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Topic:In Vitro Research

In vitro research involving horses refers to the study of equine cells, tissues, or biological molecules outside their normal biological context, typically in controlled laboratory environments. This research approach allows scientists to investigate cellular processes, molecular interactions, and the effects of various treatments without the ethical and logistical complexities of in vivo studies. In vitro studies contribute to understanding equine physiology, pathology, and pharmacology by providing insights into cellular responses to pathogens, drugs, and other stimuli. This page compiles peer-reviewed research studies and scholarly articles that explore various in vitro methodologies and their applications in equine science, including cell culture techniques, molecular assays, and drug efficacy testing.
The effect of strenuous versus moderate exercise on the metabolism of proteoglycans in articular cartilage from different weight-bearing regions of the equine third carpal bone.
Osteoarthritis and cartilage    May 1, 1997   Volume 5, Issue 3 161-172 doi: 10.1016/s1063-4584(97)80011-8
Little CB, Ghosh P, Rose R.Articular cartilage degeneration in the middle carpal joint is a common problem in racing horses. This study evaluated the effect of exercise on the in-vitro synthesis of the large aggregating proteoglycans (aggrecan) and two small proteoglycans, biglycan and decorin, in articular cartilage taken from three weight bearing regions of the third carpal bone of horses which were subjected to moderate or strenuous exercise. Twelve Standardbred horses free from clinical and radiographic disease of the middle carpal joint were subjected to an 8 week moderate exercise program. The horses were then ran...
Role of endothelium and nitric oxide in the response of equine colonic arterial rings to vasoconstrictor agents.
Veterinary surgery : VS    May 1, 1997   Volume 26, Issue 3 182-188 doi: 10.1111/j.1532-950x.1997.tb01482.x
Venugopalan CS, Moore RM, Holmes EP, Sedrish SA.To determine the in vitro contractile responses of equine colonic arteries to angiotensin II, histamine, serotonin, norepinephrine, prostaglandin F2 alpha, vasopressin, and a thromboxane-B2-analogue. Methods: The tension generated in colonic arterial rings placed in organ baths with oxygenated Tyrode's solution at 37 degrees C after exposure to the previously mentioned chemical agents was measured using force-transducers interfaced with a polygraph. Methods: Large colon arterial rings collected from eight horses. Methods: The rings were allowed to equilibrate for 45 minutes after applying 2 g ...
Insulin-like growth factor 1 and corticosteroid modulation of chondrocyte metabolic and mitogenic activities in interleukin 1-conditioned equine cartilage.
American journal of veterinary research    May 1, 1997   Volume 58, Issue 5 524-530 
Frisbie DD, Nixon AJ.To evaluate potential stimulatory or matrix-sparing effects of insulin-like growth factor 1 (IGF-1), alone or in combination with a corticosteroid, in an interleukin 1 (IL-1)-induced model of cartilage degradation. Methods: Cartilage from the weightbearing surfaces of trochlea and condyles of clinically normal 2-year-old male horses. Methods: Triamcinolone acetonide and IGF-1 effects were evaluated by assessing: matrix responses by sulfated glycosaminoglycan (GAG) assay and [35S]sulfated GAG synthesis; collagen content by hydroxyproline assay; and mitogenic response by [3H]thymidine incorporat...
Distribution and functional effects of neuropeptide Y on equine ureteral smooth muscle and resistance arteries.
Regulatory peptides    April 30, 1997   Volume 69, Issue 3 155-165 doi: 10.1016/s0167-0115(97)00003-7
Prieto D, Hernández M, Rivera L, García-Sacristán A, Simonsen U.The distribution of neuropeptide Y (NPY)-immunoreactive (IR) nerves, as well as the functional effects of NPY and the Y1- and Y2-receptor agonists, [Leu31,Pro34]NPY and NPY(13-36), respectively, have been investigated in vitro in both visceral and arterial smooth muscle of the horse intravesical ureter. NPY-IR nerve fibres were widely distributed along the entire length of the ureter, although the intravesical part was the most richly innervated region, and the only one where NPY-IR ganglion cells were found. NPY (10(-7) M) did not affect either basal tone or spontaneous rhythmic contractions ...
Cloning, expression, purification, and characterization of the major core protein (p26) from equine infectious anemia virus.
