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Biomedical subjects

M Rausch

Publications and source records attributed to M Rausch.

30 records · Page 2Linked to original sources
PubMed1996

Visualization of lCBF changes during cortical infarction using IR thermo-encephaloscopy.

Infrared thermo-encephaloscopy (IR-TE) was used for two-dimensional imaging of local cortical blood flow (lCBF) with high spatio-temporal resolution. The basis of this method is the transfer of thermal energy from circulating blood to cortical tissue depending on local perfusion. Temperature fields that emerge from differences in lCBF can be measured with a high resolution thermo-scanner. Infarctions 2 mm in diameter were produced by photochemically induced thrombosis and IR-TE was used to visualize lCBF changes in and around the focal infarction. The infarcted region was characterized by a lower temperature (0.1-0.3 K) than that of the surrounding tissue. In addition to the visualization of persistent blood flow changes it was possible to detect dynamic lCBF changes that might correlate with long-lasting hyperaemia and episodes of cortical spreading depression (SD).

Animals↗
PubMed1996

Radiological modalities in the staging of colorectal tumors: new perspectives for increasing accuracy.

The purpose of this study was to evaluate the diagnostic accuracy of contrast-enhanced endorectal MRI for the staging of rectal adenoma versus rectal carcinoma in correlation to findings from biopsy and histopathology. Ten volunteers and 20 patients underwent body-coil and endorectal MRI (1.5T supraconducting unit) using plain, T1-weighted (w) T2-w SE and TSE-w sequences, a dynamic Gd-DTPA enhanced protocol (turboFLASH), and postcontrast T1-w-SE sequences. Histopathological correlation via biopsy (n = 10) and surgical resection (n = 19) were conducted for all patients. An independent, two-observer, reader evaluation was performed and qualitative and quantitative data calculated. In volunteers and all patients endorectal MRI reliably delineated normal wall layers. Rectal adenomas (n = 7) were identified by a visualization of an intact muscularis mucosae, a homogeneous inner structure, and a significant contrast enhancement. T1 carcinomas (n = 4) were best identified in dynamic turboFLASH sequences by delineation of an intact muscularis propria. The visualization of contrast-enhancing tumor tissue was indicative of a T2 carcinoma (n = 4). All T3 (n = 3) and T4 (n = 2) carcinomas were correctly staged on dynamic and static MRI. The endorectal MRI stage agreed with the staging results from pathological study in 16 of 20 (80%) patients. Endorectal surface coil MRI provides reliable data for the preoperative staging and evaluation of rectal lesions.

Adult↗
PubMed1996

Hyper-immunoglobulin G2 production by B cells from patients with localized juvenile periodontitis and its regulation by monocytes.

Localized juvenile periodontitis (LJP) runs in families, and a predisposition to develop disease appears to be inherited in an autosomal dominant fashion. Patients with LJP have elevated levels of serum immunoglobulin G2 (IgG2), and this is most striking in black LJP patients. We hypothesized that the markedly elevated serum IgG2 levels related to LJP status and race may be attributable to a fundamental difference in the response of black LJP leukocytes. To test this possibility, leukocytes from black LJP patients, black non-periodontitis (NP) controls, and white NP controls were cultured with a nonspecific mitogen (pokeweed mitogen) which stimulates immunoglobulin production. The levels of IgG2 produced were measured using an enzyme-linked immunosorbent assay. The results revealed that the serum IgG2 level differences among black LJP patients and white and black NP subjects were reproducible in peripheral blood leukocytes in vitro. Analysis revealed that B cells from the LJP patients appeared to be predisposed to produce high levels of IgG2. Further analysis supported the concept that the high IgG2 responses of B cells from black LJP patients were regulated by monocytes. Replacing the monocytes in cultures from white NP subjects with LJP monocytes from black patients resulted in production of IgG2 at levels that were comparable with those produced by the LJP B cells from black patients. In short, B cells from black LJP patients produce elevated levels of IgG2 in vitro, and at least part of this elevation appears to be attributable to regulation via the LJP monocytes.

Adult↗
PubMed1995

[CT angiography in carotid stenosis. Diagnostic value compared to color-coded duplex ultrasonography and MR angiography].

PURPOSE: To evaluate the accuracy of different diagnostic methods for the visualization of the carotid arteries and their pathological changes in order to avoid invasive angiography whenever surgery was considered. MATERIAL AND METHODS: 24 patients with clinically suspected stenosis or occlusion of the carotid arteries were prospectively examined via CT angiography. MR angiography and colour-coded duplex sonography (ccds) to evaluate the degree of stenosis and the extent of calcification. RESULTS: In 36 cases stenoses of different extent could be documented with CT angiography, 33 cases were found using colour-coded duplex sonography and MRA. Sonography could not prove mild stenoses (< 30%), and in two patients with sonographically suspected total occlusion vessel perfusion was documented via CT angiography. MR angiography led to a overestimation in patients with high-grade stenosis compared to the degree of stenosis obtained via ccds and CTA. With regard to the diagnosis of calcification MIP, reconstructions after CT examination showed best correlation to the plain CT slices referring to length (94.6%) and thickness (89.2%). CONCLUSION: CTA with MIP reconstructions is an excellent screening method and, in combination with ccds, CT angiography may replace DSA before surgery or intervention.

