/kg). In addition, the infusion of LY288513 alone increased MPF. These results are surprising in that pentagastrin's anxiogenic properties would appear to make it likely to facilitate motor activity, not suppress it.
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Lewis PJ, Siegel A, Siegel AM, Studholme C, Sojkova J, Roberts DW, Thadani VM, Gilbert KL, Darcey TM, Williamson PD. Does performing image registration and subtraction in ictal brain SPECT help localize neocortical seizures? J Nucl Med 2000; 41:1619-26. [PMID: 11037989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
UNLABELLED Ictal brain SPECT (IS) findings in neocortical epilepsy (patients without mesiotemporal sclerosis) can be subtle. This study is aimed at assessing how the seizure focus identification was improved by the inclusion of individual IS and interictal brain SPECT (ITS)-MRI image registration as well as performing IS - ITS image subtraction. METHODS The study involved the posthoc analysis of 64 IS scans using 99mTc-ethyl cysteinate dimer that were obtained in 38 patients without mesiotemporal sclerosis but with or without other abnormalities on MRI. Radiotracer injection occurred during video-electroencephalographic (EEG) monitoring. Patients were injected 2-80 s (median time, 13 s) after clinical or EEG seizure onset. All patients had sufficient follow-up to correlate findings with the SPECT results. All patients had ITS and MRI, including a coronal volume sequence used for registration. Image registration (IS and ITS to MRI) was performed using automated software. After normalization, IS - ITS subtraction was performed. The IS, ITS, and subtraction studies were read by 2 experienced observers who were unaware of the clinical data and who assessed the presence and localization of an identifiable seizure focus before and after image registration and subtraction. Correlation was made with video-EEG (surface and invasive) and clinical and surgical follow-up. RESULTS Probable or definite foci were identified in 38 (59%) studies in 33 (87%) patients. In 52% of the studies, the image registration aided localization, and in 58% the subtraction images contributed additional information. In 9%, the subtraction images confused the interpretation. In follow-up after surgery, intracranial EEG or video-EEG monitoring (or both) has confirmed close or reasonable localization in 28 (74%) patients. In 6 (16%) patients, SPECT indicated false seizure localization. CONCLUSION Image registration and image subtraction improve the localization of neocortical seizure foci using IS, but close correlation with the original images is required. False localizations occur in a minority of patients.
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Kuhn JC, Siegel A, Poplack S, Arrick B. Chest wall recurrence of breast cancer detected by scintimammography. Clin Nucl Med 2000; 25:104-6. [PMID: 10656643 DOI: 10.1097/00003072-200002000-00004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A case of chest wall recurrence of breast cancer detected by scintimammography is presented. A 63-year-old woman who had a right mastectomy for breast carcinoma 24 years earlier was evaluated for left axillary adenopathy. Although it was suspected that a second primary malignancy had developed in the left breast, results of mammography and magnetic resonance imaging of that breast were negative. Scintimammography performed with Tc-99m sestamibi confirmed a normal left breast but revealed a lesion in the right chest wall at the site of the previous mastectomy. This was surgically confirmed as recurrent breast carcinoma, which subsequently altered patient management.
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Siegel A, Kuhn JC, Crow H, Holtzman S. Gallbladder ejection fraction: correlation of scintigraphic and ultrasonographic techniques. Clin Nucl Med 2000; 25:1-6. [PMID: 10634521 DOI: 10.1097/00003072-200001000-00001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE The assessment of gallbladder function and ejection fraction using sincalide-enhanced biliary scintigraphy is a useful way to evaluate patients with recurrent right upper quadrant pain but no gallstones. MATERIALS AND METHODS We wanted to determine whether gallbladder contraction measured by ultrasonography could be used in place of biliary scintigraphy. Biliary scans with an infusion of sincalide and concurrent ultrasonography were performed in 17 patients with histories of recurrent abdominal pain and no evidence of gallstones by ultrasound. RESULTS Gallbladder ejection fractions calculated by ultrasound and scintigraphy using standard techniques showed only a weak correlation. The poor performance of ultrasound appears to arise because the variable shape of the gallbladder invalidates the calculation of its volume by the formula for a prolate spheroid. When gallbladders that were ellipsoidal were subselected, correlation was improved. The level of training of the sonologist did not have a significant effect on the results. CONCLUSION Gallbladder ejection fraction calculated by ultrasonography cannot be used routinely as a substitute for biliary scintigraphy.
