Studies of rat liver microsomal diglyceride acyltransferase and cholinephosphotransferase using microsomal-bound substrate: effects of high fructose intake.

Radiolabeled phosphatidate and diglyceride were prepared bound to rat liver microsomes. These compounds were used as substrates in studies of diglyceride acyltransferase, cholinephosphotransferase, and CTP:phosphatidic acid cytidylyltransferase. Optimum incubation conditions for these reactions in microsomes from normal male rats are described. High fructose diets were fed to rats for 11 days; this resulted in an increased rate of neutral lipid formation from sn-glycerol-3-phosphate by liver microsomal preparations. This was attributed, in part, to a previously reported increase in liver phosphatidate phosphatase activity. The significance of this increase is supported by the finding of a fall in microsomal phosphatidate content and a doubling in microsomal diglyceride. In addition, diglyceride acyltransferase measured with microsomal-bound diglyceride was increased twofold with no equivalent change in cholinephosphotransferase activity. Such a change should result in preferential triglyceride formation from the increased microsomal diglyceride pool. CTP:phosphatidic acid cytidylytransferase activity was depressed by the high fructose diet. These combined alterations would lead to an accelerated hepatic triglyceride formation, a result found in vivo during high fructose feeding. The high fructose diet decreased slightly the total microsomal phospholipid content and markedly depressed phosphatidylethanolamine levels.     

Decreased thrombogenicity of vascular prostheses following gas denucleation by hydrostatic pressure

The high rate of thrombosis of 1.0-mm polytetrafluoroethylene (PTFE) grafts has limited their use in microvascular surgery. One possible reason for this is the blood-gas interface due to entrapped air in the interstices. The present study examines the effect on patency rates of elimination of this blood-gas interface by high pressurization. Comparing pressurized and nonpressurized grafts in the same animals showed a patency rate of 100 percent at 7 days for treated grafts, while the control (nonpressurized) grafts had all clotted by 1 hour. The implications for microvascular surgery as well as vascular surgery in general are discussed.     

Morphological innovation through gene regulation: an example from Devonian Onychodontiform fish

The recent development of novel phenotypic designs by changes in gene regulation has been extensively discussed within the context of evolution and development. The fossil record shows many new designs (or body plans) which appear rapidly at various stratigraphic levels. One example of this is the arrival of the lobe finned fish in the Early Devonian, when a great variety of new forms appeared. These include the dipnoans, the onychodontids, the porolepiforms and the osteolepiforms, which differ widely in a number of characters. Each of these groups originated from an unspecified sarcopterygian source and they have since evolved independently. They also carry over the primitive genes of the parent or parents and similar changes in these genes will not produce synapomorphies between members of the different lineages. Unless care is exercised, homoplasies will be used as synapomorphies. Evidence must be found to find groups of features that define uniform functional entities. These define monophyletic groups. Recognition of homoplasy of characters thus becomes important. The study of the new functional structures and the areas from which they were derived by changes in gene regulation, would give us more evolutionary information.     

Inhibition by cycloheximide of degradation of cytochrome P-450 in primary cultures of adult rat liver parenchymal cells and in vivo

Degradation of cytochrome P-450 was studied in adult rat liver parenchymal cells in primary monolayer culture. In cells incubated in standard culture medium, the amount of cytochrome P-450 decreased at an accelerated rate relative to either the rate of degradation of total protein in the cells or the turnover of cytochrome P-450 in vivo. This change was succeeded by a spontaneous increase in the activity of haem oxygenase, an enzyme system that converts haem into bilirubin in vitro, measured in extracts from the cultured cells. This finding suggests that the rate of cytochrome P-450 breakdown may be controlled by factor(s) other than the activity of haem oxygenase. The decline in cytochrome P-450 and the subsequent increase in haem oxygenase activity was prevented by incubation of hepatocytes in medium containing an inhibitor of protein synthesis such as cycloheximide, puromycin, actinomycin D, or azaserine. The effect of cycloheximide appeared to be due to decreased breakdown of microsomal (14)C-labelled haem. By contrast, cycloheximide was without effect on the degradation of total protein, measured either in homogenates or in microsomal fractions prepared from the cultured cells. These results suggest that the conditions of cell culture stimulate selective degradation of cytochrome P-450 by a process that is inhibited by cycloheximide and hence may require protein synthesis. The findings in culture were verified in parallel studies of cytochrome P-450 degradation in vivo. After administration of bromobenzene, the degradation of the haem moiety of cytochrome P-450 was accelerated in vivo in a manner resembling that observed in cultured hepatocytes. Administration of cycloheximide to either bromobenzene-treated rats or to untreated rats decreased the degradation of the haem moiety of cytochrome P-450. However, the drug failed to affect degradation of haem not associated with cytochrome P-450, suggesting that cycloheximide is not a general inhibitor of haem oxidation in the liver. These findings confirm that the catabolism of hepatic cytochrome P-450 haem is controlled by similar cycloheximide-sensitive processes in the basal steady state in vivo, as stimulated by bromobenzene in vivo, or in hepatocytes under the conditions of cell culture. We conclude that the rate-limiting step in this process appears to require protein synthesis and precedes cleavage of the haem ring.     

