Mammary tumor virus antigen: sensitive immunoassay.

A rapid, sensitive immuno-assay for mammary tumor virus antigen based on inhibition of passive hemagglutination has been developed. The method permits measurement of this antigen in mouse milk from which the fat has been removed.

The origin of the chemiluminescence of phagocytosing granulocytes.

Granulocytes engaged in the phagocytosis of opsonized zymosan emit light by a process that is inhibited by superoxide dismutase and catalase. In the present report is is shown that light emission is the result of reactions between certain unspecified constituents of the ingested particles and some or all of the oxidizing agents (H2O2, O2),and possibly the hydroxyl radical and singlet oxygen) produced by the activated cells. This conclusion is based on a study of light emission by both activated cells ans artificial O2 generating system containing xanthine oxidase and purine. With these two systems light production required the presence of both zymosan and oxidizing agent, suggesting that the oxidation of particle components is necessary for luminescence to occur. The characteristics of the emission spectrum as well as the finding that granulocytes activated by a nonparticulate agent (F-) fail to liminesce show that light emission by the relaxation of singlet oxygen to the ground state does not contribute in a major way to the chemiluminescence of phagocytosing granulocytes; whether singlet oxygen contributes to chemiluminescence in other ways cannot be decided from the data available. Inasmuch as the oxidation of constituents of ingested particles is an important bacterial killing mechanism in the granulocyte, chemiluminescence may be viewed as a manifestation of the microbicidal activity of the cell.

Visual chromophore electronic structure.

The implications that recent work on the electronic structure of polyenes have for the low lying electronic states of retinal reviewed and a very simple model for the diffusenesss of the absorption spectra of visual chromophores is presented.

A continuous method for the determination of leucine aminopeptidase in human serum with L-leucinamide as substrate.

A continuous procedure for the determination of leucine aminopeptidase is described. L-leucinamide is used as substrate and the liberated ammonia is determined with the glutamate dehydrogenase reaction. The enzyme is Mn2+-activated and 30 mumol/l MnCl2 is necessary for an optimal activity measurement. Influence of buffer type, buffer concentration and pH are reported together with the apparent Km values of leucine aminopeptidase for L-leucinamide and of glutamate dehydrogenase for 2-oxoglutarate. Amastatin, a potent inhibitor, inhibits the reaction of leucine aminopeptidase completely, whereas it has no inhibitory effect on the reaction with glutamate dehydrogenase. The normal reference interval for leucine aminopeptidase is 12-65 U/l at 37 degrees C. The properties of the enzyme are discussed.

Electronic structure of polyenes related to the visual chromophore. A simple model for the observed band shapes.

A model is presented which attributes the widths of absorption bands in carotenoids to conformational disorder induced by the beta-ionylidene moiety. With reasonable parameter choices, the model gives a good quantitative fit to the spectra observed for four carotenoids and at the same time accounts for the lack of structure in the long-wavelength absorption of retinal.

Effects of temperature on measurement of aspartate aminotransferase and alanine aminotransferase in commercial control sera.

The catalytic activity concentrations of aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) in several commercial control sera were determined at three different temperatures. Although these sera were of various biological origins, the temperature-conversion factors calculated are nearly identical to those for native human sera. The proportional increase of the activity concentration caused by adding pyridoxal-5'-phosphate to the reaction mixture is independent of the reaction temperature. Arrhenius plots and some thermodynamic activation parameters of both enzymes are independent of the presence of the coenzyme pyridoxal-5'-phosphate.

Resonance enhanced Raman spectrum of all-trans anhydrovitamin A.

The Raman spectrum of all-trans anhydrovitamin A in hexane at 77 degrees K is presented. The similarity of the Raman spectra of anhydrovitamin A and the protonated Schiff base of retinal is striking. The implications of this for visual pigment studies and bacteriorhodopsin are discussed. Tentative assignments of geometry for four cis-trans isomers of anhydrovitamin A are made on the basis of the observed room-temperature absorption spectra.

Absorption spectra for the complexes formed from vitamin-A and beta-lactoglobulin.

The interactions between vitamin-A and beta-lactoglobulin have been investigated. We have found that two different complexes can be formed: one involving vitamin-A, and one involving a derivative of vitamin-A that most probably has a retro-beta-ionylidene structure. Room temperature absorption spectra for these complexes in phosphate buffer at pH 7.50 are reported and discussed.

cis-trans photoisomerization of 1,3,5,7-octatetraene in n-hexane at 4.2 K.