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Siegel A, Rückert U, Wenzl M. [Rare indication for a simple hip prosthesis with an extra-large femoral head following multiple failed exchange operations]. Chirurg 1999; 70:1353-6. [PMID: 10591778 DOI: 10.1007/s001040050793] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In certain rare cases of failure following multiple exchange arthroplasty at the hip, it is possible to create a strong and reliable connection between the pelvis and the femur, without replacing the acetabulum, by fitting a custom-made extra-large femoral head into the existing and stable large cavity. Two cases in which this method was used are described here and recommended for consideration in similar situations.
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Kehrer-Sawatzki H, Röck H, Götz H, Siegel A, Krone W. Monosomy 6 in human cultured fibroblast-like cells permanently stimulated by fibroblast growth factor 1: evidence for selection. CYTOGENETICS AND CELL GENETICS 1999; 86:28-33. [PMID: 10516428 DOI: 10.1159/000015424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The appearance of cells with monosomy 6 (mono6 cells) in cultures of human fibroblast-like cells during long-term stimulation with acidic fibroblast growth factor (FGF1) was confirmed in five of the six lines newly investigated. Aneugenic pretreatment at the start of the cultures accelerated the emergence of mono6 cells, as would be expected if selection, rather than induction, is the main mechanism involved. This could be confirmed by using an incidental rearrangement, der(8)t(6p;8p), that emerged in one of the lines by monitoring the proliferation of the mono6 cells (here monosomic for 6p22.1-->qter) in mixtures with normal cells. During growth in the presence of FGF1, the proportion of mono6 cells increased six fold, whereas in the absence of FGF1, it declined to background levels. Selection rather than induction of the mono6 cells is further supported by their clonal origin, as ascertained on the basis of X-inactivation patterns in three informative cases. In addition, colonies grown in the presence of FGF1 from single cells did not reveal higher proportions of mono6 cells by fluorescence in situ hybridization analysis than those grown without the growth factor. During permanent stimulation with FGF1, the growth of mono6 cells did not become dependent on FGF1, nor did these cells lose their responsiveness to FGF1. Although evidence in favor of selection of preexistent mono6 cells by FGF1 is provided in this study, the contribution of a primary inducing mechanism cannot be entirely excluded.
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Yao R, Rameshwar P, Donnelly RJ, Siegel A. Neurokinin-1 expression and co-localization with glutamate and GABA in the hypothalamus of the cat. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1999; 71:149-58. [PMID: 10521569 DOI: 10.1016/s0169-328x(99)00173-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Recent behavioral studies using pharmacological techniques have demonstrated that the high affinity substance P (SP) receptor, neurokinin-1 receptor (NK-1), in the medial hypothalamus could be important in mediating defensive rage behavior in the cat. These observations prompted us to use molecular techniques to determine the distribution of NK-1 in the hypothalamus and in other regions of the forebrain relevant to the control of rage behavior. We cloned a 650 bp fragment of the cat NK-1 cDNA. Partial DNA sequence analyses of this fragment indicate 90% homology with the human cDNA. By in situ hybridization (ISH), we showed that NK-1 mRNA was localized in the cytoplasm but not nuclei of cat forebrain neurons. Furthermore, NK-1 mRNA was co-localized in neurons that displayed positive immunolabeling for glutamate or GABA. Moderate labeling was visualized in the anterior medial hypothalamus which receives significant SP input via the stria terminalis from the medial amygdala. Strong labeling was also observed in the basal amygdaloid complex. The functional significance of this labeling pattern is suggested from the observation that both the medial and basal complex of amygdala serve as powerful modulators of defensive rage behavior. Weaker labeling was seen over the posterior medial and lateral hypothalamus. The distribution of NK-1 in the hypothalamus was matched by that of SP-immunoreactive axons and pre-terminals that were observed in the hypothalamus. The overall findings provide anatomical evidence to show that the high affinity SP receptor, NK-1, is linked to glutamate and GABA neurons in the anterior medial hypothalamus and further suggests its likely role in the regulation of feline aggression.
