Search PubMed⌕ Search

Biomedical subjects

W Hirsch

Publications and source records attributed to W Hirsch.

At least 19 recordsLinked to original sources
PubMed2006

Congenital oesophageal atresia discordant for tracheo-oesophageal fistula occurring in a set of dizygotic twins.

The authors present a set of female diamnionic and dichorionic twins with different blood types and congenital oesophageal atresia (EA) in both. Surgical management was successful. It can be assumed that EA with tracheo-oesophageal fistula in twin B occurred during an early embryological stage whereas the isolated EA in twin A was the result of a later event. To our knowledge, this is the first published set of dizygotic twins with different types of EA.

Diseases in Twins↗
PubMed2005

Pediatric MR-guided interventions.

MRI guided interventions are a relatively new but steadily growing field within surgery in pediatric age. Besides the advantages of MRI, such as multiplanar capability and excellent soft tissue contrast and spatial resolution, particularly relevant for the pediatric population is the lack of ionizing radiation. There is meanwhile a group of well defined diagnostic or therapeutic indications for applying MR imaging during pediatric interventions. Aim of this review is to give an overview about indications of MR-guided procedures in children as well as the advantages and disadvantages of MR-guided interventions. We also briefly discuss interventional MR-systems and MR-compatible devices. It is our opinion that MR-guidance for pediatric interventions is a promising technique at the beginning of its development.

Child↗
PubMed2003

[MRI-guided pediatric interventions].

AIM: There are only a few diagnostic or therapeutic procedures where MR imaging is applied during pediatric interventions. This study will describe indications, complications as well as the advantages and disadvantages of MRI-guided interventions based on a case study in an open MRI scanner. MATERIALS AND METHODS: 14 procedures were performed in an open MRI scanner (Signa SP/i, GEMS) on 13 children (1 - 16 yr) with bone, soft tissue and brain lesions (1 - 4 cm diameter). Localization of the pathology, targeting and final control of the result were based on images acquired with SE-, 3D-, GE-sequences pre- and post-contrast as well as FSE-sequences. Interactive MRI-guided instrument navigation was performed using a multiplanar T1w GE-sequence. RESULTS: Eight biopsies (incl. 1 rebiopsy), two tumor resections, one removal of a free joint mouse and three tumor-markings were performed without complications. Five biopsies provided appropriate sample quality for a histological diagnosis while two samples were too fragmented requiring a second biopsy (one of them MRI-guided). Surgical progress during tumor resection and marking could be controlled during the intervention without repositioning the patient. DISCUSSION: MR image guided pediatric interventions combine the advantage of an imaging system without ionizing radiation and the high soft-tissue contrast. The low number of these kinds of procedures can be explained by the relatively high costs for the intervention, the increased duration for each procedure and the limited availability of open MRI systems. The integrated localization-system helps during planning of the access path when facing complex anatomical structures and provides safe navigation in sensitive regions like the epiphyseal cartilage. Recent and expected developments of the required MR-compatible biopsy instruments could provide higher efficiency for appropriate sample size and quality. Summarizing, MRI-guided pediatric interventions have shown to be a promising method at the beginning of its development.

Adolescent↗
PubMed2003

Importance of F18-fluorodeoxy-D-2-glucose positron emission tomography (FDG-PET) for staging and therapy control of Hodgkin's lymphoma in childhood and adolescence - consequences for the GPOH-HD 2003 protocol.

The prognosis for children and adolescents with Hodgkin's lymphoma is excellent. However, many patients will show secondary malignancies 15-30 years after the initial diagnosis, which appears to be connected with the intensity of treatment during primary disease. In the GPOH-HD 95 trial, the indication for radiotherapy was limited to patients who did not show a complete remission after chemotherapy, as determined radiographically. In the future protocol, the indication for radiotherapy in patients with early-stage Hodgkin's lymphoma should be further refined by using FDG-PET for evaluating the response to chemotherapy. Furthermore, in patients at an advanced stage of the disease, it should be determined if sequential FDG-PET research during chemotherapy can separate patients into subgroups with an excellent or a poor prognosis. This article gives a review of the current literature on FDG-PET in patients with Hodgkin's lymphoma and outlines the consequences for future protocols.

Adolescent↗
PubMed2002

Unusual presentation of central nervous system relapse with oculomotor nerve palsy in a case of CD56-positive acute myeloid leukemia following allogeneic stem cell transplantation.