Photoisomerization of the linear polyene 1,3,5,7-octatetraene has been observed in an n-hexane matrix maintained at the boiling point of helium. To a good approximation, only the trans,trans and cis,trans isomers participate in the photochemistry. These compounds have been unambiguously identified by comparing the observed high-resolution fluorescence spectra to those of chromatographically purified reference compounds. Although the quantum yield of this process is probably low, its microscopic rate seems to compete favorably with vibrational deactivation.

Free jet excitation and emission spectra of diphenylbutadiene.

Highly resolved emission and one-photon fluorescence excitation spectra for 1,4-diphenyl-1,3-butadiene seeded in a supersonic expansion of helium have been measured. The spectra show a long-lived (52.8 nsec for excitation at the 0-0) state at 29,652.5 cm(-1), approximately 1,150 cm(-1) below the well-characterized (1)B(u) state, which is assigned as (1)A(g)-i.e., we have directly observed a polyene (1)A(g) state in the gas phase. Emission spectra and decay times for the (1)A(g) state were measured at a number of different excitation energies. These data clarify the ordering of excited singlet states and the photophysical behavior of diphenylbutadiene.

The penetration of ofloxacin into lung tissue.

After a single oral 600 mg dose, ofloxacin concentrations were measured in lung tissue, whole blood and plasma in 11 patients undergoing thoracotomy for a bronchial malignancy. To correct for blood contamination in the tissue samples, the tissue haemoglobin content was measured using a method based on the binding of haemoglobin by haptoglobin. Ofloxacin concentrations in plasma and whole blood did not differ significantly. The calculated blood content in the tissue samples was 0.12 +/- 0.05 ml/g lung tissue. After correction for blood admixture, the mean lung tissue concentration 2 h after administration of ofloxacin was 17.7 +/- 9.2 micrograms/g. At the same time the mean plasma concentration was 8.7 +/- 4.2 mg/l (P less than 0.02). The high concentration of ofloxacin obtained in lung tissue does not result from the preparation technique. After a single 600 mg dose the tissue concentrations proved to exceed MIC values for most pathogens frequently involved in respiratory tract infections.

Measurement of peritoneal fluid handling in children on continuous ambulatory peritoneal dialysis using dextran 70.

Fluid kinetics were studied in children treated with continuous ambulatory peritoneal dialysis (CAPD) aged between 2 and 15 years. Dextran 70 was used as a volume marker. A 4-h dwell was studied with a dwell volume of 40 mg/kg. Transcapillary ultrafiltration was measured as well as marker clearance, which is the best available approximation of lymphatic absorption in the clinical setting. In 11 children in whom dialysate was used containing 1.36% glucose transcapillary ultrafiltration was 250 +/- 79 ml/4 h/1.73 m2 and marker clearance 236 +/- 101 ml/4 h/1.73 m2. In 13 children dialysed with 3.86% glucose, transcapillary ultrafiltration was 829 +/- 226 ml/4 h/1.73 m2 and marker clearance 307 +/- 176 ml/4 h/1.73 m2. These values are similar to those found in adult patients. There was a positive correlation between age and transcapillary ultrafiltration in the group receiving dialysate containing 3.86% glucose (r = 0.69, P = 0.009). There was no correlation between age and marker clearance. It is concluded that fluid kinetics in children and adults on CAPD are similar when corrected for body surface area. In young children transcapillary ultrafiltration is lower, probably because dwell volume is low in relation to peritoneal surface area in these children.

Intravenous magnesium supplementation during cisdiammine-dichloroplatinum administration prevents hypomagnesemia.

Ten patients with disseminated testicular cancer were studied during 3 cycles of 20 mg/m2/day x 5 d CDDP combined with bleomycin and vinblastine or etoposide. Five of the patients (= group A) received 0.4 mmol KCl/kg/day and 0.3 mmol MgCl2/kg/day; the other five (= group B) received only KCl intravenously during the CDDP infusions. In group A no decrease of serum and red blood cell Mg concentration was noted. In group B the serum Mg concentration decreased from 0.84 +/- 0.04 mmol/l to 0.57 +/- 0.10 (p less than 0.001) on day 47, to 0.64 +/- 0.08 (p less than 0.005) on day 50 and to 0.72 +/- 0.02 (p less than 0.05) on day 57. The Mg concentration in the red blood cells decreased, but not significantly in group B. Furthermore, the fractional calcium excretion in group B was significantly lower than in group A during the CDDP infusions.