Demonstration of phenolic compounds in plant tissues by an osmium-iodide postfixation procedure

A simple procedure to stain phenols in plant tissues is described. Postfixation with an aqueous solution prepared by mixing 2 cc of 2% osmium tetroxide and 8 cc of 3% potassium iodide yields brilliant visualization of phenol-containing vacuoles in different tissues of plants (e.g., coffee, oak, tobacco and spruce) bearing high concentration of phenolic compounds. Areas bearing phenols become dark gray to black. Chemical experiments demonstrate that osmium-potassium iodide (Os-KI) mixture reacts rapidly with several naturally occurring plant phenols, developing black solutions from which black solids precipitate. Phenols containing omicron-dihydroxy groups react with Os-KI solution more rapidly than other structurally different phenols. Therefore, omicron-dihydroxy units in an aromatic ring seem to function as primary sites of reactivity with the osmium-iodide complexes.

A convenient procedure for the isolation of intact translatable mRNA by potassium iodide gradient centrifugation

High concentrations of KI were found to efficiently protect RNA against degradation by RNases. When a sufficient amount of solid KI was added to cell lysates or subcellular fractions (9 g per 10 ml), the solutions could be stored at room temperature for several days without measurable degradation of mRNA. Ribonucleic acids were selectively sedimented when these KI-containing solutions were centrifuged at 72,000 x g for 24 h. The RNA pellets were found to be readily dissolved in bidistilled water and the redissolved RNA could be immediately submitted to oligo(dT)-cellulose chromatography to isolate the poly(A)-containing RNA. However, extraction with phenol/chloroform was found to be necessary, if total RNA or poly(A)-minus RNA was to be analysed. This procedure was found to be superior to other methods currently in use - especially with respect to the isolation of intact, translatable high-molecular-weight mRNA.

A photoreversible conformational change in 124 kDa Avena phytochrome

Tryptophan (Trp) fluorescence quenching of phytochrome has been studied using anionic, cationic and neutral quenchers, I-, Cs+ and acrylamide, respectively, in an effort to understand the molecular differences between the Pr and Pfr forms. The data have been analyzed using both Stern-Volmer and modified Stern-Volmer kinetic treatments. The anionic quencher, I-, was proven to be an ineffective quencher with Stern-Volmer constants, Ksv, of 0.60 and 0.63 M-1, respectively, for the Pr and Pfr forms of phytochrome. The cationic quencher, Cs+, showed about a 2-fold difference in the Ksv of Pr and Pfr, indicating a significant change in the fluorescent Trp environments during the Pr to Pfr phototransformation. However, only 25-37% of the fluorescent Trp residues were accessible to the cationic quencher. Most of the fluorescent Trp residues were accessible to acrylamide, but the quenching by acrylamide was indistinguishable for the Pr and Pfr forms. An additional quenching by acrylamide after a saturated quenching with Cs+ showed more than 40% increase in the Ksv of Pfr over Pr. These observations, along with the finding of two distinct components in the Trp fluorescence lifetime, indicate the existence of Trp residues in at least two different sets of environments in the phytochrome protein. The two components of the fluorescence had lifetimes of 1.1 ns (major) and 4.7 ns (minor) for Pr and 0.9 ns (major) and 4.6 ns (minor) for Pfr. Fluorescence quenching was found to be both static and dynamic as the Stern-Volmer constants for the steady-state fluorescence quenching were higher than for the dynamic fluorescence quenching. Based on the quenching results, in combination with the location of Trp residues in the primary structure, we conclude that the Pr to Pfr phototransformation involves a significant conformation change in the phytochrome molecule, preferentially in the 74 kDa chromophore-bearing domain.

