[Point mutation at codon 12 of c-Ki-ras oncogene in human pancreatic neoplasms and normal human pancreas tissue]

Point mutation at codon 12 of c-Ki-ras oncogene was tested from 2 normal human pancreas, 7 pancreatic endocrine neoplasms and 15 pancreatic adenocarcinomas, including 5 resected pancreatic adenocarcinomas, 3 cell lines of pancreatic adenocarcinoma and 7 nude mice transplanted tumors by dot blot and single-strand conformation polymorphism (SSCP) after PCR amplification, c-Ki-ras codon 12 point mutation was found only in pancreatic adenocarcinomas (11/15 by dot blot and 13/15 by SSCP). No mutation was detected in normal human pancreatic tissue and endocrine tumors. By our experience, SSCP is more convenient and faster than dot blot in detecting gene mutation. Point mutation at codon 12 of c-Ki-ras oncogene may play an important role in the development of human pancreatic carcinoma.

The effect of cycloheximide and ganglioside GM1 on the viability of retinotectally projecting ganglion cells following ablation of the superior colliculus in neonatal rats

The time-course and extent of death of retinal ganglion cells (RGCs) following ablation of the superior colliculus (SC) in neonatal Wistar rats has recently been described [Harvey, A. R. and Robertson, D. (1992) J. Comp. Neurol., 325, 83-94]. Normal and pyknotic nuclei of retinotectally projecting ganglion cells were visualized using the fluorescent retrograde tracer diamidino yellow (DY), which had been injected into the SC at P2 (day of birth = P0), 2 days prior to tectal removal. The present report sets out to determine whether cycloheximide, an inhibitor of protein synthesis, or ganglioside GM1 reduced this lesion-induced RGC death. All surgery was carried out under ether anaesthesia; DY was injected into the left SC at P2 and the injected area was removed at P4. Cycloheximide (20-500 ng) was injected into the vitreous chamber of the right eye immediately after the lesion and again 11-12 h later. In some rats, cycloheximide administration was delayed until 12 h after the SC ablation. Control rats received SC lesions alone or lesions plus sham eye injections of saline. Different doses of GM1 were applied i.p. or intraocularly. Rats were perfused 24 h after the SC lesion, at the time of peak RGC death. Retinae of lesion only or sham eye injected rats contained approximately 11% pyknotic RGCs and the density of normal RGCs was approximately 3400/mm2. The rate of pyknosis in cycloheximide treated retinae was reduced to approximately 3%. Normal RGC density in these retinae was approximately 5500/mm2, similar to that found in retinae of unlesioned animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural study of moniliformin induced lesions of myocardium in rats and mice

Effects of moniliformin on the ultrastructure of the myocardium of mice and rats were studied. Mice were given moniliformin orally at a dose of 29.46 mg.kg-1 the LD50. One h after dosing, lesions of the mitochondria of the myocardial cells were found which became more severe in 2 and 3 h. Ultrastructural lesions were also observed in the myofibrils and sarcolemma. Rats were given moniliformin orally at the dosage of 6 mg.kg-1 once daily for 56 d. Lesions of mitochondria and myofibrils were relatively mild. In the myocardiac specimens taken from the 21d post-toxin administration, lesions of the sarcolemma became more obvious. These moniliformin-induced lesions were similar to the ultrastructural changes in the myocardium of patients with Keshan disease. Our findings indicate that there may be a close and important relationship between moniliformin intoxication and Keshan disease.

Noninvasive estimation of cardiac output

A noninvasive method of measuring cardiac output is described. The method uses adaptive aorta models in conjunction with femoral and carotid pulse contour waveform measurements to calculate aortic flow. Results are presented from measurements on dogs using internal pressure recordings made with fluid-filled catheters and compared with electromagnetic flow measurements taken in the ascending aorta. Preliminary results using external pulse measurements on patients are also presented and compared with thermal dilution measurements.