Application of expert systems to mammographic image analysis.

A prototype expert system was designed for differentiation of 16 circumscribed breast abnormalities utilizing findings identified by a human observer from X-ray mammograms, clinical data, and patient history. An off-the-shelf expert system shell served as the foundation for the rule base. The system runs on standard microcomputer hardware. Preliminary results suggest the expert system may be valuable in improving the ability of relatively unskilled observers to screen X-ray mammograms. Overall, radiology residents with limited experience in mammographic image analysis obtained a diagnostic accuracy level of 40% on their own, whereas they attained 73% accuracy level when using the expert system. A group of biomedical engineering students with no prior experience in mammographic image analysis obtained on the average an 80% diagnostic accuracy level utilizing the expert system in comparison with the 70% average accuracy level obtained by practicing radiologists without use of the system.

Oxalate degradation by gastrointestinal bacteria from humans.

Anaerobic bacteria that metabolize oxalic acid have only recently been isolated from the rumen and from other gastrointestinal habitats. They constitute a new genus and species, Oxalobacter formigenes. This report presents the first comparison of cultural counts of these organisms from human feces and indicates that numbers as high as 10(7)/g may be present in feces from normal humans. Rates of oxalate degradation by mixed bacterial populations in feces from seven normal humans ranged from 0.1 to 4.8 mumol/(g X h). With fecal samples from eight patients that had undergone jejunoileal bypass surgery, rates were much lower [0-0.006 mumol/(g X h)]. We propose that oxalic acid degradation by Oxalobacter formigenes may influence absorption of oxalate from the intestine and that lower rates or lack of oxalate degradation in the colons of jejunoileal bypass patients may contribute to the increased absorption of dietary oxalate and the hyperoxaluria commonly associated with such patients.

Oxalate degradation by microbes of the large bowel of herbivores: the effect of dietary oxalate.

Rates of oxalate degradation by microbes in gastrointestinal contents from rabbits, guinea pigs, swine and a horse increased after additional of oxalate to diets. A similar response was previously observed with ruminal microbes from cattle and sheep. Bacterial that utilize oxalate for growth appear to be selected by increased levels of dietary oxalate.

Effect of environmental temperature stress on intramammary infections of dairy cows and monitoring of body and intramammary temperatures by radiotelemetry.

Four dairy cows were stressed by exposure to hot and cold environments in tests to determine the effect of environment on milk yield, somatic cell counts, and California mastitis test scores of milk from all mammary quarters and on bacterial counts of milk from infected quarters. Two cows were held in temperature-controlled rooms for successive 5-day periods at moderate (21 to 28 C), cold (-16 C), moderate, hot (36 to 37 C), and moderate environments. The cold and hot sequences were reversed for the other 2 cows. Temperature transmitters were surgically implanted in the skeletal muscles of the loin and gluteal regions; however, only one of these transmitters (gluteal region) functioned continuously throughout the experiment. At the end of this experiment, a transmitter was implanted in the gland cistern of a rear quarter of 1 cow, and the sequence of holding in the cold before the hot environment was used. Mean body temperature was approximately 1 degree higher (39.2 C) in the hot room (1 cow) and 3 to 4 degrees lower (35 C and 33 C), respectively, for 2 cows) in the cold room than that during the moderate temperature periods. A similar comparison showed that the mean intramammary temperature was 1 to 2 degrees higher (39.5 C) in the hot room and approximately 9 degrees lower (29.4 C) in the cold room. Exposure of the cows to hot and cold environments caused a greater loss in milk production in the 2 medium-yielding cows (23 to 28 kg/day) than in the 2 low-yielding cows (9 to 13 kg/day). The effect of the extreme temperatures on the somatic cell counts in uninfected quarters was limited to only a few quarters and was inconsistent (mean counts increased and decreased at both temperatures). The California mastitis test reactions showed no consistent changes during periods of heat and cold stress. Also, the effect of the environmental temperature on the intramammary infections also was inconsistent. The effect on bacterial counts appeared to vary with the type of organism. Some mean counts decreased in the heat and cold (Streptococcus agalactiae, Micrococcus sp), some increased (Pseudomonas sp), and another seemed independent (Streptococcus uberis) of the environmental temperature at which the cow was held.

Electrocardiographic changes after induced hypercalcemia and hypocalcemia in cattle: reversal of the induced arrhythmia with atropine.

The relationship between the Q-oTc interval of the ventricular complex of calves and cows and the total calcium and calcium ion activity was quantitated. A proportional relationship of the Q-oTc existed between total calcium concentrations in the plasma of 5.5 to 8.2 mEq/L and calcium ion activities of 0.75 to 3.2 mEq/L. At higher calcium concentrations, the relationship was curvilinear and very variable. The Q-oTc interval was lengthened during induced hypocalcemic states and shortened during hypercalcemic states. Hypercalcemia seemed to decrease atrial activity and increase ventricular activity, as evidenced by the appearance of bradycardia, sinus arrest, and ectopic ventricular beats. Vagal activity seemed altered by the changes in plasma calcium concentrations and involved in the production of the arrhythmia, because atropine could abolish the arrhythmia created by the infusion of the calcium solutions.

Preliminary study of appearance of endotoxin in circulatiory system of sheep and cattle after induced grain engorgement.

Edotoxin was detected, using the limulus amebocyte lysate (LAL) test, in the blood of 3 sheep and 1 steer which had been experimentally "overfed" (induced grain engorgement) with a mixture of corn and oats (2:1). The 1st postfeeding blood samples were collected 24 hours after overfeeding. In 2 sheep and 1 steer, the 24-hours blood samples were test positive. In 1 sheep which died, the 48-hour blood sample was the 1st test-positive sample. In all cases, pre-overfeeding blood samples were taken just before overfeeding.

Changes in motility and ph in the digestive tract of experimentally overfed sheep.

Motility of the digestive tract of 4 sheep was studied with radiotelemetric equipment. After base line records were made, each sheep was overfed with 70 g of grain per kilogram of body weight. The ruminoreticulum did not become static until the ingesta pH was less than 5. The cecum had the same patterns of motility and pH as did the ruminoreticulum, but these returned to normal more quickly in surviving sheep. The motility patterns of the abomasum and the small intestine were more erratic. Results indicated that considerable quantities of grain (substrate for microbial growth) reached the cecum before ruminoreticular motility was inhibited.

Physiologic studies of experimentally grain-engorged cattle and sheep.

Seven sheep weighing 34 to 41 kg, each, 3 steers and 1 heifer weighing 230 to 460 kg each, were experimentally, "overfed" (induced grain engorgement). The most significant changes occurred in ruminal ingesta pH, blood pH, packed cell volume (PCV), hemoglobin (Hb), carbon dioxide pressure (PCO2, total CO2 (volume %), blood D-lactic acid, blood HCO3, and base excess. There was no common denominator that was especially pathognomonic.