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Biomedical subjects

L C Anderson

Publications and source records attributed to L C Anderson.

At least 91 records · Page 5Linked to original sources

Cimetidine prophylaxis for gastric ulcers in laboratory swine.

Bleeding gastric ulcers were a major cause of morbidity and mortality in young swine subjected to surgery, chronic catheterization, and daily experimental manipulation. Some of the animals died suddenly due to exsanguination into the gastrointestinal tract, while others survived for several days following the onset of clinical signs. These signs included dark, tarry stools, lethargy, pale mucous membranes, decreased appetite, and dyspnea. Abnormal clinical laboratory findings included decreased hematocrit, hemoglobin and erythrocyte counts indicative of chronic blood loss anemia. On postmortem examination, single or multiple ulcers of variable sizes were found in the nonglandular cardiac portion of the stomach, and the gastrointestinal tract often contained blood. Histologically, the ulcers had a base of granulation tissue with surface suppuration. Prophylactic treatment of these ulcers was initiated using cimetidine, a histamine II blocker. The drug was administered via the drinking water at 15 mg/kg body weight/day. Fourteen of 62 (22.5%) pigs that did not receive cimetidine developed bleeding ulcers. Of 45 animals given daily prophylactic doses of cimetidine, none manifested clinical signs indicative of a bleeding ulcer. These results indicated that cimetidine was effective in preventing morbidity and mortality due to bleeding gastric ulcers in young swine used in chronic laboratory experiments.

Animals↗

The effect of alloxan diabetes and insulin on the rate of protein synthesis in the rat submandibular gland.

The incorporation of radioactively labeled leucine into TCA-precipitable proteins by submandibular gland tissue slices from control, alloxan diabetic, and insulin supplemented diabetic rats was measured in vitro. Incorporation decreased in alloxan diabetes and could be restored to control levels within three hours after insulin administration. The effects of alloxan diabetes and insulin on 3H-leucine incorporation paralleled their effects on a secretory enzyme, peroxidase. Insulin in vitro stimulated the incorporation of 3H-leucine within 15 minutes of addition to the incubation medium. Further, the response to insulin was found to be dose-related. The conclusion drawn from these results is that insulin has a rapid, direct effect on the rate of protein synthesis in the rat submandibular gland.

Animals↗

Responses of fetal sheep to simulated no-decompression dives.

The effect of simulated standard no-decompression dives to 60 and 100 ft of seawater was tested in 12 near term sheep carrying 16 fetuses. In the immediate postdive period there were no significant changes in fetal blood pressure or fetal placental or renal blood flow, but the maternal blood pressure was elevated and the maternal placental blood flow was depressed. Six surgically prepared fetuses were dived to 100 ft. Five died within 20 min of ascent and the sixth suffered severe cardiac arrhythmia and hypotension. At autopsy all fetuses were observed to have massive bubbling in the arterial system and heart. Five fetuses were dived to 100 ft without surgery. Two were alive 3 h later and no bubbles were present at autopsy, and three were born alive at term. With the 60-ft dives, three fetuses were subjected to surgery and all suffered massive bubbling. Two fetuses were dived to 60 ft without surgery; one was alive after 3 h and the other was born alive at term. We conclude that surgery and monitoring result in the formation of postdive gas bubbles that would not otherwise appear.

Animals↗

Sustained release of sulphadiazine.

An implantable system was developed which released sulphadiazine in mice over an extended period of time efficacious against infective challenges by Plasmodium berghei. The most successful preparation was a copolymer of L(+)-lactic acid + (+/-)-lactic acid (90 and 10% by weight, respectively) with a molecular weight of 150 000, with which sulphadiazine was mixed at 33.3% of the total weight, in a formulation as beads of 1.5 mm diameter. This preparation released sulphadiazine at a nearly constant rate over three months as measured by the appearance in urine of mice of radioactivity from [35S] sulphadiazine in transplanted material. When implanted in mice, the beads gave effective protection against repetitive (weekly) infective challenges with P. berghei by implanted beads at dosages equivalent to 57 mg kg(-1) sulphadiazine and greater over 21 weeks.

Animals↗

Cellular glycosaminoglycans in lymphocytes from patients with cystic fibrosis.

Cellular glycosaminoglycans were isolated from lymphocytes from patients with cystic fibrosis and controls. The isolated glycosaminoglycans were fractionated by cellulose acetate electrophoresis, analyzed for glucosamine and galactosamine content, and subjected to hydrolysis with bovine testicular hyaluronidase. The total glycosaminoglycan content, the per cent glucosamine and galactosamine, and the distribution of cellular glycosaminoglycans in circulating lymphocytes in cystic fibrosis were no different from controls.

Cystic Fibrosis↗

Generation of T memory cells in one-way mixed lymphocyte culture. IV. Primary and secondary responses to soluble and insoluble membrane preparations and to ultraviolet-light-inactivated stimulator cells.

Neither normal CBA (H-2k) nor purified spleen T cells respond in vitro to soluble or insoluble membrane preparations or to ultraviolet-light-inactivated stimulator cells of the allogeneic DBA/2 (H-2d) strain. However, CBA spleen cells deprived of phagocytic cells show a slight proliferative response under these conditions. After being primed against mitomycin-blocked DBA/2 cells in one-way mixed lymphocyte culture, the secondary blast-derived T 'memory' cells display a good secondary blast (proliferative) response to both membrane antigens and to ultraviolet-light-inactivated stimulator cells. In addition to this, the secondary T lymphocytes--in contrast to nonprimed T cells--respond by cytotoxicity when ultraviolet-light-inactivated cells are used as the second stimulant.

Animals↗

Electrophoretic fractionation of guniea pig lymphocytes: evidence for different subsets of T and B cells in spleen and lymph node.

Guinea pig lymph node and blood lymphocytes have been physically fractionated in preparative cell electrophoresis into two functionally viable populations, the high mobility cell population (HMC) and the low mobility cell population (LMC). By using cell surface markers and functional tests known to be specific for T and B lymphocytes, respectively, it is shown that the T lymphocytes localize in the HMC population and the B lymphocytes in the LMC population. The spleen lymphocytes do not separate into the two populations. They move into one single broad peak containing both T and B cells. This finding indicates the presence of electrokinetically different subsets of T and B lymphocytes in the spleen on one hand and in the lymph node and blood on the other hand.

Animals↗

Heat sterilization of water in a large open vessel.

A safe, convenient, and economical method of preparing and dispensing a large volume of sterile water in a movable container is described. A caster-mounted, rectangular, 100-gal, stainless-steel water tank was fabricated. An audible, solid-state water-level alarm was developed for use with a detachable sensing probe that could be autoclaved. A filter system was constructed to allow the tank to be autoclaved as an open vessel. Thermocouples were mounted within the tank of water to study the time-temperature relationships of the water during the sterilization cycle. In a downward displacement autoclave with a hot jacket, 75 min were required for the water temperature to rise from 140 to 240 F (60 to 116 C). A total of 3 hr for heating and holding includes an adequate safety factor to insure the sterility of the water immediately after autoclaving. The long-term sterility of the water and the safety of the system were verified by using the water to maintain a germ-free animal colony.

Hot Temperature↗