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Biomedical subjects

M Hauser

Publications and source records attributed to M Hauser.

At least 109 records · Page 6Linked to original sources
PubMed1996

Care of central venous catheters for total parenteral nutrition.

This report summarizes data obtained via a mailed questionnaire from 129 Department of Veterans Affairs (VA) hospitals regarding current practices in the care of central venous catheters (CVCs) used for total parenteral nutrition (TPN). The size of VA hospitals' acute medical-surgical beds ranged from 14 to 1320 (median 168) beds. Over 6000 patients annually received CVCs for TPN. Hospitals reported using triple-lumen catheters most frequently as their CVC for TPN (80.3%). A povidone-iodine scrub was used to prepare the skin for CVC insertion by 72.6% of reporting hospitals. Sixty percent of hospitals used transparent polyurethane dressings. Care of CVCs varied among hospitals. Catheter-related infection and sepsis rates were within the national average, although < 50% of responding hospitals provided data on these outcomes. The results of this survey point to the need for a national standardized database relative to patients receiving TPN via a CVC.

Bandages↗
PubMed1995

Processing of complex sounds in the macaque nonprimary auditory cortex.

Neurons in the superior temporal gyrus of anesthetized rhesus monkeys were exposed to complex acoustic stimuli. Bandpassed noise bursts with defined center frequencies evoked responses that were greatly enhanced over those evoked by pure tones. This finding led to the discovery of at least one new cochleotopic area in the lateral belt of the nonprimary auditory cortex. The best center frequencies of neurons varied along a rostrocaudal axis, and the best bandwidths of the noise bursts varied along a mediolateral axis. When digitized monkey calls were used as stimuli, many neurons showed a preference for some calls over others. Manipulation of the calls' frequency structure and playback of separate components revealed different types of spectral integration. The lateral areas of the monkey auditory cortex appear to be part of a hierarchical sequence in which neurons prefer increasingly complex stimuli and may form an important stage in the preprocessing of communication sounds.

Acoustic Stimulation↗
PubMed1995

Bilateral solid multifocal intrarenal and perirenal lesions: differentiation with ultrasonography, computed tomography and magnetic resonance imaging.

The differential diagnosis of bilateral solid multifocal intrarenal and perirenal lesions includes neoplastic, infiltrative, inflammatory, and vascular disorders. In a retrospective study 560 solid lesions were examined with cross-sectional imaging modalities (computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI). The results suggest that focal inflammatory disease can often be recognized because the lesions are poorly defined and may show a rather characteristic peripheral rim enhancement following the administration of intravenous contrast. Angiomyolipomas can be accurately diagnosed with CT, MR and US imaging. Because of their unique histomorphology they show fat-equivalent attenuation values at CT, hyperintense signal on T1 and hypointense signal on T2-weighted MR images, and appear homogeneous and hyperchoic with smooth margins at US. By the radiologic appearance alone renal metastases cannot be distinguished from lymphoma or renal cell carcinoma or adenoma. However, when multiple bilateral solid intrarenal or perirenal lesions are found with synchronous metastatic involvement of other organs or occur in the setting of a known primary tumour, the diagnosis of renal metastases is very likely. In the absence of these additional findings, malignant lymphoma has a higher probability. Infiltration of perinephric fat and thickening of the perinephric fascia may occur in inflammatory disease and lymphoma. CT remains the most suitable imaging technique to screen for these additional perirenal and extrarenal findings because of ready availability and relatively short scanning time as compared to MR imaging.

Adult↗
PubMed1995

Real-time biplanar needle tracking for interventional MR imaging procedures.

PURPOSE: To evaluate real-time biplanar tracking of a specially designed needle with magnetic resonance (MR) imaging guidance. MATERIALS AND METHODS: The needle is made of polyetheretherketone and has a miniature radio-frequency coil incorporated into the tip. Tracking software on two workstations is used to compute three-dimensional coordinates of the coil and to display the position as a moving symbol in two imaging planes. Validation of needle tracking was performed in a harvested human liver. T2-weighted fast spin-echo images were used to target a 1-cm cyst. Success of needle placement was confirmed with aspiration and with updated gradient-recalled-echo images. RESULTS: The cyst was successfully targeted from different approaches. Tracking procedures were monitored in real time simultaneously on two separate images. CONCLUSION: Real-time biplanar needle tracking may prove to be useful for both diagnostic and therapeutic interventional MR imaging procedures.

Artifacts↗
PubMed1995

Management of congenital angiodysplasia of the lower limb: magnetic resonance imaging and angiography versus conventional angiography.

The purpose of the study was to compare magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) with conventional angiography in distinguishing congenital angiodysplasia amenable to radical cure from that in which only palliation is feasible and to design a rational pre-operative work-up in those patients undergoing an interventional procedure. Axial T1, T2 weighted spin-echo and contrast-enhanced 3D SPGR sequences were performed in 13 patients with angiodysplasia, followed by time-of-flight MRA. The results were compared with conventional arteriography and venography. Dysplasia was arteriovenous with microshunts in nine cases and purely venous in the remaining four. MRI was the best method for assessing the extent of malformation and involvement of anatomical structures. MR arteriography and MR venography were inferior to conventional techniques. It is concluded that MRI is valuable in distinguishing patients amenable to radical cure from those in whom only palliation is feasible. Pre-operatively, conventional arteriography and venography remain mandatory.

