Showing papers by "Case Western Reserve University published in 1974"

Pathologic changes in the peripheral airways of young cigarette smokers.

Abstract: The lungs of young smokers and controls of comparable age from a population of sudden non-hospital deaths were systematically studied to determine the relation between cigarette smoking and pathologic changes in peripheral airways. The characteristic lesion observed was a respiratory bronchiolitis associated with clusters of pigmented alveolar macrophages and was present in the lungs of all smokers studied but rarely seen in nonsmokers (p<0.002). The lungs of smokers also showed small but significant increases in mural inflammatory cells and denuded epithelium in the membranous bronchioles as compared to controls (p<0.05). We postulate that this respiratory bronchiolitis is a precursor of centriacinar emphysema and may be responsible for the subtle functional abnormalities observed in young smokers. (N Engl J Med 291: 755–758, 1974)

The Mechanical Properties of Cortical Bone

Abstract: The Mechanical Properties of Cortical Bone DONALD REILLY;ALBERT BURSTEIN; The Journal of Bone & Joint Surgery

The structure of native cellulose

Abstract: Native cellulose has been shown to consist of a crystalline array of parallel chains, based on the X-ray diffraction data for specimens from the sea alga Valonia ventricosa. The unit cell is monoclinic with dimensions a = 16.34 A, b = 15.72 A, c = 10.38 A (fiber axis), and β = 97.0°. The space group is P21 and the cell contains disaccharide segments of eight chains. Models containing chains with the same sense (parallel) or alternating sense (antiparallel) were refined against the intensity data using rigidbody least squares procedures. The results show a preference for a parallel chain structure with specific chain polarity with respect to the c axis. The refinement places the CH2OH side chains approximately 20′ from the so-called tg conformation, with a result that an 02′H…06 intramolecular bond is formed. The structure also contains an 03H…05′ intramolecular bond and an 06H…03 intermolecular bond along the a axis. All these bonds lie in the 020 planes, and the structure is an array of hydrogen-bonded sheets. A major consequence of this work is that regular chain folding can be ruled out and cellulose is seen as extended chain polymer single crystals.

A comparative study of serum progesterone levels in pregnancy and in various types of pseudopregnancy in the rat

Abstract: The changes in the peripheral serum levels of progesterone in the pregnant rat werecompared with those found during ordinarypseudopregnancy, the pseudopregnancy of lactation (large litter), and the pseudopregnancies prolonged by decidualization, or by acute or chronic hysterectomy. The level in the ordinary pseudopregnant rat rose steadily to a peak on day 5 and remained at a plateau of about 70 ng/ml until day 9, after which it fell progressively. Neitheracute hysterectomy nor decidualization increased the level significantly above that found in ordinary pseudopregnancy but both treatments extended the plateau to at least day 16. In the pregnant rat, the progesterone level did not differ significantly from that of these types of pseudopregnancy until after day 11, when it rose to a peak of about 130 ng/ml on day 15; a rapid fall began after day 19. In contrast to the above, both the lactating and the chronically hysterectomized rats' progesterone levels rose steeply to values of over 120 ng/ml by day 5, ...

The prediction of the size of unerupted canines and premolars in a contemporary orthodontic population

Abstract: Moyer’s scheme of prediction of unerupted permanent canine and premolar size in the patient with mixed dentition is compared to a contemporary study that involves patients from the Cleveland area. Linear regression equations for the prediction of the mesiodistal widths of unerupted canines and premolars were calculated for a large sample of recent orthodontic patients. The form of the equations, as well as the size of the various confidence belts, were generally similar to those in the widely used but incompletely characterized Michigan Mixed Dentition Analysis. Although either set of tables would seem equally appropriate, a simple approximation—half the width of the mandibular incisors plus either 11.0 for the maxillary canine-premolar segments, or 10.5 for the mandibular segments—is of comparable accuracy.

