Radioimmunoguided surgery for colorectal cancer.

BACKGROUND: Improving the survival rate of surgical treatments of cancer depends upon accurate staging of disease and the subsequent ability to completely resect the lesions. Radioimmunoguided surgery (RIGS) has been employed in the treatment of colon and rectal cancer, and a multicenter trial is under way. METHODS: Twenty-eight patients with either primary or recurrent colorectal cancer were injected with the monoclonal antibody CC49 labeled with iodine 125. A hand-held gamma-detecting probe was used intraoperatively to detect radiolabeled antibody. At surgery the patients underwent both traditional and RIGS explorations. RESULTS: RIGS detected radiolabeled antibody in 73% (14 of 19) of patients with primary colorectal cancer and in 100% (7 of 7) of patients with recurrent disease. Based on RIGS, 26% (5 of 19) of patients with primary cancer were upstaged from stage I/II to stage III/IV. CONCLUSIONS: Although the final results of this phase III trial are incomplete, RIGS appears to provide immediate, valuable information that is not available from more conventional methods.

Feeding and mating strategies in anopheles (Diptera: Culicidae): theoretical modeling approach.

The effects of various ecological factors, such as the probability of finding mates and hosts and of successfully obtaining a blood meal, on the mating and feeding strategies of domestic female anopheline mosquitoes was investigated using theoretical models. The models calculated the mean fitness of 1,000 nonblood-fed, anautogenous, virgin anophelines. One model simulated females that always mate before blood feeding, whereas another simulated females that are able to feed opportunistically if a host was detected before they mated. The models demonstrated highest fitness for mosquitoes capable of opportunistic feeding under nearly all simulated conditions. This advantage increased as the probability of finding hosts and mates decreased as a function of host and mate availability.

Host response profiles: a new theory to help us understand why and how attractants attract.

Much insect behavior is better described in terms of response profiles than by classical stimulus-response patterns; the response to a particular stimulus may vary with changing internal and external conditions, making it important to qualify statements such as "compound X is an attractant." Because of the large number of conditions that may affect responses, it is crucial to develop a theoretical basis to direct the collection of field and experimental data, and their interpretation. A theory-driven model can help us predict response profiles over a wide range of such conditions. We describe an example of such a model, the assumptions upon which it is based, how the model is constructed, and the types of results that a computer implementation of the model can produce.

Screening for colorectal cancer: the rationale and a recent advance in the detection of fecal occult blood.

For the very first time, an occult blood test has been designed to conform to convenient and natural bathroom habits. For the very first time, we therefore expect the general public to agree willingly to participate in occult blood testing. For the very first time, we expect Early Detector to successfully screen the general public, so that survival rates from colon and rectal cancer may show a significant improvement in the next decade.

Sulindac suppression of colorectal polyps in Gardner's syndrome.

Sulindac causes both regression and suppression of colorectal polyps in patients with Gardner's syndrome and familial polyposis coli. Three patients with Gardner's syndrome and multiple colonic polyps had complete regression of polyps after two to three months of sulindac therapy. The implication that sulindac may prevent colorectal cancer and prophylactic surgery in patients with hereditary polyps of the colon is intriguing but has not yet been substantiated.

The cause and treatment of idiopathic pruritus ani.

Six common foods can cause the clinical entity called "idiopathic" pruritus ani. They are coffee, tea, cola, beer, chocolate, and tomatoes. Pruritus ani occurs in 24 to 48 hours when a patient consumers more than a threshold amount of one or more of these foods and disappears spontaneously in a few days provided the threshold is not exceeded again.

The study of insect blood-feeding behaviour. 2. Recording techniques and the use of flow charts.

This paper continues a discussion of approaches and methodologies we have used in our studies of feeding in haematophagous insects. Described are techniques for directly monitoring behaviour: electrical recording of feeding behaviour via resistance changes in the food canal, optical methods for monitoring mouthpart activity, and a computer technique for behavioural event recording. Also described is the use of "flow charts" or "decision diagrams" to model interrelated sequences of behaviours.

