Biomedical subjects
Publications and source records attributed to J Raymond.
A detailed radiologic, colonoscopic, and histologic analysis is described in the case of a cecal web presenting as a "cecal mass." The demonstration of a transverse band-like lucency proximal to the ileocecal valve should prompt careful double-contrast barium studies, to which endoscopy may be added, enabling a correct diagnosis to be made.
Explore the source record for details and available documents.
A study was carried out to assess the effect of total body irradiation on pancreatic and parotid isoenzymes of amylase in patients about to undergo bone-marrow transplantation who had received high-dose cyclophosphamide. Twelve patients were studied, enzyme activity being measured before and at various times after total body irradiation. Serum total amylase activity rose rapidly within 12 hours of irradiation to a maximum at 36 hours, returning to normal by six days; most of the increase was derived from salivary damage, with a much smaller pancreatic component. These results confirm that radiation produces acute changes in amylase activity, which may be of use in assessing radiation-induced damage.
The cytogenesis of the two cell populations of the vestibular sensory epithelium-hair cells and supporting cells-was investigated in explanted Mouse embryo otocysts using tritiated thymidine autoradiography. The otocysts were explanted on the 13th day of gestation and grown in vitro for 7 days. A close in vitro and in vivo correspondence was found in the cytodifferentiation of the sensory epithelium. At different times after explanation, a single administration of tritiated thymidine was added to the otocysts. The time schedule of the hair cell generation in the explants was essentially different from that observed during normal development. In contrast, the time schedule of the supporting cell generation was only mildly altered. The data suggest that the generative processes of the two cell populations are influenced differently, depending on their later specific differentiation.
Slices of the cat third oculomotor nucleus were incubated in vitro with [3H]glutamic acid. Electron microscopic radioautographs revealed that glutamate had been taken by small nerve endings distributed on the oculomotor motoneuron distal dendrites. In contrast, there was no uptake in the other types of terminals. The labeled terminals seem to correspond to the excitatory vestibulo-oculomotor nerve endings and different correlations suggest their glutamergic nature.
Some multiple sclerosis patients with 20/20 acuity complain of poor vision. In a previous report we accounted for this in our patient group by showing that multiple sclerosis had caused a depression of contrast sensitivity while sparing visual acuity. In this study we investigated whether some of this measured depression might be due to abnormally rapid or severe adaptation during the test procedure rather than a true permanent loss. Our finding was opposite to this supposition: adaptation was normally slight and/or slow. Depressed contrast sensitivity was not well correlated with abnormal adaptation to contrast. In patients whose contrast sensitivity losses were restricted to a band of spatial frequencies, we found no evidence that abnormalities of contrast adaptation were restricted to this same spatial frequency band. Further evidence of dissociation between abnormal contrast sensitivity and abnormal contrast adaptation is that some patients with normal contrast sensitivity showed abnormally small adaptation.
Explore the source record for details and available documents.
Epithelial cells of normal rat liver origin (strain RL34) synthesized the alpha 1 peptide of type I collagen. In nononcogenic cultures (RL34 and RL34EC) and a marginally oncogenic culture (RL34HII), the peptide was continuously secreted from the proliferating cells. Part of the soluble peptide was incorporated into the intercellular matrix of contact-inhibited cells after confluency, while the remainder was degraded. The intercellular matrix contained characteristic collagen fibrils which were argyrophilic and revealed a 64 nm axial periodicity. Epithelial cells of an oncogenic culture (RL34HT) secreted procollagen into the medium continuously throughout their proliferative phases and were unable to accumulate collagen fibrils in the intercellular matrix. The depletion of collagen accumulation in the hepatocarcinoma cell culture was ascribed to lack of the binding of native collagen molecules to the cell membrane and the persistence of high proteolytic activity on the cell surface.
The projection of vestibular pathways to the oculomotor nuclei ws investigated by electron microscopic radioautography. Unilateral injection of tritiated amino acids into the rostral vestibular complex was used in order to characterize the location and to identify the different types of labeled synaptic terminals involved in these pathways. In the normal oculomotor nuclei, 4 types of synaptic boutons were identified. Following the labeling of the vestibular synapses, in the ipsilateral oculomotor nucleus, types I and II boutons are the most prominent group and make up 75% of the synaptic vesicles, they are distributed on the cellular soma and the large dendrites of the oculomotor neurons. In contrast, in the contralateral oculomotor nucleus, type III boutons which are smaller and have larger diameter synaptic vesicles were predominant; they are prevalent on the distal part of the dendritic tree. From the results obtained, a relationship between the present anatomical findings and previously published physiological studies is established. The following conclusion is suggested: the inhibitory vestibular inputs probably terminate on the oculomotor neurons by these large types I and II boutons and the excitatory vestibular inputs by the smaller type III boutons. Also discussed is the complexity of the pattern of afferentation and the functional arrangement of the oculomotor nuclei.
