Studies on the control of antibody synthesis. IX. Effect of boosting on antibody affinity.

The effect of boosting on antibody affinity was studied in a haptenic system. Generally, boosting results in the prompt synthesis of high affinity anti-hapten antibody. However, repeated boosting frequently leads to a decrease in the amount and affinity of the serum antibody. Repeated boosting with hapten on a carrier different from that used for priming selectively stimulates synthesis of the highest affinity anti-hapten antibody and does not result in a decrease in affinity. Priming with soluble antigen without adjuvants results in the synthesis of low affinity antibody. After such priming, boosting stimulates low affinity antibody synthesis and repeated boosting leads to a moderate increase in antibody affinity.     

Studies on bacteriophage fd DNA. II. Localization of RNA initiation sites on the cleavage map of the fd genome.

In an in vitro RNA synthesizing system, a single size of A-start RNA and three different sizes of G-start RNA are predominantly transcribed on the doubly closed replicative form (RFI) DNA of phage fd. When the RFI DNA was cleaved into three fragments (HinH-A, HinH-B and HinH-C) by a restriction endonuclease from Haemophilus influenzae H-I, the A-start RNA was predominantly initiated on HinH-B and the three G-start RNAs on HinH-A. RFI DNA was further cleaved into smaller pieces by two other restriction endonucleases from H. aphirophilus and H. gallinarum. Upon mixing the digests with RNA polymerase, two specific fragments derived from HinH-A were bound to the polymerase with GTP present. G-start RNA was efficiently initiated on the fragments isolated by this procedure. On the basis of these observations and estimates of the size of RNA formed on each fragment, the initiation sites for major RNA species were localized on the cleavage map of the phage fd genome previously constructed.     

Pharmacological studies on the pulmonary vein of the horse. I. Effects of selected spasmogens.

Horses suffer from a respiratory condition, similar to human allergic asthma, that is characterized by severe dyspnea, wheezing, coughing, and mucus production. Mediator substances released during the allergic reaction may contract airways and pulmonary vasculature. Nothing is known of the effects of autacoids and other vasoactive substances on equine pulmonary vessels. Therefore, spiral strips of equine pulmonary vein were prepared in vitro and the effects of histamine (H), 5-hydroxytryptamine (5HT), bradykinin (BK), carbachol (Carb), and phenylephrine (phen) were studied. The order of contractile effectiveness for the agonists on the vein was found to be 5HT greater than H greater than Bk greater than Phen greater than Carb, although H consistently produced the greatest maximal effects. H1-receptors appeared to mediate H contractions while H2-receptors had no measurable effect. 5HT responses were mediated directly by 'D-type' smooth muscle receptors. Bk produced contractions but of a lesser magnitude than either H or 5HT. Varying degrees of tachyphylaxis were observed for each agent. alpha-Adrenergic receptor stimulation by Phen initiated low-magnitude contractions whereas Carb exhibited virtually no activity on the pulmonary vein. Contractile responses of pulmonary veins to various spasmogens may contribute to the equine asthmatic response by raising vascular hydrostatic pressure, thereby enhancing edema formation.     

Studies on Thermoactinomyces sp. TM9208. I. Description of the strain

A strain of Thermoactinomyces sp., TM9208, isolated from a soil sample in the Taipei area showed antagonistic activity to Gram positive bacteria but not to the Gram negative on the potato extract agar plate by the cross streaking method. The strain showed strong starch hydrolysis, beta type of hemolysis, brownish yellow growth on the potato extract agar and green on the nutrient agar. Its aerial mycelium, white to grayish white, was long and straight with short branches. The spores are single and have smooth surface. It is a good utilizer of starch, maltose and cellobiose as carbon source, but utilizes dulcitol, salicin, sucrose, rhamnose and sorbitol poorly.     

Influence of cycloheximide on the lung.

