IL-1-mediated inhibition of IL-6-induced STAT3 activation is modulated by IL-4, MAP kinase inhibitors and redox state of HepG2 cells

It is known that during acute phase reaction IL-6 activates STAT3 in hepatoma cells and IL-1 downregulates this response. We found that the inhibitory properties of IL-1 on STAT signalling cascade in human hepatoma HepG2 cells are considerably decreased not only in the presence of MAP kinase inhibitors SB203580 and PD98059 but also by some antioxidants (N-acetyl cysteine and pyrrolidine dithiocarbamate) and by anti-inflammatory cytokine IL-4. It appears that cytokine crosstalk between IL-6 and IL-1 includes a direct pathway sensitive to antioxidants and MAP kinase inhibitors, whereas the indirect prolonged response depends probably on synthesis of suppressors of cytokine signalling (SOCS).     

A compartmental model for oxygen transport in brain microcirculation in the presence of blood substitutes

A compartmental model is developed for oxygen (O(2)) transport in brain microcirculation in the presence of blood substitutes (hemoglobin-based oxygen carriers). The cerebrovascular bed is represented as a series of vascular compartments, on the basis of diameters, surrounded by a tissue compartment. A mixture of red blood cells (RBC) and plasma/extracellular hemoglobin solution flows through the vascular bed from the arterioles through the capillaries to the venules. Oxygen is transported by convection in the vascular compartments and by diffusion in the surrounding tissue where it is utilized. Intravascular resistance and the diffusive loss of oxygen from the arterioles to the tissue are incorporated in the model. The model predicts that most of the O(2) transport occurs at the level of capillaries. Results computed from the present model in the presence of hemoglobin-based oxygen carriers are consistent with those obtained from the earlier validated model (Sharan et al., 1989, 1998a) on oxygen transport in brain circulation in the absence of extracellular hemoglobin. We have found that: (a) precapillary PO(2) gradients increase as PO(2) in the arterial blood increases, P(50 p) (oxygen tension at 50% saturation of hemoglobin with O(2) in plasma) decreases, i.e. O(2) affinity of the extracellular hemoglobin is increased, the flow rate of the mixture decreases, hematocrit decreases at constant flow, metabolic rate increases, and intravascular transport resistance in the arterioles is neglected; (b) precapillary PO(2) gradients are not sensitive to (i) intracapillary transport resistance, (ii) cooperativity (n(p)) of hemoglobin with oxygen in plasma, (iii) hemoglobin concentration in the plasma and (iv) hematocrit when accounting for viscosity variation in the flow; (c) tissue PO(2) is not sensitive to the variation of intravascular transport resistance in the arterioles. We also found that tissue PO(2) is a non-monotonic function of the Hill coefficient n(p) for the extracellular hemoglobin with a maximum occurring when n(p) equals the blood Hill coefficient. The results of the computations give estimates of the magnitudes of the increases in tissue PO(2) as arterial PO(2) increases,P(50 p) increases, flow rate increases, hematocrit increases, hemoglobin concentration in the plasma increases, metabolic rate decreases, the capillary mass transfer coefficient increases or the intracapillary transport resistance decreases.     

Identification and characterization of polymorphisms at the HAS alpha1-acid glycoprotein (ORM*) gene locus in Caucasians

Human alpha(1)-acid glycoprotein (AGP) or orosomucoid (ORM) is a major acute phase protein that is thought to play a crucial role in maintaining homeostasis. Human AGP is the product of a cluster of at least two adjacent genes located on HSA chromosome 9. Using a range of restriction endonucleases we have investigated DNA variation at the locus encoding the AGP genes in a group of healthy Caucasians. Polymorphisms were identified using BamHI, EcoRI, BglII, PvuII, HindIII, TaqI and MspI. Nonrandom associations were found between the BamHI, EcoRI and BglII RFLPs. The RFLPs detected with PvuII, TaqI and MspI were all located in exon 6 of both AGP genes. The duplication of an AGP gene was observed in 11% of the individuals studied and was in linkage disequilibrium with the TaqI RFLP. The identification and characterization of these polymorphisms should prove useful for other population and forensic studies.     

Tuning of the optical and electrochemical properties of the primary donor bacteriochlorophylls in the reaction centre from Rhodobacter sphaeroides: spectroscopy and structure

A series of mutations have been introduced at residue 168 of the L-subunit of the reaction centre from Rhodobacter sphaeroides. In the wild-type reaction centre, residue His L168 donates a strong hydrogen bond to the acetyl carbonyl group of one of the pair of bacteriochlorophylls (BChl) that constitutes the primary donor of electrons. Mutation of His L168 to Phe or Leu causes a large decrease in the mid-point redox potential of the primary electron donor, consistent with removal of this strong hydrogen bond. Mutations to Lys, Asp and Arg cause smaller decreases in redox potential, indicative of the presence of weak hydrogen bond and/or an electrostatic effect of the polar residue. A spectroscopic analysis of the mutant complexes suggests that replacement of the wild-type His residue causes a decrease in the strength of the coupling between the two primary donor bacteriochlorophylls. The X-ray crystal structure of the mutant in which His L168 has been replaced by Phe (HL168F) was determined to a resolution of 2.5 A, and the structural model of the HL168F mutant was compared with that of the wild-type complex. The mutation causes a shift in the position of the primary donor bacteriochlorophyll that is adjacent to residue L168, and also affects the conformation of the acetyl carbonyl group of this bacteriochlorophyll. This conformational change constitutes an approximately 27 degrees through-plane rotation, rather than the large into-plane rotation that has been widely discussed in the context of the HL168F mutation. The possible structural basis of the altered spectroscopic properties of the HL168F mutant reaction centre is discussed, as is the relevance of the X-ray crystal structure of the HL168F mutant to the possible structures of the remaining mutant complexes.     