Neurotrophic control of limb regeneration in the newt

Abstract: There are many animals that regenerate lost external body parts; however, when the wound stump is denervated and the denervated condition maintained for a prolonged period, regeneration does not occur. This neurotrophic phenomenon is demonstrated most readily in regeneration of the limb in amphibians, particularly larval and adult newts and salamanders. These animals regenerate their limbs after amputation, and the new part resembles the old in structure and function. The sequence in regeneration repeats the phases of limb embryogenesis (reviewed by Singer16 and Thornton29). After a period of healing and closure of the wound with a thickened epithelium, internal soft tissues of the wound region gradually dissolve and mesenchyme-like cells simultaneously appear. In a short time the cells form a mound (blastema) resembling a benign tumor (FIGURE 1). There follows a period of rapid enlargement during which are formed successively a conically elongate structure; then a bend, reflecting elbow formation and accompanied by flattening of the distal end to anticipate the new hand; and finally the tiny rudiments of fingers, which gradually lengthen as successive phalanges are formed. Accompanying morphogenesis is a sweep of cellular and tissue differentiation beginning at about the conical stage and extending distally as the form of the limb emerges (FIGURE 2). During all these stages and, indeed, as early as two days after amputation, regenerating nerve fibers pervade the wound and regenerating tissues. If the limb stump is denervated at the time of amputation or when the regenerate is in the blastemal stage, regeneration is blocked and the denervated blastema is resorbed. Unlike other neurotrophic phenomena, the dependence of regeneration on the nerve is easily demonstrated. For this reason reports appeared in the li-terature some time before demonstration of neurotrophic control in other systems. Indeed, the first report that nerves control limb regeneration was in 1823.28 The early regenerate is a particularly instructive model for neurotrophic studies because it is an undifferentiated structure (FIGURE 1) at the time when the nerve exerts a maximal effect on its growth. The variable of functional loss (for example, disuse atrophy and loss of protective reflexes) is therefore not as important as in other neurotrophic phenomena. The regenerate is also a useful model because the limb is innervated by sensory and motor fibers, and the neurotrophic effects of these nervous components can be evaluated individually. In other trophic phenomena, with few exceptions, the end organ is innervated by only one component-motor, sen-

Temporal aspects of the regulation of corpus luteum function by luteinizing hormone, prolactin and placental luteotrophin during the first half of pregnancy in the rat.

Abstract: Intact rats were injected once, subcutaneously, with either 1.0 mg of ergocornine, free base (ECO), to prevent prolactin release, or an equine antiserum to bovine LH (LH-AS), to neutralize endogenous LH, on one of the days between days 6 and 12 of pregnancy. ECO treatment was uniformly abortifacient on day 6, only slightly less so on day 7, and was ineffective at 0400 hr or later on day 8. LH-AS treatment on day 6 or 7 induced abortion in very few rats; at 0400 hr on day 8, it induced abortion in 92%, and at 1200 or 1600 hr on day 8 or at 1200 hr on day 10, in 100% of the rats; when given on day 12, it was again ineffective. ECO did not depress serum LH or FSH levels, but abolished the nocturnal surge of prolactin; ECOinduced abortions could be prevented by treatment with prolactin but not with LH. Absorption of the LH-AS with LH, but not with either FSH or bovine serum abolished its abortifacient effect. A severe fall in the serum progesterone level occurred within 12 to 48 hr after treatment with either...

The active fiber in a volume conductor

Abstract: This paper considers the quantitative description of intracellular and extracellular fields of a single circular cylindrical fiber resulting from the propagation of an action potential (AP). Several formulations are noted, but one, which permits identification of free-space source-sink relationships, is examined in some detail; the physical models which it gives rise to are described and developed. Desirable approximations are considered and the conditions of their validity are discussed. A convolution integral formulation to field patterns (from their sources) is presented. Axially symmetric anisotropic media are also considered.

Fracture of Glass in Vacuum

Abstract: The fracture of 6 glasses was studied in vacuum, <10−4 torr (10−2 N/m2), as a function of temperature from 25° to 775°C. Subcritical crack growth was observed in 4 of the glasses. Activation energies for crack motion ranged from 60 to 176 kcal/mol. The glasses which did not exhibit slow crack growth were “anomalous” glasses with abnormal thermal and elastic properties. Critical stress intensity factors for these 2 glasses increased ∼10% as the temperature increased to ∼600°C. It is felt that subcritical crack growth is not the result of alkali-ion diffusion or viscous flow but rather of a thermally activated growth process which depends on the crack-tip structure in the glass. A narrow cohesive region at the crack tip favors subcritical crack growth, whereas a wide region favors abrupt fracture.

