Histogenesis of dermatofibrosarcoma protuberans]

In order to specify the histogenetic appurtenance of dermatofibrosarcoma protuberance, the ultrastructure of cells from three tumors was studied. The similarity between the ultrastructure of the tumor cells and normal fibroblasts suggests the fibroblastic origin of the tumor.     

The isolation of eukaryotic ribosomal proteins. The purification and characterization of the 40 S ribosomal subunit proteins S2, S3, S4, S5, S6, S7, S8, S9, S13, S23/S24, S27, and S28

The proteins of the small subunit of rat liver ribosomes were separated into five groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5 (Collatz, E., Lin, A., St?ffler, G., Tsurugi, K., and Wool, I.G., (1976) J. Biol. Chem. 251, 1808-1816). From the several groups, 12 proteins (S2,S3, S4, S5, S6, S7, S8, S9, S13, S23/S24, S27, and S28) wereisolated by ion exchange chromatography on carboxymethylcellulose, by chromatography on sulfopropyl-Sephadex, and by gel filtration through Sephadex G-75. The amount of protein obtained varied from 1 to 9 mg depending on the number of steps required for the preparation; several proteins had no detectable contamination and the impurities in the others were no greater than 9%. The molecular weight of the proteins was estimated by polyazrylamide gel electrophoresis in sodium dodecyl sulfate; the amino acid composition was determined.     

Electrophysiologic study of trace changes in the excitability of the rat spinal cord

In white rats, retention of the amplitude asymmetry of the monosynaptic reflex responses (MSRR) in the ventral roots of the spinal lumbosacral segments due to removal of half of the cerebellum, was studied. The MSRR asymmetry remained after the consequent spinal cord section at the thoracic level if it had existed over 20 min (fixation period) before this section. When tested with electric stimuli applied to the nerves of muscles-antagonists, the stable MSRR asymmetry could be unidirectional or reciprocal. Prolonged unilateral stimulation of the muscle nerve central end in the spinal rat with stimuli of different frequency and intensity evoked no MSRR amplitude asymmetry during subsequent bilateral testing of the same nerves. But in decerebrated rats the MSRR asymmetry has frequently appeared after such stimulation. Asymmetry of the reticular descending influence is supposed to play a major role in the trace stable changes of excitability of the spinal cord neuronal substrate as well as different capacities of different neurons (or their elements) for fixation and retention of such changes.     

Initial experience in vascular plastic surgery in the surgical treatment of metastases of laryngopharyngeal cancer

The paper concerns conduction of the internal carotid artery and internal jugular vein reconstruction in 3 and 2 patients, respectively, operated for metastases of laryngopharyngeal carcinoma. 4 patients are still alive, 1 died on postoperative day 6. Bilateral one-stage Crile operation with application of autograft venous reconstruction of the internal jugular vein is detailed. Further research in this field is necessary.     

Excitatory interactions in neuronal networks which include cells of the auditory cortex and the medial geniculate body

The use of the method of cross-correlation analysis to elucidate the interactions between simultaneously recorded neurons from various loci of the auditory cortex (AC) and the medial geniculate body (MGB) has made it possible to identify the following characteristics of the functional organization of the excitatory interactions in the thalamocortical neuronal networks: the interdependant impulse action of neurons located at various loci of the AC and MGB was determined by reciprocal excitatory connections; the efficiency of the connections between neurons of the AC, 400-500 microns apart, and between tonotopically associated neurons of the AC and MGB was approximately identical (associations were identified in 12% of the cases); the "divergent" properties of the MGB (AC) neurons were manifested in the fact that one and same neuron could simultaneously excite both neighboring cells and neurons from one or several loci of the AC (MGB); the "convergent" properties of the AC and MGB neurons were manifested in the fact that cells located at various loci of the AC and MGB simultaneously excited one neuron. The results make it possible to explain the deviations observed in the investigation of RF of neurons of the AC and MGB from the principle of tonotopical organization. It is hypothesized that the character of the organization of the excitatory connections in the thalamocortical networks may promote the creation of the necessary conditions for the modification of the efficiency of synapses between all of the elements of the network during the stimulation of individual elements.     

Reduced chaperone-like activity of alpha A(ins)-crystallin, an alternative splicing product containing a large insert peptide

alpha-Crystallin is a multimeric protein complex which is constitutively expressed at high levels in the vertebrate eye lens, where it serves a structural role, and at low levels in several non-lenticular tissues. Like other members of the small heat shock protein family, alpha-crystallin has a chaperone-like activity in suppressing nonspecific aggregation of denaturing proteins in vitro. Apart from the major alpha A- and alpha B-subunits, alpha-crystallin of rodents contains an additional minor subunit resulting from alternative splicing, alpha A(ins)-crystallin. This polypeptide is identical to normal alpha A-crystallin except for an insert peptide of 23 residues. To explore the structural and functional consequences of this insertion, we have expressed rat alpha A- and alpha A(ins)-crystallin in Escherichia coli. The multimeric particles formed by alpha A(ins) are larger and more disperse than those of alpha A, but they are native-like and display a similar thermostability and morphology, as revealed by gel permeation chromatography, tryptophan fluorescence measurements, and electron microscopy. However, as compared with alpha A, the alpha A(ins)-particles display a diminished chaperone-like activity in the protection of heat-induced aggregation of beta low-crystallin. Our experiments indicate that alpha A(ins)-multimers have a 3-4-fold reduced substrate binding capacity, which might be correlated to their increased particle size and to a shielding of binding sites by the insert peptides. The structure-function relationship of the natural mutant alpha A(ins)-crystallin may shed light on the mechanism of chaperone-like activity displayed by all small heat shock proteins.     

Purification of influenza virus with Arcton 113

Arcton 113 has proved effective in the removal of host membrane fragments which cosediment with influenza virus during differential centrifugation. The virus appeared morphologically undamaged by the procedure and retained its infectivity, neuraminidase, and hemagglutinating activity. Pyrogenicity, however, was considerably reduced.     

The role of microsatellite instability in gastric carcinoma

Hernia repair may involve the use of an implant to augment or replace autologous tissue, but the best material for use in this application has not been established. We developed a dog model to evaluate the mechanical strength of fascial defects repaired using carbon fibers, compared with the strength of similar defects repaired using polypropylene mesh (Marlex). Unrepaired defects were included as an additional control. Bilateral defects (1 cm square) were made in the fascia of the back, and the ultimate mechanical strength and stiffness at the repair sites were measured 3-12 months after operation. Defects repaired with carbon fibers were significantly stronger 12 months after operation compared with defects repaired with polypropylene mesh and compared with unrepaired defects. It is concluded that carbon fibers are biocompatible and significantly increase mechanical strength at the repair site. A randomized clinical trial involving patients undergoing hernia repair seems justified to determine whether carbon fibers are superior to standard therapy.