Modification of human thrombin: effect on thrombomodulin binding

Thrombomodulin, an endothelial cell protein, binds thrombin with high affinity and alters thrombin from a procoagulant to an anticoagulant molecule. In this study, chemical and/or proteolytic modification of thrombin was carried out to identify the essential components required for its interaction with thrombomodulin. Modification of thrombin at the catalytic site serine and histidine residues, with Diisopropylfluorophosphate and Tosyl-L-lysine chloromethyl ketone, resulted in loss of clotting and amidolytic activity. Both Diisopropyl phosphoryl-thrombin and Tosyl-L-chloromethyl ketone-thrombin inhibited native-thrombin: thrombomodulin catalyzed protein C activation with Ki values of 5 nM and 6 nM respectively indicating no loss of affinity for thrombomodulin. Oxidation of tryptophan residues with N-bromosuccinimide or iodination of tyrosine residues of thrombin led to reduced clotting and amidolytic activity as well as a reduced ability to interact with thrombomodulin. Modification of arginine residues with Phenylglyoxal and 2,3,Butanedione led to loss of thrombomodulin binding affinity. Limited proteolysis of thrombin by trypsin yielded the derivative beta-thrombin which had also lost its ability to interact with thrombomodulin. Deglycosylation of thrombin did not alter its binding affinity for thrombomodulin. These results indicate that one or more tryptophan, arginine and tyrosine residues are essential for the recognition of thrombin by thrombomodulin whilst the carbohydrate side chain and the active site residues of the thrombin molecule are not involved in thrombomodulin binding.

Effect of non-volatile scavengers of hydroxyl radicals on thymine radical formation induced by gamma-rays and ultrasound

In order to investigate the mechanism of sonolysis of nucleic acid constituents, the yield of thymine radicals generated by 50 kHz ultrasound in Ar-saturated aqueous solution was compared with that formed by gamma-radiolysis in N2O-saturated solutions in the presence of various non-volatile scavengers, which cannot act in the gas phase of the cavitation bubbles. For comparison of thymine radical yields by sonolysis and gamma radiolysis, the method of spin trapping with 3,5-dibromo-4-nitrosobenzenesulphonate (a water-soluble, non-volatile, aromatic nitroso spin trap) combined with ESR was used. The efficiency of OH radical scavenging is expressed by the reciprocal value of C1/2, the scavenger concentration at which the thymine radical yield is decreased by 50 per cent. In gamma radiolysis the scavenging efficiencies of the solutes depend on their rate constants with OH radicals. For sonolysis the C1/2 values were similar to those obtained for gamma radiolysis except for the hydrophobic 5,5-dimethyl-1-pyrroline-N-oxide. These results suggest that thymine radicals induced by ultrasound are produced in the bulk of the solution as well as in the interfacial region.

Fluorescence studies on dopamine beta-monooxygenase: effects of salts, pH changes, metal-chelating agents and Cu2+

The intrinsic protein fluorescence of dopamine beta-monooxygenase (3,4-dihydroxyphenethylamine, ascorbate:oxygen oxidoreductase (beta-hydroxylating), EC 1.14.17.1) has been characterized. The fluorescence is dominated by emission from tryptophans in a hydrophobic environment. Changes in the conformation of the enzyme induced by anions, pH changes, metal-chelating agents and Cu2+ have been determined. Conformational transitions induced by anions take place at concentrations between 0.05 and 0.2 M. Most anions give rise to a blue-shift, while ClO4- induces a red-shift of the emission spectrum. pH dependence of the protein fluorescence revealed a conformational change between pH 6.0 and 5.0. The interactions between dopamine beta-monooxygenase and seven different metal-chelating agents have been investigated using protein fluorescence, heat inactivation, and inhibition measurements. All the metal-chelating agents are able to remove the active-site copper as demonstrated by complete inhibition of enzyme activity, restoration of activity by the addition of copper, and the observation that the enzyme becomes more sensitive to heat inactivation in the presence of chelating agents, thus behaving similarly to the copper-free apoenzyme. The charge and size of the chelating agents are of importance for the reaction with the active-site copper, which is consistent with a mechanism for removal of the copper, including a ternary enzyme-copper chelating agent complex. By contrast, under turnover conditions in the presence of substrates, dissociation of the active-site copper and chelation of the free copper is a dominating mechanism. Three distinct conformations were characterized on the basis of the fluorescence spectra and the degree of quenching by Cu2+ and I-. For the copper-free apoenzyme a unique binding site for binding of the first copper was demonstrated by larger quenching of the protein fluorescence than for binding of additional copper.

