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Biomedical subjects

R H Larson

Publications and source records attributed to R H Larson.

At least 19 recordsLinked to original sources
PubMed1982

Esophageal manifestations of Crohn's disease.

Two patients with concurrent esophagitis and ileocolitis due to Crohn's disease are presented. The initial feature of esophageal involvement was dysphagia caused by severe inflammation of the distal esophagus with mucosal ulcerations and polypoid folds. Long-term observation of both cases revealed a gradually progressive course leading to development of rigid esophageal structure, intramural sinus tract, and esophagobronchial or esophagogastric fistulas. The clinical and radiographic manifestations of Crohn's esophagitis in these 2 patients and in 18 previously reported cases are reviewed.

Adult↗
PubMed1982

Automation of internal library operations in academic health sciences libraries: a state of the art report.

A survey of automated records management in the United States and Canada was developed to identify existing on-line library systems and technical expertise. Follow-up interviews were conducted with ten libraries. Tables compare the features and availability of four main frame and four minicomputer systems. Results showed: a trend toward vendor-supplied systems; little coordination of efforts among schools; current system developments generally on a universitywide basis; and the importance of having the cooperation of campus computer facilities to the success of automation efforts.

Automation↗
PubMed1981

The morbidity of total thyroidectomy.

Of 245 total thyroidectomies done over a ten-year period, most were in patients who had previously received irradiation about the head and neck for benign conditions in infancy and childhood. There was no operative mortality, and only one patient had postoperative bleeding requiring reoperation. Of six patients with paralyzed recurrent laryngeal nerves in the immediate postoperative period, vocal cord function returned in all but one over one year. Forty-nine patients required at least one dose of calcium postoperatively, and 41 were taking calcium when discharged from the hospital. After one year, only two patients took calcium regularly; in both, lymph nodes were removed from both paratracheal grooves. In evaluating comparative statistics, increased morbidity of total thyroidectomy needs to be considered on a long-term basis rather than in the immediate postoperative period.

Adult↗
PubMed1979

Pancreatic duct arteriovenous fistula and the metastatic fat necrosis syndrome.

This report summarizes the course of a patient with asymptomatic chronic pancreatitis associated with hemorrhage into the pancreatic duct and metastatic fat necrosis. Retrograde cannulation of the pancreatic duct and superior mesenteric arteriography established the presence of a pseudocyst with a pancreatic duct-arteriovenous (DAV) fistula as the cause of the syndrome. Ligation of feeder vessels with external drainage of the cyst as the initial surgical procedure stopped the bleeding but failed to prevent recurrence of the pancreatic duct-venous fistula. A pancreaticoduodenectomy with resection of the cyst and fistula was required to arrest destruction of distant tissues. Although serum and urine amylase concentrations were markedly elevated, serum lipase levels were normal throughout the patient's course. Elevation of serum lipase does not seem to be a necessary condition for the development of the metastatic fat necrosis syndrome.

Adult↗
PubMed1978

Effect of dextranase on plaque formation and caries development in the rat.

Plaque formation and caries development were studied in 0-M rats fed Diet 2000 and infected with S. mutans 6715 and fecal flora from older caries-active rats. Merck dextranase, Beckman dextranase or Beckman glucanase 447 were administered singly or in combination to groups of 12 rats either as an addition to the diet or as a "mouthwash" twice daily, 5 per week. All enzymes studied were associated with significant inhibition of both plaque formation and caries development, especially on the buccal and lingual surfaces.

Animals↗
PubMed1978

Sources of variability in rat caries studies: microbial infection and caging procedure.

Two sources of variability in rat caries experiments have been investigated: infection with two S mutans strains and two types of caging. Results indicated that strain 6715 was more virulent than was strain 10449 when 24-day-old rats were orally infected with the organism under standardized conditions. Caging of rats (2 per cage) in stainless steel, raised bottom cages resulted in higher level of caries than in plastic tubs (3 per cage) with hardwood bedding. Infection and caging conditions are two of the factors which may contribute to variability in caries pattern and severity in experimental rats.

Age Factors↗
PubMed1977

Collaborative evaluation of a rat caries model in six laboratories.

When highly controlled parallel rat caries studies were run simultaneously in six laboratories, a similar pattern of caries developed in every laboratory with a range in mean values such that the results of no investigator were significantly different from those of at least two others. These results indicate that the major factors influencing development of rat caries have been recognized and can be controlled within reasonable limits.

Animals↗
PubMed1974

Diminished virulence of glucan synthesis-defective mutants of Streptococcus mutans.

The virulence of cell surface-associated, glucan synthesis-defective mutants of Streptococcus mutans strain 6715-13 was studied. Representatives from three groups of such mutants were tested for their pathogenicity in conventionalized, specific pathogen-free rats and gnotobiotic rats. The mutants differ from the wild-type strain in that each failed to form plaque on the smooth surfaces of the teeth and to cause smooth surface caries. Although the ability to form cell surface-associated glucans was not a strict requirement for the expression of virulence in the sulci of the teeth, it augmented virulence at such sites. However, the ability to form cell surface-associated glucans and to adhere to the teeth was clearly not the sole determinant of virulence.

Animals↗