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Utah State University

1985

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Articles 31 - 60 of 263

Full-Text Articles in Life Sciences

Role And Responsibilities Of Agencies For Wildlife Damage Control - An Overview, James E. Miller Sep 1985

Role And Responsibilities Of Agencies For Wildlife Damage Control - An Overview, James E. Miller

Wildlife Damage Management Conference

"A well balanced wildlife management program includes research, the acquisition of land, the development of habitat, the careful regulation of hunting or harvest, the protection of certain species, the enforcement of laws -- and -- the control of animal depredations. Though necessary, this is among the least popular and most controversial of the wildlife management functions. It is, nevertheless, one of the activities which a responsible agency must undertake." This statement is a direct quote from the International Association of Fish and Wildlife Agencies' (IAFWA) Position Paper on Animal Damage Control (1981).


Future Of Wildlife Damage Control And The Cooperative Extension Service, Peter T. Bromley Sep 1985

Future Of Wildlife Damage Control And The Cooperative Extension Service, Peter T. Bromley

Wildlife Damage Management Conference

The driving forces which determine the role of the Cooperative Extension Service in wildlife damage control are (1) the demand for information by the public, (2) the degree of support for programs at the national level, and (3) the level of professionalism exhibited by Cooperative Extension Agents and subject matter Specialists. Analysis of several trends suggests that the Cooperative Extension Service role in Wildlife Damage Control will increase in coming years. The movement of urban people into rural settings will create greater demands for wildlife damage control information. Likewise, the expansion of wildlife population into urban and suburban environments due …


What You Wanted To Know About All You Ever Heard Concerning Snake Repellents, Gary J. San Julian, David K. Woodward Sep 1985

What You Wanted To Know About All You Ever Heard Concerning Snake Repellents, Gary J. San Julian, David K. Woodward

Wildlife Damage Management Conference

Have you ever heard about a way to keep snakes away from your house? Many people in North Carolina have been told by their elders of various ways to repel snakes. When we first started working on this problem in North Carolina, we were amazed at the number of "home remedies" that people believed would protect their property from snakes; and we began to keep a record of these remedies. In 1981, a grant from the Pesticide Impact Assessment Program allowed us to begin to test some of these remedies to determine their value.


Double-Crested Cormorant Damage To A Commercial Fishery In The Apostle Islands, Wisconsin, Scott R. Craven, Esther Lev Sep 1985

Double-Crested Cormorant Damage To A Commercial Fishery In The Apostle Islands, Wisconsin, Scott R. Craven, Esther Lev

Wildlife Damage Management Conference

The endangered classification of the double-crested cormorant (DCC) in Wisconsin resulted in complete protection and significant management efforts in the 1970's. These efforts, probably coupled with reduced pesticide loads, resulted in a resurgence of Wisconsin cormorant populations from a low of 66 pairs in 1972 to 1028 pairs in 1982. The DCC was reclassified as a threatened species in 1982. This apparent success story did not take into consideration the potential negative impact of an abundant piscivorous bird. In 1978 a colony of DCC's became established on a remote rocky island in the Apostle Islands National, Lakeshore, in Lake Superior. …


Minimum Effective Level Of Methiocarb For Protecting Sprouting Rice In Louisiana From Blackbird Damage, N. R. Holler, P. W. Lefebvre, A. Wilson, R. E. Matteson, G. R. Gutknecht Sep 1985

Minimum Effective Level Of Methiocarb For Protecting Sprouting Rice In Louisiana From Blackbird Damage, N. R. Holler, P. W. Lefebvre, A. Wilson, R. E. Matteson, G. R. Gutknecht

Wildlife Damage Management Conference

Blackbirds cause locally serious losses to rice. The Denver Wildlife Research Center, U. S. Fish and Wildlife Service, and the Rice Research Station, Louisiana State University Agricultural Center have been cooperating in tests to determine the efficacy of methiocarb seed treatments for protecting sprouting rice in Louisiana from blackbird damage. Results from four field tests (1980, 1982, 1983, and 1984) have shown that methiocarb provides good protection when applied to rice seed at the rate of 2.4 g and 1.25 g active ingredient (a.i.)/kg of rice seed (0.25 and 0.125%). Seed treated at 0.6 g a.i ./kg appeared to be …


Commercial Wildlife Pest Control Permits An Alternative Approach, Gerard W. Wendt Sep 1985

Commercial Wildlife Pest Control Permits An Alternative Approach, Gerard W. Wendt

Wildlife Damage Management Conference

No abstract provided.