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Kreisel W, Siegel A, Bahler A, Spamer C, Schiltz E, Kist M, Seilnacht G, Klein R, Berg PA, Heilmann C. High prevalence of antibodies to calreticulin of the IgA class in primary biliary cirrhosis: a possible role of gut-derived bacterial antigens in its aetiology? Scand J Gastroenterol 1999; 34:623-8. [PMID: 10440614 DOI: 10.1080/003655299750026100] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND In a preliminary study we showed that antibodies to the endoplasmic reticulum protein calreticulin (CR) occur in primary biliary cirrhosis (PBC) and autoimmune hepatitis type 1 (AIH). Since anti-CR antibodies have also been found in patients with infectious diseases, we investigated their prevalence and immunoglobulin classes in patients with various hepatic and intestinal diseases, hoping to get some information on a possible relationship between an infectious trigger and the induction of a certain class of anti-CR antibodies. METHODS Sera were tested for anti-CR antibodies of the IgA, IgG, and IgM class by Western blotting, using CR isolated from human liver: in autoimmune liver diseases (primary biliary cirrhosis (PBC) (n = 86) and autoimmune hepatitis (AIH) type 1 (n = 57)), alcoholic liver cirrhosis (ALC) (n = 32), viral liver infections (acute hepatitis A (n = 8), acute hepatitis B (n = 20), and chronic hepatitis C (n = 28)), and intestinal diseases (Crohn disease (CD) (n = 30), acute yersiniosis (n = 26)). Sera from 100 healthy individuals served as negative controls. RESULTS The most prominent finding was the high prevalence of anti-CR antibodies of the IgA class and the similarity in the anti-CR antibody class pattern in PBC (IgA, 62%; IgG, 43%; IgM, 55%) and yersiniosis (IgA, 62%; IgG, 39%; IgM, 42%). Class IgA anti-CR antibodies also occurred frequently in ALC (IgA, 44%; IgG, 41%; IgM, 19%). In contrast, in AIH anti-CR antibodies were predominantly of class IgG (IgA, 28%; IgG, 60%; IgM, 33%). In hepatitis A anti-CR antibodies were absent. In the other diseases they had a low prevalence and were mostly of class IgG (acute hepatitis B: IgA, 0%; IgG, 15%; IgM, 0%; chronic hepatitis C: IgA, 7%; IgG, 21%; IgM, 0%; CD: IgA, 13%; IgG, 20%; IgM, 13%). Of the healthy individuals 7% had anti-CR antibodies exclusively of class IgG. CONCLUSIONS The high prevalence of anti-CR antibodies of class IgA in patients with PBC and yersiniosis as well as in alcoholic liver disease reflects a reactivity of the gut-associated immune system and could imply that a still undefined gut-derived bacterial (?) agent may trigger PBC.
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Siegel A, Marota JJ, Boas D. Design and evaluation of a continuous-wave diffuse optical tomography system. OPTICS EXPRESS 1999; 4:287-98. [PMID: 19396285 DOI: 10.1364/oe.4.000287] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Diffuse optical tomography (DOT) can image spatial variations in highly scattering optical media. We have built an inexpensive and portable continuous-wave DOT system containing 18 laser diode sources (9 at 780nm and 9 at 830nm) and 16 silicon detectors, which can acquire 288 independent measurements in less than 4 seconds. These data can then be processed using a variety of imaging algorithms. We first discuss the design of diffuse imaging equipment in general, and then describe our instrument, along with the technical issues that influenced its design. The technical challenges involved in performing DOT over large optode areas are discussed. We also present rat brain measurements following electrical forepaw stimulation using DOT. These results clearly demonstrate the capabilities of DOT and set the stage for advancement to quantitative functional brain imaging.
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Siegel A, Roeling TA, Gregg TR, Kruk MR. Neuropharmacology of brain-stimulation-evoked aggression. Neurosci Biobehav Rev 1999; 23:359-89. [PMID: 9989425 DOI: 10.1016/s0149-7634(98)00040-2] [Citation(s) in RCA: 236] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Evidence is reviewed concerning the brain areas and neurotransmitters involved in aggressive behavior in the cat and rodent. In the cat, two distinct neural circuits involving the hypothalamus and PAG subserve two different kinds of aggression: defensive rage and predatory (quiet-biting) attack. The roles played by the neurotransmitters serotonin, GABA, glutamate, opioids, cholecystokinin, substance P, norepinephrine, dopamine, and acetylcholine in the modulation and expression of aggression are discussed. For the rat, a single area, largely coincident with the intermediate hypothalamic area, is crucial for the expression of attack; variations in the rat attack response in natural settings are due largely to environmental variables. Experimental evidence emphasizing the roles of serotonin and GABA in modulating hypothalamically evoked attack in the rat is discussed. It is concluded that significant progress has been made concerning our knowledge of the circuitry underlying the neural basis of aggression. Although new and important insights have been made concerning neurotransmitter regulation of aggressive behavior, wide gaps in our knowledge remain.
