Showing papers by "University of Miami published in 1971"

Intercellular communication and tissue growth : V. A cancer cell strain that fails to make permeable membrane junctions with normal cells.

Abstract: A method is described for testing communication between a normal and a cancerous cell in culture without inserting microprobes into either cell; microprobes are put into other normal cells coupled to the normal cell in question. It is shown with this method that a cell strain (class-A), of epithelial morphology, isolated from Morris' liver tumor (H-5123) fails to make communicative junctions with several types of normal cells; small inorganic ions and fluorescein do not pass from the normal cells to the class-A cells (they do pass from the normal cells to normal cells, even between normal cells of different type). The class-A cells also appear incapable of junctional communication among themselves. The cells of class-A are cancerous: they are not 'contact inhibited' by each other or by the normal cells and they form malignant tumors when injected into test animals. Another cell strain (class-B), of fibroblastic morphology, derived from the same liver tumor as class-A makes communicative junctions readily. This strain is 'contact inhibited' and does not produce tumors when injected into the animals.

Landward Movement of Carbonate Mud: New Model for Regressive Cycles in Carbonates: ABSTRACT

Abstract: Repeated regressive cycles are characteristic of the Paleozoic shallow-water carbonates of North America; similar cycles are present, although less abundant, in Mesozoic and Cenozoic strata worldwide. Several of these cyclic carbonates contain major hydrocarbon reservoirs: Permian, Central Basin platform; Mississippian, Saskatchewan; Ordovician and Silurian, Montana. Studies of comparable recent deposits in Florida, the Bahamas, and the Persian Gulf suggest an alternative to the accepted tectonic explanation of these cycles. The Florida Bay lagoon and the tidal flats of the Bahamas and Persian Gulf are traps for fine sediment produced on the large adjacent open platforms or shelves. The extensive source areas produce carbonate mud by precipitation and by the disintegration of organic skeletons. The carbonate mud moves shoreward by wind-driven, tidal or estuarinelike circulation, and deposition is accelerated and stabilized by marine plants and animals. Because the open marine source areas are many times larger than the nearshore traps, seaward progradation of the wedge of sediments is inevitable. This seaward progradation gives a regressive cycle from open marine shelf or platform to supratidal flat. As the shoreline progrades seaward the size of the open marine source area decreases; eventually reduced production of mud no longer exceeds slow continuous subsidence and a new transgression begins. When the source area expands so that production again exceeds subsidence a new regressive cycle starts. The seaward progradation suggested by this model should be observable in ancient deposits. End_of_Article - Last_Page 340------------

The Distribution of the Major and Some Minor Elements in Marine Animals Part II. Molluscs

Abstract: INTRODUCTIONIt has been known for a long time that the soft tissues of molluscs contain relatively high concentrations of certain trace elements—mainly transition metals (see, for example, Vinogradov, 1953; Bowen, 1966). However, with the exception of the work by Brooks & Rumsby (1965) on the occurrence of 12 elements in 3 New Zealand bivalves, most of the investigations have concerned the distribution of only one or two elements. This has prevented a study being made of possible interelement correlations. The present work was carried out in an endeavour to determine the usual levels of several minor elements in a variety of molluscs from the Irish Sea and to seek evidence for such correlations.

Fossil Fuels as a Source of Mercury Pollution

Abstract: The upper limit of the quantity of mercury released by weathering processes is approximately 230 metric tons per year. The quantity of mercury released by burning of coal is estimated to be of the order of 3000 tons per year, a quantity comparable to that emitted as waste from industrial processes.

Atrioventricular conduction defects in patients with sinus bradycardia. Analysis by His bundle recordings.

Abstract: A-V conduction was analyzed in 75 patients (mean age, 73 years) with sinus bradycardia (SB) by His bundle (BH) recordings. Forty-five of these patients had normal QRS complexes (≦0.10 sec) and 30 had abnormal QRS complexes (≧0.12 sec). The conduction times through the atrium (P-A), A-V node (A-H), and His-Purkinje system (H-V) were measured during normal sinus rhythm and transient right atrial pacing up to rates of 150/min. The normal range of conduction times through various regions is: P-A = 25 to 45 msec; A-H = 50 to 120 msec, and H-V = 35 to 45 msec. Overall A-V conduction was completely normal only in 25 (33%) patients. Of these 25 patients, 20 had a narrow QRS complex and five had an abnormal QRS complex. The remaining 50 patients showed abnormal A-V conduction in one or more regions (P-A in 10, A-H in five, BH in six, H-V in 10, and mixed in 19). In some patients despite normal ECGs, the H-V time was abnormal and 1:1 A-V conduction was present during atrial pacing up to 150/min. An abnormal H-V tim...