Role And Responsibilities Of State Cooperative Extension Services For Wildlife Damage Control, James L. Byford Sep 1985

Role And Responsibilities Of State Cooperative Extension Services For Wildlife Damage Control, James L. Byford

Wildlife Damage Management Conference

The Cooperative Extension Service was established by the Smith-Lever Act in 1914. It was designed to improve the lives of people, through education in: agriculture, natural resources, home economics and community development. Its audiences include both adult and youth. 4-H is the primary youth audience. The Cooperative Extension Service is an "extension" of the Land employees include university faculty (specialists) and professional agents in every county, in every state in the country. Extension's primary mission is to conduct an educational program, using research-based information. Research results are condensed into a form that the average person can understand. The role of …


Wildlife Damage Control - The Role And Responsibilities Of The U.S. Fish And Wildlife Service, Leroy W. Sowl Sep 1985

Wildlife Damage Control - The Role And Responsibilities Of The U.S. Fish And Wildlife Service, Leroy W. Sowl

Wildlife Damage Management Conference

No abstract provided.


Cathodoluminescence Study Of Defects In Iii-V Substrates And Structures, M. Cocito, P. Franzosi, G. Salviati, F. Taiariol Sep 1985

Cathodoluminescence Study Of Defects In Iii-V Substrates And Structures, M. Cocito, P. Franzosi, G. Salviati, F. Taiariol

Scanning Electron Microscopy

Solid state detector cathodoluminescence studies of semiconducting and semi-insulating GaAs and InP crystals, were performed. The origin of the dislocation contrast in GaAs:Si doped substrates, in the carrier concentration range from 1016 to 6 · 1018 cm-3, were discussed. The image contrast was explained on the basis of the emission efficiency versus carrier concentration curve, obtained in the transmission mode. Single dislocations and dislocation arrangements in addition to growth striations, clusters and precipitate-like microdefects were evidenced. The above mentioned microdefects were detected in GaAs: Te, S and Si doped and InP: Sn doped specimens. Commercial InP:Sn …


Recommended Species For Vegetative Stabilization Of Training Lands In Arid And Semi-Arid Environments, United States Department Of Defense, Army Corps Of Engineers Sep 1985

Recommended Species For Vegetative Stabilization Of Training Lands In Arid And Semi-Arid Environments, United States Department Of Defense, Army Corps Of Engineers

Plants

Maintaining natural resources on western military installations has received increasing attention in recent years. Of special interest are training ranges where the environmental impact of tracked and wheeled vehicles is significant. Revegetation and soil stabilization on the arid and semi-arid regions of these western installations require special techniques. This report identifies key plant species that may be useful to installation land managers seeking to maintain or rehabilitate training land in these areas. The plant species are described in terms of their regional and environmental adaptations, limitations, uses, establishment requirements, and availability. In addition, recommendations for short- and long-term revegetation efforts …


A High Efficiency Cathodoluminescence System And Its Application To Optical Materials, A. D. Trigg Aug 1985

A High Efficiency Cathodoluminescence System And Its Application To Optical Materials, A. D. Trigg

Scanning Electron Microscopy

A high collection efficiency spectroscopic cathodoluminescence (CL) system based on an in-line ellipsoidal mirror has been constructed for use on a Cambridge S250 scanning electron microscope (SEM). It can be fitted to or removed from the SEM in about 30 minutes and requires no significant modification of the instrument. It can be used to obtain total CL images, monochromatic CL images or CL spectra with an ultimate spectral resolution of 1 nm.

The system has been applied to the study of doped synthetic quartz crystals, optical fibres and optical fibre preforms, and to yttrium aluminium garnet, bismuth silicon oxide and …


Fundamental Aspects Of Energetic Particle/Solid Interactions, Nicholas Winograd Aug 1985

Fundamental Aspects Of Energetic Particle/Solid Interactions, Nicholas Winograd

Scanning Electron Microscopy

The interaction of keV particles with solids has been characterized by the measurement of the angle and energy distribution of sputtered secondary ions and neutrals. The results are compared to classical dynamics calculations of the ion impact event. Examples using secondary ions are given for clean Ni{001}, Cu{001} reacted with O2, Ni{001} and Ni{7 9 11) reacted with CO, and Ag{111} reacted with benzene. The neutral Rh atoms desorbed from Rh{001} are characterized by multiphoton resonance ionizaton of these atoms after they have left the surface.