Aged↗
PubMed1994

[Color-coded duplex sonography in the differential diagnosis of cervical lymph node enlargements].

55 patients with cervical lymph node enlargement were studied prospectively by colour coded duplex sonography. The aim was to demonstrate the perfusion of individual lymph nodes and to determine whether the resistance and pulsatile index are able to show the cause of the enlargement. The lymph nodes were subsequently examined histologically. Useful perfusion measurements were obtained in 177 lymph nodes out of 216. Perfusion index < 1.6 and resistance index < 0.8 distinguishes between reactive lymph node enlargement and lymph node metastases with an accuracy of 91%. Reliable differentiation between lymphoma and metastases was not possible. Tuberculous lymph nodes and cysts showed significantly reduced resistance and pulsatile index when compared with metastases. Further information on the type of disease was obtained from the perfusion patterns. Reactive lymph nodes showed increased central perfusion of the hilum, whereas metastases tended to show increased peripheral perfusion.

Diagnosis, Differential↗
PubMed1993

Modified therapy with 5-fluorouracil, doxorubicin, and methotrexate in advanced gastric cancer.

BACKGROUND: In an attempt to decrease the toxic effects of fluorouracil, doxorubicin, and methotrexate (FAMTX) by reducing the dose of methotrexate from 1500 mg/m2, according to the original regimen, to 1000 mg/m2, the authors designed the modified FAMTX treatment that was evaluated in a prospective Phase II-III randomized trial. METHODS: Patients with advanced gastric cancer were randomized to receive modified FAMTX treatment or supportive measures only (control group). In the middle of the study, the randomization was interrupted because of strong evidence of benefit in terms of tumor reduction and projected survival in the treatment arm receiving chemotherapy. By the end of the study, 30 assessable patients had received chemotherapy and 10 had received supportive treatment. RESULTS: The overall response rate was 50% (15 patients); 12 patients (40%) had partial responses and 3 (10%) had complete responses (CR). One patient with extensive peritoneal carcinomatosis attained a CR pathologically documented by laparoscopic examination and peritoneal biopsy. The median overall survival time of the treated group was 9 months, whereas that of the control group was only 3 months (P = 0.001). The median overall survival time of the responders was 16 months, and their median remission duration was 8 months. The regimen was well tolerated, with a very acceptable toxicity profile. There was one toxic death resulting from neutropenia and sepsis in a patient who did not receive adequate leucovorin rescue. CONCLUSIONS: This regimen appears to prolong survival in patients with advanced gastric cancer, and the reduction of the methotrexate dose does not seem to compromise its efficacy.

Adult↗
PubMedDate not supplied

Orientation-specific relationship between populations of excitatory and inhibitory lateral connections in the visual cortex of the cat.

The topography of lateral excitatory and lateral inhibitory connections was studied in relation to orientation maps obtained in areas 17 and 18. Small iontophoretic injections of biocytin were delivered to the superficial layers in regions where orientation selectivity had been mapped using electrode recordings of single- and multi-unit activity from various cortical depths. Biocytin revealed extensive patchy axonal projections of up to 3.5 mm in both areas while labelled somata occurred chiefly at the injection site, indicating that the labelling was primarily anterograde. Two types of boutons could be clearly distinguished: (i) putative excitatory boutons either en passant or having a short stalk and (ii) inhibitory boutons which were invariably of the basket-type. Three-dimensional reconstructions of all labelled boutons showed that the excitatory and the inhibitory networks had a distinctively different relationship to orientation maps. The overall distribution of connections showed that 53-59% of excitatory and 46-48% of inhibitory connections were at iso-orientation, +/-30 degrees; oblique-orientation, +/-(30-60) degrees, was shown by 30% of excitatory and 28-39% of inhibitory connections; cross-orientation was shown by 11-17% of excitatory and 15-24% of inhibitory connections. Although excitatory patches occupied mainly iso-orientation locations, interpatch regions representing chiefly non-iso-orientations (oblique + cross orientation) were also innervated. There was considerable overlap between the excitatory and inhibitory network. Nonetheless, inhibitory connections were more common than excitatory connections with non-iso-orientation locations. There was no significant difference between the orientation topography of area 17 and area 18 projections. The results suggest that in general the lateral connectivity system is not orientation specific, but shows a moderate iso-orientation preference for excitation and an even weaker iso-orientation preference for inhibition. The broad orientation spectrum of lateral connections could provide the basis for mechanisms that requiring different orientations, as for example in detecting orientation discontinuities.

Animals↗
PubMedDate not supplied

Management of the patient with sickle cell disease.

Sickle cell disease is a group of genetic disorders of hemoglobin synthesis, of which sickle cell anemia is the most severe. In the United States, sickle cell disease primarily affects persons of African-American and Hispanic origin. An estimated 50,000 Americans have the disease, and approximately 2.5 million persons carry the sickle cell trait. The primary pathophysiologic features are chronic hemolysis and vaso-occlusion. This disease is recurrent and unpredictable, causing considerable physiologic and psychologic stress. This article provides an overview of the disease and addresses the role of the infusion nurse in the care and support of the patient with sickle cell disease in the hospital and home setting.

Anemia, Sickle Cell↗