Hydrolysis of Bradykinin by Angiotensin-Converting Enzyme

Abstract: Two dipeptides, phenylalanylarginine (Phe-Arg) and serylproline (Ser-Pro), are released sequentially from bradykinin by angiotensin-converting enzyme purified from hog lungs; chloride increases the rate of release of both dipeptides. Using an automated ninhydrin-reagent method, we studied the kinetics of bradykinin hydrolysis. The reaction proceeded in the absence of chloride; however, the addition of chloride increased the rate of hydrolysis by decreasing Km and increasing Vm. The Km values for bradykinin were 3.9 x 10-6M in the absence of chloride and 0.85 x 10-6M in the presence of 0.01m NaCl (optimal concentration). Both of these Km values were well below the value of 30 x 10-6M determined for angiotensin I at its optimal chloride concentration of 0.1M. Hydrolysis of bradykinin had a pH optimum of 7 and was inhibited by low concentrations (10-6M) of ethylenediaminetetraacetic acid or the nonapeptide pyroglutamyl (Pyr)-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro. It is concluded that one enzyme, acting as a dipept...

Mutations affecting sexual conjugation and related processes in Saccharomyces cerevisiae. I. Isolation and phenotypic characterization of nonmating mutants.

Abstract: Nonmating mutants were also isolated from haploid strains of yeast of both mating types. The mutants were characterized with respect to their ability to produce and respond to specific yeast sex factors, their ability to mate at low frequencies, and the ability of the low-frequency diploids to sporulate. Loss of the ability to mate by either mating type was invariably accompanied by the loss of one or more, and in some cases, all, of the above capabilities. The results strongly indicate that the sex factors are functionally involved in the conjugation process.

Interventions into group process: An approach to improving the effectiveness of groups

Abstract: Some new directions for research on group effectiveness are proposed. These include: (a) explicit recognition of group interaction process as the moderator of input-output relationships in groups; (b) research which focuses on the functions of group interaction in influencing group performance; and (c) use of experimental interventions which create new, non-typical patterns of interpersonal behavior in groups as an approach to studying group effectiveness. The results of two studies based on these proposals are summarized. One study examines the effectiveness of implicit vs. explicit discussion of group task “strategies”; the other addresses the effects of implicit (“traditional”) vs. explicit (“adaptive”) approaches to the maintenance of internal social relationships in work groups. Implications of the research are drawn both for future research on group effectiveness, and for the design of interventions aimed at improving the performance of on-going groups in organizations.

Surface dipole moments of close-packed un-ionized monolayers at the air-water interface

Abstract: Surface potentials (ΔV) of insoluble monolayers spread at the air-water interface have usually been interpreted in terms of the equation ΔV = 4Πnμ⊥. Here n is the number of film molecules/cm2 and μ⊥ is defined as the surface dipole moment. It may be assumed that μ⊥ is a composite quantity and that μ ⊥ = μ 1 D 1 + μ 2 D 2 + μ 3 D 3 Here μ1, μ2 and μ3 are the contributions to μ⊥ from substrate molecules, spread film terminal (in the water) dipoles and spread film terminal (out of the water) dipoles, respectively, and D1, D2 and D3 are local effective dielectric constants. This paper shows how all these quantities may be estimated from bulk dipole moment data and experimental measurements of surface potentials. The calculated quantities are then used to predict the surface conformations of other insoluble monolayer films and to explain observed differences in surface potentials for aliphatic and aromatic film forming molecules with similar terminal polar groups.

Mutations affecting sexual conjugation and related processes in Saccharomyces cerevisiae. II. Genetic analysis of nonmating mutants.

Abstract: Rare diploids formed by sterile mutants have been studied by tetrad analysis. Sixteen classes of mutants representing at least five distinct genetic loci have been defined. One group of mutations, isolated only in α, maps at the mating-type locus, while none of the others shows any linkage to mating type. Some of the mutations are nonspecific for mating type, while others act only on a or α. In addition, mutations were found that prevent sporulation when heterozygous in diploids. These appear to be mutations of the mating-type alleles.

Epiphyseal-plate cartilage. A biomechanical and histological analysis of failure modes.

Abstract: With a variable strain-rate testing machine, we loaded the proximal tibial epiphyses of male and female rats twenty-five to sixty-five days old. We measured tibial lengths, epiphyseal-plate cross-sectional areas, loads at failure, and displacements at failure in 560 tibiae, and calculated total energy absorption, nominal shear stress, and maximum tension (bending) stress for each epiphyseal plate. In fifty-six tibiae, we used subfailure loads to locate the initiation of cartilage failure. Increasing loads were required to cause failure at increasing but physiological rates of loading, demonstrating a viscoelastic property of the cartilage. The strength of cartilage from female rats was usually greater than that from age-matched males. There was a decrease in strength at pubescence. The mean values of maximum bending stress and nominal shear stress decreased significantly for females at forty-five days old and for males at fifty days. On histological examination of tibiae loaded to 50 per cent of failure energy, internal cracks within the plates were seen which were in planes developing the highest shear stresses. These cracks preceded the disruption of the posterior fibers that were in maximum tension, but usually were included in the eventual path of the failure crack.