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Ganz J, Siegel A, Bussert W, Harth K, Ruf MW, Hotop H, Geiger J, Fink M. On the Ne(2p5ns',nd') autoionisation resonances: high-resolution measurement and quantum defect analysis. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0022-3700/16/19/003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Siegel A, Ganz J, Bussert W, Hotop H. Electron angular distributions and total cross sections for photoionisation of polarised Ne(3p3D3) atoms near threshold. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0022-3700/16/16/015] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ganz J, Lewandowski B, Siegel A, Bussert W, Waibel H, Ruf MW, Hotop H. Photoionisation of Ne(2p53p3D3) atoms and the production of state-selected, polarised Ne+(2p5 2P3/2) ions. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0022-3700/15/14/001] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Porsch M, Siegel A. [Artificial hip replacement in young patients with hip dysplasia--long-term outcome after 10 years]. ZEITSCHRIFT FUR ORTHOPADIE UND IHRE GRENZGEBIETE 1998; 136:548-53. [PMID: 10036744 DOI: 10.1055/s-2008-1045184] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE The experience gained in three decades of hip arthroplasty includes observations on patients with congenital dysplasia of the hip (CDH) under 20 years of age. A study dealing with hip arthroplasty in patients with osteoarthritis following CDH in such young age is not known in the literature. In the present study we report about a long-term follow-up of 41 total hip arthroplasties which were performed using bone-cement in 29 patients from 1966 to 1995. METHODS The evaluation of this retrospective study was performed with an questionnaire and a clinical and radiological investigation (Harris hip score, Sutherland activity score). RESULTS 18 patients with 27 THR (62%) were evaluated clinically and radiologically after a mean duration of follow-up of 10 years and 8 months. Seven additional THR had been revised in the meantime. Kaplan-Meier survival analysis showed a survival rate after 10 years of 64%. Acetabular loosening occurred three times as often as femoral loosening (overall revision rate 41.2%). CONCLUSION The overall loosening rate of total hip replacement of young patients is significantly elevated. These findings suggest that total hip replacement in young patients with dysplastic hips should be considered most carefully. Implantation of a hip prosthesis is only justified in special cases where alternative procedures are contra-indicated or unacceptable.
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Luo B, Cheu JW, Siegel A. Cholecystokinin B receptors in the periaqueductal gray potentiate defensive rage behavior elicited from the medial hypothalamus of the cat. Brain Res 1998; 796:27-37. [PMID: 9689451 DOI: 10.1016/s0006-8993(98)00310-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Defensive rage behavior is mediated over a descending pathway from the medial hypothalamus to the dorsolateral midbrain periaqueductal gray (PAG) where further integration of this response takes place. The present study sought to determine the roles of CCK-A and CCK-B receptor activation in the PAG in modulating defensive rage behavior. The 'hissing' component of the defensive rage response was used throughout the experiment as the measure of defensive rage behavior. The basic design of the experiment involved placement of monopolar electrodes into the medial hypothalamus from which defensive rage could be elicited and cannula electrodes into the dorsal PAG for purposes of identifying defensive rage sites in this region and for microinjections of CCK compounds into these sites at a later time. Microinjections of the selective CCK-B receptor antagonist, LY288513 (1.05, 4.2, 17.0 nmol/0.25 microliter), into the PAG suppressed the hissing response in a dose- and time-dependent manner. Microinjections of the CCK-B agonist, pentagastrin, (0.5 and 1.0 nmol/0.25 microliter) facilitated the occurrence of defensive rage behavior. Moreover, administration of LY288513 (17 nmol/0.25 microliter) 55 min prior to pentagastrin (1.0 nmol/0.25 microliter) delivery blocked the facilitatory effects of pentagastrin. Administration of the CCK-A antagonist, PD140548 (34 nmol/0.25 microliter), into the PAG failed to alter response latencies for defensive rage behavior. In contrast, microinjections of the CCK-B antagonist, LY288513 (4.2, 17.0 nmol/0.25 microliter), facilitated the occurrence of predatory attack behavior elicited from the lateral hypothalamus. This finding demonstrates the specificity of the effects of CCK-B receptor blockade upon hissing. A combination of immunocytochemical and retrograde tracing procedures using microinjections of Fluoro-Gold (8%, 6 microliters) into the PAG were employed to identify the possible loci of CCK neurons that project to the PAG. The data revealed that neurons labeled for both CCK and Fluoro-Gold were located in the dorsolateral aspect of the midbrain tegmentum, identifying this region as a source of CCK inputs to the PAG. Overall, the findings demonstrate that CCK-B receptors in the PAG potentiate defensive rage behavior and likely suppress predatory attack.