A method of determining the radiopacity of dental materials and foreign bodies

The desirability of radiopacity in dental materials and other materials that may become foreign bodies is documented. No simple, reliable methods are available for the determination of radiopacity, and no standard specifications have been devised with regard to the radiopacity of dental materials. A method that enables radiopacity to be determined is described. The theoretical aspects of radiopacity in relation to the method are considered. Possible applications of this method in the development of standards for radiopacity are suggested.

Histochemical techniques to localize rubber in guayule (Parthenium argentatum Gray)

There are few histochemical techniques for staining rubber in the cells of guayule. With regard to specificity, clarity and retention of the stain we found staining with oil red O or iodine-potassium iodide for bright field, and a combination of oil red O and dansyl chloride for epifluorescence microscopy to be the best methods. The plausible mechanisms of staining are discussed.

The ultrapurification of indium-111 for radiotracer studies

We have developed a procedure for the ultrapurification of 111In. A dried sample of 111InCl3 is dissolved in 1 ml of a freshly prepared KI solution of 4% in 4 N H2SO4. After 3 ml of anhydrous diethylether has been mixed well with the aqueous and centrifuged for 5 minutes at 2000 X g, the iodide salt of 111In is recovered with the organic solvent layer at approximately 92% of the original radioactivity. The organic phase is evaporated under a gentle stream of inert gas. After the sublimation of iodine, 111In is dissolved in a solvent of choice. The extraction is highly selective for In and separates it from, at least, Fe, Al, and Zn, principle associated cationic contaminants.

Colorimetric determination of certain phenothiazine drugs by using morpholine and iodine-potassium iodide reagents

A colorimetric method was developed for the quantitative estimation of 11 phenothiazine drugs. The method is based on the interaction of unsulfoxidized drug with morpholine and iodine-potassium iodide reagents. The interaction for all studied phenothiazine drugs yields a blue product with 2 absorption maxima: one in the range of 620-640 nm with lower molar absorptivity and the other in the range of 662-690 nm with higher molar absorptivity. The color was stable for at least 10 h. The reproducibility and recovery of the method were excellent. The method was applied successfully to the analysis of various commercially available phenothiazines in different dosage forms. The results were comparable to those obtained by official procedures. The suitability of the method for detection and estimation of promethazine excreted in urine has been suggested by preliminary experiments. Reaction products have been isolated and identified.

All-reagent test tablets and method for rapid and selective alpha-amylase iodometric determination

The new type of test tablets (Iodocrom) for alpha-amylase assay contain crosslinked (CL)-amylose or CL-starch (specific substrates for alpha-amylase only) and the reagent (KIO3/KI) generating iodine (in acidic medium, when the reaction is stopped). The method--amyloclastic in nature--is based on selective action of alpha-amylase on the CL-substrate liberating soluble polysaccharide chains large enough and in a conformation suitable to allow the formation of iodine inclusion complexes. Unlike the classical iodometric methods, the reaction is followed by an increase in iodine complex blue color. The method has some common points with the well-known chromogenic (e.g., Phadebas) methods. Both use insoluble substrates which are not susceptible to attack by exoamylases and in both cases the enzymatic reaction is followed by the release of soluble products. The amounts of these released chains and the absorbances of their inclusion complexes with iodine are in a linear dependence with the enzyme concentration (activity).