We examined the time course of the influence of cycloheximide on descending pressure-volume curves of excised lungs and on protein and lecithin synthesis and oxygen consumption by lung slices. We also looked at the influence of cycloheximide on granular pneumocyte ultrastructure. Excised lungs from cycloheximide-treated animals are more compliant than controls. After ventilation with air, lungs from control and cycloheximide animals show increased retractive forces and a shift to the right of the deflation P-V curve. Incubation at 38 degrees C for 30 min reverses these changes in control lungs, but not in lungs from cycloheximide-treated rabbits. There is no change in liquid delfation P-V curves after cycloheximide. Cycloheximide causes an immediate decrease of 50% in incorporation of radioactive leucine into protein by lung slices. Incorporation of radioactive palmitate into lecithin and oxygen consumption are also decreased by 50% 6 h after cycloheximide. Lamellar bodies in granular pneumocytes are smaller after cycloheximide. Cycloheximide causes a significant increase in the surface density of the lamellar body envelope. Cytoplasmic area of granular pneumocytes is increased after cycloheximide.     

XIII.—A Note on the Structure of the Feather.

F or some time past I have been engaged on the photographic analysis of a feather, and my attention has been concentrated on the glazed portion of the underside of the primaries of certain birds. Chandler (University of California Publications, Zoology, xiii. 1916, pp. 243–446), referring to the subject states:—
"The ventral edges of the rami are produced into horny keels usually with no evident cell structure, known as the ventral ridges. Although in the great majority of birds the ridge forms only a narrow, inconspicuous border for the ramus, in a few birds it is extraordinarily developed as a very thin translucent film, which bends distally and overlaps the following ramus, giving a smooth, glazed appearance to the under surface of the feather which is conspicuous at the most casual glance."     

Objectives and Program of the A.M.A. Committee on Nursing

The continued achievement of high standards of patient care in the preventive, curative, and restorative aspects of illness depends upon a harmonious, collaborative relationship between medicine and nursing. In an effort to protect and foster an enduring alliance of understanding and cooperation between these 2 major health professions, the Committee on Nursing has instituted a continuing program of liaison, communication, education, and research. The Committee has authorized publication of the following report on its objectives and program.     

Controversies on the origin of life.

Different viewpoints, many with deep philosophical and historical roots, have shaped the scientific study of the origin of life. Some of these argue that primeval life was based on simple anaerobic microorganisms able to use a wide inventory of abiotic organic materials (i.e. a heterotrophic origin), whereas others invoke a more sophisticated organization, one that thrived on simple inorganic molecules (i.e. an autotrophic origin). While many scientists assume that life started as a self-replicative molecule, the first gene, a primitive self-catalytic metabolic network has also been proposed as a starting point. Even the emergence of the cell itself is a contentious issue: did boundaries and compartments appear early or late during life's origin? Starting with a recent definition of life, based on concepts of autonomy and open-ended evolution, it is proposed here that, firstly, organic molecules self-organized in a primordial metabolism located inside protocells. The flow of matter and energy across those early molecular systems allowed the generation of more ordered states, forming the cradle of the first genetic records. Thus, the origin of life was a process initiated within ecologically interconnected autonomous compartments that evolved into cells with hereditary and true Darwinian evolutionary capabilities. In other words, the individual existence of life preceded its historical-collective dimension.     

Studies on live attenuated mumps vaccine. II. Follow-up study on the efficacy of Biken Vaccine.

Clinical and serological follow-ups were made on 18 children for 3 years and on another 18 children for 4 years, after immunization against mumps by attenuated mumps vaccine; Biken vaccine. To evaluate the protective efficacy of the vaccine, matched controls were studied during the same period. Serological examinations revealed that 77% of the vaccinees and 93% of the controls were infected with mumps after close contacts with mumps patients. Regular mumps was contracted by 88% of the controls, but none of the vaccinees. There was no substantial decrease in the antibody titers in unexposed vaccinees after vaccination.     

Studies on the morphology of colonies of bacilli of BCG-Poland substrain. I. The influence of iron on the type of BCG-Poland colonies.

The influence of iron concentration in Sauton's medium solidified with agar on the type of colonies of BCG-Poland substrains, BCG-Rio de Janeiro, BCG-France, BCG-Denmark and BCG-Japan substrains has been examined. Of all the studied BCG substrains only the BCG-Poland substrain formed rough (R) and smooth (S) colonies. In the investigated substrains rough colonies became smaller with the decrease of iron concentration but they retained their characteristic surface roughness. The smooth colonies which in the same conditions appeared only in BCG-Poland substrain did not display such dependency on iron concentration. When the incubation period was prolonged secondary rough colonies appeared among the smooth ones, regardless of the iron concentration in the medium.     