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Buck A, Frey LD, Bläuenstein P, Krämer G, Siegel A, Weber B, Schubiger PA, Wieser HG. Monoamine oxidase B single-photon emission tomography with [123I]Ro 43-0463: imaging in volunteers and patients with temporal lobe epilepsy. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1998; 25:464-70. [PMID: 9575241 DOI: 10.1007/s002590050245] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Imaging of monoamine oxidase of subtype B (MAO B) is of interest in various neurological diseases. In the past non-invasive assessment of MAO B has only been possible with positron emission tomography (PET) ligands. Given the limited availability of PET, a single-photon emission tomography (SPET) ligand would be desirable. In this study SPET imaging with the new MAO B inhibitor [123I]Ro 43-0463 was performed in five volunteers and nine patients with temporal lobe epilepsy (TLE). In two volunteers a second study was performed 12 h following blockade with deprenyl. In the TLE patients the tracer was administered as bolus (n = 4) or as prolonged infusion (n = 5). The regional uptake pattern correlated well with the known distribution of MAO B. In the two blocking studies ligand uptake was substantially reduced compared with baseline. In the TLE patients increased uptake was found in the ipsilateral mesial temporal lobe and, surprisingly, in the ipsilateral putamen. This study indicates the potential of the new SPET ligand [123I]Ro 43-0463 to map MAO B concentration in the human brain. The new finding of increased MAO B in the putamen of TLE patients needs further studies to elucidate its exact pathophysiology.
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Cheu JW, Siegel A. GABA receptor mediated suppression of defensive rage behavior elicited from the medial hypothalamus of the cat: role of the lateral hypothalamus. Brain Res 1998; 783:293-304. [PMID: 9507168 DOI: 10.1016/s0006-8993(97)01357-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Recently, our laboratory has demonstrated that predatory attack behavior in the cat, elicited by electrical stimulation of the lateral hypothalamus, is suppressed following activation of the region of the medial hypothalamus from which defensive rage behavior is elicited [Han, Y., Shaikh, M.B., Siegel, A., Medical amygdaloid suppression of predatory attack behavior in the cat: II. Role of a GABAergic pathway from the medial to the lateral hypothalamus, Brain Res., 716 (1996) 72-83.]. The mechanism for this suppression is a direct GABAergic projection from the medial to lateral hypothalamus. The present study tested the hypothesis that the inhibitory relationship between these two regions of hypothalamus is reciprocal, namely, that a GABAergic neuron, which also projects from the lateral to medial hypothalamus, serves to suppress defensive rage elicited from the medial hypothalamus. Monopolar stimulating electrodes were implanted into lateral hypothalamic sites from which predatory attack behavior was elicited. In addition, cannula-electrodes were implanted into the medial hypothalamus for elicitation of defensive rage behavior and for microinjections of GABA compounds. Initially, in the absence of drug administration, the effects of dual stimulation of the lateral and medial hypothalamus upon response latencies were compared with those following single stimulation of the medial hypothalamus alone. Dual stimulation significantly (p<0.01) suppressed defensive rage behavior elicited from the medial hypothalamus. Then, administration of the GABAA receptor antagonist, bicuculline (10-60 pmol), into medial hypothalamic sites from which defensive rage was elicited blocked the suppressive effects of lateral hypothalamic stimulation. The GABAA receptor agonist, muscimol (0.3-30 pmol), microinjected into the medial hypothalamus, suppressed defensive rage elicited by single stimulation of the medial hypothalamus in a dose dependent manner. These suppressive effects of muscimol upon defensive rage were blocked following pretreatment with bicuculline (60 pmol). Administration of muscimol into adjoining regions of the lateral hypothalamus had no effect upon defensive rage, indicating its site specificity. Bicuculline (60 pmol) delivery into the medial hypothalamus had no effect upon defensive rage, suggesting the, presence of a phasic rather than tonic mechanism. A combination of immunocytochemical and retro grade