Biomedical subjects

G Jung

Publications and source records attributed to G Jung.

601 records · Page 34Linked to original sources

PubMedDate not supplied

Prospective comparison of fast SE and GRASE sequences and echo planar imaging with conventional SE sequences in the detection of focal liver lesions at 1.0 T.

PURPOSE: Our goal was to investigate the value of T2-weighted fast SE (FSE) sequences, FSE sequences with shortened echo spacing (UFSE), combined gradient and spin echo sequences (GRASE), and segmented T1-weighted echo planar imaging (EPI) in comparison with conventional SE sequences in the detection of focal liver lesions. METHOD: Thirty-five patients with malignant focal liver lesions underwent MRI at 1.0 T. RESULTS: All fast T2-weighted imaging techniques (FSE, UFSE, GRASE) showed fewer artifacts and overall better image quality than the conventional SE sequence. Quantitative analysis demonstrated that UFSE imaging had the highest tumor/liver contrast/noise ratio (C/N) (13.9 +/- 5.5) followed by FSE (12.7 +/- 4.5), T2 SE (10.9 +/- 4.2), and GRASE (10.0 +/- 4.8) sequences. The differences in C/N between the UFSE and T2 SE sequences was statistically significant (p < 0.05). C/N was significantly higher (p < 0.01) for the T1 SE (-7.4 +/- 3.8) than for the EPI sequence (-0.5 +/- 5.6). CONCLUSION: FSE sequences with shortened echo spacing are valuable for liver imaging at 1.0 T. In comparison with the T2 SE sequence, they yielded better image quality and comparable tumor/liver C/N.

Adult↗

PubMedDate not supplied

Abdominal lymphoma staging: is MR imaging with T2-weighted turbo-spin-echo sequence a diagnostic alternative to contrast-enhanced spiral CT?

PURPOSE: To evaluate the diagnostic value of MR imaging in abdominal lymphoma staging, in comparison with that of the established spiral CT, within the context of a prospective study. METHODS: 50 patients with non-Hodgkin (n = 27) and Hodgkin lymphoma (n = 23) were examined with a plain T2-weighted TSE sequence (parameters: TE 90 ms, TR >2.500 ms, slice thickness 8 mm, slice interval 0.8 mm, ETL 20, NEX 4), and with spiral CT following oral and intravenous administration of contrast agent. RESULTS: Both CT and MR imaging agreed in showing abdominal lymphomas in 34/50 cases. The size of the detected lymphomas was between 1.5-9 cm (mean: 4.3 +/-2.2 cm). In the analysis of the individual lymph node sites, CT showed involvement of the paraaortic lymph nodes in 29/50 patients, compared with 28/50 in MRI, and involvement of the portal lymph nodes in 15/50, compared with 12/50. Both techniques showed the iliac lymph nodes in 21/50 patients, the inguinal lymph nodes in 10/50, and the mesenteric lymph nodes in 11/50. Both techniques also showed focal organ lesions in 12/50 cases. CONCLUSIONS: In the staging of abdominal lymphomas, MR imaging with a T2-weighted TSE sequence can be regarded as equal to spiral CT in the detection of lymph adenopathy and the demonstration of focal organ lesions. In addition to the absence of ionizing radiation, the advantage of MR imaging is that there is no necessity for oral or intravenous administration of contrast agent.

Abdominal Neoplasms↗

PubMedDate not supplied

Solid phase peptide synthesis of lipopeptide vaccines eliciting epitope-specific B-, T-helper and T-killer cell response.

Lymphocyte subpopulations involved in the self and nonself recognition processes are antibody producing cells, T-helper cells and T-killer cells. By using lipopeptide adjuvants and lipopeptide-antigen conjugates each of the major pathways of immune response can be specifically addressed on the molecular level of minimized synthetic lipopeptide vaccines. The immunologically active principle of the lipopeptide constructs is the synthetic N-terminus of bacterial lipoprotein, tri-palmitoyl-S-glycerylcysteine, which can be covalently linked to B-, T-helper and CTL epitopes. Methods of multiple peptide synthesis based on Merrifield's solid-phase synthesis allow the economic production of the high numbers of overlapping lipopeptides required for the complete immunological screening of viral proteins.

Amino Acid Sequence↗

PubMedDate not supplied

Modifications of platelet shape change and ATP release during cardiopulmonary bypass.