Rapid microchemical identification of four phenothiazine antiemetics with gold bromide and iodine-potassium iodide reagents: collaborative study

A microchemical method was developed for the rapid identification of 4 phenothiazine antiemetics. Perphenazine, promethazine, thiethylperazine, and triflupromazine were positively identified and differentiated with the aid of a gold bromide reagent and an iodine-potassium iodide reagent. Only promethazine and triflupromazine yielded microcrystalline derivatives with gold bromide; only perphenazine and thiethylperazine reacted with iodine-potassium iodide. For each pair of positive reactions, the crystalline products were morphologically distinguishable under a microscope. The 2 tests were collaboratively studied by 7 independent laboratories and found to be simple, rapid, and effective for identifying the phenothiazines of interest. The method has been adopted official first action.

Salt-induced inhibition of the precipitin reaction of concanavalin A with polysaccharides and glycoprotein

The time course of the precipitin reactions of concanavalin A with glycogen, dextran and ovalbumin was investigated by a light-scattering method near 30 degrees C in 10 mM-Tris/HCl buffer, pH 7.4, containing neutral salts, i.e. NaCl, KCl, NaBr, KI and NaClO4. With 0.8 microM-lectin and 0.36 mg of glycogen/ml, the half-life, t 1/2, of the precipitin reaction was independent of salt concentration between 0.1 M and 1.5 M, and was the same (175s) in the presence of NaCl, KCl, NaBr and KI but was significantly (27%) higher in NaClO4. In contrast, the five salts caused significant to marked enhancement in t 1/2 for the reactions of concanavalin A with dextran and ovalbumin. Likewise, whereas the turbidity produced in 1 h as a result of lectin-glycogen precipitation remained unchanged, those measured for the binding of dextran and ovalbumin were decreased in the presence of three salts. The increase in t 1/2 and decrease in turbidity were found to be higher with NaClO4, followed by KI; NaBr produced moderate and NaCl (or KCl) small but generally significant inhibition of the precipitin reactions with dextran and ovalbumin. The results showed that the lectin-ligand precipitin reactions involve salt-sensitive polar interactions that are less pronounced with compactly folded ligands such as glycogen.

Impregnation of biological material by ZnI2-OSO4, KI-OSO4 and NaI-OSO4 mixtures for electron microscopic observations: chemical interpretation of the reaction

Alkaline iodide-osmium tetroxide mixtures were used in an electron microscopic study of plant cells and gave better results in the preservation of the cell structure in contrast to the cell structure observed when ZnI2-OSO4 mixtures are used. The electron density observed in the reactive sites of the cell by OSO4-iodide mixtures is controlled by the presence and oxidation state of iodine that acts as a regulator of the potential redox of the reaction of OSO4 with the biological material.

Moisture sorption kinetics for water-soluble substances. III: Theoretical and experimental studies in air

As an extension of the model of heat transport control developed for the kinetics of water sorption by water-soluble substances from an atmosphere of pure water vapor, equations have been developed to account for limitations of diffusion on mass transport of water vapor when air is present. Although the inability to determine the vapor diffusion layer thickness prevents using these equations to predict sorption behavior a priori, minimum water sorption rates can be calculated by assuming a diffusion layer thickness equal to the sample chamber radius. Combining heat transport and mass transport produces equations which describe very well the observed sorption by three water-soluble salts in one atmosphere of air. As in the absence of air, sorption rates are predicted and observed to be constant at a given atmospheric relative humidity.

A comparison between tracer gas and tracer particle techniques in evaluating the efficiency of ventilation in operating theatres

Images

The mystery of the unstained Golgi complex cisternae

The Champy-Maillet OsKI reaction has been used upon Golgi complexes to show two kinds of staining. It stains material being processed as it passes along the secretory pathway of the rough endoplasmic reticulum (RER) and Golgi cisternae (GC) up to crystallization in secretory vesicles. It also stains separately the environment within parts of the GC. This GC staining may occur in all compartments (transition vesicles, saccules, condensing vacuoles), but it is characteristically missing from any one of them. The unstained cisternae may be explained if outer saccules are made from either stained or unstained transition vesicles, both of which occur. The presence of empty, unstained transition vesicles is dictated by the surface to volume ratios of microvesicles in relation to saccules. Most transition vesicles must return their membrane to the endoplasmic reticulum, but from time to time it is presumed that they fuse to make a saccule. Saccules, stained and unstained, then mature through the stack. OsKI reactions with tissues and test molecules suggest that in the RER and GC the stain detects labile--S . S--bridges before they lock the tertiary configuration of proteins.