The Biotransformation of Ēthrane in Man

Abstract: The biotransformation of Ēthrane was studied in seven healthy female patients by measuring urinary fluorine excretion. The total amount of Ēthrane recovered was 85.1 per cent of the amount absorbed; 82.7 ± 18.8 per cent was recovered as unchanged Ēthrane in exhaled air and 2.4 per cent as nonvolatile fluorinated metabolites in urine. Of the urinary fluorine, 0.5 per cent was excreted in inorganic form and 1.9 per cent in organic form. Following anesthesia, urinary excretion rates of fluoride in reached a maximum in seven hours. Maximum excretion of organic fluorine metabolites was reached on the second day. Urinary excretion then assumed a simple exponential decay, with half-times of 1.53 days for inorganic fluoride and 3.69 days for or-ganic fluorine. The excretion of unaltered Ēthrane in exhaled air assumed a three-term exponential decay, with half-times of 17.8 minutes, 3.2 hours, and 36.2 hours.

Faber Polynomials and the Faber Series

Abstract: (1971). Faber Polynomials and the Faber Series. The American Mathematical Monthly: Vol. 78, No. 6, pp. 577-596.

Peridotite-gabbro-basalt complex from the equatorial Mid-Atlantic Ridge

Abstract: Rocks were dredged where the Mid-Atlantic Ridge is intersected by the Chain, Romanche, St Paul and Vema Fracture Zones, and from unfractured portions of the Ridge between 6 and 8° N. Peridotites are common at the fracture zones, but were found also in unfractured sections of the Ridge; harzburgites prevail, but lherzolites, dunites and plagioclase peridotites are also present. A variety of gabbros was recovered, generally above the peridotites, including norites, troctolites, quartz gabbros and theralites. The chemistry of these gabbros indicates a marked crystal-liquid fractionation, following both a ‘tholeiitic’ and an ‘alkali’ trend. The basalts show also both trends, but less markedly. Metamorphic rocks ranging from ‘greenschist’ to ‘amphibolite’ facies are found throughout the sections. Strontium isotopic data suggest that the peridotites (excluding St Peter-Paul rocks) are not related genetically to the associated gabbro-basalt, in a situation similar to that of alpine complexes on the continents. The peridotites are probably residual and were depleted of lithophile elements at some early stage of their history, before the opening of the Atlantic rift. It is postulated that in the upper mantle below the equatorial Atlantic a zone exists of residual, alpine-type peridotite, while the lower crust consists of a mixture of ultramafics and intrusive gabbros. The data indicate strong similarities between the Mid-Atlantic Ridge and alpine complexes from various parts of the world.

On the Significance of Cross-Bridges Between Microtubules and Synaptic Vesicles

Abstract: Observations on the fine structure of synaptic and non-synaptic axoplasm in the spinal cord of the lamprey ammocoete (Petromyzon marinus) are described. Previous studies on this material revealed a close association between spherical vesicles and axoplasmic microtubules near central synapses, and observations were consistent with the suggestion that synaptic vesicles become detached from oriented microtubules in the focal clusters adjoining the presynaptic membrane across which transmitter release takes place. These observations have been extended to include axons containing non-spherical or ellipsoidal vesicles-possibly containing a transmitter chemically and functionally distinct from that in spherical synaptic vesicles. Structural cross-bridges between both microtubules and vesicle populations are now described; these are found not only in the vesicle concentrations bordering synaptic foci, but also in non-synaptic axoplasmic regions where sparsely distributed vesicles are found in association with microtubules. It is suggested that the bridging between vesicles and microtubules may reflect a mechanism for transport of the former-a possibility in accord with cumulative evidence of involvement of microtubules in rapid intracellular translocation in a variety of cells. It is proposed that arrival of excitation at a synaptic site is not only coupled with transmitter release across the axon plasma membrane, but that events at the cell membrane may in turn be coupled with a means of supplying vesicles to the synaptic locus. This hypothesis suggests that the synapse may rely on distant parts of the neuron, perhaps including the cell body, for materials involved in synaptic transmission.

Left ventricular function in chronic obstructive lung disease.

Abstract: In 15 patients with chronic obstructive lung disease, biventricular cardiac catheterization showed that left ventricular end-diastolic pressure was elevated in seven, and abnormal left ventricular function curves were found in 14. Analysis of left ventriculography revealed increased wall thickness or diastolic chamber size (or both) in nine of 10 observations and impaired ventricular performance in three of eight. The degree of functional impairment was not influenced by the presence or absence of right-sided heart failure. Appreciable coronary narrowing was found in only two of 10 subjects studied by cineangiography. Left ventricular dysfunction was present in most of the patients studied. The pathogenesis of the dysfunction is not clear.