Experiments have been carried out to explore the proteolytic cleavage of rabbit skeletal myofibrils by a calcium dependent neutral proteinase (CaANP). Polyacrylamide gel elctrophoresis on great slabs showed the ability of CaANP to degrade myofibrils more readily than supposed. Besides the hydrolysis of troponin T and the apparition of degradation product of 30,000 molecular weight, the activity of this enzyme is obvious too on some components of the M-line and on heavy subunits of tropomyosin as well as on three unidentified proteic fractions. The variety of the degradation products which appear suggest that the specificity of CaANP is not as selective as presumed. The participation of this proteinase in the postmorten evolution of muscle and its intervention in the turnover of myofibrillar proteins is discussed.
The relationship between the oncogenicity and the surface properties of cultured liver epithelial cells has been studied with the newborn Wistar rat-derived euploid line, RL34, and its heteroploid variants. An oncogenic variant, RL34HT, appeared to be more functionally active than its nononcogenic counterparts with respect to cell surface adenosine 5'-triphosphatase (ecto-ATPase) as well as to cytoplasmic enzymes such as tyrosine aminotransferase, gamma-glutamyl transpeptidase, and alkaline phosphatase. The cell surface of RL34HT was distinguished from those of nononcogenic and marginally oncogenic cell populations by the presence of abundant microvilli and by the absence of large external transformation-sensitive protein (fibronectin). High-Km and high-Vmax Ca2+-Mg2+ -ecto-ATPase was found in RL34HT. All nononcogenic cell lines had a flat granular surface membrane with high levels of fibronectin and also exhibited ecto-ATPase activity with low Km and low Vmax. When RL34HT was grown in dibutyryl cyclic adenosine 3',5'-monophosphate and theophylline, the external cell surface was partially restored to the polypeptide compositions of RL34, and there was an increase in Vmax of ecto-ATPase without a change in Km. The high-Km ecto-ATPase may be a useful indicator reflecting the lineage and cytodifferentiation of oncogenic liver epithelial cells, since it is also known to be localized at the bile canalicular microvilli of normal adult hepatocytes.
Ca(2+)-activated neutral proteinase was purified from rabbit skeletal muscle by a method involving DEAE-Sephacel chromatography, affinity chromatography on organomercurial-Sepharose and gel filtration on Sephacryl S-200 and Sephadex G-150. The SDS (sodium dodecyl sulphate)/polyacrylamide-gel-electrophoresis data show that the purified enzyme contains only one polypeptide chain of mol.wt. 73000. The purification procedure used allowed us to eliminate a contaminant containing two components of mol.wt. about 30000 each. Whole casein or alpha(1)-casein were hydrolysed with a maximum rate at 30 degrees C, pH7.5, and with 5mm-CaCl(2), but myofibrils were found to be a very susceptible substrate for this proteinase. This activity is associated with the destruction of the Z-discs, which is caused by the solubilization of the Z-line proteins. The activity of the proteinase in vitro is not limited to the removal of Z-line. SDS/polyacrylamide-gel electrophoresis on larger plates showed the ability of the proteinase to degrade myofibrils more extensively than previously supposed. This proteolysis resulted in the production of a 30000-dalton component as well as in various other higher- and lower-molecular-weight peptide fragments. Troponin T, troponin I, alpha-tropomyosin, some high-molecular-weight proteins (M protein, heavy chain of myosin) and three unidentified proteins are degraded. Thus the number of proteinase-sensitive regions in the myofibrils is greater than as previously reported by Dayton, Goll, Zeece, Robson & Reville [(1976) Biochemistry15, 2150-2158]. The Ca(2+)-activated neutral proteinase is not a chymotrypsin- or trypsin-like enzyme, but it reacted with all the classic thiol-proteinase inhibitors for cathepsin B, papain, bromelain and ficin. Thus the proteinase was proved to have an essential thiol group. Antipain and leupeptin are also inhibitors of the Ca(2+)-activated neutral proteinase.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A study of the pathways and ascending vestibular projections was carried out in the cat after unilateral injection of tritiated leucine into the rostral vestibular complex. Radioautographic analysis revealed a gradual decline in the density of labeling as ascending fibers were found to progress towards more rostral relays. The pathways and projections were very compact in the oculomotor nuclei, became less intense in the Cajal and Darkschewitsch nuclei, and thinned out considerably until they reached a transitional zone in the thalamus between the ventrobasal and ventrolateral complexes. These results confirm established and previous findings in this laboratory obtained by neurophysiological and neurohistological examination procedures. They provide the first anatomical evidence concerning the existence of vestibulothalamic projections and pathways.