Structural descriptions and the limitations of visual images

Abstract: Two experiments are reported that require Ss to judge whether or not the second of two sequentially presented patterns is a part of the first pattern. The results suggest that Ss code the pattern as a structural description and find it difficult to recognize a part of the pattern which does not match the description. It is proposed that a structural description is a combination of visual and verbal codes and that visual images lack detail when not supported by verbal concepts.

Peptidase Mutants of Salmonella typhimurium

Abstract: Six peptidase activities have been distinguished electrophoretically in cell extracts of Salmonella typhimurium with the aid of a histochemical stain. The activities can also be partially separated by chromatography on diethylaminoethyl-cellulose. These peptidases show overlapping substrate specificities. Mutants ( pepN ) of the parent strain leu-485 lacking one of these enzymes ( peptidase N ) were obtained by screening for colonies that do not hydrolyze the chromogenic substrate l-alanyl-β-naphthylamide. The absence of this broad-specificity peptidase in leu-485 pepN − mutants allowed the selection of mutants unable to use l-leucyl-l-alaninamide as a leucine source. These mutants ( leu-485 pepN − pepA − ) lack a broad-specificity peptidase (peptidase A) similar to aminopeptidase I previously described in Escherichia coli . Mutants ( pepD ) lacking a dipeptidase (peptidase D) have been isolated from a leu-485 pepN − pepA − parent by penicillin selection for mutants unable to use l-leucyl-l-glycine as a leucine source. Mutants ( pepB ) lacking a fourth peptidase (peptidase B) have been isolated from a leu-485 pepN − pepA − pepD − strain by penicillin selection for failure to utilize l-leucyl-l-leucine as a source of leucine. Single recombinants were obtained by transduction for each of the peptidases missing in a leu-485 pepN − pepA − pepD − pepB − strain. The growth response of these recombinants to leucine peptides shows that all of these peptidases can function in the catabolism of peptides and that they display overlapping substrate specificities in vivo. Images

The choice of pulse duration for chronic electrical stimulation via surface, nerve, and intramuscular electrodes.

Abstract: The peak current, peak voltage, charge transfer and energy dissipation necessary for equivalent stimulation were measured for several pulse durations in the range from 0.01 to 1.0 msec. The unidirectional, regulated current, rectangular waveform was studied for subcutaneous nerve and intramuscular stimulation in animals and for surface stimulation in humans. In addition, the unidirectional, regulated current, exponential waveform was studied in humans and was compared with the rectangular waveform. The question of the relationship between charge transfer and energy dissipation and possible tissue damage due to the electrochemical formation of toxic compounds or a temperature rise in the surrounding tissue was examined. The optimal pulse duration for reducing the possibility of tissue damage was concluded to be less than or equal to 0.01 msec for intramuscular stimulation in the test situation. No conclusion was made as to the optimal duration for nerve or surface stimulation. Excitation of muscle fibers was found to take place indirectly by was of muscle nerves during intramuscular stimulation. The exponential waveform required less charge transfer and energy dissipation than the rectangular waveform, but higher peak currents.

Human Chromosome 21 Dosage: Effect on the Expression of the Interferon Induced Antiviral State

Abstract: Human primary skin fibroblasts trisomic for chromosome 13, 18, or 21 and diploid human skin fibroblasts were induced for an antiviral response with human interferon. The cells that were trisomnic for chromosome 21 were three to seven times more sensitive to protection by human interferon than the normal diploid or trisomic 18 or 13 fibroblasts. The differential response in trisomnic 21 cells is consistent with the known assignment of the human antiviral gene to chromosome 21.

Ascending connections of a midbrain auditory area in a crocodile, Caiman crocodilus

