Heuristics and bias in homeopathy

The practice of Homeopathy ought to be strictly logical. In the Organon Samuel Hahnemann gives the impression that the unprejudiced observer should be able to follow an algorithmic route to the simillimum in every case. Judgement and Decision Research, however, indicates that when people grapple with complex systems like homeopathy they are more likely to use heuristics or empirical rules to help them reach a solution. Thus Hahnemann's concept of the unprejudiced observer is virtually impossible to attain. There is inevitable bias in both case-taking and remedy selection. Understanding the types of bias may enable the practitioner to reduce his/her own bias.     

Outcomes of hospitalization in pregnant women with CNS neoplasms: a population-based study

Managing a CNS neoplasm during pregnancy presents complex challenges, and population-based studies are lacking. We designed a retrospective cohort study using the Nationwide Inpatient Sample (NIS) to investigate pregnancy outcomes in women with CNS neoplasms. We constructed a logistic regression model for maternal mortality, preterm labor, intrauterine growth restriction (IUGR), and Caesarean delivery, controlling for age, comorbidities, and demographic characteristics. We identified 379 malignant brain tumors, 437 benign brain tumors, and 44 spine tumors among 19 million pregnancy-related admissions from 1988 through 2009. Malignant brain tumors were associated with maternal mortality (odds ratio [OR], 143), preterm labor (OR, 3.4), and IUGR (OR, 2.9). Benign brain tumors were associated with preterm labor (OR, 2.3). A diagnosis of hyperemesis gravidarum was more common in malignant (OR, 2.2) and benign (OR, 2.8) brain tumors. Compared with the general population, Caesarean delivery was more frequent for malignant (OR, 6.4) and benign (OR, 2.8) brain tumors and spine tumors (OR, 3.9). Admission without delivery was more common for malignant (OR, 8.6) and benign (OR, 4.3) brain tumors and spine tumors (OR, 3.8; P < .05 for all outcomes). Thirty-three percent of all hospitalizations involved neurosurgical procedures, but pregnancy complications were not significantly more likely to occur in surgical patients. In conclusion, malignant brain tumors were associated with adverse pregnancy outcomes, and CNS neoplasms were associated with higher rates of Caesarean delivery. Additional research is needed to improve understanding of obstetric risk in these patients and to assist with treatment, counseling, and monitoring during delivery.     

Perturbations in the fibrinolytic pathway abolish cyst formation but not capillary-like organization of cultured murine endothelial cells

Fibrinolytic activity and its relation to morphogenesis was investigated in several transformed murine endothelial cell lines and primary cultures of endothelial cells. Two in vitro systems, fibrin gels and Matrigel (Collaborative Research, Bedford, MA), were used. Fibrin gels model a fibrin-rich extracellular matrix that frequently supports neovascularization in vivo, and Matrigel models the basement membrane surrounding quiescent endothelial cells in vivo. The transformed endothelial cell lines have higher levels of plasminogen activator (PA) mRNA than primary cultures of endothelial cells, and an increased PA-mediated proteolytic activity was correlated with formation of cysts in fibrin gels. Addition of neutralizing anti- urokinase antibodies, plasminogen depletion, or addition of a plasmin inhibitor prevented cyst formation. Addition of plasminogen restored the ability to form cysts in the plasminogen-depleted system. Normal endothelial cells organized into capillary-like structures in fibrin gels regardless of manipulations affecting the fibrinolytic pathway. In Matrigel, both transformed and primary cultures of endothelial cells rapidly formed a capillary-like network that was not affected by plasminogen depletion or addition of plasmin inhibitors. Thus, elements of the fibrinolytic pathway necessary for cyst formation are not critical in capillary-like structure formation on a reconstituted basement membrane. These results suggest that plasmin is essential for hemangioma formation but is not critical to the organizational behavior of normal endothelial cells.     

Idiopathic hyperphosphatasia with dermal pigmentation. A twenty-year follow-up

Hyperphosphatasia, or hereditary bone dysplasia with hyperphosphatasaemia, is a rare genetic disorder which is characterised by failure to transform woven into lamellar bone. Clinical, radiological and histological features establish the diagnosis, fractures, deformities, diffuse sclerosis on radiographs and high serum alkaline phosphatase being characteristic. We report the case of a 27-year-old man with follow-up at the same hospital for 20 years. Attempts at treatment with calcitonin and disocium etidronate (EHDP) failed, but stapling of the growth plates at the knee was successfully performed. Transverse "brittle" fractures of the humerus, lower leg and ribs healed normally, but internal fixation and late bone grafting were required for a subtrochanteric stress fracture of the femur at the age of 24 years. At present the patient has no clinical problems and leads a normal life.     

Role of small GTPases in Trypanosoma cruzi invasion in MDCK cell lines

Trypanosoma cruzi can modulate a large number of host intracellular responses during its invasion. GTPases such as RhoA, Rac1 and Cdc42 are examples of molecules that could be activated at this moment and trigger changes in the pattern of F-actin cytoskeleton leading to the formation of structures like stress fibers, lamellipodium and fillopodium, respectively. Here we investigate the role of these GTPases in the cytoskeletal rearrangement of MDCK cell transfectants expressing variants of RhoA, Rac1 and Cdc42 during T. cruzi infection. The adhesion, internalization and the survival rate were determined. Rac1 mutants showed the higher adhesion and internalization indexes but the lower survival index after 48 h of infection. Confocal laser scanning microscopy showed changes in the pattern of F-actin distribution and reorganization at the site of trypomastigote invasion. These observations suggest that these GTPases act in the signaling mechanisms that affect the F-actin cytoskeleton during T. cruzi invasion.