The Cathodoluminescence Mode Of The Scanning Electron Microscope: A Powerful Microcharacterization Technique, D. B. Holt, F. M. Saba Aug 1985

The Cathodoluminescence Mode Of The Scanning Electron Microscope: A Powerful Microcharacterization Technique, D. B. Holt, F. M. Saba

Scanning Electron Microscopy

By detecting cathodoluminescence (CL) in a scanning electron microscope (SEM), pan and monochromatic micrographs and CL spectral analyses analogous to x-ray mode point analyses can be obtained. Complete microcharacterization requires alternate examination of both micrographs and spectra. New techniques for near infra-red CL and low-temperatures to produce sharp spectra are of increasing importance. CL emission is due to electron transitions between quantum mechanical states so the radiative defects present can be unambiguously identified at liquid helium temperatures. Strongly luminescent impurities can be detected to below one part in 108. This is 104 times as sensitive as the …


Liquid Metal Sources In Ion Microscopy And Secondary Ion Mass Spectrometry, G. L. R. Mair, T. Mulvey Aug 1985

Liquid Metal Sources In Ion Microscopy And Secondary Ion Mass Spectrometry, G. L. R. Mair, T. Mulvey

Scanning Electron Microscopy

This paper reports on state-of-the-art developments in liquid metal sources and some of the finer points of their operating characteristics that are especially relevant to the satisfactory functioning of analytical ion scanning microscopes equipped with secondary ion mass spectrometers. Such effects include unwanted emissions from the source and their exclusion by means of filters and mass separators in the ion-optical column. The design of the ion-optical column is also discussed and some applications of this rapidly advancing form of analytical microscopy are described.


Secondary Ion Mass Spectrometry Of Glasses: Aspects Of Quantification, H. Odelius, A. R. E. Lodding, L. O. Werme, D. E. Clark Aug 1985

Secondary Ion Mass Spectrometry Of Glasses: Aspects Of Quantification, H. Odelius, A. R. E. Lodding, L. O. Werme, D. E. Clark

Scanning Electron Microscopy

SIMS routines have been developed for the analysis of oxide materials, with applications particularly in element profiling of corrosion layers on glasses after weathering or leaching. The possibilities of quantification and reproducibility have been found critically sensitive to the buildup of charge on the insulating specimens. With control of constant specimen potential, relative sensitivity factors in the positive mass spectrum have been determined for about 20 elements in 10 different alkali-borosilicate glasses. Secondary ion yields were studied as functions of the energy range of ions admitted to the analyzer. At relatively low energies, including the top of the energy distribution, …


A New Approach For Studying Semithin Sections Of Human Pathological Material: Intermicroscopic Correlation Between Light Microscopy And Scanning Electron Microscopy, G. Pasquinelli, C. Scala, G. P. Borsetti, F. Martegani, R. Laschi Aug 1985

A New Approach For Studying Semithin Sections Of Human Pathological Material: Intermicroscopic Correlation Between Light Microscopy And Scanning Electron Microscopy, G. Pasquinelli, C. Scala, G. P. Borsetti, F. Martegani, R. Laschi

Scanning Electron Microscopy

In order to obtain useful and complete information on the study of pathological material, we observed by scanning electron microscopy (SEM) the same semithin sections observed by light microscopy (LM). For this purpose, the specimen must have, at the same time, chromatic and electron dense characteristics.

We thus developed different specimen preparation methods, subjecting the semithin sections to specific polychromatic staining with high atomic number (Z) elements, to monochromatic staining followed by routine contrasting with uranyl acetate and lead citrate, and to specific cytochemical and immunocytochemical procedures.

The specimens were examined in sequence by LM, by SEM equipped with secondary …


Contribution Of Scanning Electron Microscopy And Associated Analytical Techniques To The Study Of Atherosclerotic Disease, R. Laschi Aug 1985

Contribution Of Scanning Electron Microscopy And Associated Analytical Techniques To The Study Of Atherosclerotic Disease, R. Laschi

Scanning Electron Microscopy

Human carotid atheroma has been examined by scanning electron microscopy (SEM) utilizing both secondary and backscattered electron detectors and transmission electron microscopy (TEM) both at conventional and high voltage.