Studies on the interference by haemoglobin in the determination of bilirubin

Haemoglobin interference in the determination of bilirubin was compared in 7 different methods using the Jendrassik-Grof procedure, the Jendrassik-Grof-Nosslin modification, and the more recent procedures using nitrophenyldiazonium, 2,5-dichlorophenyldiazonium, 2,4-dichloraniline, and a direct reading method. To a variable degree, haemoglobin decreased the apparent absorption of the reaction product in all procedures. The extent of this decrease depended on the reagent used, the wavelength, incubation time, bilirubin concentration and the type of blank used. In an attempt to elucidate the mechanism of interference, haemoglobin was found to destroy the bilirubin diazo-compound whereas haemoglobin was ineffective. Likewise, storage of haemolytic samples for several days led to a disappearance of haemoglobin. H2O2, which had no effect in the absence of haemoglobin, potentiated the action of haemoglobin on diazobilirubin coupling. From our observations it can be concluded that haemoglobin disturbs the diazo-bilirubin reaction by a dual mechanism. H2O2, formed from oxyhaemoglobin by autoxidation, destroys the diazo bilirubin colour. In accordance with this explanation, potassium iodide stabilized the diazo compound against the peroxidative effect of oxyhaemoglobin; stabilization was not effective with superoxide dismutase, mannitol or ascorbate.

Pyruvate as a fluorescence quencher: a new spectroscopic assay for pyruvate reactions

Pyruvate ion, which is biologically ubiquitous and participates in many metabolic reactions, was found to be an effective quencher of fluorescence. Compared to other negatively charged quenchers such as I-, pyruvate is not toxic to proteins. By adding an inert, long-lived fluorophore to systems transacting pyruvate, it is possible to estimate activity by measuring the time course of the change in pyruvate quenching of the fluorophore. The procedure is illustrated by measuring the myosin subfragment-1 ATPase activity with a high sensitivity.

Inflammatory cells, IgA, C3, fibrin and fibronectin in skin lesions in dermatitis herpetiformis

Skin lesions were produced by application of 50% potassium iodide to twelve patients with dermatitis herpetiformis (DH). Perivascular cellular infiltrates were found to be characteristic of developing lesions. The cells were mainly round cells; alpha-naphthyl acetate esterase staining revealed that in 24-h lesions the mean percentage of T-lymphocytes was 43%, that of mononuclear phagocytes 6% and that of non-T/non-M cells (mainly B-lymphocytes) 44%. The percentage of the latter was highest (mean 81%) in 6-h specimens, suggesting that these cells are participating in the early stages of lesion formation. The infiltrating cells in dermal papillae and within subepidermal vesicles were predominantly polymorphonuclear leukocytes (mean 86%) with some mononuclear phagocytes and non-T/non-M cells. Immunofluorescence examination confirmed that fibrin deposition is characteristic of the initial lesions of DH and showed that the same is true of fibronectin. Seven out of eight patients had fibronectin deposits in dermal papillae. IgA was found in all and C3 in most of the specimens and, with the exception of papillary vesicles and blister cavities, the intensity of IgA and C3 fluorescence showed no marked alterations during the development of lesions.

