Extraction and analysis of superoxide free radicals (·O−2) from whole mammalian liver

Extraction of whole lobes of normal rat liver with dimethyl sulphoxide (DMSO) under N₂ gives extracts which contain 5—10 μmol/l·O^?₂ (50-100 nmol·O^?₂ per 10 ml extract per 4 g liver; 1.25-2.50 nmol·O^?₂ per millilitre per gram liver). Evidence for ·O^?₂ in the extracts is given by: (1) electron spin resonance signals (ESR), (2) differential pulse polarography (DPP), (3) chemiluminescence (CL), and (4) nitroblue tetrazolium reduction (NBT). All tests yield results identical with those obtained with authentic ·O^?₂. Extraction of ·O^?₂ is enhanced by tetrabutyl ammonium ion, and is maximal at 1-3 min. These results raise the possibility that substantial amounts of ·O^?₂ are normally sequestered in protective membranous sites in vivo.     

Three-dimensional geometrical and mechanical modelling of the lumbar spine.

The main objective of this study is to design a three-dimensional geometrical and mechanical finite element model of the lumbar spine. The model's geometry is constructed using six parameters per vertebra. These parameters are digitized from two X-rays (anterio-posterior and lateral), thus yielding an individualized model which can be arrived at from the radiographs of a tested specimen. This procedure makes the model validation easier, as geometry is generally a factor of dispersion in experimental results. The geometrical reconstruction, in the form of a finite elements mesh, was effected for the whole lumbar spine. The global coherence of the model was verified.     

An enzyme immunoassay of phaseolinone and its application in estimation of the amount of toxin in Macrophomina phaseolina-infected seeds.

A microtiter plate-based enzyme immunoassay has been developed for phaseolinone, a phytotoxin isolated from the culture filtrate of the plant-pathogenic fungus Macrophomina phaseolina (Tassi) Goid. The smallest amount of phaseolinone detectable by the method is 5 pg per well. The method is validated by comparison with high-performance liquid chromatography and used to confirm and estimate phaseolinone production in seeds infected with the fungus. The degree of seed inhibition correlated well with the amount of toxin produced in infected seeds, 50% inhibition being observed at a toxin concentration of 0.60 micrograms/g of wet tissue.     

Action of general and alpha-smooth muscle-specific actin antibody microinjection on stress fibers of cultured smooth muscle cells

Arterial smooth muscle cells express alpha- and gamma-smooth muscle, as well as beta- and gamma-cytoplasmic actins. Two actin antibodies, one recognizing smooth muscle and cytoplasmic actin isoforms, the other recognizing specifically alpha-smooth muscle actin, were microinjected into cultured aortic smooth muscle cells. The effect of these antibodies on stress fiber organization was examined by staining with rhodamine-labeled phalloidin and by immunofluorescence with the same antibodies. Microinjection of the general actin antibody abolished most of the stress fiber staining with all reagents, but did not significantly affect the shape of the injected cells. This suggests that stress fiber integrity is not absolutely necessary for the maintenance of cell shape within the time of observation. Microinjection of the specific alpha-smooth muscle antibody abolished to various extents the staining of stress fibers with this antibody, but left practically intact their staining with rhodamine-labeled phalloidin and with the general actin antibody. This suggests that the incorporation of alpha-smooth muscle actin is not absolutely necessary for the maintenance of stress fiber integrity in cultured smooth muscle cells.     

Detection of Vibrio cholerae O1 in the aquatic environment by fluorescent-monoclonal antibody and culture methods.

Vibrio cholerae O1 in plankton samples collected from ponds and rivers between February 1987 and January 1990 in Matlab, Bangladesh, was detected by the fluorescent-monoclonal antibody (FA) technique. Samples were collected at sites which were monitored fortnightly (fixed sites) as well as at sites that were part of a case-control study. FA results were compared with those obtained by conventional culture methods (CM). A total of 876 samples were collected; V. cholerae O1 was detected in 563 samples (64.27%) by the FA method and in 3 samples (0.34%) by CM. Of the fixed-site plankton samples, 439 (63.62%) were positive by FA and none were positive by CM. Of the 93 case sites sampled on the day after the occurrence of a case of cholera, 73 (78.49%) were positive for V. cholerae O1 by FA and 3 (3.2%) were positive by CM. In comparison, of the 93 first-day sample collections at control sites at the time a case of cholera occurred, only 51 (54.83%) were positive by FA and none were positive by CM. From the data, it is concluded that V. cholerae O1 is present throughout the year in the ponds and rivers of Bangladesh that were examined in this study and that V. cholerae can be detected by FA but not always by CM. The FA procedure was found to be very useful in detecting V. cholerae in plankton, with which it was associated and often occurred in large numbers in the nonculturable stage. Thus, studies investigating the significance of the role of environmental factors in the epidemiology of cholera can be performed effectively by using FA. Such studies are in progress.     

Calcium antagonists: A new class of therapeutic agents

A new class of therapeutic agents, sharing inhibition of the slow calcium channel, will soon be available to the American patient. Selective action of these agents upon the atrioventricular node, the smooth muscle of coronary and peripheral arteries, and the contractility of cardiac muscle opens new vistas in cardiovascular pharmacology. Early release of these agents by the Federal Drug Administration for general use is urged, based upon the already wide and successful experience in the European and South American continents.     

Synthesis of thromboxane B2 and 6-keto-prostaglandin F1α by bovine gastric mucosal and muscle microsomes

Bovine gastric mucosal and muscle microsomes synthesize prostaglandins and thromboxane B₂ (TXB₂) from arachidonic acid (AA). TXB₂ and 6-keto-prostaglandin F₁α (6-keto-PGF₁α) were the major products synthesized by pylorus, body, and cardiac region of the gastric mucosa. Gastric muscle mainly synthesized 6-keto-PGF₁α. TXB₂ and 6-keto-PGF₁α synthesis occurs at an appreciable rate from endogenous precursors but more rapidly with added arachidonate. Prostaglandins E₂, F₂α and D₂ were synthesized in smaller amounts under the conditions studied.     

On the application of wave scattering theory for the diagnosis of muscle diseases

This investigation is concerned with a scattering matrix approach which is proposed for the non-destructive, differential diagnosis of muscle diseases. A number of muscle diseases are classified according to their various pathological indications and appropriate material parameters are derived for utilization as input data for a theoretical model. In the mathematical analysis phase of the model, Waterman's T-matrix approach in conjunction with statistical averaging for both position and orientation of muscle fibers are employed to obtain the attenuation due to geometric dispersion for a wide range of frequencies. The numerical results not only exhibit qualitative agreement with existing experimental data for normal muscle but also display differentiable patterns for the various muscle disease cases. The formulation is an improvement over the previously applied scattering theory in that it obtains the attenuation over a continuous frequency spectrum.