Benefits of spinal anesthesia for urologic surgery in the youngest of patients

INTRODUCTION

Increasing concerns regarding potential negative effects of early use of inhalational and intravenous anesthetics on neurocognitive development have led to a growing interest in alternative forms of anesthesia in infants. The study institution's outcomes with spinal anesthesia (SA) for urologic surgery in infants aged less than 90 days are reported and their outcomes with a matched cohort of patients who underwent general anesthesia (GA) are compared.

METHODS

This is a retrospective single-center analysis. Patients aged less than 90 days who underwent SA for four urologic surgeries (inguinal hernia repair, scrotal exploration, posterior urethral valve ablation, and ureterocele puncture) were identified from the study institution's SA database. An age- and procedure-matched control cohort was identified from a list of patients who underwent the aforementioned four procedures under GA since 2013. Outcomes of interest included success rate of SA, complications from spinal placement, narcotic use, need for supplemental medications and oxygen, and length of hospital stay.

RESULTS

Forty patients were identified; 20 in the SA and 20 in the GA group. Mean patient age was 54 (standard deviation, 35) days. There were no significant differences between the groups in age, gender, weight, history of prematurity, or presence of comorbidities. Eighty percent of SA patients had successful SA; reasons for conversion to GA included failure of spinal needle placement (75%) and agitation during operative procedure (25%). Ninety-six percent of patients who received GA (primarily or converted) had an endotracheal tube (ETT) placed. No patient in the SA group had a complication from spinal needle placement. Patients in the SA group were less likely to receive narcotics during the operative procedure (P = 0.001) and also had a lower mean morphine equivalent dose/kilogram (P = 0.002). Patients in the SA group were also less likely to receive any supplemental medications during the operative procedure (P = 0.001), particularly intravenous corticosteroids (P < 0.001). There were no significant differences in the length of hospital stay.

CONCLUSIONS

The use of SA has clear advantages for this medically vulnerable population. For the majority of patients, it obviates the need for ETT placement and airway management and avoids the potential negative effects of GA on neurocognitive development. It also decreases the use of narcotics and other supplemental medications. In scenarios in which the benefit of surgery must be weighed against the risk of GA, such as neonatal torsion, SA may allow a paradigm shift in the timing of surgery.

Expression of the human alpha1,2-fucosyltransferase in transgenic pigs modifies the cell surface carbohydrate phenotype and confers resistance to human serum-mediated cytolysis

Hyperacute rejection (HAR) is the first critical immunological hurdle that must be addressed in order to develop xenogeneic organs for human transplantation. In the area of cell-based xenotransplant therapies, natural antibodies (XNA) and complement have also been considered barriers to successful engraftment. Transgenic expression of human complement inhibitors in donor cells and organs has significantly prolonged the survival of xenografts. However, expression of complement inhibitors without eliminating xenogeneic natural antibody (XNA) reactivity may provide insufficient protection for clinical application. An approach designed to prevent XNA reactivity during HAR is the expression of human alpha1, 2-fucosyltransferase (H-transferase, HT). H-transferase expression modifies the cell surface carbohydrate phenotype of the xenogeneic cell, resulting in the expression of the universal donor O antigen and a concomitant reduction in the expression of the antigenic Galalpha1,3-Gal epitope. We have engineered various transgenic pig lines that express HT in different cells and tissues, including the vascular endothelium. We demonstrate that in two different HT transgenic lines containing two different HT promoter constructs, expression can be differentially regulated in a constitutive and cytokine-inducible manner. The transgenic expression of HT results in a significant reduction in the expression of the Galalpha1,3-Gal epitope, reduced XNA reactivity, and an increased resistance to human serum-mediated cytolysis. Transgenic pigs that express H-transferase promise to become key components for the development of xenogeneic cells and organs for human transplantation.