Mechanism of Auxin-induced Ethylene Production.

Abstract: Indoleacetic acid-induced ethylene production and growth in excised segments of etiolated pea shoots (Pisum sativum L. var. Alaska) parallels the free indoleacetic acid level in the tissue which in turn depends upon the rate of indoleacetic acid conjugation and decarboxylation. Both ethylene synthesis and growth require the presence of more than a threshold level of free endogenous indoleacetic acid, but in etiolated tissue the rate of ethylene production saturates at a high concentration and the rate of growth at a lower concentration of indoleacetic acid. Auxin stimulation of ethylene synthesis is not mediated by induction of peroxidase; to the contrary, the products of the auxin action which induce growth and ethylene synthesis are highly labile.

Cellular dynamics of comedo formation in acne vulgaris.

Abstract: Epithelial turnover was compared on the faces and backs of normal and acne subjects using autoradiographs prepared after intra-dermal injection of tritiated thymidine, glycine and histidine. The percentage of thymidine labelled nuclei in the epidermis, sebaceous follicles and open and closed comedones was determined. The movement of glycine or histidine labelled horny cells into comedones was followed. No differences in cellular kinetics were found between acne and non-acne subjects. Turnover of the facial epidermis was almost twice as fast as of the back epidermis. Follicle labelling was similar to the contiguous epidermis. The labelling index of the comedo was much greater than in the normal sebaceous follicle. Cellular multiplication was faster in closed than in open comedones. Labelled horny cells moved in an elliptical band into the substance of the open comedo. Labelled cells eventually sloughed through the patulous orifice. This did not happen in closed comedones up to the maximum time of observation (2 months). Comedo formation is the resultant of two abnormalities: 1. increased formation of horny cells and 2. increased coherence.

Endothelial projections as revealed by scanning electron microscopy.

Abstract: Scanning electron micrographs of the endothelium of the pulmonary artery reveal that the entire surface is covered by a meshwork of irregular projections which vastly increase the surface area. The size and density of the projections suggest that they may function to direct an eddying flow of plasma along the endothelial surface.

His Bundle Electrograms in Patients with Short P-R Intervals, Narrow QRS Complexes, and Paroxysmal Tachycardias

Abstract: His bundle electrograms were recorded in three patients with short P-R intervals, narrow QRS complexes, and a history of paroxysmal tachycardias. During sinus rhythm or atrial stimulation with long cycle lengths, the shortening of the P-R interval was due to a decrease in the low right atrium-His (LRA-H) interval (representing A-H conduction time). The latter was also short during retrograde (V-A) conduction. These findings support the existence of an A-V nodal bypass operation in both directions. In one patient, the LRA-H interval did not lengthen when the atrial rate was increased. Intermittent atrial pacing was performed in the two other patients. The LRA-H interval was short at long coupling intervals, but it started to increase (progressively) at a given Stimulus1-Stimulus2 interval. Apparently, the refractory period of the accessory bundle was encountered so that the impulse was propagated, with various degrees of delay, through the A-V node. A James bundle need not be present in all patients with similar electrocardiograms. Abnormalities of unknown origin could cause this phenomenon. Reciprocating tachycardias were induced by stimulation of the atria in one patient. The triggering beat consistently had a long A-V conduction time. Although in this case retrograde (V-A) propagation most probably occurred through the accessory communication, the possibility of a functional intranodal dissociation of a single anatomical pathway could not be excluded.

Utilization of carbon sources by Pullularia pullulans for the elaboration of extracellular polysaccharides.

Abstract: The yeastlike fungus Pullularia pullulans utilizes simple mono- and disaccharides both in the production of cell mass and the elaboration of extracellular polysaccharide. The utilization pattern of these sugars and the effect obtained by varying the pH of the medium are studied, and the ability of the organism to utilize and elaborate extracellular polysaccharides from noncarbohydrate sources is explored.