Physical capacity and functional abilities improve in young adults with intellectual disabilities after functional training

Individuals with an intellectual disability (ID) have higher rates of obesity, lower rates of physical activity, cardiorespiratory fitness, and muscular endurance than do typically developed individuals (TDI) and are twice as likely to develop chronic disease, living half as long as TDIs do. The purpose of this study was to examine the improvements in physical capacity and functional ability in Special Olympic Athletes (SOAs) aged 19-22 years after participating in a functional training (FT) program and compare these scores with those of the SOAs in a resistance weight training (WT) program. Twenty SOAs (13 men, 7 women with mild to moderate ID) participated in a 1-hour FT program, twice a week, for 10 weeks, compared with 22 same-aged SOAs (14 men, 8 women) participating in a 1-hour WT program (2× week for 8 weeks). Prefitness and postfitness tests consisting of heart rate (HR) for the 3-minute step test, static plank, body weight squats, static bar hang, and knee push-ups were conducted. Two-tailed, paired sample t-tests (p < 0.05) were used to evaluate the differences in the FT group. Change scores were used to compare FTG with the WT group. The HR decreased by 31.8 b·min?1 pre-post in the FTG (p < 0.001). Static plank duration improved by 22.4 seconds in the FTG (p = 0.016); static plank change scores improved (p = 0.037) for the FTG (26.5 ± 32.1 seconds compared with that for the WT group (4.6 ± 22 seconds). Height and weight values were unchanged in both the groups. The results of this study demonstrate the value of FT programs for this population, because weight equipment is not always available in many settings.     

The structure and stratigraphy of<Emphasis Type="Italic">Speonesydrion</Emphasis> from New South Wales,Australia, and the dentition of primitive dipnoans

New material ofSpeonesydrion iani, an Early Devonian dipnoan from New South Wales, has provided additional Information on the dentition and jaws. Two new partial palates have been found, and X-rays of the parasphenoid shows that the structure is well preserved. The palatal teeth are well worn even in partly grown material, and they do not originate at a growth point, but at a thickening of the palate. More mandibles have been collected, and thin sections have been prepared to allow a discussion of their histology. On the mandible the teeth are clear, and they are much more defined than they are on the palate. The dental heel is variably developed, and grows in phases by thickening of the dentine at the contact with the bone. Dentine forms on the bone at the base of the heel, partly by Solution of the bone and the addition of dentine from the pulp canals, but also by direct growth from the pulp canals dorsal to the bone. In the latter case the dentine and bone are in contact, and the two tissues intermingle. The teeth are also formed on a thickened bone and consist of dentine capped with enamel making a crest. Dentine and bone are related as in the heel. We conclude that the teeth inSpeonesydrion are not homologous with the teeth in other dipnoans, and are formed by a different process involving the aggregation of denticles.     

Preoperative positioning of the protruding premaxilla in the bilateral cleft lip patient

The rationale and technique for preoperative retraction of a protrusive premaxilla in the bilateral complete cleft lip and palate patient are presented. Two types of pinned intraoral appliances are presented that can expand the palatal shelves while retracting the premaxillary segment. Findings from lateral cephalometric x-ray studies of eight appliance patients and six control patients with bilateral clefts but no appliance treatment are presented at age 15. The data indicate that the cephalometric values at age 15 are within the normal range for most patients. Incisor angulation was quite varied among the subjects.     

Late development of hematoma around a breast implant, necessitating removal

We present a patient who bled into the pocket around a breast implant 2 1/2 years after an augmentation mammaplasty. She had received inflatible silicone prostheses, each containing 40 mg of triamcinolone acetonide. Our belief is that this large dosage of corticosteroid was responsible for the late erosion of the medium-sized artery, which caused the hemorrhage. Exploration and evacuation of the hematoma was followed by an uneventful postoperative course.