Effects of aging on the kidney.

A host of abnormalities of renal structure and function accompany advancing age. This presentation briefly surveys the renal anatomical and functional changes associated with senescence. Four areas of renal functional change have been selected for in-depth discussion: a) renal blood flow; b) glomerular filtration rate; c) renal sodium handling; and d) renal concentrating ability. The methodologic considerations including population selection which confound the assessment of the effects of aging on renal function are discussed. In addition, the functional changes associated with senescence are discussed in the context of longitudinal studies and studies utilizing appropriate patient cohorts, including potential kidney transplant donors. The clinical implications of senescent changes with regard to adjusting "normative" standards to fit the age of the patient are addressed. Furthermore, the implications of age-related renal functional alterations in predisposing the elderly patient to a number of fluid and electrolyte derangements are considered.--Epstein, M. Effects of aging on the kidney.     

Geometry of the human erythrocyte. I. Effect of albumin on cell geometry.

The effects of albumin on the geometry of human erythrocytes have been studied. Individual red cells, hanging on edge from coverslips were photographed. Enlarged cell profiles were digitized using a Gradicon digitizer (Instronics Ltd., Stittsville, Ontario). Geometric parameters including diameter, area, volume, minimum cylindrical diameter, sphericity index, swelling index, maximum and minimum cell thickness, were calculated for each cell using a CDC 6400 computer. Maximum effect of human serum albumin was reached at about 1 g/liter. Studies of cell populations showed decreases in mean cell diameter of up to 6%, area 6%, and volume 15%, varying from sample to sample. The thickness of the rim was increased while that at the dimple was decreased. Studies of single cells showed that area and volume changes do not occur equally in all cells. Cells with lower sphericity indices showed larger effects. In the presence of albumin, up to 50% of the cells assumed cup-shapes (stomatocytes). These cells had smaller volumes but the same area as biconcave cells. Mechanical agitation could reversibly induce biconcave cells to assume cup shapes without area or volume changes. Experiments with de-fatted human albumins showed that the presence of bound fatty acids in varying concentrations does not alter the observed effects. Bovine serum albumin has similar effects on human erythrocytes as human serum albumin.     

Experimental studies on the origin of monsters. II. Regarding the morphogenesis of duplicities

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Experimental studies on the origin of monsters. II. Regarding the morphogenesis of duplicities

     

Histochemical studies on the mucopolysaccharides of the developing chick kidney. II. Mucopolysaccharides of the collecting tubules and excretory ducts.

Mucopolysaccharides of the collecting tubules and excretory ducts of developing chick kidney were studied histochemically to elucidate the relations, between the changing chemical properties of these compounds and excretory processes during pronephric, mesonephric and metanephric developmental stages. At the pronephric ammonotelic stage the collecting tubules contain only neutral mucopolysaccharides, whereas at the mesonephric ureotelic stage neutral mucopoly saccharides are found till the 9th day. Sialic acids make their appearance in luminal border regions of the mesonephric collecting tubules from the 9th day on, their concentration being highest on the 15th day. Hyaluronic acid is observed from the 16th day on. Its concentration is predominant in hatched young birds and increases with age. The physiological significance of alterations in the mucopolysaccharides contents is discussed.     

Gel filtration studies of oxyhemerythrin. I. Effects of pH on the association-dissociation equilibria.

The pH dependency of the dissociation of oxyhemerythrin has been studied by frontal gel chromatography on Sephadex G-75. The extent of dissociation is markedly pH dependent increasing below pH 6.0 and above pH 8.8. In addition, the nature of the dissociation reaction undergoes dramatic change with pH. Below pH 6.4 the rate of equilibration between species is slow relative to their time of passage through the column and they are thus resolved on chromatography. Above pH 6.6 the rate of equilibration is rapid and the various forms of hemerythrin are not resolved on migration through the column. Below pH 7.4 the dissociation is an all-or-none process with no detectable intermediates. Above pH 8.0 several intermediate species can be detected. Values for Keq and deltaG degrees are presented for various forms of oxyhemerythrin at the several pH's studied.     