Biochimica et biophysica acta    April 25, 1997   Volume 1339, Issue 1 62-72 doi: 10.1016/s0167-4838(96)00215-4
Birkett AJ, Yélamos B, Rodríguez-Crespo I, Gavilanes F, Peterson DL.The gene coding for the major core protein (p26) of the lentivirus equine infectious anemia virus (EIAV) was cloned from EIAV infected serum, expressed in E. coli, and the resultant protein purified to electrophoretic homogeneity. The protein was expressed in a soluble form and was purified by conventional protein separation methods. When analyzed by SDS-PAGE, under both reducing and non-reducing conditions, the purified protein migrated as a 26 kDa monomer. Recombinant p26 (rp26), therefore, does not contain any intermolecular disulfide bond. Gel filtration chromatography also indicated that ...
A kinase-negative mutation of DNA-PK(CS) in equine SCID results in defective coding and signal joint formation.
Journal of immunology (Baltimore, Md. : 1950)    April 15, 1997   Volume 158, Issue 8 3565-3569 
Shin EK, Perryman LE, Meek K.The equine SCID defect is more severe than its murine counterpart in that SCID foals are incapable of forming either coding or signal joints, whereas SCID mice manifest normal signal joint formation. To determine the basis of this difference and whether DNA-dependent kinase, catalytic subunit (DNA-PK(CS)), is involved in signal joint formation, equine DNA-PK(CS) transcripts were cloned and sequenced from normal and SCID cell lines. In the mutant allele, a frame-shift mutation truncates the protein N terminal of the domain with homology to the phosphatidylinositol 3-kinase family resulting in c...
Intracytoplasmic sperm injection (ICSI) versus conventional IVF on abattoir-derived and in vitro-matured equine oocytes.
Theriogenology    April 15, 1997   Volume 47, Issue 6 1139-1156 doi: 10.1016/s0093-691x(97)00095-2
Dell'Aquila ME, Cho YS, Minoia P, Traina V, Fusco S, Lacalandra GM, Maritato F.Conventional IVF as well as several assisted microfertilization techniques have shown limited success in the horse. After recent positive results achieved with intracytoplasmic injection of a single spermatozoon (ICSI) in human IVF, we chose to try the method in the horse. We compared conventional IVF to ICSI by fertilization rates of oocytes with compact and expanded cumuli and by developmental potential of the resulting embryos. Cumulus-oocyte complexes (COCs) were obtained by aspirating the follicular fluid from the ovaries of slaughtered mares. Complexes showing complete cumulus investment...
In-vitro modulation of plasminogen activator activity, prostaglandin E and nitric oxide production by interleukin-1 in pregnant mare serum gonadotrophin-primed theca-interstitial cells.
Human reproduction (Oxford, England)    April 1, 1997   Volume 12, Issue 4 774-779 doi: 10.1093/humrep/12.4.774
Hurwitz A, Finci-Yeheskel Z, Milwidsky A, Yagel S, Adashi EY, Laufer N, Mayer M.To examine the participation of the theca-interstitial (TI) compartment in cytokine modulation of ovarian function, the effects of interleukin-1beta (IL-1) on plasminogen activator (PA) activity and on prostaglandin E (PGE) and nitric oxide (NO) production were examined in cultures of pregnant mare serum gonadotrophin (PMSG)-primed rat TI cells. Exposure to IL-1 (10 ng/ml) resulted in a 25% reduction (P < 0.001) in PA activity, concurrent with a 4.6-fold increase in the ability of the corresponding conditioned media to inhibit exogenous urokinase activity. IL-1 also produced a 4.7-fold incr...
Membrane contact with oviductal epithelium modulates the intracellular calcium concentration of equine spermatozoa in vitro.
Biology of reproduction    April 1, 1997   Volume 56, Issue 4 861-869 doi: 10.1095/biolreprod56.4.861
Dobrinski I, Smith TT, Suarez SS, Ball BA.Interaction of equine spermatozoa with oviductal epithelial cells (OEC) prolongs sperm viability and maintains low intracellular calcium concentration ([Ca2+]i) in spermatozoa. Experiments were designed to investigate 1) whether release of spermatozoa from OEC in vitro is associated with elevated [Ca2+]i and 2) whether soluble products from OEC or direct membrane contact between spermatozoa and OEC mediates the effects of OEC on sperm [Ca2+]i. In the first experiment, changes in [Ca2+]i in spermatozoa loaded with indo-1 acetoxymethylester were determined in motile spermatozoa released from OEC...