Allogeneic stem cell transplantation (allo-SCT) plays an important role in the treatment of infants and children with acute myelogenous leukemia (AML). Leukemic relapse after allo-SCT is responsible for a high rate of treatment failure. Extra-medullary relapse (EMR), without involvement of bone marrow, is rare compared to medullary relapse. CD56, the neural cell adhesion molecule, may contribute to the higher frequency of CNS relapse in CD56-positive AML. We observed an isolated EMR on the oculomotor nerve of a 17-month-old girl 12 weeks after cord blood transplantation (CBT), who was transplanted because of CD56-positive AML. Diagnosis of relapse was suspected clinically and confirmed by magnetic resonance imaging (MRI), and fluorescence-activated cell sorter (FACS) and chimerism analysis of cerebrospinal fluid (CSF). Therapy consisted of intra-thecal chemotherapy, CNS irradiation, and systemic immunomodulation by cyclosporin A (CsA) and basiliximab withdrawal. Twenty-one months after relapse, the patient shows full remission of symptoms and previously described oculomotor nerve infiltration.

CD56 Antigen↗
PubMed2001

[MR angiography in diagnosis of vasculitis and benign angiopathies of the central nervous system].

PURPOSE: To evaluate TOF 3D magnetic resonance angiography (MRA) of the intracranial arteries in patients with vasculitis or vasculitis-like benign angiopathy of the central nervous system (CNS). METHOD: The results of MRA in 20 patients with clinically and radiographically proven vasculitis (17/20) or vasculitis-like benign angiopathy (3/20) of the CNS were retrospectively analysed. Patients with hyperintense lesions of more than 3 mm on T2-weighted MRI images were included in this trial. An inflammatory, embolic, neurodegenerative or metastatic origin of these lesions was excluded by extensive clinical studies. For the MR-examination a TOF 3D FISP sequence was used on a 1.5 T imager. RESULTS: MRA showed characteristic changes for vasculitis or angiopathy in 15 of 20 patients (75%). CONCLUSIONS: In patients suspected of having a vasculitis or vasculitis-like angiopathy, MRA is recommended as a non-invasive modality. If the results of MRI and extensive clinical studies are carefully correlated, MRA may substitute conventional angiography in cases with typical vascular changes.

Adolescent↗
PubMed2000

Reliability of cranial CT versus intracerebral pressure measurement for the evaluation of generalised cerebral oedema in children.

OBJECTIVE: To examine the extent to which intracranial pressure (ICP) in children after severe brain trauma can be determined by cranial CT. MATERIALS AND METHODS: Two experienced paediatric radiologists, without any knowledge of the clinical symptoms, evaluated 124 CT scans from 65 children (average age 5.4 years) who underwent intracranial measurement of their cerebral pressure. RESULTS: CT had high sensitivity (99.1%) for 'high cerebral pressure' but a much lower specificity (78.1%). The examiners tended to estimate ICP as 'high' even when actual ICP was low. Since therapy for lowering cerebral pressure involves potential risks, actual cerebral pressure measurement, particularly in children, should be considered before intervention (e.g. hyperventilation or trepanation). We report the change in different intracerebral fluid compartments with varying cerebral pressure and modifications of the density of the brain tissue in an inter- and intraobserver comparison. CONCLUSION: The radiologist cannot differentiate, for methodological reasons, between a change in the intracranial fluid compartments not associated with a change in ICP and one in which it is critically elevated. Before any interventional treatments such as decompression-trepanation or hyperventilation are instituted, measurement of ICP should be considered, especially in children.

Brain Edema↗
PubMed1998

Phenylglyoxylate:NAD+ oxidoreductase (CoA benzoylating), a new enzyme of anaerobic phenylalanine metabolism in the denitrifying bacterium Azoarcus evansii.