The study of insect blood-feeding behaviour. 1: Feeding equipment, physical and endogenous factors, dose effect analysis, and diet destination.

Experimental techniques that we have found useful during our studies of insect blood-feeding behaviour are reviewed. Some of the principal findings resulting from these techniques are discussed. Where directly applicable, the work of others is included, but no complete review of the subject has been attempted.

Dietary restrictions and fecal occult blood testing.

"Unprepped" sigmoidoscopy and fecal occult blood testing were performed simultaneously in 1,000 patients with no dietary restrictions. A total of 102 patients had a positive fecal occult blood test. Of these, 86 had visible blood in the rectum as demonstrated by sigmoidoscopy. Only two of the remaining 16 patients probably had a dietary-induced false-positive result on the occult blood test. Dietary restrictions for guaiac occult blood testing are unnecessary in more than 99 percent of patients.

A general theory for host seeking decisions in mosquitoes.

We develop a theory for host seeking decisions in mosquitoes that explicitly considers the tradeoffs mosquitoes face in allocation to somatic and gametic function. Specifically, we consider conditions under which mosquitoes should seek out nectar and blood hosts upon encountering host odours. Results from development of a dynamic model that considers free and crop energy states suggest that mosquitoes should seek out blood hosts under a wide variety of conditions but that decisions to seek nectar depends upon crop volume, concentration and free energy. This pattern arises because mosquitoes carrying large crop loads are constrained in their ability to obtain large blood meals due to space limitations in the abdomen. The predicted patterns of behaviour are supported by published observations of mosquito behaviour.

Diphosphoglycerate and phytic acid as feeding stimulants for the blood-feeding bug Rhodnius prolixus.

1. The compounds 2,3-diphosphoglycerate (DPG), phytic acid (PA) and adenosine triphosphate (ATP) were tested as gorging stimulants for Rhodnius prolixus. All three are potent phagostimulants, with ED50 values less than 10 microM; in contrast, only ATP stimulates the black fly Simulium venustum, with an ED50 of 13 microM. 2. Equimolar mixtures of DPG and ATP showed pronounced synergism, causing 75% of test R. prolixus to gorge at a dose of 0.3 microM. 3. The response to DPG and PA supports the hypothesis that R. prolixus detects blood during biting by tasting signal chemicals released from red blood cells.

Outpatient anorectal surgery.

Over a period of 16 months, three-fourths of the proctologic surgery performed by our clinic was done on an outpatient basis. By doing so, 1,200 patient visits and approximately 300 histories, physicals, and discharge summaries are eliminated, while obviously benefiting patients and reducing health care costs. Thus, we can conclude that hospitalization is not necessary for the majority of proctologic surgery patients.

Purinergic reception by culicine mosquitoes.

1. Adult female Culex pipiens and Culiseta inornata have purinergic receptors that respond to extracellular ADP and related compounds. Stimulation of these receptors caused ingestion of artificial diets. Addition of bicarbonate to the saline solvent enhanced the phagostimulatory effect. Saline-bicarbonate was as effective a solvent as blood plasma for Cx. pipiens, and was used in the dose-effect determinations. Ranking of the potencies was: ADP greater than AMP-PNP greater than ATP = AMP greater than AMP-PCP much greater than 2'dAMP greater than 2'dADP greater than 2'dATP. At 1 mM concentration, ITP, GTP, CTP, UTP, c-AMP, 2'AMP, 3'AMP, DPG, or GSH + glucose caused fewer than 50% of the insects to gorge, as did 2'3'dd-ATP, A tetra P, and AMP-CPP at 100 microM. 2. The potency ranking for Cu. inornata was: ADP greater than AMP-PNP greater than ATP greater than AMP-PCP much greater than AMP much greater than AMP-S. The concentrations required to produce the ED50 response (inducing 50% of the test insects to gorge) were much higher than those required for Cx. pipiens; however, saline, not saline-bicarbonate, was used as the solvent. With the exception of the very low potency of AMP for Cu. inornata, the ADP potency index values for the other chemicals tested on both species are similar.(ABSTRACT TRUNCATED AT 250 WORDS)