A redetermination of the concentration of alpha 2-macroglobulin in human plasma

The concentration of alpha 2-macroglobulin in human plasma has been remeasured utilizing a carefully isolated and characterized sample of alpha 2-macroglobulin as a standard. A highly purified sample of alpha 2-macroglobulin with a total trypsin binding capacity of 1.7 mol trypsin/mol alpha 2-macroglobulin was used as a standard for both a radial immunodiffusion and a rocket immunoelectrophoresis technique. With this preparation as a standard, the concentration of alpha 2-macroglobulin in a normal plasma pool over 10,000 donors was found to be about 1.2 mg/ml. A similar concentration (1.3 mg/ml) was found when using a functional trypsin binding assay. This concentration is considerably less than the usually accepted mean of the normal range for alpha 2-macroglobulin.     

Preparation and characterization of a soluble dextran alpha(1) proteinase inhibitor complex

Purified human alpha(1) proteinase inhibitor, a plasma glycoprotein with a molecular weight of 5.3 x 10(4) daltons and a major serine protease inhibitor has been covalently coupled to dextrans with molecular weights of 1.77 x 10(4) and 1.03 x 10(4) daltons. The coupled conjugates were soluble in aqueous medium and stable up to 6 months at +5 degrees C. Increased moles of dextran/mole protein ratio during coupling resulted in progressive decreases of inhibitory capacity, immunogenicity, and the association constant (k(assoc)) between the enzyme and the inhibitor. Compared to the native protein, the soluble conjugates showed improved stability at pH 3.0 and heat stability at 60 degrees C. At 60 degrees C, no loss of inhibitory capacity has been seen up to 60 min for the conjugates during which time the native protein lost greater than 90% of its inhibitory capacity. The presence of antioxidant catalase was needed to prevent oxidative degradation by hydrogen peroxide.     

Mitosis and cytokinesis in subconfluent endothelial cells exposed to increasing levels of shear stress

An in vitro flow apparatus in combination with cultured endothelium was used to determine the effects of fluid-generated shear stress on cells undergoing mitosis and cytokinesis. Cell responses were recorded by time-lapse video microscopy under phase contrast or Hoffman modulation contrast optics. Completion of cell division in mitotic cells was dependent upon both the initial presence of intercellular attachments and the magnitude of fluid wall shear stress. In nonisolated populations, 95.3%, 69.5%, and 57.1% of the cells completed cell division as opposed to 66.6%, 20.4%, and 11.9% in the isolated cell groups at 2.8, 14.1, and 33 dynes/cm², respectively. Prestressing cells for 14 h prior to monitoring failed to increase retention of isolated mitotic cells. The presence of neighboring cells facilitated replication by providing an anchoring attachment or a luminal surface for completion of division. Cell detachment most commonly occurred at the onset of cytokinesis when substrate contact areas were minimal and focal contacts were absent. A comparison between no flow controls and shear stress specimens indicated no significant differences in transit times for mitosis and cytokinesis. Thus, subconfluent endothelial cells may be more susceptible to detachment during cell division due to increases in shear stress, the absence of intercellular attachments, and reduced cell-substrate contacts. © 1994 wiley-Liss, Inc.     

Volume regulation by flounder red blood cells in anisotonic media

The nucleated high K, low Na red blood cells of the winter flounder demonstrated a volume regulatory response subsequent to osmotic swelling or shrinkage. During volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation after osmotic swelling is referred to as regulatory volume decrease (RVD) and was characterized by net K and water loss. Since the electrochemical gradient for K is directed out of the cell there is no need to invoke active processes to explain RVD. When osmotically shrunken, the flounder erythrocyte demonstrated a regulatory volume increase (RVI) back toward control cell volume. The water movements characteristic of RVI were a consequence of net cellular NaCl and KCl uptake with Na accounting for 75 percent of the increase in intracellular cation content. Since the Na electrochemical gradient is directed into the cell, net Na uptake was the result of Na flux via dissipative pathways. The addition of 10(-4)M ouabain to suspensions of flounder erythrocytes was without effect upon net water movements during volume regulation. The presence of ouabain did however lead to a decreased ration of intracellular K:Na. Analysis of net Na and K fluxes in the presence and absence of ouabain led to the conclusion that Na and K fluxes via both conservative and dissipative pathways are increased in response to osmotic swelling or shrinkage. In addition, the Na and K flux rate through both pump and leak pathways decreased in a parallel fashion as cell volume was regulated. Taken as a whole, the Na and K movements through the flounder erythrocyte membrane demonstrated a functional dependence during volume regulation.     