Molten globule state of equine beta-lactoglobulin.
Proteins    April 1, 1997   Volume 27, Issue 4 567-575 doi: 10.1002/(sici)1097-0134(199704)27:4<567::aid-prot9>3.0.co;2-7
Ikeguchi M, Kato S, Shimizu A, Sugai S.The acid-unfolded state of equine beta-lactoglobulin was characterized by means of circular dichroism, nuclear magnetic resonance, analytical gel-filtration chromatography, and analytical centrifugation. The acid-unfolded state of equine beta-lactoglobulin has a substantial secondary structure as shown by the far-ultraviolet circular dichroism spectrum but lacks persistent tertiary packing of the side chains as indicated by the near-ultraviolet circular dichroism and nuclear magnetic resonance spectra. It is nearly as compact as the native conformation as shown by the gel filtration and sedime...
Corneal concentrations and preliminary toxicological evaluation of an itraconazole/dimethyl sulphoxide ophthalmic ointment.
Journal of veterinary pharmacology and therapeutics    April 1, 1997   Volume 20, Issue 2 100-104 doi: 10.1046/j.1365-2885.1997.00822.x
Ball MA, Rebhun WC, Trepanier L, Gaarder J, Schwark WS.The objectives of this study were to determine the concentration of itraconazole achieved in corneal tissue and aqueous humour after topical application of a 1% itraconazole ointment: to determine the effect of including dimethyl sulphoxide (DMSO) in the ointment on achievable ocular tissue itraconazole concentrations; and to assess if any gross or histopathologic ocular toxicity results from the topical application of 1% itraconazole with or without the addition of DMSO. The experimental trial consisted of 6 horses considered to have normal eyes. Each horse had one eye treated with 0.3 mL of ...
An in vitro biomechanical investigation of the mechanical properties of dynamic compression plated osteotomized adult equine tibiae.
Veterinary surgery : VS    March 1, 1997   Volume 26, Issue 2 126-136 doi: 10.1111/j.1532-950x.1997.tb01475.x
McD○ LA, Stover SM, Taylor KT.To determine the monotonic mechanical properties of osteotomized adult equine tibiae stabilized with two dynamic compression plates (DCP) and to compare the mechanical properties with those of intact tibiae and in vivo loads. Methods: The compressive, bending, and torsional mechanical properties of plated and intact tibiae were assessed in vitro. Methods: Twelve pairs of adult equine tibiae. Methods: Tibiae were loaded in axial compression, craniocaudal 3-point bending, or torsion in external rotation in a single cycle to failure. Mechanical properties were determined from load-displacement da...
Oxidative energy metabolism in equine tendon cells.
Research in veterinary science    March 1, 1997   Volume 62, Issue 2 93-97 doi: 10.1016/s0034-5288(97)90127-2
Birch HL, Rutter GA, Goodship AE.Hypoxia has been suggested as a possible cause of tissue degeneration and subsequent rupture in equine tendons. To determine whether low oxygen tension is likely to be detrimental to tendon cell function, experiments were designed to investigate oxidative energy metabolism in freshly isolated and cultured equine tendon cells. Freshly isolated tenocytes and cultured fibroblasts possessed activities of the mitochondrial enzyme citrate synthase similar to those of other mammalian cells, with well defined oxidative metabolism. D-[6(-14)C]-glucose oxidation was measurable in both freshly isolated a...
Methods for the isolation, culture and characterisation of equine pulmonary artery endothelial cells.
Research in veterinary science    March 1, 1997   Volume 62, Issue 2 147-152 doi: 10.1016/s0034-5288(97)90137-5
MacEachern KE, Smith GL, Nolan AM.Equine endothelial cells were isolated from the pulmonary artery by enzymatic digestion and grown to confluency. The cells were characterised by positive immunofluorescent staining for von Willebrand factor and NADPH-diaphorase staining for nitric oxide synthase. Measurements of endothelins indicated that there were significant release rates from the cells for up to six hours. Measurements of intracellular calcium concentration showed that the application of bradykinin caused a transient increase in calcium concentration with similar characteristics to those observed in other endothelial cell ...
Nitric oxide production by equine articular cells in vitro.