Platelet activation is accompanied by characteristic morphological changes: smooth-disc platelets become more spherical in shape and develop psudopods. The purpose of this study is to investigate whether platelets change after extracorporeal bypass. Twenty-two patients undergoing cardiopulmonary bypass (CPB) were studied prior to anesthesia and immediately after the operation. Platelets activated by different agonists were monitored simultaneously for morphological changes, ATP release and aggregation. While shape change measured before surgery was large, it was significantly reduced after bypass surgery (p < 0.01); morphological changes were quicker postoperatively. Several other parameters also changed: the time lapse between administration of the agonist and the start of ATP secretion decrease significantly (p < 0.01). After activation with high concentrations of ADP, ATP release was significantly increased (p < 0.01). On the other hand, less ATP was released after platelet activation with collagen and arachidonic acid, suggesting a change in platelet adhesion or a downregulation of endoperoxide synthesis. In our study, the importance of preactivation change in shape, estimated quantitatively by percent loss in ability of changing shape, can be compared using various agonists, with proportional defects in release and aggregation. These data provide evidence for different intrinsic levels in platelet defects after CPB.

Adenosine Diphosphate↗

PubMedDate not supplied

The treatment of lacrimal apparatus obstruction with the use of an inner canthal Jones tube insertion via a transcaruncular route.

BACKGROUND AND OBJECTIVE: To evaluate the clinical utility of the lacrimal bypass surgery using Bowman's probe in treatment of obstruction of the lacrimal apparatus. PATIENTS AND METHODS: This study evaluated 124 cases of obstruction of the lacrimal passage systems with mean epiphora of 2.7 years. An incision was made on the side of the caruncle, and the lacrimal bone was penetrated between the lacrimal sac and the nasal mucosa by Bowman #0. Insertion of a Jones tube was made at the new lacrimal pathway, a puctum dilator or scissors was introduced through the caruncle and dilated across the lacrimal bone into the nasal cavity. The Jones tube was introduced over the probe into the nasal cavity, and fixed at the caruncle with nonabsorbable suture material. RESULTS: Complete resolution of epiphora was accomplished in 120 (96.8%) of 124 eyes; only 4 (3.2%) eyes failed during a mean of 17.1 months of follow-up. CONCLUSION: This procedure is simple and safe with no facial scarring, short operation time, high success rate, and can be performed under local anesthesia. Therefore, the clinical utility of this procedure seems to be of value in treatment of complicated obstruction of the lacrimal apparatus.

Adolescent↗

PubMedDate not supplied

FTICR-mass spectrometry for high-resolution analysis in combinatorial chemistry.

The diversity of compound collections required for finding lead structures in pharmaceutical research can be provided by means of combinatorial organic chemistry. The resultant enormous number of single compounds but also of compound mixtures represents a challenge for the analyst. With the introduction of Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS or FT-MS), a new and, as yet, not widespread mass spectrometric technique (a means of analysis of such compound libraries with a very high mass resolution) high mass accuracy and high sensitivity has become available. Moreover, in combination with electrospray ionization (ESI), not only high-throughput measurements via flow-injection analysis (FIA) but also coupling with separation techniques such as high-performance liquid chromatography (HPLC) or capillary electrophoresis (CE) is possible. Structural verification by way of decomposing ions (MS(n); n > or = 2) using a variety of different dissociation techniques can be performed by FTICR-MS. This is the first review specifically covering applications of FTICR-MS in the field of combinatorial chemistry.

Automation↗

PubMedDate not supplied

Semiautomated T-bag peptide synthesis using 9-fluorenyl-methoxycarbonyl strategy and benzotriazol-1-yl-tetramethyl-uronium tetrafluoroborate activation.

Multiple peptide synthesis using the T-bag method is considerably facilitated using 9-fluorenyl-methoxycarbonyl strategy and benzotriazol-1-yl-tetramethyl-uronium tetrafluoroborate activation. Convenient protocols were achieved when semiautomation was applied. Successful syntheses of analogues of neuropeptide Y demonstrate the advantages of these improvements. Various peptides consisting of up to eighteen residues were built up with unusual amino acid residues. Useful hints are given for semiautomated multiple peptide synthesis for up to 120 different peptides.

Amino Acid Sequence↗