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Biomedical subjects

M M Lane

Publications and source records attributed to M M Lane.

At least 19 recordsLinked to original sources

Early detection of colorectal cancer by quantitative fluorescence image analysis of exfoliated cells.

Early-stage colorectal cancer is potentially curable. In the present study, we applied quantitative fluorescence image analysis (QFIA) cytology to the detection of experimental colorectal cancer in a rodent model. QFIA cytology combines visual cytologic examination with quantitation of DNA content in single exfoliated cells. Cancer was induced by treating 110 rats with subcutaneous 1,2-dimethylhydrazine. Sequential colon washes were obtained weekly from each animal for 20 weeks. Control animals were treated identically except for the administration of carcinogen. Cells that were cytologically abnormal or had increased DNA content were found starting in the second week. By the eighth week, roughly 50 percent of animals had positive results, and this level remained approximately constant for the duration of the study. Tissue pathologic results were normal during weeks 1 to 7. Dysplasias became common during weeks 8 to 15 whereas most cancers appeared during weeks 16 to 21. These results indicate that QFIA cytology is a highly sensitive method for detecting even preneoplastic changes resulting from carcinogen administration and may prove useful in detecting human colorectal cancer.

Animals

Effects of prior administration of steroids upon recovery from lethal sepsis.

The effects upon survival of large doses of steroid administered to dogs prior to challenging them with lethal sepsis was evaluated in this study. Dogs were given 30 milligrams per kilogram of body weight per day of methylprednisolone sodium succinate for one, two or eight days and then were infused with 9.72 +/- 0.35 X 10(9) Escherichia coli per kilogram of body weight. All dogs in group 1 (n equals six) not given steroid died within 25 hours. Of the dogs in group 2 (n equals 12) given one or two doses of steroid previously, 42 per cent permanently survived (more than seven days). All dogs in group 3 (n equals five) given eight daily doses of steroid prior to infusion of Escherichia coli died within 17 hours. Dogs in group 4 (n equals six) were given eight daily doses of steroid prior to infusion of Escherichia coli and treated on the day of infusion of Escherichia coli with a regimen of methylprednisolone and gentamicin sulfate which results in a 100 per cent survival rate when given to dogs that have not received prior treatment with steroid. Thirty-three per cent of the dogs in group 4 permanently survived. One or two daily large doses of steroid did not detrimentally affect survival of the dogs. Eight days of steroid administration suppressed endogenous cortisol production. When the dogs were treated with six hours of steroid-antibiotic therapy, survival benefits were limited.

Adrenal Cortex Hormones

Reoperation in congenital aortic stenosis.

Over a 22-year period, 81 patients underwent initial operations for critical aortic stenosis at our institution. Their ages ranged from 3 days to 20 years (mean, 7.3 +/- 5.9 years). Fourteen (17%) were infants less than 1 year old. Three children died perioperatively (3.7%). We have followed the survivors and 3 children who underwent initial operations elsewhere for a mean of 9.0 +/- 6.8 years (range, 2 to 23 years). To the present, 27 patients have undergone one reoperation (24 of our initial survivors) at a mean interval of 7.3 years, with 2 perioperative deaths. Ten of these patients have required a second reoperation at a mean interval of 3.7 years, with 2 deaths perioperatively. There were 3 late cardiac deaths after the initial procedure and 1 after a third operation. Actuarial reoperation-free survival is 56.7% at 10 years. While overall survival is 88.6% at 10 years, we find a significantly poorer survival among those patients with valvular stenosis compared with those with subvalvular lesions (p = 0.03). We believe that for children with all levels of aortic stenosis, good functional results and survival can best be obtained by follow-up, recatheterization, and reoperation.

Actuarial Analysis

Trends in bacterial susceptibility to antimicrobial agents.

Concern over the development of drug resistance by common pathogens has grown over recent years. In order to discover and describe possible trends at this institution, susceptibility data for 18 organisms and 21 antimicrobial agents for the years 1975 through 1982 at the Veterans Administration Medical Center in Oklahoma City were reviewed. Summaries of susceptibility data for 64 major combinations of drugs and organisms are presented. Two gram-positive organisms (enterococcus group D and Staphylococcus aureus) as well as a gram-negative (Pseudomonas aeruginosa) appear to be decreasing in susceptibility to several drugs. However, some gram-negative bacilli (Proteus, Serratia, and Enterobacter spp. and Klebsiella pneumoniae) showed evidence of markedly increasing susceptibility to certain drugs.

Anti-Bacterial Agents

Senning repair for transposition of the great arteries in the first week of life.

Infants with D-loop transposition of the great arteries (D-TGA) may have unacceptable results after the balloon septostomy while awaiting surgery. It has been our policy to repair defects in infants with D-TGA and intact ventricular septum or small ventricular septal defect at the time of diagnosis. We report our experience with the Senning operation in 18 newborns less than 1 week of age. The mean age at operation was 3 days (range 12 hr to 7 days) and the mean weight was 3.5 kg (range 2.8 to 4.8). There were two early postoperative deaths (11%) and one late death (5%). Early mortality was associated with preoperative acidosis and congestive heart failure. Late mortality was associated with severe left ventricular outflow tract obstruction (LVOTO). The 15 long-term survivors have been followed for an average of 27 months and 11 of the 16 perioperative survivors have undergone postoperative catheterizations. There was no evidence of systemic or pulmonary venous obstruction. One patient developed LVOTO that led to his death. Two patients had residual atrial shunts. Electrocardiograms revealed no major arrhythmias. All patients are clinically asymptomatic. Good hemodynamic, electrocardiographic, and clinical results can be obtained with correction of D-TGA in the first week of life.

Arteries

Renal gluconeogenesis and increased glucose utilization in shock.

The roles of renal gluconeogenesis and glucose utilization in control, hemorrhaged, and endotoxin-injected animals were investigated using anesthetized, eviscerated, nonnephrectomized and nephrectomized dogs. Results demonstrate an increased glucose utilization in both hemorrhagic and endotoxic shock which was marked after endotoxin. Since blood glucose values dropped more in nephrectomized, hemorrhaged animals, in contrast to the nonnephrectomized, hemorrhaged dogs, the kidneys were assumed to perform a significant gluconeogenic role. The kidneys did not appear to perform gluconeogenesis in endotoxin shock since blood glucose levels were comparable in eviscerated, endotoxin-treated animals whether nephrectomized or not. To ascertain the tissue responsible for the increased glucose utilization in endotoxin shock, a study was performed with endotoxin added to blood in vitro (estimated LD100 concentration). The endotoxin-treated blood (n = 7) demonstrated an increased glucose utilization compared with saline controls (n = 7) (P less than or equal 0.02). Acclerated glucose utilization rates were comparable between the eviscerated, nephrectomized animals and in vitro experiments. These data suggest that excessive glucose demand by certain blood components may partially explain the lethal hypoglycemia of endotoxin shock.

Animals