Phenylglyoxylate (benzoylformate) is an intermediate in the anoxic metabolism of phenylalanine and phenylacetate. It is formed by alpha-oxidation of phenylacetyl-CoA. Phenylglyoxylate is oxidatively decarboxylated by phenylglyoxylate-oxidoreductase to benzoyl-CoA, a central intermediate of anaerobic aromatic metabolism. The phenylglyoxylate oxidizing enzyme activity in the denitrifying bacterium Azoarcus evansii was induced during anaerobic growth with phenylalanine, phenylacetate and phenylglyoxylate, but not with benzoate. The new enzyme phenylglyoxylate:acceptor oxidoreductase was purified and studied. The oxygen-sensitive enzyme reduced both NAD+ and viologen dyes. It was composed of five subunits of approximately 50, 48, 43, 24, and 11.5 kDa; the native mass as determined by gel filtration was 370 kDa, suggesting an alpha2 beta2 gamma2 delta2 epsilon2 composition. Phenylglyoxylate:acceptor oxidoreductase exhibited an ultraviolet/visible spectrum characteristic for an iron-sulfur protein and contained 35 +/- 4 mol Fe, 36 +/- 4 mol acid-labile sulfur, and 1.1 +/- 0.2 mol FAD/mol. The enzyme was specific for phenylglyoxylate (Km 45 microM) and coenzyme A (Km 55 microM); 2-oxoisovalerate was oxidized with 15% of the rate. The turnover number with benzyl viologen at 37 degrees C was 46 s(-1) at the optimal pH of 8. The enzyme catalyzed a NAD(P)H:viologen dye transhydrogenation reaction, NAD(H) being the preferred coenzyme. It also catalyzed an isotope exchange between CO2 and the carboxyl group of the substrate. The data are consistent with the following hypothesis. The enzyme complex consists of a core enzyme of four subunits with the composition alpha2 beta2 gamma2 delta2, as reported for archaeal 2-oxoacid:ferredoxin oxidoreductases; this complex is able to reduce viologen dyes. The holoenzyme contains in addition an epsilon2 unit that catalyzes the transfer of electrons from a small ferredoxin-like subunit of the core complex to NAD+; this unit also catalyzes the transhydrogenase reaction, carries FAD and resembles ferredoxin:NAD(P)+-oxidoreductase.

Amino Acid Sequence↗
PubMed1996

Color doppler in the diagnosis of the gastroesophageal reflux in children: comparison with pH measurements and B-mode ultrasound.

Eighty-four high risk children were examined for suspected gastroesophageal reflux comparing 24-h esophageal pH measurements with ultrasound (US) scans with and without the use of color Doppler (CD). In 83.3 % of the patients there was unequivocal agreement (reflux or no reflux) among all three techniques; 60.7 % of the children showed reflux by pH-metry as compared to 51.2 % by B-mode US and 59.5 % by CD US. In 87 % of patients there was agreement between pH-metry and B-mode US as compared to 94 % between pH-metry and CD US. The sensitivity of reflux detection increased from 84.4 % to 98 % when CD was added to B-mode US. This improvement was thought to be due to the higher sensitivity of CD for rapid and small quantities of reflux. The small number of discrepancies between pH-metry and CD US is probably due to the inability of the former to detect neutral reflux of contents or short duration (< 30 s), while CD US may miss some cases of acid reflux due to the short time of the examination (10 min). The addition of CD increases the sensitivity of US for detecting reflux. This rapid, easy and reliable method can be used to screen high risk populations when reflux is thought to be the cause of respiratory symptoms.

Child↗
PubMed1995

Acute disseminated encephalomyelitis (ADEM) or ADEM-like inflammatory changes in a heart-lung transplant recipient: a case report.

Acute disseminated encephalomyelitis (ADEM) is a white matter inflammatory disease which usually follows a viral infection or pharmaceutical intervention. We describe a case of presumed ADEM in a heart/lung transplant patient, the etiology of which cannot be elucidated. The fascinating aspect is the mode of clinical presentation and the rapid resolution of radiologic abnormalities. Histologic examination of the brain is provided in an attempt to elucidate the radiographic abnormalities.

Adult↗
PubMed1995

Clinical significance of technetium-99m methylene diphosphonate myocardial uptake: association with carcinoma of the prostate.

Benign myocardial uptake of technetium-99m labelled phosphates, not related to cardiac or metabolic disorders, has been documented except in the case of 99mTc-methylene diphosphonate (MDP). The aim of this study was to assess the frequency of myocardial uptake and its possible association with malignant tumours in general and prostatic carcinoma in particular. We reviewed bone scintigrams performed with either 99mTc-hydroxydiphosphonate (HDP) or 99mTc-MDP over a period of more than 2 years for all patients with prostatic carcinoma and a matching group of patients suffering from other malignant and non-malignant disorders. A total of 965 scintigrams of 812 patients (males = 559, females = 253; age range 50-91 years, average age 69.2 years) were reviewed. Increased myocardial uptake was detected in 19 scintigrams (MDP = 13, HDP = 6) of 18 patients (17 males, one female). Most of the male patients with increased myocardial uptake had prostatic carcinoma (13/17) and were over 80 years of age (12/17). All patients were free of any cardiac or noncardiac disorder that might account for such uptake. When scintigraphy was repeated in the same patient, the uptake of 99mTc-HDP was more diffuse and of higher grade than that of 99mTc-MDP. "Benign" myocardial uptake of 99mTc-MDP is more common than previously thought. Although uptake of radiophosphates is attributed to asymptomatic atherosclerotic changes associated with old age, a strong association with prostatic carcinoma exists which may indicate variations in the bone: soft tissue affinity of different MDP complexes.