tracing procedures were then employed to determine the origin of the putative GABAergic pathway projecting to the medial hypothalamus. In this experiment, the retrograde tracer, Fluoro-Gold (8%, 0.5 microl), was microinjected through a cannula-electrode in the medial hypothalamus from which defensive rage had been elicited. Following survival periods of 5-6 days, cats were perfused with 4% paraformaldehyde and brain tissue was processed for immunocytochemical staining of GABA neurons. Retrogradely labeled, immunopositively labeled, as well as Fluoro-Gold and GABA labeled cells, were identified in the lateral hypothalamus. Each type of neuron was distributed over wide regions of the lateral hypothalamus, extending from the area immediately caudal to the optic chiasm to the level of the posterior hypothalamus. Together, the behavioral pharmacological and anatomical data provide evidence of a direct inhibitory projection from the lateral to medial hypothalamus whose functions are mediated by GABAA receptors. When coupled with our previous findings, these results reveal the presence of reciprocal GABAergic inhibitory pathways between the medial and lateral hypothalamus. The findings suggest that functions associated with either the lateral or medial hypothalamus, but not both, can be activated at a given time.
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Krone W, Kehrer-Sawatzki H, Siegel A, Röck H, Götz H. Monosomy 6 in human cultured fibroblast-like cells after long-term stimulation with acidic fibroblast growth factor (FGF1). CYTOGENETICS AND CELL GENETICS 1997; 78:96-102. [PMID: 9371397 DOI: 10.1159/000134636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Long-term exposure to fibroblast growth factor type 1 (FGF1) of fibroblast-like cells derived from neurofibromas of patients with neurofibromatosis type 1, from angiofibromas of patients with tuberous sclerosis, and from foreskin of unaffected donors resulted in the outgrowth of monosomy 6 in 7 out of 14 cell lines examined. After their initial detection by cytogenetic analysis, the proportion of cells which had lost one chromosome 6 was monitored by FISH using a-satellite probes specific for chromosome 6 and 7, and by PCR analysis of polymorphic microsatellite markers. Monosomy 6 exceeding baseline levels developed only in cultures exposed to FGF 1, and the emergence of monosomic cells could not be correlated with a given donor's genotype. During serial culture, the proportion of monosomic cells increased to over 90% in 5 of the 7 affected strains. A conspicuous change of cellular morphology from spindle-shaped to more epithelial-type cells was noted in monosomic cultures, even though none of them converted to a permanent cell line during the observation period. We conclude that long-term exposure of human fibroblast-like cell strains to FGF1 results in the emergence of monosomy 6 in 50% of the cultures so treated. A selective advantage for such monosomic cells is the most likely explanation for their steady increase during serial culture.
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Siegel A, Mazurek R. Early dynamic SPECT acquisition for the imaging of hepatic hemangiomas utilizing Tc-99m labeled red blood cells. Clin Nucl Med 1997; 22:745-8. [PMID: 9363380 DOI: 10.1097/00003072-199711000-00001] [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: 02/05/2023]
Abstract
PURPOSE To determine whether rapid, dynamic SPECT imaging with Tc-99m labeled red blood cells was technically feasible and of value in the detection of cavernous hemangiomas of the liver. MATERIALS AND METHODS The acquisition protocol for Tc-99m labeled red blood cell imaging of hepatic hemangiomas was modified with six sequential 3-minute SPECT images replacing the planar flow phase. Delayed 20-minute SPECT of the liver was then performed 2 hours later. RESULTS The authors present examples of pathologically proven positive and negative cases and retrospectively review their patient series. Examination of 19 patients with 41 lesions revealed no evidence of a false-positive examination results and only one false-negative result. Only one lesion seen to be positive with a 2-hour delayed study was not seen within 18 minutes. Lesions as small as 1.0 cm could be detected with a 3-minute SPECT. CONCLUSIONS Rapid, dynamic early SPECT hemangioma imaging is feasible, provides images with relatively good quality, and can replace the planar flow phase.
