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The polypeptide and phosphoprotein profiles of a spectrum of B16 melanoma clones of defined metastatic potential have been analyzed by two-dimensional gel electrophoresis. To accommodate the documented instability of metastatic properties in B16 clones, in vitro biochemical assays were always accompanied by in vivo assays of the metastatic behavior using replicate samples of the same clonal populations harvested on the same day. To exclude differences in polypeptide and phosphoprotein profiles resulting from inherent variation in electrophoretic measurements made at different times, polypeptides and phosphoproteins were analyzed in unison for every clone, and a series of clones was examined in parallel in each experiment. Also, samples were electrophoresed simultaneously using a custom-designed apparatus capable of accommodating 20 two-dimensional samples. When tested under these stringent conditions, the polypeptide profiles of B16 clones were indistinguishable. Significant qualitative and quantitative differences in phosphoprotein expression were detected in each clone, but no correlations were found between alterations in protein phosphorylation and metastatic potential. Over 200 discrete phosphoproteins were detected in each clone, but interclonal variation was confined to approximately 10 to 15 phosphoproteins. Expression of three phosphoproteins with the following molecular weights (in kilodaltons) and isoelectric points was strictly qualitative: pp96 (7.9); pp30 (8.2); and pp30 (8.8). In any given clone, they were present individually at equal intensities or were completely absent, but their expression was not coordinate. The data indicate that expression of polypeptide gene products is similar in B16 melanoma clones with widely differing metastatic abilities, but considerable clonal variability exists in posttranslational covalent modification of cell proteins. The possible contribution of protein phosphorylation and other posttranslational pathways in generating the extensive phenotypic heterogeneity observed in tumor cell subpopulations within the same tumor and in the rapid generation of new clonal variants with altered metastatic properties are discussed.

Operative biliary endoscopy is traditionally performed through a common duct incision, through a very dilated cystic duct lumen. The development of the new ultra thin biliary scopes makes visual examination of the biliary tree possible through a normal cystic duct lumen. The operative approach to the gallbladder is unchanged. The indications for choledochoscopy of the cystic duct are the same as for operative cholangiogram. This examination can be of better quality and is less expensive than an operative roentgenogram. Unlike an operative cholangiogram, which at best visualized the bile ducts, the ultra thin scope gives the surgeon additional information concerning the ampulla of Vater, differentiating ductal spasm from stricture by its tactile feedback through the Bakes-like probe. When disease is present, it is possible for the scope to become a therapeutic instrument without the need for choledochotomy and its associated morbidity and cost. The high incidence of choledocholithiasis in this small series may be attributed to the sample size. It is also possible that more occult stones were found. If this is the case, most of these stones are being passed spontaneously and are never clinically apparent. It is those few patients who have small, occult stones that do not pass who benefit most from this new technology. This study was undertaken to develop and investigate the potential uses of a new biliary scope. These scopes require a learning period before the entire biliary tract can be visualized, but have the potential to be of significant value in the diagnosis and treatment of biliary tract disease.

Two mechanisms of brightness perception (1) brightness induction by local contrast and (2) assimilation, were examined for a variety of visual stimuli. Local contrast is the primary determinant of brightness perception, making objects appear brighter on a background of lower luminance and darker on a background of greater luminance. Assimilation is the opposite effect, whereby objects on a brighter (but not necessarily more luminant) background appear brighter or on a dark background appear darker. We have compared the relative strength of the two effects using stimuli which permit them to be studied separately. Brightness induction by local contrast is quantitatively stronger in all situations. Further, the strength of assimilation is strongly dependent on spatial parameters in the visual scene. These results are shown to be true both for simple visual stimuli as well as for complicated Mondrian-like patterns. The Retinex theory of brightness perception predicts that the two effects are equal. Our results show a range of relative strengths (assimilation vs brightness induction due to contrast) from 0.59 to 0.63 at 5' down to 0.34 at 43'.

Space and territory have been the hidden dimensions of human and other animal life. Beginning with studies reported in animals, and incorporating the few formal studies and several informal observations of man, this paper explains the importance of mastering the unwritten rules of space and territory which differ with individual cultures in relation to the behavioral aberrations possibly resulting from the disrupted territoriality of modern urban life.

