Choosing a future from a murky past: A generalization-based model of behavior.

Remembering the past appears critical in allowing organisms to detect order in an environment, and hence to behave in accordance with likely future events. Yet the shortcomings of remembering and perceiving typically mean that the remembered past differs from the actual past, and hence that behavior does not perfectly track the structure of the environment. Here, we outline how the process of generalization might be used to understand differences between what an organism does, and the structure of the past and potential structure of the environment. We explore how different sources of generalization - both from within the same stimulus situation, and from different stimulus situations - might be modeled quantitatively, and how predictions made by this modeling approach are supported by research. Finally, we discuss how generalization from multiple stimulus situations, longer-term experience, and from stimulus situations in the past that are not identical to the stimulus situation in the present, might contribute to our understanding of how an organism's experience translates into behavior.

Hypermobility of the first ray in patients with planovalgus feet and tarsometatarsal osteoarthritis.

BACKGROUND: Hypermobility in the foot is a common observation but difficult to quantify. Primary tarsometatarsal arthritis is less common and its aetiology uncertain. This study introduces a novel means of clinical measurement for range of motion of the medial column and investigates the association between hypermobility, planovalgus foot shape and tarsometatarsal arthritis. METHOD: 32 planovalgus feet with symptomatic tarsometatarsal arthritis were compared with 36 controls. Radiographic angular measurements and arthritic grade were recorded from standing radiographs. Medial column flexion and extension was measured clinically using a validated electronic goniometer. RESULTS: There was a significant difference in medial column range of motion between the patient and control groups (17±5° compared to 9±3° [P<0.001]). CONCLUSION: Patients with planovalgus feet and tarsometatarsal osteoarthritis have greater range of motion of the medial column than controls with normal feet when measured using this technique. Recognition of this association may lead to progress in prevention and treatment.

Hepatic abscesses after liver transplantation secondary to traumatic intrahepatic bile duct injuries in a cadaveric allograft donor.

We report the case of an ultimately successful liver transplant recipient whose post-transplant course was complicated by the early development of multiple abscesses in the graft. Post-transplant cholangiography identified multiple shear injuries to the second and third order intrahepatic bile ducts, originating from blunt trauma to the donor liver. Treatment was non-operative following recent reports of the successful management of intrahepatic bile duct injury in the stable trauma patient. This discussion adds to the limited literature available on the transplantation of injured donor livers, despite this being a relatively common practice. Further experience is needed in determining the appropriate criteria for the use of traumatized donor livers. Cholangiography carried out on the back table may help to determine if such injured livers are suitable for transplantation.

Germline truncating mutations in both MSH2 and BRCA2 in a single kindred.

There has been interest in the literature in the possible existence of a gene that predisposes to both breast cancer (BC) and colorectal cancer (CRC). We describe the detailed characterisation of one kindred, MON1080, with 10 cases of BC or CRC invasive cancer among 26 first-, second- or third-degree relatives. Linkage analysis suggested that a mutation was present in BRCA2. DNA sequencing from III: 22 (diagnosed with lobular BC) identified a BRCA2 exon 3 542G>T (L105X) mutation. Her sister (III: 25) had BC and endometrial cancer and carries the same mutation. Following immunohistochemical and microsatellite instability studies, mutation analysis by protein truncation test, cDNA sequencing and quantitative real-time PCR revealed a deletion of MSH2 exon 8 in III: 25, confirming her as a double heterozygote for truncating mutations in both BRCA2 and MSH2. The exon 8 deletion was identified as a 14.9 kb deletion occurring between two Alu sequences. The breakpoint lies within a sequence of 45 bp that is identical in both Alu sequences. In this large BC/CRC kindred, MON1080, disease-causing truncating mutations are present in both MSH2 and BRCA2. There appeared to be no increased susceptibility to the development of colorectal tumours in BRCA2 mutation carriers or to the development of breast tumours in MSH2 mutation carriers. Additionally, two double heterozygotes did not appear to have a different phenotype than would be expected from the presence of a mutation in each gene alone.

Archeological evidence of parasitic infection from the 19th century company town of Fayette, Michigan.

Archeological deposits from the 19th century company town of Fayette, Michigan were analyzed for evidence of endoparasitic infection in the human population residing in the town between 1867 and 1891. Three privies were associated with upper-income and middle-income neighborhoods; 2 household refuse disposal areas were found in a predominately lower-income immigrant working class neighborhood. Sediment samples from 2 privies associated with dwellings in the middle-income neighborhood were positive for eggs of the human whipworm Trichuris trichiura. The parasite was probably also present among residents of the lower income neighborhood, but the shallow nature of the refuse deposits in that locality precluded preservation of the eggs. Contemporary epidemiologic studies of helminth infections support the belief that T. trichiura may have been a common parasite of 19th century school-age children given the natural inclination of young children to defecate indiscriminately, play freely in the dirt, and eat without washing their hands.

Payment by salary or fee-for-service. Effect on health care resource use in the last year of life.

OBJECTIVE: To investigate the effect of physician payment method on use of health care resources. DESIGN: Retrospective analysis of patient health care data collected for 3 years (1994 to 1996) from the Vital Statistics Department of the British Columbia Ministry of Health. Billing numbers identified physician payment method. SETTING: Salaried and fee-for-service primary care practices in the Capital Region District of Victoria, BC. PARTICIPANTS: A total of 582 patients in their last year of life: 106 were attended by salaried family physicians at a community health clinic; 476 were attended by fee-for-service practitioners. Groups were comparable in age, sex, and geographical location. MAIN OUTCOME MEASURES: Number and cost of specialist and diagnostic services and medications, number of days in hospital (acute and extended care), and main causes of death. RESULTS: None of the dependent measures showed any statistically significant differences based on comparisons between many variables for patients in the two groups. Costs of pharmaceutical, specialist, and diagnostic services were not significantly different for the two groups. There were three main causes of death, according to codes on death certificates: heart disease, malignant neoplasms, and cerebrovascular disease. CONCLUSION: Whether physicians were paid by salary or fee-for-service had no empirical effect on health care resource use.