Equine veterinary journal    March 1, 1997   Volume 29, Issue 2 98-102 doi: 10.1111/j.2042-3306.1997.tb01649.x
Frean SP, Bryant CE, Fröling IL, Elliott J, Lees P.Recent research in several species has suggested nitric oxide (NO) as a mediator of articular cartilage damage and an inhibitor of cartilage matrix neosynthesis. This study investigated NO production by cultured equine articular chondrocytes in response to 2 arthritogenic molecules, namely lipopolysaccharide (LPS) and interleukin-1 beta (IL-1 beta), and compared NO production by cultured equine synoviocytes stimulated with LPS. Synoviocytes exhibited a low basal level of NO synthesis (measured as nitrite, a NO metabolite) that was neither significantly increased nor decreased by exposure to LP...
Antibody directed against plasma membrane components of equine spermatozoa inhibits adhesion of spermatozoa to oviduct epithelial cells in vitro.
Biology of reproduction    March 1, 1997   Volume 56, Issue 3 720-730 doi: 10.1095/biolreprod56.3.720
Thomas PG, Ball BA, Ignotz GG, Dobrinski I, Parks JE, Currie WB.Before fertilization, equine spermatozoa adhere to oviduct epithelial cells (OEC) of the mare. The biochemical basis for this adhesion has not been determined. Our objective was to produce an antiserum to block this interaction. Ejaculated spermatozoa were subjected to nitrogen cavitation and spermatozoal plasma membranes enriched by sucrose density gradient centrifugation; membrane enrichment was confirmed by comparative alkaline phosphatase analysis, electron microscopy, and one- and two-dimensional PAGE. Periacrosomal plasma membrane was used as an immunogen for the production of an antiser...
Amantadine and equine influenza: pharmacology, pharmacokinetics and neurological effects in the horse.
Equine veterinary journal    March 1, 1997   Volume 29, Issue 2 104-110 doi: 10.1111/j.2042-3306.1997.tb01650.x
Rees WA, Harkins JD, Woods WE, Blouin RA, Lu M, Fenger C, Holland RE, Chambers TM, Tobin T.Amantadine is an antiviral agent effective against influenza A viruses. We investigated 1) the antiviral efficacy, 2) analytical detection, 3) bioavailability and disposition, 4) pharmacokinetic modelling and 5) adverse reactions of amantadine in the horse. In vitro, amantadine and its derivative rimantadine suppressed the replication of recent isolates of equine-2 influenza virus with effective doses (EDs) of less than 30 ng/ml. Rimantadine was more effective than amantadine against most viral isolates; we suggest a minimum plasma concentration of 300 ng/ml of amantadine for therapeutic effic...
Expression of horse and donkey LH in COS-7 cells: evidence for low FSH activity in donkey LH compared with horse LH.
The Journal of endocrinology    March 1, 1997   Volume 152, Issue 3 371-377 doi: 10.1677/joe.0.1520371
Chopineau M, Martinat N, Troispoux C, Marichatou H, Combarnous Y, Stewart F, Guillou F.Horse (Equus caballus) luteinizing hormone (eLH) and chorionic gonadotrophin (eCG), which have the same amino acid sequence, are unusual in that, although they express only LH activity in equids, they express dual LH and FSH activities in all other species tested. Donkey (Equus asinus) LH (dkLH) and CG (dkCG), which also share an identical peptide backbone, have been less well characterized and conflicting results concerning their FSH activity in heterologous species have appeared in the literature. In order to assess and compare the intrinsic LH and FSH activities of the horse and donkey LHs ...
In vitro cultivation of Babesia equi: detection of carrier animals and isolation of parasites.
The Onderstepoort journal of veterinary research    March 1, 1997   Volume 64, Issue 1 51-56 
Zweygarth E, Just MC, De Waal DT.By means of an in vitro culture technique, 75 samples of horse blood were examined for Babesia equi, a causative agent of equine piroplasmosis. At the time of culture initiation, 15 samples were microscopically positive for B. equi, and this was subsequently confirmed by culture diagnosis. Sixty samples showed no parasites in Giemsa-stained thin blood smears. However, after the culturing process, parasites were found in blood smears of 36 of these samples. The sensitivity of the in vitro culture method was such that 2.5 microliters (1/40 of the usual volume used for the above-mentioned samples...
An infectious arterivirus cDNA clone: identification of a replicase point mutation that abolishes discontinuous mRNA transcription.
