Use of the ATP bioassay to assess toxic effects in marsh treatment systems

A firefly luciferase bioluminescent assay of bacterial adenosine triphosphate (ATP) was used to measure the toxic effects of metal ions on six bacterial genera isolated from two geographically different marsh treatment systems. The toxicity of eleven different metals, as well as metal mixtures, was monitored using the agar plate test and the resazurin reduction test in addition to measurement of intracellular ATP. All the organisms surveyed tended to be sensitive to much lower concentrations of metals when the metals were present in mixtures. Isolates from a marsh system constructed on normal soil exhibited lower metal resistance patterns than organisms isolated from a marsh built on mine tailings. The intracellular ATP assay appeared to be the most sensitive method of determining the viability of bacterial cells following metal treatment.     

Dominant A1: angiographic and clinical correlations with anterior communicating artery aneurysms.

It has been observed but never proven that anomalies of the anterior communicating artery complex are associated with anterior communicating artery aneurysms (ACAA). Therefore, in an effort to understand the significance of haemodynamic factors in the genesis, as well as the clinical course of ACAA, we evaluated the correlation between certain angiographic patterns of flow in the anterior circulation and the clinical findings of 51 patients with ACAA compared with 50 matched controls. Four significant associations which have never been validated were identified: 1) a dominant A1 (filling both A2's) was found in 57% of ACAA patients versus 14% of controls (p less than 0.001). 2) Unilateral hypoplasia of the opposite A1 was present in 24% of ACAA patients versus 6% of controls (p = 0.01). 3) Exclusive filling of the ACAA from one A1 occurred in 78%. 4) No statistically significant relationship was found between the anatomic flow patterns studied and the patients clinical presentation including age, sex, or grade. We conclude that anterior communicating artery aneurysms are significantly related in a majority of patients with the presence of a dominant A1, probably as the result of enhanced haemodynamic stress caused by this anatomic abnormality in the circulation. However, this association is not constant, and a dominant pattern of flow did not correlate with the clinical course. This is probably a reflection of the differences between factors initiating aneurysm formation and those influencing its growth, as well as of the relative limitations of angiography when pathophysiological extrapolations are attempted.     

The comparison of susceptibility of two target cells (HuRBC and L1210) to antibody dependent lymphocyte cytotoxicity

Antibody-dependent lymphocyte cytotoxicity was compared in two test procedures. Human erythrocytes (group O R1R1 or R2R2) and mouse lymphoma cells (line L1210) were used as target cells. Anti-Rh (anti-C + D) serum obtained from a hyperimmunized blood donor and serum obtained from rabbit immunized with L1210 cells were used as the source of antibody specific for target cells. In both tests, lymphocytes (PBL) or mononuclear cells (MNC) isolated from heparinized or defibrinated blood were used as effectors. In both tests comparable results were obtained.     

Postpartum mood disorders

Depression is a common disorder in women of childbearing age. Many women experience depressive symptoms during the postpartum period, ranging from mild postpartum blues to significant mood disorders such as postpartum depression and postpartum psychosis. The ‘baby blues‘ are extremely common, affecting 30-75% of new mothers. This form of postpartum mood change is self-limited and requires no specific treatment other than education and support. While less common, occurring in 10-15% of births, postpartum depression has the potential for significant impact on both the health of the mother and baby. Unfortunately, affective illness in women frequently goes unrecognized and untreated. While there are effective pharmacological treatments for postpartum depression, the treatments for postpartum depression are often not utilized due to concerns about lactation. Postpartum psychosis is extremely rare, affecting one to two women per 1000 births; each case represents a true psychiatric emergency. Identifying and treating postpartum affective illness in women is critical to the health of both mother and infant. This paper reviews the literature on the diagnosis and treatment of mood disorders in the postpartum period: postpartum blues, postpartum depression and postpartum psychosis.     

Adhesion of platelets to surface-bound fibrinogen under flow

After platelet activation, fibrinogen mediates platelet-platelet interactions leading to platelet aggregation. In addition, fibrinogen can also function as a cell adhesion molecule, providing a substratum for adhesion of platelets and endothelial cells. In this report, we studied the adhesion of platelets to surface-immobilized fibrinogen under flow in different shear rates. Heparinized whole blood containing mepacrine-labeled platelets was perfused for two minutes at various wall shear rates from 250 to 2,000 s-1 in a parallel plate flow chamber. The number of adherent fluorescent platelets was quantitated every 15 seconds with an epifluorescent videomicroscope and digital image processing system. When compared with platelet adhesion and aggregation seen on glass surfaces coated with type I bovine collagen, a significant increase in platelet adhesion was observed on immobilized fibrinogen up to wall shear rates of 800 s-1. The adherent platelets formed a single layer on fibrinogen-coated surfaces. Under identical conditions, no significant adhesion was observed on fibronectin- or vitronectin-coated surfaces. Although platelet adhesion to collagen was substantially inhibited by the platelet inhibitors prostaglandin E1 and theophylline, these inhibitors had no effect on platelet adhesion to fibrinogen. Platelets adhered to recombinant homodimeric wild-type (gamma 400-411) fibrinogen, but not to the recombinant homodimeric gamma' variant of fibrinogen. Platelet adhesion to recombinant fibrinogen with RGD to RGE mutations at positions alpha 95-97 and alpha 572-574 was similar to that with plasma-derived fibrinogen. These results show that platelets adhere to fibrinogen-coated surfaces under moderate wall shear rates, that the interaction is mediated by the fibrinogen 400-411 sequence at the carboxy-terminus of the gamma chain, and that the interaction is independent of platelet activation and the RGD sequences in the alpha chain.     

Meal frequency and timing in health and disease

Although major research efforts have focused on how specific components of foodstuffs affect health, relatively little is known about a more fundamental aspect of diet, the frequency and circadian timing of meals, and potential benefits of intermittent periods with no or very low energy intakes. The most common eating pattern in modern societies, three meals plus snacks every day, is abnormal from an evolutionary perspective. Emerging findings from studies of animal models and human subjects suggest that intermittent energy restriction periods of as little as 16 h can improve health indicators and counteract disease processes. The mechanisms involve a metabolic shift to fat metabolism and ketone production, and stimulation of adaptive cellular stress responses that prevent and repair molecular damage. As data on the optimal frequency and timing of meals crystalizes, it will be critical to develop strategies to incorporate those eating patterns into health care policy and practice, and the lifestyles of the population.