Observations on the biological activity of epitestosterone.

Epitestosterone, a 17 alpha-epimer of testosterone is a normal constituent of body fluids in many species including man. It has long been believed that it is devoid of any biological significance. However, it is now demonstrated that in in vivo experiments on castrated male mice it counteracts the action of testosterone on androgen-dependent organs. In vitro experiments show that on the overall antiandrogenicity of epitestosterone participate true antiandrogenic action due to the binding to androgen receptors, strong 5 alpha-reductase inhibiting activity as well as a weak antigonadotropic activity. Epitestosterone is devoid of any embryotoxicity as checked by chick embryo-toxicity screening test.     

Gel filtration studies on oxyhemerythrin. II. Effect of temperature and ionic strength on the association-dissociation equilibria.

The effects of temperature and ionic strength on the association of oxyhemerythrin have been studied. deltaH degrees and deltaS degrees for association at pH 7.0 are -2.6 kcal and +16.5 eu per mol of monomer. These values suggest that solvent adjacent to the surface of the protein undergoes rearrangement on association. Increasing ionic strength is observed to promote dissociation while decreasing the rate of attainment of equilibrium between monomers and octamers. Qualitatively similar results are observed on lowering the pH from 7.0 to 4.8, thereby linking the effects of increasing ionic strength to those of protonation of specific amino acid residues at the subunit contacts of hemerythrin. The apparent enthalpy of ionization of the amino acid residue controlling dissociation at acidic pH was found to be -1.9 to +2.1 kcal/mol. These values are consistent with a carboxyl group.     

Safe biotechnology. 7. Classification of microorganisms on the basis of hazard

 The current systems for classifying human pathogens on the basis of hazard are well developed and their basic criteria are in general agreement one with another. Of more importance, the safety practices based on these classifications have generally been successful. They have enabled extensive research activities, medical practice and industrial production to be conducted on an ever-increasing scale, involving dangerous microorganisms (e.g. in vaccine production and treatment of infected patients) with a very low incidence of adverse effects on the workers involved and the general public. Although the EU has adopted a harmonised list of agents in groups 1–4 there is as yet no complete agreement among member states and individual microbiologists. The purpose of this paper is to present a historical survey and to discuss the current processes for identifying and classifying the hazards posed by the use of microorganisms in research and technology. This is essential in the design of appropriate methods of counteracting potential risks. Received: 8 December 1995/Received revision: 29 February 1996/Accepted: 4 March 1996     

XXXII.—Some Spring Observations on the Birds of the Camargue.

T he present communication embodies the combined observations of the authors on several spring visits to the Camargue. W. B. A. paid a visit in March 1905, and another, in company with Mr. H. M. Wallis, M.B.O.U., from 26 April to 2 May, 1928. T. H. H. spent from 13 to 18 April, 1931, in the area. W. B. A., H. J. R. P., and B. W. T. made a joint expedition from 9 to 13 April, 1932, and H. J. R. P. remained on until 28 April.     

Studies on pituitary follitropin. II. Isolation and characterization of the subunits of the ovine hormone.

The α and β subunits of highly potent ovine follitropin have been isolated by dissociation in 8 m urea, pH 7.5, and chromatography on DEAE-Sephadex A25. The isolated subunits display microheterogeneity on polyacrylamide gel electrophoresis and have very low activity in follitropin-specific radioreceptor and radioimmunoassays. The tryptophan fluorescence spectra of native follitropin and the isolated β subunit are different. The recombinant of follitropin α + β subunit had the same activity as the native hormone in the radioimmunoassay, but its activity in the radioreceptor and in vivo bioassay was about 65% of the intact hormone. Substitution of the follitropin α by ovine lutropin α subunit (prepared by a method not involving urea) to form the recombinant restored full activity in all the three assays investigated. The formation of recombined hormone proceeds at a rapid rate and is almost complete by 6 h. The α and β subunits of ovine follitropin differ from each other in amino acid composition. No significant differences were apparent in their carbohydrate composition. The amino acid composition of the ovine follitropin α and lutropin α subunits are very similar. The oxidized α subunit has phenylalanine at its NH₂-terminus while aspartic acid is present at this position in the oxidized β subunit.