Proceedings of the National Academy of Sciences of the United States of America    February 4, 1997   Volume 94, Issue 3 991-996 doi: 10.1073/pnas.94.3.991
van Dinten LC, den Boon JA, Wassenaar AL, Spaan WJ, Snijder EJ.Equine arteritis virus (EAV) is a positive-strand RNA virus that uses a discontinuous transcription mechanism to generate a nested set of six subgenomic mRNAs from which its structural genes are expressed. A stable bacterial plasmid (pEAV030) containing a full-length cDNA copy of the 12.7-kb EAV genome was constructed. After removal of a single point mutation in the replicase gene, RNA transcripts generated in vitro from pEAV030 were shown to be infectious upon electroporation into BHK-21 cells. A genetic marker mutation was introduced at the cDNA level and recovered from the genome of the pro...
Case report: field-acquired subclinical Babesia equi infection confirmed by in vitro culture.
Journal of clinical microbiology    February 1, 1997   Volume 35, Issue 2 474-476 doi: 10.1128/jcm.35.2.474-476.1997
Holman PJ, Hietala SK, Kayashima LR, Olson D, Waghela SD, Wagner GG.A horse with no prior clinical history of equine piroplasmosis tested negative for Babesia caballi and Babesia equi in the complement fixation test before importation into the United States from France. After 5 years in residence in the United States, the animal tested serologically positive for B. equi by the complement fixation test, the immunofluorescent antibody test, and Western blot analysis. The carrier status of the horse was confirmed by culture of B. equi parasites. In vitro culture offers an efficient and comparatively inexpensive method to determine the carrier status of horses sus...
Subjecting horse spermatozoa to hypoosmotic incubation: effects of ouabain.
Theriogenology    February 1, 1997   Volume 47, Issue 3 765-784 doi: 10.1016/s0093-691x(97)00033-2
de la Cueva FI, Rigau T, Bonet S, Miró J, Briz M, Rodríguez-Gil JE.Although hypoosmotic tests are widely used to assess spermatozoal quality in different species, they have not been used extensively in the stallion. Moreover, the role of the Na (+)K (+), ouabain sensitive-ATP-ase in the response of equine sperm to hypoosmotic shock is not well understood. This study tests two hypotheses: 1) that equine spermatozoa will respond to a hypoosmotic medium by swelling of the tail, and 2) that addition of ouabain will increase the percentage of swollen sperm tails. Ejaculates from 3 stallions were collected with an artificial vagina and diluted in Kenney's medium (T...
The influence of progesterone-induced proteins on glucose metabolism in early equine embryos.
Theriogenology    January 15, 1997   Volume 47, Issue 2 441-456 doi: 10.1016/s0093-691x(97)00003-4
Brück I, Anderson GA, Hyland JH.The influence of different maternal plasma progesterone concentrations on embryonic glucose metabolism was studied. Uterine flushes were obtained after treating ovariectomized mares (n = 3) with 0 (control), 100 or 200 mg progesterone daily for 7 d. A group of progesterone-induced proteins (PIP) of Mr approximately 20,000 were identified in flushes from progesterone treatments by SDS-PAGE but were not observed in control flushes. Progesterone-induced proteins were removed from half the pooled flush in each treatment group by Sepharose blue CL-6B. In a 3 x 2 factorial (progesterone treatments, ...
Production of free estrogens and estrogen conjugates by the preimplantation equine embryo.
Theriogenology    January 15, 1997   Volume 47, Issue 2 457-466 doi: 10.1016/s0093-691x(97)00004-6
Choi SJ, Anderson GB, Roser JF.In vitro production of free estrogens and estrogen conjugates by intact Day 12.5, 13.5 and 14.5 equine embryos was measured at 2-h intervals over a 24-h culture period. Production of free estrogens was higher for Day 14.5 than Day 12.5 embryos. Differences in production of conjugated estrogens were not significant, but a trend toward increased production with increased age of embryo was apparent. No trend toward increased free and conjugated estrogen production per cell was observed with age. Embryo diameter and number of cells increased with age but varied considerably within groups. The amou...
1H-NMR study of inter-segmental hydrogen bonds in sperm whale and horse apomyoglobins.