The potassium iodide patch test in the dermatitis herpetiformis in relation to treatment with a gluten-free diet and dapsone

The potassium iodide patch test was studied in twenty-six patients with dermatitis herpetiformis. Histological assessment was found more sensitive than clinical. All of five patients with active disease and not on treatment had a positive test, whereas only two of six patients taking a gluten-free diet (GFD) and one of eight taking dapsone were positive. In another two patients taking a GFD, but in whom the diet had not been strict, the test was positive. All three patients in remission and both patients with the linear pattern of IgA (but with active disease) were negative. Immunofluorescence studies showed no difference in the presence, quantity, or distribution of immunoglobulin, complement or fibrinogen between the patch test site and uninvolved skin, or in the uninvolved skin between patients with and without active lesions.

Concentration-dependent influence of various cytochalasins and chaetoglobosins on the phalloidin-induced polymerization of G-actin in 0.6 M potassium iodide

Phalloidin, a bicyclic peptide from the poisonous Amanita phalloides mushroom, stimulates the viscosimetrically determined polymerization of G-actin to F-actin in 0.6 m potassium iodide, a medium in which spontaneous polymerization does not occur. The cytochalasins B, D, E, and G (CB, CD, etc.) and the chaetoglobosins A, B, C, E, F, and J (Ch-A, Ch-B, etc.) have been found to influence the rat of polymerization in different ways, depending on their chemical structure and concentrations applied. Class I cytotoxins, e.g., CB, CG, Ch-C, Ch-E, and Ch-F, which exert on F-actin a weak degradative power (DP, "Spudich effect"), increase the polymerization rate when present in a ratio of 4 mol to 1 mol of actin. Polymerization is slightly enhanced or retarded at molar ratios ranging from 0.04:1 to 0.4:1. Class III cytotoxins of strong degradative power, i.e., high affinity for actin, such as CE, Ch-B, and Ch-J, decrease the polymerization rate at a molar ratio of 4:1 during the first 30-40 min; however, they increase it at a molar ratio of 0.4:1. Members of class II (CD, Ch-A) exert an effect that can be interpreted as a combination of the effects of class I and class III cytotoxins. An explanation of this difference in behavior is offered on the basis of experiments on F-actin degradation by Ch-J and its reconstitution by phalloidin in the presence of Ch-J.

Optimum energy for performing CT iodinated constrast studies

A study has been made of CT contrast for iodine as a function of X-ray energy from 80 to 140 kV constant potential. The EMI CT 1010 scanner was used for phantom measurements of contrast signal, noise, artefact and dose. The results show that optimum detectability occurs at 80-100 kV, with the close efficiency being somewhat better at 80kV.

[Selective Lugol's solution staining in the diagnosis of carcinomatous and inflammatory lesions of the esophagus]

The selective character of staining the intact mucosa with Lugol's solution is dependent on the glycogen content in the superficial epithelial layer of the oesophagus. The inflammatory or carcinomatous epithelium being not stained is accounted for by changes in the glycogen content in the oesophageal epithelium which makes the staining method useful for diagnozing carcinomatous and inflammatory diseases of the oesophagus.

DNA strand scission induced by adriamycin and aclacinomycin A

The binding of adriamycin and aclacinomycin A with PM2 DNA, and the consequent cleavage of DNA have been demonstrated by agarose gel electrophoresis, using an ethidium bromide assay. Adriamycin was observed to induce a single strand scission of DNA in the presence of a reducing agent, but aclacinomycin A caused much less degree of DNA breaks. The DNA cleavage was enhanced by Cu2+ and Fe2+, but not significantly by Ni2+, Zn2+, Mg2+ and Ca2+, suggesting that reduction and auto-oxidation of the quinone moiety and H2O2 production participate in the DNA-cutting effect. The DNA degradation was dependent upon concentrations of the anthracyclines and CuCl2. The degree of DNA cleavage at 0.04 mM adriamycin was similar to that at 0.4 mM aclacinomycin A in the presence of 1 mM NADPH and 0.4 mM CuCl2. DNA was degraded to small fragments at 0.4 mM adriamycin and 0.2 mM CuCl2. The anthracycline-induced DNA cleavage was stimulated by H2O2, but partially inhibited by potassium iodide, superoxide dismutase, catalase and nitrogen gas atmosphere. The results suggested that both free radical of anthracycline quinones and hydroxyl radical directly react with DNA strands.

