Spermatocytic seminoma of testis with sarcomatous transformation. A report of five cases

Five cases of spermatocytic seminoma of the testis associated with a sarcomatous component, one of them of rhabdomyosarcomatous type, are presented. No recognizable teratomatous structures were identified in any of the cases. The presence of the sarcomatous elements transformed the usually innocuous spermatocytic seminoma into a highly aggressive neoplasm, which led to the patients' death in at least two cases. The sarcomatous elements may represent a nonseminomatous germ cell component, but we prefer to view them as an expression of anaplastic transformation of the tumors, analogous to that seen in tumors in other organs.     

Pattern-dependent, simultaneous plasticity differentially transforms the input-output relationship of a feedforward circuit

Memories are believed to be encoded by changes in the synaptic connections between neurons. Although many forms of synaptic plasticity have been identified, it remains unknown how such changes affect local circuits. Feedforward inhibitory networks are a common type of local circuitry and occur when principal neurons and their afferent inhibitory interneurons receive the same input. Using slices of cerebellar cortex, we explored how synaptic plasticity at multiple sites within a feedforward inhibitory network consisting of parallel fibers, interneurons, and Purkinje neurons alters the output of this circuit. We found that stimuli resembling baseline activity potentiated feedforward excitatory and simultaneously depressed feedforward inhibitory pathways. In contrast, stimuli resembling sensory-evoked patterns of firing potentiated both types of feedforward connections. These distinct forms of ensemble plasticity change the way Purkinje neurons subsequently respond to inputs. Such concerted changes in the circuitry of cerebellar cortex may contribute to certain forms of sensorimotor learning.     

Acute lung injury after blood transfusion in mechanically ventilated patients

BACKGROUND: Liberal transfusion strategy increases the risk of acute lung injury (ALI), but specific transfusion-related factors have not been characterized. We tested the hypotheses that storage age and specific type of blood products are associated with increased risk of ALI in mechanically ventilated patients. STUDY DESIGN AND METHODS: From a database of mechanically ventilated patients, we identified those who received blood products during the first 48 hours of intensive care. We extracted information about underlying ALI risk factors as well as the type, amount, and shelf age of administered blood products. Outcome was assessed by an independent, blind review of chest radiographs and clinical findings. RESULTS: Of 181 patients transfused during the first 48 hours of mechanical ventilation, 60 (33%) developed ALI. There was no difference in average duration of red blood cells storage between patients who did and did not develop ALI (median, 18.5 vs. 17.5 days; p = 0.22). In a multivariable logistic regression analysis, important risk factors associated with the development of ALI were thrombocytopenia (odds ratio, 5.9; p = 0.004) and transfusion of fresh frozen plasma (odds ratio, 3.2; p = 0.023). CONCLUSION: Thrombocytopenia and transfusion of fresh frozen plasma, but not storage age of red blood cells, were associated with the development of ALI in this cohort of mechanically ventilated patients.     

Evaluating the Fabreville Heart Health Program in Laval,Canada: a dialogue between two paradigms,positivism and constructivism

As part of the Canadian Federal-Provincial Initiative in Heart Health, the goal of the Fabreville Heart Health Program was to sensitize a district of Laval, Quebec's second most populous city, to heart-healthy behaviours. The program was planned and implemented by a committee composed of Fabreville community leaders and professionals from the Public Health Department. Between 1992 and 1994, intervention objectives were defined by the department in terms of changing individual behaviours associated with cardiovascular risk factors, namely diet, sedentariness and smoking, as well as adapting physical and social environments to facilitate these changes. However, from 1994 to its conclusion in 1997, the program was re-oriented to engage the population in mobilizing their own community and taking charge of interventions themselves. Actions then became dependent on the interests and motivation of Fabreville residents to transform their lifestyles and aspects of their physical environment. The initial evaluation process, based on the positivist paradigm, was designed to measure changes in individual behaviours and certain physical environments, such as an increase in designated non-smoking areas. However, following the re-orientation towards community mobilization, it was decided that evaluation should go beyond the professional production of data to include a process of the collective construction of knowledge. Evaluation methodology then became based on the constructivist paradigm. Yet field constraints such as lack of community involvement in both leadership and process evaluation, and the need to ensure evaluation standards and fulfil sponsor obligations, compelled the Public Health Department to return to using a certain number of positivist methods. The ensuing inter-paradigm dialogue helped broaden the scope of evaluation and contributed to gaining a more in-depth understanding of the processes and outcomes of community mobilization.     

Colorectal carcinoma in black and white race

Worldwide, colorectal carcinoma (CRC) varies by race-ethnicity. The highest incidence occurs in whites of European descent. Rates in blacks of South Africa are much lower, but rise with migration to westernized countries, i.e. African Americans (blacks) in the US. In the US, CRC age-specific incidence rates increased dramatically with biologic aging for black and white men and women. For all ages, rates were slightly higher for black than for whites. Among whites, overall annual rates peaked in the 1980s then declined. Stage- and subsite-specific rate shifts suggested earlier detection of cancers through screening, particularly in the distal colon. Blacks have not experienced the same stage- and subsite temporal shifts, which were observed in whites. CRC racial differences have been attributed to biologic and/or non-biologic factors as well as to routine screening patterns. Racial variations demonstrate the need for a more comprehensive understanding of colorectal carcinogenesis, epidemiology, and colorectal screening patterns for low- and high-risk populations.