European journal of biochemistry    January 15, 1997   Volume 243, Issue 1-2 292-298 doi: 10.1111/j.1432-1033.1997.0292a.x
Yamamoto Y.NMR signals for HisB5 N(delta)H and HisEF5 N(epsilon)H protons of sperm whale and horse apomyoglobins were assigned and compared with the corresponding signals of the holoproteins in terms of pH and temperature dependence behaviors of their shifts and line widths in order to gain insight into structural difference between the apoproteins and the holoproteins. Since these protons are involved in internal hydrogen bonds at the interfaces between the B helix and the GH corner and between the EF corner and the H helix, local structures of the interfaces in these proteins have been inferred from th...
Dose-response of X-irradiated human and equine lymphocytes.
Mutation research    January 3, 1997   Volume 373, Issue 1 9-16 doi: 10.1016/s0027-5107(96)00178-9
Catena C, Asprea L, Carta S, Tortora G, Conti D, Parasacchi P, Righi E.We have investigated and compared DNA damage and cell killing induced in human and equine lymphocytes after in vitro X-irradiation. Our data show that the cytogenetic and the lethality effects are both greater in equine lymphocytes, but that the difference is wider for lethality. The ratios between doses inducing the same effect are 1.3, 1.7 and 9.4 for the number of binucleated cells with micronuclei, micronucleus frequency in binucleated cells and DNA synthesis inhibition, respectively. The very different radiosensitivity observed for the two mammalian species encourages us to use their lymp...
Cytogenetic analysis of horse oocytes matured in vitro for different periods of time.
Reproduction, nutrition, development    January 1, 1997   Volume 37, Issue 1 63-68 doi: 10.1051/rnd:19970107
Sosnowski J, Lechniak D, Brzozowska M, Switoński M.This paper presents the results of recovering horse oocytes by aspiration and maturation in vitro for 24, 30, 36 or 42 h. A total of 522 oocytes were recovered from 221 ovaries (2.4 per ovary) and 271 oocytes (51.9%) were selected for in vitro maturation (IVM). Oocytes were cultured in maturation medium (TCM 199 + estrus cow serum [ECS] + follicle-stimulating hormone [FSH] + 17 beta-estradiol + gentamycin). One hundred and seventy oocytes were cytogenetically analysed (68.3%). Cytogenetic analysis showed that the stage of maturation (first telophase-TI or second metaphase-MII) for fertilizatio...
Nucleotide sequence of equine MxA cDNA.
DNA sequence : the journal of DNA sequencing and mapping    January 1, 1997   Volume 7, Issue 3-4 239-242 doi: 10.3109/10425179709034043
Chesters PM, Steele M, Purewal A, Edington N.A 2.6 kb cDNA species has been isolated from a cDNA library prepared from interferon-alpha stimulated equine peripheral blood leucocytes and the nucleotide sequence determined. The cDNA has a single open reading frame potentially encoding a 660 amino acid polypeptide showing a high degree of homology with known mammalian Mx proteins, including the possession of three consensus GTP-binding motifs. The protein has a calculated pI = 6.1 and in accordance with proposed nomenclature we have designated it equine MxA.
Some parameters influencing immunoassay of human and horse myoglobins.
Archivum immunologiae et therapiae experimentalis    January 1, 1997   Volume 45, Issue 2-3 229-233 
Kochanowska IE, Kuropatwa M, Szewczuk A.It was noted that human and horse sera as well as human heart and skeletal muscle homogenates or extracts distinctly decrease immunoassays of purified myoglobins. The assays of homogenate and extract myoglobins could be many times increased by precipitation certain proteins with concentrated ammonium sulfate or sodium chloride. Also in homogenates and extracts incubated for several days increased assays of myoglobins were noted. The obtained results indicate that both myoglobins occur in complex with other tissue component(s).
Method for the growth of equine airway epithelial cells in culture.
Research in veterinary science    January 1, 1997   Volume 62, Issue 1 30-33 doi: 10.1016/s0034-5288(97)90176-4
Sime A, McKellar Q, Nolan A.A serum-free cell culture method was developed for equine tracheal epithelial cells which allowed the growth and characterisation of the phenotypical properties of this cell type. Several variables influenced the efficacy of the attachment and growth of the isolated cells. Serum and a collagen matrix were essential components for efficient cell attachment. Once attachment had occurred, cell growth was enhanced by a serum-free medium containing bovine pituitary extract, retinoic acid, insulin, hydrocortisone, transferrin, epidermal growth factor, adrenaline and triiodothyronine. The mean time t...