Search PubMed⌕ Search

Biomedical subjects

A Siegel

Publications and source records attributed to A Siegel.

At least 19 recordsLinked to original sources
PubMed2001

[Fatal pelvic vein injury caused by guidewire used with the dynamic hip screw].

There are only a few reports about injury to vital anatomical structures by Kirschner wires in literature. In the case described here the guide wire of the dynamic hip screw caused a fatal injury to the external iliac vein which was not at first evident. The guide wire had obviously become caught up in the combination three-diameter drill and screwed by the drill into the pelvis. After a stable interval the patient suffered circulatory collapse. Emergency treatment and resuscitation attempts followed with no possibility of surgical intervention. The nature of the injury was established and described in a postmortem examination (photos). The distances were measured on the actual bone. The conclusion of the two experts assessing this case was that this rare injury was not due to malpractice.

Bone Screws↗
PubMed2001

Brain structures and neurotransmitters regulating aggression in cats: implications for human aggression.

1. Violence and aggression are major public health problems. 2. The authors have used techniques of electrical brain stimulation, anatomical-immunohistochemical techniques, and behavioral pharmacology to investigate the neural systems and circuits underlying aggressive behavior in the cat. 3. The medial hypothalamus and midbrain periaqueductal gray are the most important structures mediating defensive rage behavior, and the perifornical lateral hypothalamus clearly mediates predatory attack behavior. The hippocampus, amygdala, bed nucleus of the stria terminalis, septal area, cingulate gyrus, and prefrontal cortex project to these structures directly or indirectly and thus can modulate the intensity of attack and rage. 4. Evidence suggests that several neurotransmitters facilitate defensive rage within the PAG and medial hypothalamus, including glutamate, Substance P, and cholecystokinin, and that opioid peptides suppress it; these effects usually depend on the subtype of receptor that is activated. 5. A key recent discovery was a GABAergic projection that may underlie the often-observed reciprocally inhibitory relationship between these two forms of aggression. 6. Recently, Substance P has come under scrutiny as a possible key neurotransmitter involved in defensive rage, and the mechanism by which it plays a role in aggression and rage is under investigation. 7. It is hoped that this line of research will provide a better understanding of the neural mechanisms and substrates regulating aggression and rage and thus establish a rational basis for treatment of disorders associated with these forms of aggression.

Aggression↗
PubMed2001

Co-localization of NK(1)-receptor mRNA with glutamate immunopositivity in cat hypothalamic neurons by the combination of in situ hybridization and immunohistochemistry.

Previous studies had demonstrated that, in the cat, aggression is mediated by glutamatergic neurons in the anterior medial hypothalamus which project to the periaqueductal gray. Additionally, NK(1) receptor activation in the medial hypothalamus plays a role in the regulation of aggressive behavior by the medial amygdala. In the present study, in situ hybridization and immunohistochemistry were combined in order to provide neurochemical characterization of medial hypothalamic neurons containing NK(1)-receptor mRNA. In order to identify NK(1) receptors in cat brain, a 650-bp fragment of the cat NK(1) cDNA was cloned. This fragment was used to synthesize a riboprobe for in situ hybridization. Partial DNA sequence analysis of the fragment indicated a 90% homology with human cDNA. In situ hybridization revealed the presence of NK(1)-receptor mRNA in cat hypothalamic neurons. Tissue used to localize NK(1) receptors was also processed for glutamate immunopositivity. The results demonstrated that NK(1)-receptor mRNA is present in glutamate-immunopositive neurons in the anterior medial hypothalamus of cat, thus reinforcing the hypothesis that NK(1) receptors play an important role in this neural circuit.

Aggression↗
PubMed2001

Primary arthroplasty of infected hips and knees in special cases using antibiotic-loaded bone-cement for fixation.

As a consequence of successful 1-stage exchange of infected joint prostheses, we decided to treat bacterial infection of the hip or knee by joint resection, synovectomy, and primary implantation of a hip or stabilized knee prosthesis. Since 1984, we have performed this procedure on 51 hips and 32 knees. All operations were preceded by identification of the causative organism and choice of appropriate antibiotics for addition to the bone-cement. The long-term rate of success corresponds to that of 1-stage exchange of infected prostheses. The different anatomic conditions at the hip and knee have to be taken into consideration. This treatment is restricted to special cases and should be performed only in specialized clinics with competent assistance from a bacteriologist.

Aged↗
PubMed2000

[Therapy of bacterial knee joint infection by radical synovectomy and implantation of a cemented stabilized knee joint endoprosthesis].

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.

Adult↗
PubMed2000

Gallbladder ejection fraction: correlation of scintigraphic and ultrasonographic techniques.

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.

Abdominal Pain↗
PubMed2000

Chest wall recurrence of breast cancer detected by scintimammography.

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.

Breast Neoplasms↗
PubMed2000

Trans-abdominal monitoring of fetal arterial blood oxygenation using pulse oximetry.

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.

Abdomen↗
PubMed2000

The effect of a cholecystokinin agonist on masseter muscle activity in the cat.

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.

Animals↗
PubMed2000

Does performing image registration and subtraction in ictal brain SPECT help localize neocortical seizures?

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.

Adult↗
PubMed1999

Neurokinin-1 expression and co-localization with glutamate and GABA in the hypothalamus of the cat.

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.

Animals↗
PubMed1999

[Rare indication for a simple hip prosthesis with an extra-large femoral head following multiple failed exchange operations].

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.

Aged↗
PubMed1999

Neuropharmacology of brain-stimulation-evoked aggression.

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.

Aggression↗
PubMed1999

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?

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.

Antigens, Bacterial↗