Histopathological evidence in support of the association of elevated proton spin-lattice relaxation times with the malignant state.

The pulsed nuclear magnetic resonance technique was explored for its potential diagnostic value in human cancer. Measurements of proton spin-lattice relaxation times (T1) of cellular water protons of normal and malignant esophageal tissues showed elevated T1 values in the latter. In some cases, tissues which appeared normal on gross examination assumed as uninvolved tissues had T1 values higher than the other grossly uninvolved tissues and often closer to the T1 of the corresponding tumor tissue. A histopathological study of the assumed uninvolved areas also studied for the T1 values was therefore undertaken. A preliminary study demonstrated the presence of malignant cell groups or clusters in some of the uninvolved samples with higher T1 compared to the true uninvolved tissues, which had a normal histological picture and low T1 values. This observation has brought out the importance of histopathological studies in addition to relaxation studies to comprehend contributory factors to relaxation. Secondly, it lends support to the thesis of elevated T1 values being characteristics of the malignant state.

Filtration and agar embedding applied to fine needle aspirates for tumor diagnosis by electron microscopy. A combined technique.

OBJECTIVE: To develop a novel method for processing of fine needle aspirates subjected to electron microscopic (EM) study. STUDY DESIGN: Included 70 cases of poorly differentiated malignant tumors in which a definitive diagnosis was not possible on light microscopic (LM) examination and that thus required application of an ancillary technique such as FNA/EM, for diagnosis. We have established a novel method of processing, a technique of filtration through nylon mesh filters to eliminate red blood cells (RBCs) and necrotic debris, followed by agar well embedding to avoid loss of diagnostic material during processing without centrifugation at later steps after agar embedding, thus minimizing the time required for processing. It was successfully carried out in 70 cases. RESULTS: The combined technique was extremely effective in eliminating RBCs and necrotic debris. It also avoided further loss of valuable diagnostic material. An accurate diagnosis was rendered in 70 cases; that was not possible by LM alone. The whole procedure saves two to three hours of processing as centrifugation is not required after the agar embedding step. CONCLUSION: This technique was found to be cost- and time-effective, particularly suitable for developing countries, where financial resources are limited.

Role of 'cell type' in proton relaxation in normal and neoplastic lymph nodes characterized by pulsed NMR spectroscopy.

Pulsed NMR studies have been undertaken on malignant lymphomas. It has been observed that water proton spin-lattice relaxation times of lymph node tissues show increase in lymphnodes of Hodgkin's and Non-Hodgkin's lymphoma as compared to those in normal subjects. The T1 values of normal lymphnodes showed a range of 200-300 msec, while the metastatic lymphnodes showed a range of 400-600 msec at 20 MHz. These studies have brought out the importance of histopathological significance and the role of 'cell type' and biomolecules as a factor influencing water proton relaxation times. Further the relevance of the present in vitro studies to Magnetic Resonance Imaging of ex vivo images of normal and metastatic lymphnodes has become evident from some recent studies reported in normal and afflicted lymphnodes.