Different cytochemical techniques have been used to map elastic fibers, proteoglycans, calcium, non esterified cholesterol. By immunocytochemistry the distribution of factor VIII related antigen and actin has been studied.

With SEM it was possible to detect aspects of carotid plaques not appreciated when using other conventional techniques. With TEM some modifications of the structural and/or functional features of connective tissue macromolecules have been observed. The occurrence of anomalous collagen has been …


Clinical Applications Of Scanning Electron Microscopy In Gastrointestinal Diseases, F. Bonvicini, G. Zoli, M. C. Maltarello, D. Bianchi, G. Pasquinelli, P. Versura, G. Gasbarrini, R. Laschi Aug 1985

Clinical Applications Of Scanning Electron Microscopy In Gastrointestinal Diseases, F. Bonvicini, G. Zoli, M. C. Maltarello, D. Bianchi, G. Pasquinelli, P. Versura, G. Gasbarrini, R. Laschi

Scanning Electron Microscopy

We considered the role of scanning electron microscopy (SEM) in clinical investigation of different gastrointestinal diseases. The following clinical applications of SEM may be suggested on the basis of our original data and those reported in literature:

in peptic ulcer: assessment of the completeness of healing, by observing the mucosal surface architecture of the scars; identification of mucosal changes, namely enterocytic surface membrane alterations, predictive of recurrence;

in coeliac disease: early assessment of the response to gluten-free diet and follow-up of the patients by staging the process of mucosal repair in cerebriform, intermediate and villous patterns;

in ulcerative …


Scanning Electron Microscopy Of The Human Myocardium, S. Siew Aug 1985

Scanning Electron Microscopy Of The Human Myocardium, S. Siew

Scanning Electron Microscopy

Owing to the impossibility of fixation, in the human being, by means of perfusion in vivo and the rare availability of fresh comparatively intact hearts resected at transplantation, the possibility was explored of using post-mortem material in instances where the autopsies were performed within 2 hours of demise of the patients. Four cases were examined: 2 normal adult hearts and 2 hearts of hypertensive patients in the stage of decompensation. The hearts were fixed by means of perfusion with 2.5% glutaraldehyde in phosphate buffer, pH 7.4. Contiguous blocks were taken for light microscopy (LM) and scanning electron microscopy (SEM) from …


Scanning And Transmission Electron Microscopy Of Bacterial Attachment To Mucosal Surfaces With Particular Reference To The Human Fallopian Tube, Morris D. Cooper, Christine Jeffery Aug 1985

Scanning And Transmission Electron Microscopy Of Bacterial Attachment To Mucosal Surfaces With Particular Reference To The Human Fallopian Tube, Morris D. Cooper, Christine Jeffery

Scanning Electron Microscopy

Neisseria gonorrhoeae and Chlamydia trachomatis are the common bacteria isolated from bacterial cervicitis and are the leading etiological agents for pelvic inflammatory disease. Neisseria gonorrhoeae cause infection of the mucosa of fallopian tubes in organ culture by (a) attaching to microvilli of nonciliated cells, (b) phagocytosis by these cells, (c) transport across and exocytosis from the epithelial cells. In contrast the Chlamydia attach to the epithelial surface without apparent ligand binding and are taken into the cytoplasm of the epithelial cell. Exocytosis of Chlamydia is into the tubal lumen and not into the subepithelial spaces. The ciliated epithelial cells of …


Characteristic Energy Losses With High Energy Electrons Up To 2.5 Mev, B. Jouffrey, J. Sevely, G. Zanchi, Y. Kihn Aug 1985

Characteristic Energy Losses With High Energy Electrons Up To 2.5 Mev, B. Jouffrey, J. Sevely, G. Zanchi, Y. Kihn

Scanning Electron Microscopy

Some aspects of the influence of the energy of the incident electrons in electron energy loss spectroscopy (EELS) are considered. It is shown that this method of analysis used in high voltage electron microscopy, permits one to observe, with a better edge jump ratio than at lower accelerating voltages, the characteristic edges. One important question is to eliminate artefacts in the counting and to record only electrons from the true spectrum. Some recent examples are given. One of them concerns extended energy loss fine structures (EXELFS). It seems high voltage electron microscopy (HVEM) could be very useful in this domain.