Protein-lipid interactions in the purple bacterial reaction centre

The purple bacterial reaction centre uses the energy of sunlight to power energy-requiring reactions such as the synthesis of ATP. During the last 20 years, a combination of X-ray crystallography, spectroscopy and mutagenesis has provided a detailed insight into the mechanism of light energy transduction in the bacterial reaction centre. In recent years, structural techniques including X-ray crystallography and neutron scattering have also been used to examine the environment of the reaction centre. This mini-review focuses on recent studies of the surface of the reaction centre, and briefly discusses the importance of the specific protein-lipid interactions that have been resolved for integral membrane proteins.     

Morphometric classification of hairy cell leukemia in bone marrow trephine biopsy

OBJECTIVE: To analyze cytologic and histologic parameters in bone marrow trephine biopsy in an attempt to define heterogeneity of hairy cell leukemia cells. STUDY DESIGN: The study group consisted of 28 trephine biopsies. Immunohistochemistry for CD20 antigen was used. Image processing and measurements were performed with AnalySIS 3.0 image analysis system (Soft Imaging System GmbH, Germany) and custom built programs. For planimetric measurements of nuclei, automatic segmentation was implemented. The measured parameters were: surface area, perimeter, minimum, mean and maximum diameter, and a set of form factors. Relative volumes of bone trabeculae, adipose tissue, hematopoietic tissue and neoplastic infiltrate were assessed by the point counting method. Nuclear volume was measured by the point sampled intercept method. Bone marrow fibrosis was assessed using a curvilinear line test system. RESULTS: Significant variability of cell nuclei was found, and their classification into 3 types was possible. The relative frequency of those types was different in various cases and allowed subdivision of cases into 3 groups that differed in some clinical and histologic manifestations. CONCLUSION: The present study demonstrated the heterogeneity of cell populations of hairy cell leukemia.     

Melatonin concentrations in patients with large goiter before and after surgery

OBJECTIVES: Surgical removal of a very large goiter may traumatize adjacent anatomical structures. The manipulations that involve superior cervical ganglia may alter melatonin secretion. To test this hypothesis we decided to study diurnal serum melatonin profiles in patients with a very large goiter before and after the surgery. MATERIAL AND METHODS:The study was performed on 10 women (mean age-46.5+/-1.6 years; mean+/-SEM; range 39-54 years) with very large non-toxic nodular goiter (mean thyroid volume-125.8+/-25.9 cm (3); mean+/-SEM; range 82.6-326.7 cm(3)). Diurnal serum melatonin profiles were estimated two days before the operation and 10 days after the surgery. Blood samples were collected at 08:00, 12:00, 16:00, 20:00, 22:00, 24:00, 02:00, 04:00, 06:00 and 08:00 h. Melatonin concentration was measured using RIA kit. RESULTS: Nocturnal serum melatonin concentrations (at 24, 02, and 04 hours) were significantly higher after the surgery than before the operation. CONCLUSIONS: Very large goiter may compress the superior cervical ganglia altering indirectly the melatonin synthesis. It cannot be excluded, however, that the presence of the large goiter in some other way affects melatonin secretion.     

Bone tissue changes in rats during prolonged restriction of motor activity

The objective of this investigation was to measure the effect of prolonged restriction of motor activity (hypokinesia) of rats on the mass, density, mineral composition, reconstruction parameters and elemental composition of their bone tissue. The studies were done during 90 days of hypokinesia (HK) on 90 male Wistar rats equally divided into two groups: (1) vivarium control rats (VCR) and (2) hypokinetic rats (HKR). For the simulation of the hypokinetic effect the HKR group was kept for 90 days in small individual cages made of wood that restricted the movements of rats in all directions without hindering food and water intakes. During the prehypokinetic period of 15 days and during the hypokinetic period of 90 days bone mass, bone density, bone calcium and phosphorus concentrations, bone reconstruction parameters and elemental composition of bones were determined. During the same periods food intake and body weight losses were also measured. In the HKR group signs of osteoporosis in the spongy structures of the tubular bones were observed; they also showed significant decrease in rat femur weight, and in cross section of the rat femur, and in mineral concentrations of the femoral head when compared with the VCR group. The HKR group also show a significant decrease in food intake and body weight when compared with the VCR group. The corresponding parameters did not change significantly in the VCR group when compared with the baseline control values. It was concluded that prolonged exposure to HK induced osteoporosis and structural changes in bones. This apparently occurred due to inhibition of bone tissue formation in the HKR group.