The role of neck muscles in the body's response to the "whiplash" type of motion which occurs during frontal impact has been studied. This type of motion was simulated by a sudden backward pull of a subject's head. Head and neck response to low-level acceleration has been researched by recording the externally applied force, the head accelerations in the median sagittal plane, and the electrical activity in the sternomastoid muscle (EMG) as functions of time. The resultant acceleration-time curve and recorded EMG have been analyzed, with numerical values of applied resistance to the external force recorded. An analog computer model was built incorporating resistance developed by two main variable: 1) the elasticity coefficient; 2) the active damping factor. Together these two variables, combined with a resistance function, enable us to measure the resistance of the head/neck response. Using this model, variations in magnitude of these two components were studied under six varying conditions of impact: 1) length of warning time; 2) type of instruction given to the subject; 3) amount of previous experience on the part of the subject in similar situations; 4) anticipation of impact by the subject; 5) magnitude and kind of impact; 6) presence or absence of a preload.

A case of pyomyositis, a deep muscle abscess, presenting as a soft tissue sarcoma is reported. Although common in the tropics, this disease is quite rare in the United States. The presentation, diagnosis, and treatment of the problem are discussed and reviewed.

We report two patients with inflammatory bowel disease in whom intravenous corticotropin therapy was complicated by bilateral adrenal hemorrhage. In one, the initial presentation was acute and unilateral, simulating colonic perforation and/or abscess. The diagnosis was made only at exploratory laparotomy. In the second patient, the presentation was subacute; multiple episodes of adrenal hemorrhage occurred subsequent to the course of corticotropin, and ultimately, hypoadrenalinism developed. Pertinent clinical and computed tomographic findings are reviewed.

Basal aryl hydrocarbon hydroxylase (AHH) activity and its kinetic properties were studied as a function of proliferation in C3H mouse embryo 10T1/2 CL8 cells. Activity was low in freshly plated cells, increased during exponential growth, peaked at confluency, and then declined. The apparent Km-values for benzo[a]pyrene (BP) and NADPH were less in proliferating (approx. 0.37 microM BP, 3.3 nM NADPH) than in confluent cells (0.74-1.39 microM BP, 33.4-53.4 nM NADPH). Cells at different growth states responded differently to benz[a]anthracene (BA) and aminophylline, an inhibitor of cyclic nucleotide phosphodiesterases. When cells were harvested at the mid log phase of growth, 12 h of exposure to aminophylline caused maximum induction, while 24 h of BA treatment were required. In contrast, at early confluence, 12 h of BA treatment gave the greatest levels of activity, while exposure to aminophylline did not induce AHH. In fact, decreases in activity were observed. These differences are indicative of different regulatory mechanisms for BA and aminophylline induction. They also suggest the regulation of basal AHH by cyclic nucleotides changes during growth. The exposure times giving maximum activity were used to determine the kinetic properties of BA-induced activity. As with basal AHH, the Km-value for BP was less in log phase (0.2-0.4 microM BP) than in confluent cells (0.64-1.05 microM BP). Moreover, the Km-values for BP and NADPH in control cultures at confluency (0.10-0.14 microM BP, 15.4-23.2 nM NADPH) were less than those for BA-treated cells (0.64 microM BP, 37.9-54.8 nM NADPH) under the same nutritional conditions. The finding that the Km-values for BP is lower in rapidly dividing cells than in confluent cells may help to explain why proliferating cells are more susceptible to transforming agents.

A series of methylated analogues of 6-hydroxydopamine (6-OHDA) has been synthesized and evaluated as irreversible inhibitors of catechol O-methyltransferase (COMT). These analogues have been prepared in an effort to elucidate the mechanism involved in the inactivation of this enzyme by 6-OHDA. The analogues prepared had methyl groups incorporated in the 2 and/or 5 positions of 6-OHDA so as to block nucleophilic attakc at these positions in the corresponding oxidation products [6-hydroxydopamine-p-quinone (6-OHDAQ), aminochromes I and II]. Such 2- and/or 5-methylated 6-OHDA analogues were found to be inhibitors of COMT with the inactivation apparently resulting from modification of an essential amino acid residue at the active site of the enzyme. The activity of these analogues as inhibitors of COMT argues against a mechanism involving a 1,4 Michael addition reaction by a protein nucleophile at the 2 or 5 positions on 6-OHDAQ or on the corresponding aminochromes. Instead, an alternative mechanism is proposed to explain these data, which involves attack of a protein nucleophile at the carbonyl group in the 6 position of 6-OHDAQ or at the imine functionality on aminochromes I and II. The results of the present experiments have provided insight into the mechanism involved in inactivation of COMT by 6-OHDA. In addition, this study has provided considerable insight into the chemical reactivity of the electrophilic species generated after oxidation of 6-OHDA.