Morphological Observations Of Mineralizing Pericardium Cardiac Grafts, P. Frasca, J. W. Buchanan, R. Z. Soriano, J. M. Dunn, L. Marmon, J. Melbin, S. J. Buchanan, E. E. Golub, I. M. Shapiro Aug 1985

Morphological Observations Of Mineralizing Pericardium Cardiac Grafts, P. Frasca, J. W. Buchanan, R. Z. Soriano, J. M. Dunn, L. Marmon, J. Melbin, S. J. Buchanan, E. E. Golub, I. M. Shapiro

Scanning Electron Microscopy

Pericardial patch grafts were implanted in the hearts of young sheep for periods ranging from two to 120 days. Explants seven to 21 days old revealed the formation of a "pseudoneointima" (PNI) on the blood contacting surface of the pericardium. The PNI was more heavily mineralized than the pericardium. Mineralization was most intense on the blood contacting surface of the PNI and on the chamber surface of the pericardium. After three weeks of implantation, the PNI was much thinner and was organized into a thin fibrous capsule without any signs of mineralization. In the pericardium, mineral deposits were seen in …


Scanning Electron Microscopy Studies Of Staphylococcal Adherence To Heart Valve Endothelial Cells In Organ Culture: An In Vitro Model Of Acute Endocarditis, Morris D. Cooper, Christine Jeffery, Debra L. Gall, Andrew S. Anderson Aug 1985

Scanning Electron Microscopy Studies Of Staphylococcal Adherence To Heart Valve Endothelial Cells In Organ Culture: An In Vitro Model Of Acute Endocarditis, Morris D. Cooper, Christine Jeffery, Debra L. Gall, Andrew S. Anderson

Scanning Electron Microscopy

Organ cultures of human heart valves were used as a model to study the initial pathobiology of acute infective bacterial endocarditis. We used Staphylococcus aureus isolated from a case of infective endocarditis to infect the in vitro culture of the heart valves. Using scanning electron microscopy, we assessed the initial damage, attachment to and invasion of the endothelial cell layer by staphylococci. Our results indicate there is initial damage to the endothelium prior to observation of staphylococci attaching to the endothelial cell. By 12 h post infection, there is significant attachment and damage. At 24 h after infection, destruction of …


Quantitation Of Scanning Electron Microscopic Urinary Cytology, M. Cano, R. B. Wilson, S. M. Cohen Jul 1985

Quantitation Of Scanning Electron Microscopic Urinary Cytology, M. Cano, R. B. Wilson, S. M. Cohen

Scanning Electron Microscopy

Using scanning electron microscopy (SEM), differences in cell surface morphology are identifiable between normal urothelium and malignant urothelia including the presence of pleomorphic microvilli (PMV). PMV have been reported in carcinomas of the urinary bladder, and they appear early in the pathogenesis of these tumors in animal models. Preliminary studies in our laboratory and others' demonstrated similar changes in tissue and cytologic specimens from patients with bladder cancer. We observed and evaluated normal and neoplastic cells of the human bladder by SEM in a preliminary assessment of surface topography with regard to tumor growth, grade, and stage. However, while these …


Simulation With Pharmacological Agents Of Radiation Damage To Small Intestinal Villi, M. Indran, F. C. Boyle, K. E. Carr Jul 1985

Simulation With Pharmacological Agents Of Radiation Damage To Small Intestinal Villi, M. Indran, F. C. Boyle, K. E. Carr

Scanning Electron Microscopy

Irradiation induces damage to intestinal villi, resulting in a progressive decline in villous height and changes in topography. Gamma and neutron radiation are reported to cause changes in the structure of smooth muscle and nerve twigs of the intestinal wall. It is possible, therefore, that villous collapse may be due partly to changes in the underlying stromal elements as a result of damage to nerve or muscle.

To test this hypothesis, mice were treated with the drug reserpine which is known to affect the neural control of intestinal smooth muscle function and the small intestine was examined for topographical and …


Stroboscopic Technique For Dynamic Observation Of Ferromagnetic Domains At Low Frequencies In Scanning Electron Microscopy, T. Ikuta Jul 1985

Stroboscopic Technique For Dynamic Observation Of Ferromagnetic Domains At Low Frequencies In Scanning Electron Microscopy, T. Ikuta

Scanning Electron Microscopy

A new stroboscopic technique for the observation of periodic phenomena at low frequencies (10 -100 Hz) in scanning electron microscopy (SEM) is developed in the present study. This new technique is based on the line-sampling stroboscopy instead of the point-sampling stroboscopy which has been commonly used for the dynamic observation at high frequencies (> 1 kHz). In this stroboscopy, a multi-frame display with the individual stroboscopic image at different phase can be easily introduced with no reduction of the detection efficiency.