Direct isolation in cell-free medium of a spiroplasma fromHaemaphysalis leporispalustris (Acari: Ixodidae) in Maryland

A spiroplasma isolate, was obtained from rabbit ticks (Haemaphysalis leporispalustris) taken from cottontail rabbits in Maryland by inoculation of tick suspensions into SP-4 medium. The isolate was indistinguishable from an experimental vertebrate pathogen (suckling mouse cataract agent spiroplasma) when tested with other plant and tick spiroplasmas in growth inhibition, deformation, and metabolism inhibition tests. The isolated organism had a pathogenic profile for suckling rats and embryonated chicken eggs that differed significantly from that of other suckling mouse cataract agent strains. This is the first report of a direct spiroplasma isolation from ticks in cell-free medium, and confirms the specific association of spiroplasmas of the suckling mouse cataract agent serogroup with rabbit ticks.     

Soothing the Threatened Brain: Leveraging Contact Comfort with Emotionally Focused Therapy

Social relationships are tightly linked to health and well-being. Recent work suggests that social relationships can even serve vital emotion regulation functions by minimizing threat-related neural activity. But relationship distress remains a significant public health problem in North America and elsewhere. A promising approach to helping couples both resolve relationship distress and nurture effective interpersonal functioning is Emotionally Focused Therapy for couples (EFT), a manualized, empirically supported therapy that is strongly focused on repairing adult attachment bonds. We sought to examine a neural index of social emotion regulation as a potential mediator of the effects of EFT. Specifically, we examined the effectiveness of EFT for modifying the social regulation of neural threat responding using an fMRI-based handholding procedure. Results suggest that EFT altered the brain''s representation of threat cues in the presence of a romantic partner. EFT-related changes during stranger handholding were also observed, but stranger effects were dependent upon self-reported relationship quality. EFT also appeared to increase threat-related brain activity in regions associated with self-regulation during the no-handholding condition. These findings provide a critical window into the regulatory mechanisms of close relationships in general and EFT in particular.     

Biodeterioration of Mayan buildings at uxmal and tulum,Mexico

Uxmal and Tulum are two important Mayan sites in the Yucatan peninsula. The buildings are mainly composed of limestone and grey/black discoloration is seen on exposed walls and copious greenish biofilms on inner walls. The principal microorganisms detected on interior walls at both Uxmal and Tulum were cyanobacteria; heterotrophic bacteria and filamentous fungi were also present. A dark‐pigmented mitosporic fungus and Bacillus cereus, both isolated from Uxmal, were shown to be acidogenic in laboratory cultures. Cyanobacteria belonging to rock‐degrading genera Synechocystis and Gloeocapsa were identified at both sites. Surface analysis previously showed that calcium ions were present in the biofilms on buildings at Uxmal and Tulum, suggesting the deposition of biosolubilized stone. Apart from their potential to degrade the substrate, the coccoid cyanobacteria supply organic nutrients for bacteria and fungi, which can produce organic acids, further increasing stone degradation.     

X-ray spectra in SEM and staining with chrome azurol S show Al deposits in leaf tissues of Al-accumulating and non-accumulating plants from the cerrado

Plant and Soil - Carbon inputs to soil are mostly site- and management-nonspecific estimates based on measured yield. However, in grasslands most carbon input is root-derived and plant carbon...