Macrophage migration stimulation factor, migration inhibition factor and the role of suppressor cells in their production.

Guinea pig lymph node lymphocytes and human peripheral blood lymphocytes when stimulated by specific antigen or mitogen will release factors that affect in vitro macrophage migration. Migration inhibition factor production appears to be under the control of suppressor cells which are T lymphocytes. When suppressor cells are generated by stimulation with Con A for 4 days, migration stimulation factor (M.St.F.) activity is found. In other situations where M.St.F. is found this is thought to be due to increased suppressor cell activity. For example, young adults produce this lymphokine when stimulated with Con A, whereas aged individuals produce MIF. Concanavalin A appears to be the mitogen of choice for M.St.F. production, and phytohemagglutinin for MIF production. The release of this putative factor M.St.F. from suppressor T cells helps to explain some of the difficulties that have existed in studies of macrophage migration inhibition.     

The X-ray crystal structure of 6-deoxy-α-l-sorbofuranose. Conformational analysis of ketohexofuranosides and their comparison with ribofuranosides and arabinofuranosides

The crystal and molecular structure of 6-deoxy-l-sorbose have been determined by the application of multisolution methods and refined to an R-index of 0.063 for 560 reflections, using three-dimensional intensity data collected on a Picker automatic diffractometer. The compound crystallizes in the space group P2₁2₁2₁ with unit-cell dimensions a = 18.470 (10), b = 7.636 (10), and c = 5.371 (8) Å; Z = 4. The molecule occurs as the α-furanose form, which is also the preponderant tautomer in solution. The puckering of the furanoid ring is C-3′-exo-C-4′-endo (₃T⁴) [equivalent to C-2′-exo-C-3′-endo (₂T³) in the numbering for d-ribose], with P and τ_m angles of -6.5 and 42.7° respectively. Conformational analysis of the known ketofuranosides shows that the ₃T⁴ (₂T³ in d-ribose numbering) puckering mode, which is typical of α-nucleosides, is favored, in contrast to the favored ³T₂ or ²T₃ puckering mode for the β-d-ribonucleosides and β-d-arabinonucleosides. The conformational differences among furanoid rings are mainly influenced by the configuration at the anomeric carbon atom. The favored orientation about the C-2′-C-1′ bond (O-5′-C-2′-C-1′-O-1′)of the ketofuranosidesis — gauche. All four hydroxyl groups are involved in donor-acceptor hydrogen bonding, and O-4′-8 appears to be involved in a bifurcated hydrogen bond to O-2′ and O-3′ of neighboring molecules.     

Radioimmunoassay studies of intestinal calcium-binding protein in the pig. I. Identification of intestinal calcium-binding protein in blood and response to a low calcium diet.

We have developed a radioimmunoassay for porcine intestinal calcium-binding protein (CaBP) and have used it to detect CaBP in pig plasma. Plasma CaBP is identical to intestinal CaBP on the basis of immunological activity, molecular size, and molecular charge properties. The plasma CaBP concentration was greater in the portal blood than in mixed venous blood, suggesting that blood CaBP originates in the gut. Two of four 15-week-old littermate pigs were placed on a low calcium diet (0.15% calcium, 0.65% phosphorus) and two on a control diet (0.65% calcium, 0.65% phosphorus). After 2 weeks, the entire small intestine was removed and divided into nine 1.8-m segments. CaBP was assayed in both plasma and intestinal mucosa. When the two pigs on a low calcium diet were compared with two control pigs, there was a general increase in immunoreactive CaBP in both plasma and intestinal mucosa. However, there was no increment in immunoreactive CaBP in the first 1.8-m segment of small intestine. Seventy-one percent of the increment in CaBP occurred distal to the first two segments. The largest fractional low calcium diet effect occurred in the ileum. The mean CaBP concentration for the total small intestine increased by a factor of 1.9. The plasma CaBP concentration increased by a factor of 2.6. In these pigs, plasma CaBP was a more reliable indicator of change in CaBP status than was the measurement in the proximal gut segment which contained the duodenum. The assay of CaBP in blood is convenient and may obviate the sampling errors inherent in intestinal biopsy.     

Continuous Biosorption of Pb,Cu, and Cd by Phanerochaete chrysosporium in a Packed Column Reactor

The dynamic removal of lead, copper and cadmium in a single component system by Phanerochaete chrysosporium was studied in packed columns. The packed columns consisted of biomass of P. chrysosporium immobilized on polyurethane foam cubes. The performances of packed columns were described through the concept of breakthrough and the values of column parameters predicted as a function of bed depth. The column biosorption data were evaluated in terms of maximum (equilibrium) capacity of the column, the amount of metal loading and the yield of the process. The maximum capacities for lead, copper and cadmium were 70.7, 43.7 and 70.8 mg, respectively, and their yields were 39.2, 40.6 and 41%, respectively. The kinetic and mass transfer aspects of the dynamic removal of the three metals were studied using three mathematical models commonly used to describe the column performance in adsorption processes. Column studies showed good agreement between the experimental data and the simulated breakthrough curves obtained with Adams-Bohart or the Wolborska model and the Clark model. While the initial segment of the breakthrough curve was defined by the Adams-Bohart and Wolborska models, the whole breakthrough curve was well predicted by the Clark model for all the three metals studied.     

Lactic acid extraction with trioctyl amine

Lactic acid extraction was carried out with trioctyl amine (TOA) in three diluents. The effect of initial lactic acid concentrations on the extraction efficiency was investigated. It was observed that although the percentage extraction remained constant or decreased but the loading ratio was increased in all the cases. The overloading was observed in the case of TOA in methyl isobutyl ketone (MIBK). The extraction of lactic acid was favored at a lower aqueous pH?in all the diluents. The improvement of the extraction efficiency at a higher aqueous pH?(=?6) was achieved by using the modified TOA (treated with HCl) in MIBK. However, the recovery of lactic was very poor in the case of modified TOA in MIBK, although the complete recovery was obtained for untreated TOA.     

Biodegradation of phenol by arthrobacter and modelling of the kinetics

The toxic effects of phenol, a common constituent of many industrial effluents, necessitates treatment of the polluted streams. Biodegradation is a popular technique and enjoys many advantages. The degradation of phenol with Arthrobacter species is studied in batch cultures and it is observed that the substrate is inhibiting. The fit of various models, including the model proposed earlier by us [17], to the experimental data is studied. The model is used to fit available data in literature, which unfortunately is very sparse. In all the cases the present model fits the data best.List of Symbols S mg/l substrate concentration - S ₀ mg/l threshold substrate concentration - K _I mg/l inhibition constant - K _m , K _s mg/l half saturation constant of growth kinetics - m, n constants - 1/h specific growth rate - _m 1/h maximal specific growth rate - X mg/l biomass concentration at time t - X ₀ mg/l initial biomass concentration Abbreviations MTCC Microbial Type Culture Collection - IMTECH Institute of Microbial Technology The cooperation of the staff of the Biosciences and Biotechnology Center, I.I.T. Madras is greatly appreciated.     

Effect of digoxin on total body potassium

Digoxin administration to 6 volunteers for 7 days was associated with a small but significant decrease in total body (90 mmol) and erythrocyte potassium (4.8 mmol/kg cells).