The main application of the present stroboscopy at low frequencies is the dynamic observation of magnetic domains. In this …


A Dynamic Single E-Beam Short/Open Testing Technique, M. Brunner, B. Lischke Jul 1985

A Dynamic Single E-Beam Short/Open Testing Technique, M. Brunner, B. Lischke

Scanning Electron Microscopy

Several electron beam techniques for electrical testing of interconnection modules have been presented by different authors in recent years. Most techniques use two or more electron beam energies to establish a charging and a non-loading reading mode. The present paper discusses the feasibility of employing the same beam energy for charging contact pads and reading pad potentials. This avoids the necessity of high voltage switching as used for altering the beam energy. A switching time of 100 us between 2 kV and 4 kV beam voltage which is restricted to this range has been reported earlier. Without switching, higher beam …


Interactions Between Spermatozoa And The Crypts, Cilia, And Mucus Of The Cervix In The Ewe, William P. Wergin Jul 1985

Interactions Between Spermatozoa And The Crypts, Cilia, And Mucus Of The Cervix In The Ewe, William P. Wergin

Scanning Electron Microscopy

In ruminants, minor cervical folds, commonly called crypts, temporarily store spermatozoa for a short interval of time between insemination and fertilization. However, the mechanism by which spermatozoa are transported to these crypts and subsequently to the uterus is not known. To study this problem, cervical tissue, which was removed from ewes that were naturally inseminated by rams at estrus, was examined with the scanning electron microscope to determine the physical associations that occur between the spermatozoa and the structural features of the cervix. The study indicates that the spermatozoa generally are not oriented parallel to the longitudinal axis of the …


The Effect Of High Energy (Hze) Particle Radiation (40ar) On Aging Parameters Of Mouse Hippocampus And Retina, D. E. Philpott, W. Sapp, J. Miquel, K. Kato, R. Corbett, J. Stevenson, S. Black, K. A. Lindseth, E. V. Benton Jul 1985

The Effect Of High Energy (Hze) Particle Radiation (40ar) On Aging Parameters Of Mouse Hippocampus And Retina, D. E. Philpott, W. Sapp, J. Miquel, K. Kato, R. Corbett, J. Stevenson, S. Black, K. A. Lindseth, E. V. Benton

Scanning Electron Microscopy

Eight month old C57BL6 mice were exposed (head only) to 0.5 rad or 50 rads of Argon particles at the Lawrence Berkeley Radiation Facility, CA. Neuromotor performance was assessed monthly for six months beginning twelve weeks post-irradiation using a ''string test". The decline in motor performance was dose-related and none of the animals was able to complete the task after four months of testing. Morphological changes were monitored six and twelve months post-irradiation by light and electron microscopy. The synaptic density in the CA-1 area of the hippocampus decreased six and twelve months after irradiation. The decrease after twelve months …


The Influence Of Epidermal Growth Factor On Surface Morphology Of Fetal Rat Hepatocytes In Primary Culture, Ira H. Ames, Robert A. Richman, Gerald B. Gordon, Barbara A. Toly, Mark R. Benedict, Maureen A. Barcza Jul 1985

The Influence Of Epidermal Growth Factor On Surface Morphology Of Fetal Rat Hepatocytes In Primary Culture, Ira H. Ames, Robert A. Richman, Gerald B. Gordon, Barbara A. Toly, Mark R. Benedict, Maureen A. Barcza

Scanning Electron Microscopy

In an attempt to understand the hormonal regulation of somatomedin secretion in the fetus, we have confirmed that epidermal growth factor (EGF) stimulates fetal rat hepatocytes in primary culture to secrete somatomedin in a time and a dose-dependent fashion. Transmission electron microscopy (TEM) revealed that the cultured cells had ultrastructural features consistent with those of fetal hepatocytes. Scanning electron microscopy (SEM) showed that cells grown in either Medium 199 or EGF supplemented Medium 199 formed cellular aggregates within 6 h. The surface features of cells in control and experimental cultures were indistinguishable up until 24 h after exposure to EGF. …