[Method for determining peroxidase activity]

The spectrophotometric method is described for the peroxidase activity determination which is based on the oxidation of guaicol and potassium iodide. Optimal conditions were elaborated for these two most sensitive substrates. The method may be applied for the quantitative peroxidase determination in different human biological fluids, in particular saliva and blood serum.

A phase-shift fluorometer using a laser and a transverse electrooptic modulator for subnanosecond lifetime measurements

We described a simple phase-shift fluorometer using continuous laser excitation. The laser enables the use of a transverse mode electrooptic modulator with a half-wave retardation voltage of about 200 V (in contrast to many kilovolts of longitudinal modulators) at frequencies up to 100 MHz. The modulated fluorescence signal is detected, after passing through a double monochromator, by a photomultiplier tube feeding a radio frequency (RF) tuned amplifier. THE RF phase is then determined by phase-sensitive detection using a double balanced mixer with the reference obtained from a PIN photodiode-turned amplifier combination which detects light split off from the main exciting beam. The laser and double monochromator allow the observation of modulated Raman solvent and Rayleigh scatterin, which are convenient for determining the zero reference phase.

Bacterial contamination in a modern operating suite. 1. Effect of ventilation on airborne bacteria and transfer of airborne particles

The effect of ventilation on airborne contamination was studied in a new operating suite containing operating rooms with conventional ventilation (17-20 turnovers/h) and operating rooms with zonal ventilation, where the turnover in the central part of the room was approximately 80/h. The efficacy of the ventilation was first examined with gas tracer experiments and found satisfactory. Experiments using potassium iodide particles showed the transfer between adjacent rooms in the suite to be less than 10(-3)% with closed doors and from 1% to 2.5 x 10(-2)% when the doors were opened once a minute. The transfer between two adjacent operating rooms was calculated to be approximately 10(-4)%. There is thus little risk of spread of airborne infection between operating rooms.Experiments with potassium iodide particles showed that in operating rooms with zonal ventilation the particle concentration in the centre of the room was about one-tenth that in the periphery; in conventionally ventilated operating rooms the concentration was about one-half. With bacteria-carrying particles generated by human activity the concentration in the centre of operating rooms with zonal ventilation was about half that in the periphery both during experimental activity and operations; in conventionally ventilated operating rooms it was about equal in both cases. Bacterial counts at the periphery were found to be lower in rooms with zonal ventilation ( approximately 50 c.f.u./m(3)) than in conventionally ventilated ( approximately 70 c.f.u./m(3)).

Separation of free and protein-bound ligands in the radioimmunoassay by gel filtration-centrifugation

The application of gel filtration-centrifugation to the separation of free and protein-bound ligands in radioimmunoassay is described. The method is simple and rapid. A large number of samples can be handled simultaneously and the bount radioactivity is directly transferred to the scintillation vial. Using a 9 X 36 mm column of Sephadex G-50 (coarse), 400 mul of the reaction mixture can be separated during 2 min centrifugation.

Flagellar doublet microtubules: fractionation of minor components and alpha-tubulin from specific regions of the A-tubule

