Biomedical subjects

J W MacKenzie

Publications and source records attributed to J W MacKenzie.

11 recordsLinked to original sources

PubMed1989

The effect of viable omentum on early bile leakage and healing of liver lacerations.

In order to determine if omental tissue accelerates the healing of liver lacerations, simulated bile leakage and collagen biosynthesis were studied in 53 rabbits. After creating a standardized complex liver laceration, hemostasis was obtained by vessel ligation and electrocoagulation. The wound was either left open (OP) or viable omentum sutured to its base (OM). Simulated bile leakage was noted in all of eight animals (four OM, four OP) studied on day of injury. None of 18 OM and two of 17 OP animals demonstrated extravasation of dye from the wound on the second and third postinjury day (N.S.). The ratio of mRNA for alpha 1(I) procollagen/actin, used as an indicator of wound healing, was 56.3 +/- 7.8 for OM and 50.6 +/- 12.1 for OP at the wound edge, and 63.5 +/- 18.6 and 69.2 +/- 7.5, respectively, for RNA isolated from the scar (N.S.). For alpha 1(III) procollagen mRNA, the ratio was 23.9 +/- 3.5 for OM and 22.4 +/- 8.3 for OP at the wound edge, and 32.4 +/- 6.5 and 31.8 +/- 7.9, respectively, for RNA isolated from the scar (N.S.). There was no difference in the scar hydroxyproline content between the two repair methods. In this model of hepatic injury and repair, bile leakage was minimal by the second postinjury day with both repair methods. Placing the omentum in liver lacerations did not contribute to accelerated wound healing as measured by simulated bile leakage and collagen biosynthesis.

Animals↗

PubMed1987

Clinical experience with the Jahnke-Barron heart support.

The Jahnke-Barron heart support has proven to be a useful adjunct to coronary artery surgery by allowing an easy access to the coronary arteries while maintaining a quiet operating field. Further, the use of this device eliminates the need for a surgical assistant or a heart holder.

Coronary Artery Bypass↗

PubMed1983

Comparison of urinary modified nucleosides and bases in rats with hepatomas and nephroblastomas.

Hepatomas were induced in rats with aflatoxin B1, and nephroblastomas with dimethylnitrosamine. Microscopic examination of livers of aflatoxin-treated rats revealed multinodular hepatocyte hyperplasia at 8 months, and by 13 months all rats had hepatomas. Nephroblastomas were observed by 4 months and by 8 months all rats had developed them. The urinary excretion of several modified nucleosides and bases by normal rats is dependent on body weight and reflects, to a certain extent, their concentrations in tissue tRNA. Increased levels of several modified nucleosides and bases were found in all rats that had cancer. Rats with hepatomas excreted essentially the same modified nucleosides and bases as did those with nephroblastomas; the quantitative patterns of excretion were different, however, suggesting that the urinary modified nucleosides and bases may be used to differentiate between neoplasms. Although the increase in urinary modified nucleosides and bases by tumor-bearing animals results primarily from more rapid turnover of neoplastic tRNAs, the data indicate that increased turnover of mRNA and possibly rRNA may occur in neoplastic tissue. Preliminary data suggest that increases in urinary modified nucleosides and bases may occur during a precancerous stage. The urinary pattern of modified nucleosides and bases by rats with hepatomas is altered if another primary tumor is present. The results obtained from these studies support the use of modified nucleosides and bases in urine as biochemical markers of cancer.

Aflatoxin B1↗

PubMed1983

Metabolism of tRNA in rats with aflatoxin B1-induced hepatomas.

This study describes effects of aflatoxin B1-induced hepatomas on RNA metabolism in rats. At 4 and 24 hours after the administration of L-(14CH3)-methionine, tRNA was isolated from the livers and hydrolyzed enzymatically to nucleosides which were quantitatively measured by HPLC. Radioactivity of the nucleosides was also determined. The data indicate that although tRNA methylation may be more rapid in livers with hepatomas, catabolism of tRNA in tumorous tissue is slower than in control livers. The large increase in some radioactive methylated nucleosides and bases by the tumor-bearing rats during the 24-hour period following the administration of labeled methionine indicates increased turnover of mRNA and rRNA as well as tRNA. Since degradation of tumor tRNA appears to be delayed, the excessive amounts of the urinary methylated nucleosides must be derived from RNA in nonneoplastic tissue.

Aflatoxin B1↗

PubMed1983

Arthritis in childhood sarcoidosis.

A 6-year-old girl with arthropathy accompanying sarcoidosis is presented. Articular, cutaneous and ocular features of sarcoidosis were prominent in this patient. Indirect immunofluorescence on HEp-2 cells revealed both antinuclear and anticytoplasmic antibodies. To determine distinguishing features between children with sarcoid arthritis and those with nonarticular sarcoidosis, reported cases from these 2 groups were reviewed. The mean age of onset of children with sarcoidosis and arthritis (2.3 years) was significantly lower than that of those with nonarticular sarcoidosis (10.8 years) (p less than 0.01). Skin was affected in 12 of 15 children with arthritis but in only 75 of 229 without arthritis (p less than 0.001). Ocular involvement was present in 14 of 15 patients with arthritis and in only 91 of 229 without arthritis (p less than 0.001). Among children with sarcoidosis the triad of arthritis, rash and uveitis occurs almost exclusively in those with an onset age of less than 5 years.

Arthritis↗

PubMed1974