Aged↗
PubMed1995

Colour DOPPLER image analysis for tissue vascularity and perfusion: a preliminary clinical evaluation.

An automated system for measuring features of colour Doppler (CD) images has been examined for its ability to measure tissue perfusion in vivo under conditions of diffuse vascularity. Seven statistical features were extracted from CD images of human calf muscle and compared with the arterial input measured by plethysmography. It was found that, when appropriate scanning procedures are employed, good correlation is achieved with arterial input (r = 0.96 to 0.99). Ultrasound beam angle was important, even for the assessment of "colour area." A sensitive velocity scale was ideal for "percentage colour" (r = 0.979). "Mean colour velocity" correlates well with arterial input (r = 0.979) when the volocity scale was optimised for each CD scan. "Integrated colour velocity per unit area" was more responsive when using a variable velocity scale (r = 0.99) than a fixed velocity scale (r = 0.98), but was less responsive to low flow. Automated CD analysis speeds up the process of quantitative assessment of tissue vasculature and perfusion. It is therefore essential for the analysis of dynamic studies of ultrasound contrast agents and serial examinations when monitoring response to therapy.

Arteries↗
PubMed1992

Brain morphologic characteristics of cirrhotic alcoholics and cirrhotic nonalcoholics: an MRI study.

Cirrhotic alcoholics, cirrhotic nonalcoholics, and normal controls were compared on planimetric and subjective ratings of the MRI of the brain. The results indicated that the cirrhotic alcoholics exhibited more gross pathology than the nonalcoholic cirrhotics on ratings of frontal, parietal, and cerebellar atrophy; however, these groups were more similar to each other than they were different on planimetric measurements. The results are discussed in terms of the etiology and localization of the neuropathologic sequelae found commonly among alcoholics.

Adult↗
PubMed1991

Correlative angiographic and pathologic findings in the diagnosis of ulcerated plaques in the carotid artery.

We determined the accuracy of angiography in the diagnosis of internal carotid ulcers by comparing the angiographic reports with the pathologic findings in 36 endarterectomy specimens. Eighteen of these specimens had microscopic ulcerations, and the observer with the highest accuracy rate read 12, of which ten were ulcerated. These results revealed a sensitivity of 56%, a specificity of 89%, and an overall accuracy of 61% for angiography. The ulcers were classified into types A, B, and C to assess the interobserver agreement rate among three readers. This resulted in a 4% interobserver agreement among a total of 75 ulcers. Because of the high interobserver disagreement and the poor correlation between angiographic and pathologic findings in the surgical specimens, we conclude that the diagnosis of carotid artery ulceration by angiography is not reliable.

Angiography↗
PubMed1991

Postoperative computed tomographic evaluation of patients with large pituitary tumors treated with operative decompression and radiation therapy.

Thirty consecutive patients who underwent operative decompression and radiation therapy for large sellar and suprasellar pituitary tumors (greater than or equal to 2 cm) were studied in terms of the serial computed tomographic (CT) changes. There were 23 men and 7 women. The mean age was 49.6 +/- 2.5 years, and the mean follow-up was 45.3 +/- 3.9 months. Twenty-eight of the 30 patients had transsphenoidal surgery, and 27 had hormonally inactive tumors. Radiation therapy was begun within 1 month of surgery with a mean dose of 4855 +/- 70 cGy. Postoperative CT scans were obtained within 1 month of surgery and at 6- to 12-month intervals thereafter. Fourteen patients (45%) had no suprasellar tumor visualized in either the early postoperative CT scans or on subsequent scans. Eleven patients (35%) had a persistent suprasellar mass during the early postoperative period that resolved on serial CT evaluation. The mean time for resolution was 10.4 +/- 1.2 months. Six patients (20%) had a persistent suprasellar mass on serial CT evaluation. A persistent postoperative mass that subsequently resolved in many of the patients was thought to be caused by the gradual retraction of the postoperative packing and hematoma, as well as the effect of radiation on any residual tumor.

Combined Modality Therapy↗