Abstract: The torus semicircularis is a tonotopically organized auditory region in the midbrain of the crocodile, Caiman crocodilus (Manley, '71). Two distinct regions of the torus can be distinguished in Caiman: an external nucleus, which is continuous with the deep layers of the optic tectum, and a central nucleus. Ascending connections of the central nucleus were studied with the light microscope by means of the Fink-Heimer procedure after unilateral, anodal stereotaxic lesions. Efferent axons leave the central nucleus in the lateral lemniscus to enter the tecto-reuniens tract where they course as far rostrally as nucleus Z. At this level, this bundle bifurcates. The majority of these fibers turn medially and then pass through and probably synapse on interposed neurons of nucleus Z, prior to their termination in nucleus reuniens. The remaining axons continue ventrally past nucleus Z to enter the ventral supraoptic decussation where they travel anteriorly to a level just posterior to the optic chiasm. Here the fascicles cross the midline and swing caudally, still in the ventral supraoptic decussation, until they reach nucleus Z of the contralateral side. At this level, these fibers enter the tecto-reuniens tract and turn medially, to pass through and perhaps end on the intercalated neurons of nucleus Z, prior to their termination in nucleus reuniens. The neuronal architecture of nucleus Z and that of the nucleus reuniens complex are described. The latter, a midline nuclear group, consists of two subdivisions: a pars centralis and a pars diffusa. Each of these subdivisions is segregated into two neuronal aggregates at the midline. Efferents of the central nucleus terminate massively in the pars centralis and, to a considerably lesser extent, in the pars diffusa of nucleus reuniens. The results of this study are compared with similar ones in pigeons and mammals. Parallels in the fiber connections of midbrain auditory and visual areas and the segregation of these modalities in the mesencephalon and diencephalon are discussed.

Substrate-attached glycoproteins mediating adhesion of normal and virus-transformed mouse fibroblasts.

Abstract: When BALB/c 3T3, simian virus 40 (SV40)-transformed 3T3 (SVT2), and revertant variants of the transformed cells are removed by EGTA treatment from the substrate on which they were grown, they leave behind a layer of glycoprotein which has been characterized biochemically (Terry, A. H. and L. A. Culp. 1974. Biochemistry. 13:414.)—substrate-attached material (SAM). The influence of SAM from normal and from transformed cells on cellular attachment to the substrate, morphology, movement, and growth has been examined. All three cell types displayed a 30% higher plating efficiency when grown on 3T3 SAM. The morphology of SVT2 colonies and of individual SVT2 cells was dramatically affected by growth on 3T3 SAM—the cells (a) were more highly spread on the substrate, (b) resisted crawling over neighboring cells, and (c) resisted movement away from the edge of colonies; SVT2 SAM was not effective in causing these changes. A cell-to-substrate attachment assay using thymidine-radiolabeled cells and untreated or SAM-coated cover slips was developed. SVT2 cells attached to 3T3 SAM- or SVT2 SAM-coated cover slips with a faster initial rate and to a higher saturation level than to untreated substrate, whereas 3T3 and revertant cells exhibited no preference; there was no species specificity in these cell-substrate attachment phenomena. Trypsin-released cells attached much more slowly than EGTA-released cells. 3T3 SAM, however, was not effective in lowering the saturation density of mass cultures of virus-transformed cells. These experiments suggest that the substrate-attached glycoproteins of normal cells affect the cellular adhesivity, morphology, movement, and perhaps growth patterns of virus-transformed cells—i.e., causing partial reversion of these properties of transformed cells to those found in contact-inhibited fibroblasts. A model for the involvement of substrate-attached glycoproteins in cell-to-substrate adhesion, and possibly cell-to-cell adhesion, has been proposed.

Evidence of a pallidohabenular pathway in the cat

Abstract: The efferent projections of the entopeduncular nucleus (internal segment of the globus pallidus) in the cat have been studied by the autoradiographic tracing method. The findings reported in this article strongly suggest the existence of a substantial pathway originating in the internal segment of the globus pallidus and terminating in a large, circumscript region of the lateral habenular nucleus. Axons of this pathway follow a wide variety of routes to reach the lateral habenular nucleus. The implications of these findings are discussed in relation to the problem of connections between the limbic system and the corpus striatum.

Acute Slipped Capital Femoral Epiphysis

Abstract: The experience at University Hospitals of Cleveland and Children's Hospital of Akron with fifty cases of acute slipped capital femoral epiphysis is reviewed. In forty-seven hips treated by manipulative reduction and epiphyseodesis, pin fixation, or both, seven cases of avascular necrosis occurred (15 per cent). In nineteen hips treated by manipulative reduction, epiphyseodesis, and plaster immobilization, one case of avascular necrosis occurred (5 per cent), and seventeen (90 per cent) satisfactory functional results were obtained. In sixteen hips treated by manipulative reduction and pin fixation, three cases of avascular necrosis occurred (25 per cent), and twelve (75 per cent) satisfactory functional results were obtained. No case of avascular necrosis occurred in eight patients treated by manipulative reduction within twenty-four hours of the onset of acute symptoms. No case of avascular necrosis occurred in a female patient.