Proteins occurring minor amounts with purified sperm flagellar doublet microtubules were identified and studied by SDS-gel electrophoresis. Methods were developed to solubilize selectively these minor components; electron microscopy (EM) of the fractionated products revealed possible locations of these proteins in the tubule. Doublet microtubules were prepared from sea-urchin (Echinus esculentus and Stronglyocentrotus droebachiensis) and scallop (Pecten maximus) sperm by dialysing flagellar axonemes against 2 mM Tris-0-2 mM EDTA-0-5 mM DTT. EM indicates that these doublet tubule preparations retain at least 70% of their radial spokes; cross-sections show a globule or fibre applied to the inside wall of the A-tubule, across from the inner B-tubule junction. On SDS-gels these preparations separate into at least 10 minor bands, accounting for 20-30% of the total protein; the remaining 75 +/- 4% migrates as tubulin. For E. esculentus the molecular weights and relative amounts of these components are: Component Ee 8 (150000 Daltons; 1%), 11 (114000; 2-5%), 15 (89000; 2%), 16 (80000; 2-5%), 17 (74000; 2%), 18 (69000; 2%), 19 (66000; 2%), 21 (48000; 4-5%), 22 (45000; 3%) and 23 (44500; 3%). Treatment of sea-urchin tubules with 0-1-0-5% sarkosyl, 0-1-0-3 M KSCN or 0-3-0-6 M KI results in the selective solubilization of: first, component 8 and some B-subfibre tubulin; second, components 11 and 23 and the remaining B-subfire tubulin; third, most of the A-subfire tubulin and components 17, 18 and 19. Thermal fractionation extracts none of these components, suggesting they are principally associated with the A-tubule. Finally 25-35% of the original protein is resistant to solubilization, and appears in the EM as ribbons of 3 protofilaments with 16-nm axial repeats. The resistant ribbons contain components 15, 16, 21 and 22 (plus component 20 in S. droebachiensis) in addition to 25 +/- 4% of the total tubulin. The data support the existence of two stable moieties in each doublet tubule: (1) a ribbon of 3 protofilaments and (2) either a second ribbon of 3 protofilaments or an equivalent amount of tubulin in some other form. EM images suggest that one ribbon forms the lateral side of the A-tubule (e.g. protofilaments A1,2,3 or A13,1,2 in the model) and that the globule applied to A13 may be a multisubunit complex of remaining minor components. Treatment of scallop tubules with 0-3 M KSCN preferentially extracts alpha-tubulin, yielding ribbons 1-4 protofilaments wide. The significance of this finding is discussed.

Anti-inflammatory effects of antimicrobial agents: an in vivo study

Antimicrobials are used emperically in a variety of inflammatory dermatoses such as rosacea and dermatitis herpetiformis, although these diseases are not believed to be of bacterial etiology. We have used potassium iodide ointment to induce follicular pustules and have found in this in vivo model properties of antimicrobials not related to their antibacterial actions. Topical demethylchlortetracycline and erythromycin (5%) lead to suppression of KI-induced inflammation (erythema, pustules) and systemic use of these drugs as well as diaminodiphenylsulfone produces the same effect.

[Random immunoglobulin. I. Use of chaotropicions and fluorescence quenching for quantitating the non-specific adsorption in the interaction of human IgG with rhodamine B]

It is shown that, when excited in the visible range, fluorescence of the dye may be either quenched or enhanced, from its initial value Fo, by addition of increasing "normal" immunoglobulin (IgGH7 S), depending if the solution is "non-chaotropic " (NaF 0,1 M) or "chaotropic" KI 1 M). Let F be the fluorescence obtained at concentration P in protein, then the plot of the quantity P.F/(FO-F)against the quantity P.F/(FO-F) gives a straight line; the zero ordinate of this is the inverse of the non-specific interaction equilibrium constant. Quenching of fluorescence by increase of temperature, and by increase of concentration of salt (KI) are also quantitatively dealed upon in order to testify that this non-specific interaction is of the "adsorption" type. Concentration of dye is 10-6M; concentration of protein is varied from 0,05 % to 0,5 %.

A more reliable gram staining technic for diagnosis of surgical infections

The purpose of this study was to identify pitfalls in the Gram staining technic that limit its diagnostic value. In our clinical experience, gram-positive organisms were often decolorized too easily. Factors have been identified that alter the susceptibility of gram-positive organisms to decolorization in the Gram staining technic. The age of the bacterial culture, the preparation of the smear, the fixation technic, and the mordant have an important influence on the ease with which gram-positive organisms are decolorized. On the basis of these studies, a more reliable and reproducible Gram staining technic has been developed for the diagnosis of surgical infections.