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Han Y, Shaikh MB, Siegel A. Ethanol enhances medial amygdaloid induced inhibition of predatory attack behaviour in the cat: role of GABAA receptors in the lateral hypothalamus. Alcohol Alcohol 1997; 32:657-70. [PMID: 9463720 DOI: 10.1093/oxfordjournals.alcalc.a008316] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The present study tested the hypothesis that the suppressive effects of ethanol upon predatory attack behaviour in the cat involve a pathway from the medial amygdala to the lateral hypothalamus, and that these suppressive effects are mediated by gamma-aminobutyric acid (GABAA) receptors located in the lateral hypothalamus. Cannula electrodes were implanted into the lateral hypothalamus for elicitation of predatory attack behaviour and for microinjections of the GABAA receptor antagonist, bicuculline. Monopolar stimulating electrodes were implanted into the medial amygdala from which subseizure levels of electrical stimulation suppressed predatory attack behaviour. In the first phase of the study, we compared response latencies for predatory attack behaviour following single stimulation of the lateral hypothalamus alone with those following paired trials of dual stimulation of the medial amygdala plus lateral hypothalamus. Dual stimulation significantly suppressed predatory attack. In the second phase of the study, peripheral ethanol administration (in doses of 0.01, 0.5 and 1.0 g/kg, i.p.) enhanced the suppressive effects of medial amygdaloid stimulation in a dose- and time-dependent manner in which peak effects were obtained 60 min post-injection. In the third phase of the study, bicuculline (0.15 nmol) was microinjected into the lateral hypothalamus both prior to and following paired trials of dual stimulation. Drug infusion blocked the suppressive effects of medial amygdaloid stimulation upon predatory attack behaviour elicited from the lateral hypothalamus, indicating the importance of GABAA receptors in mediating this suppression. In the fourth phase of the study, bicuculline, microinjected into the lateral hypothalamus at the time when ethanol's effects were maximal (i.e. 60-80 min post-ethanol administration), totally blocked the suppressive effects of medial amygdaloid stimulation as well as the enhancing effects of ethanol upon medial amygdaloid suppression of this form of aggressive behaviour. In the last phase of the study, bicuculline (0.15 nmol) infusion into the lateral hypothalamus significantly reduced the suppressive effects of ethanol (1.0 g/kg, i.p.) upon predatory attack behaviour elicited from the lateral hypothalamus. These results support the hypothesis that ethanol's suppressive effects upon predatory attack behaviour in the cat are mediated, at least in part, by GABAA receptors in the lateral hypothalamus. The present and recent findings in our laboratory support the view that GABAA receptors in the lateral hypothalamus are activated, in turn, by a GABAergic pathway which arises from the medial hypothalamus whose neurons receive inputs from the medial amygdala.
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Siegel A, Schubert KL, Shaikh MB. Neurotransmitters regulating defensive rage behavior in the cat. Neurosci Biobehav Rev 1997; 21:733-42. [PMID: 9415898 DOI: 10.1016/s0149-7634(96)00056-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This review summarizes recent findings of our laboratory that have been directed at: (1) identifying the neural circuits underlying the expression and modulation of defensive rage behavior in the cat and the neurotransmitters associated with these pathways; and (2) determining which components of the circuitry are affected by alcohol administration and which significantly alter the rage mechanism. The experiments described herein incorporated a number of converging methods, which include brain stimulation, behavioral pharmacology, immunocytochemistry, retrograde tract tracing and receptor binding. For behavioral pharmacological studies, monopolar electrodes and cannula-electrodes were implanted into selected regions along the limbic-midbrain axis for electrical stimulation and local microinfusion of drugs. The findings demonstrated: (1) a direct pathway from the anterior medial hypothalamus to the dorsal periaqueductal gray (PAG) over which this response is mediated. This pathway utilizes excitatory amino acids that act upon NMDA receptors within the midbrain PAG; (2) that the region of the dorsal PAG, from which defensive rage could be elicited, receives other inputs from the basal amygdala that facilitate this response by acting upon NMDA receptors; (3) a pathway from the medial amygdala to the medial hypothalamus that also facilitates defensive rage and whose functions are mediated by substance P receptors within the medial hypothalamus; (4) that the PAG also receives enkephalinergic inputs from the central nucleus of amygdala, which act upon mu receptors, and which powerfully suppress defensive rage; and (5) that recent findings reveal that ethanol administration facilitates defensive rage by virtue of its interactions with the medial hypothalamus, its descending projection to the PAG, and possibly with NMDA receptors within this pathway.
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