Adolescent↗
PubMed1995

The ups and downs of managing employed physicians.

The number of employed physicians is growing, posing new challenges to physician executives. Managing employed physicians begins during the hiring process. Once the new physician is on board, an organization should appoint a mentor to help the new employee adjust. Compensation remains a consistent challenge in most organizations with employed physicians. One of the most popular compensation models involves a market-based salary with the opportunity for a performance bonus.

Adaptation, Psychological↗
PubMed1994

[Fat-suppressed MR imaging sequences in the diagnosis of liver and pancreatic neoplasms at 1.5 tesla].

We investigated 55 patients with suspected neoplasms of the liver and/or pancreas using fat-suppressed spin echo and gradient echo MR sequences. T1 and T2 weighted fat-suppressed spin echo sequences provided higher sensitivity for the detection of liver metastases. In the diagnosis of pancreatic tumours, T1 weighted fat-suppressed gradient echo sequences after application of intravenous and oral paramagnetic contrast agents offered more information than other sequences. Drawbacks of fat-suppressed sequences are an increase in scan time and inhomogeneous fat-suppression at the periphery of the image.

Adipose Tissue↗
PubMed1993

[Functional therapy of Achilles tendon rupture].

We are going to present two cases with functional treatment of Achilles tendon ruptures. We define a treatment as functional if the involved limb is either not immobilized at all or whenever the immobilization is incomplete and for a limited time only and when no operation is necessary. The functional treatment is presented as an alternative, and we are going to present the advantage and disadvantage.

Achilles Tendon↗
PubMed1993

[New pathophysiologic and functional viewpoints about the insufficiency of the vena saphena parva. Preliminary report].

Insufficiency of the subfascial short saphenous vein is a distinct clinical entity and commonly associated with deep venous insufficiency. There is a high incidence of postoperative recurrence despite established surgical therapy. Preoperative imaging in 21 patients by means of ascending and descending venography as well as color doppler and color duplex sonography revealed a concomitant deep popliteo-femoral venous insufficiency in 86% of cases. The sensitivity of non-invasive color encoded sonography was comparable to phlebography. Pathophysiologically, the association of deep venous and short saphenous insufficiency can be explained as being the result of primary or secondary (postthrombotic) valve dysfunction of the deep venous system. This is different from the findings in patients with great saphenous vein insufficiency. Surgical consequences are ligation of the vein directly at the level of the sapheno-popliteal junction without leaving a short saphenous stump, and the obligation to inform the patient about the high risk for postoperative recurrence.

Adult↗
PubMed1993

[Proximo-distal course of the diameter of the great saphenous vein and distribution of the number of side branches as an inherent difficulty in infra-inguinal arterial in situ bypass].

The greater saphenous vein is still the best material for infrainguinal arterial bypasses, particularly if they have an infrapopliteal distal anastomosis. Although a lot of advantages have been presumed for the in-situ bypass, the reported results are not significantly better than with the reversed technique. To find some additional explanations, we studied post mortem the anatomy of 20 greater saphenous veins with regard to the diameter and the number of side branches and compared the results with 10 phlebographies. A minimal diameter (2.6 mm) and a maximum of side branches and venous valves were found at the proximal calf. Furthermore, this region was characterized by a lot of anatomic variants such as double systems (25%) or cross over variants (5%). These findings are surgically relevant and may reduce the bypass patency: 1. There is an increased hemodynamic resistance in longer bypasses, 2. The small diameter (particularly if smaller than 2 mm) means a risk for the patency of the distal anastomosis, 3. The high frequency of side branches requires a comparable exposition of the GSV as for the reversed technique, 4. The introduction of the valvulotomy from distally may overestimate the proximal diameter and underestimate the frequency of variants and may therefore cause significant endothelial damages or even perforation.

Humans↗
PubMed1992

The timing of partial sleep deprivation in depression.

In 26 major depressed and 4 schizoaffective inpatients (according to the RDC) early and late partial sleep deprivation (PSD) were carried out. For most of the patients (N = 25) this was done in a balanced crossover design. Residual sleep, starting at 21:00 or 2:00 respectively, was recorded polygraphically. Total sleep time was held constant between the 2 conditions (168 +/- 46 min in early sleep, 173 +/- 28 min in late sleep). Mood ratings with 5 different measures on the 2 days following each PSD revealed significant therapeutic effects from both procedures with only minor differences between them. Thus, sleep reduction as such and not the time at which it takes place (first or second half of the night) appears to be the therapeutic agent in PSD.

Adult↗
PubMed1992

[Magnetic resonance tomography and magnetic resonance angiography in lymphangiomatosis].

Generalised lymphangiomatosis is a rare benign congenital abnormality of the lymphatic vessels with a complex pattern. 3 patients with different types of lymphangiomatosis were studied by MRT and MRA and histopathologically. All patients had multiple organ involvement in the abdomen, the skeleton and the skull. The basis in each case was lymphangiomatosis of capillary-cavernous, cystic or cavernous type. The results of MRT and MRA in diagnosing splenic, vascular and skeletal changes correlated accurately with operative findings and with the histopathological classification. In summary, MRT combined with MRA and using paramagnetic contrast media are the diagnostic methods of choice for the investigation of generalised lymphangiomatosis with multiple organ involvement.

Abdomen↗