Altered Cell Microfibrillar Orientation in Ethylene-treated Pisum sativum Stems

Abstract: The roots and stems of plants typically swell when they are exposed to ethylene (1-3, 5, 8), or supraoptimal auxin (2, 3, 5, 8, 20), and root hairs are induced to form (1, 5, 6, 8). When supraoptimal IAA causes pea subapical stem sections to swell, the optical birefrigence pattern of the cell wall changes, and newly deposited wall microfibrils tend to be oriented in a longitudinal rather than radial direction (20, 21). Ethylene also alters the birefrigence of pea stem subapical cell walls when it causes the tissue to swell (3, 4, 9), producing a characteristic banded pattern. This same pattern occurs in pea stem tissue which has swelled after treatment with supraoptimal IAA (4, 9). The similar effects of ethylene and supraoptimal IAA on pea tissue have been attributed to the fact that supraoptimal IAA induces ethylene formation (2, 3). According to the multinet hypothesis (13, 19), cells elongate predominantly in a longitudinal direction because of the restraining influence of newly deposited, radially oriented microfibrils. If a cell is to expand radially under the influence of ethylene or supraoptimal IAA, newly deposited microfibrils no longer should be oriented in a radial direction. The present communication describes the effect of ethylene on microfibrillar organization in various regions of the cell wall, and shows it to be similar to that resulting from auxin treatment (20, 21). Pea seedlings were grown in vermiculite for 7 days in complete darkness and then treated continuously in a desiccator with 50 ,tl/liter ethylene for 24 to 96 hr, except for one complete aeration each day. Within 24 hr the seedlings displayed a typical triple response to ethylene and thereafter swelling intensified progressively throughout the 96-hr experimental period. Subapical stem pieces were fixed with 3% glutaraldehyde in 0.1 M phosphate buffer, pH 7.2, for 12 hr, rinsed with buffer, postfixed with 1% osmium tetroxide in phosphate buffer for 1 hr, dehydrated with an ethanol series, and embedded in Epon-Araldite epoxy resin. After sectioning, the tissue was stained with uranyl acetate and lead citrate. For light microscope studies, freehand sections were made from swollen subapical tissue without fixation, and the sections were stained with 0.05 % toluidine blue 0 (16). The effects of ethylene, IAA, kinetin, BIA,2 BA, and colchicine on the growth of excised 1-cm subhook sections from 7-day-old control plants were studied singly and in combination by incubating lots of 10 sections in 125-ml Erlenmeyer flasks containing 10 ml of 2% sucrose, 5 mm potassium phosphate buffer, pH 6.8, and 5 mm cobalt chloride solution plus the added hormone or hormones. All manipulations were carried out under dim green light, the flasks were sealed with vaccine caps, ethylene injected with a syringe when required, and tissue incubated in the dark with gentle shaking for 18 hr at 23 C. Ethylene production was then determined by gas chromatographing 5 ml of air from each flask (2), and the tissue was weighed and measured. The concentrations of coichicine, BIA, kinetin, and BA used in these studies were selected to provide maximum swelling with little or no growth inhibition; higher concentrations inhibited growth markedly and did not induce significantly more ethylene production. Control tissue from intact seedlings had the wall structure typical of elongating cells (Fig. 1 a), with radially oriented microfibrils at the inner wall surface, more randomly distributed microfibrils in the center of the wall, and longitudinally oriented microfibrils in the outer region of the wall. The cell depicted in Figure la is an epidermal cell, but similar wall structure was noted in cortical and pith cells. After 24 hr of treatment with ethylene a very different wall structure appeared uniformly in epidermal, pith, and cortical cells of the swollen subapical zone. This structure is illustrated in Figure lb. The microfibrils at the inner surface of the wall are oriented in a predominantly longitudinal direction, whereas those in the center of the wall are radially oriented. The newly deposited longitudinal microfibrils at the inner surface should restrict longitudinal expansion and allow the cell to grow in a radial direction. Those microfibrils originally laid down in a radial direction before ethylene was applied are now located nearer to the center of the wall; they are maintained in a radial configuration by the forces created during radial cell expansion. The microfibrils in the outer portion of the wall had already been pulled into a predominantly longitudinal orientation before ethylene was applied. However, the gas greatly slows cellular elongation, and therefore any further tendency for these fibrils to be pulled into a longitudinal pattern. Instead, because of the forces created during radial expansion, these microfibrils tend now to be pulled into a radial orientation. The wall microfibrillar pattern observed in control tissue was not changed during 48 hr of additional growth of the seedlings; the pattern observed in ethylene-treated tissue was similar at 24 and 48 hr. The experiment was repeated 3 times, and in each case the subapical zones from five control and five ethylene-treated seedlings were fixed and prepared for electron microscopy. Several randomly selected sections were examined from each subapex, and without exception the ethylene-treated and control cells had the distinctly different wall structures depicted in Figures la and lb. 1 Present address: Department of Horticulture, Michigan State University, East Lansing, Michigan 48823. 2 Abbreviations: BIA: benzimidazole; BA: benzyladenine.