The use of transgenic animals in biotechnology

The development of a technique that allows for oocyte and early embryo manipulation is one of the major scientific endeavors in the field of genetic manipulation for animal disease models, basic science in gene regulation and commercial applications. Dr. Ralph Brinster is one of the most prestigious scientists in the development of this science. Through his direction and support, the undertaking of the mechanisms that are involved in the earlier stages of embryology have been productive and enlightening. This paper outlines just some of the experimental successes that evolved from Dr. Brinster's insight and mentorship of one of his pupils. The essay outlines several experimental approaches that have contributed to this field. Specifically, it addresses how the mouse oocyte and the zygote respond to messenger RNA when introduced into the cell, in comparison to comparable non-mammalian species embryos. In addition, this paper discusses some transgenic animal models, both from a basic science point of view and a commercial extension of these techniques. This extension of Dr. Brinster's pioneering work is through technology that allows for the introduction of foreign DNA that can be expressed in targeted organs, such as the mammary gland for production of pharmaceuticals for use in clinical applications.

Region-specific central nervous system expression and axotomy-induced regulation in sympathetic neurons of a VIP-beta-galactosidase fusion gene in transgenic mice

To assess the activity of cis-acting elements that direct human vasoactive intestinal peptide (VIP) expression in vivo, two independent transgenic mouse lines were created using a transgene comprised of 1.9 kb of 5'-flanking sequence of the human VIP gene joined to the Escherichia coli beta-galactosidase reporter gene. Transgene expression in brain was assessed using beta-galactosidase histochemistry and compared to the distribution of endogenous VIP expression. Transgene expression was observed in most central and peripheral nervous system sites in which endogenous VIP is expressed. We investigated whether the VIP-beta-galactosidase transgene was regulated in sympathetic neurons in experimental paradigms in which VIP regulation is dependent on the release of leukemia inhibitory factor (LIF). After dissociation in vitro and postganglionic axotomy in vivo there were parallel increases in endogenous VIP and transgene expression in superior cervical ganglia. These results indicate that the 1.9 kb region of 5'-flanking sequence of the human VIP gene includes genomic elements important for cell-specific expression and LIF-dependent regulation in neurons.

Mouse half embryos: viability and allocation of cells in the blastocyst

We have investigated the developmental capacity of mouse embryos in which one blastomere was destroyed by lysis at the 2-cell stage. The allocation of cells to the trophectoderm and inner cell mass (ICM) was documented by differential cell counts on single embryos after 2 days under different culture conditions. Viability and further developmental potential were tested by embryo transfer to foster mothers. The conditions used were: (1) in vitro culture in modified BMOC-2 medium, (2) in vivo oviduct transfer to immature (prepuberal) females, and (3) in vivo oviduct transfer to pseudopregnant females. Half embryos almost always fared less well for all parameters of development than control embryos developing under the same conditions. Lower total cell numbers in half embryos were accounted for by decreases in both ICM and trophectoderm with a disproportionate decrease in ICM in smaller embryos. In both half and control embryos, the growth conditions affected the rate of morphological development, the total cell number, and embryo viability. Unlike the effect of halving embryos, the growth condition effects on total cell number can be accounted for primarily by differences in ICM cell number, with trophectoderm cell number remaining constant. These results provide new information on the ability of the mouse embryo to differentially regulate ICM and trophectoderm cell number under different conditions, and confirm our previous work showing the advantage of short-term development in vivo over short-term in vitro culture (Papaioannou and Ebert [1986] J. Reprod. Fertil. 76:603-608).(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic diversity of cultured Penaeus vannamei shrimp using three molecular genetic techniques

Three molecular genetic techniques, restriction fragment length polymorphisms (RFLPs), random amplification of polymorphic DNA (RAPD), and allozyme variability, were used to evaluate the genetic diversity of two specific-pathogen-free (SPF) populations (numbers 1 and 2) and one candidate SPF population (number 4) of Penaeus vannamei developed and maintained by the U.S. Marine Shrimp Farming Program. A total of 114 individuals were tested, which included 30 each from families 1.5 and 1.6 of population 1 and from population 2, and 24 from population 4. Two HhaI mitochondrial DNA polymorphisms (A and B) were found in all the animals examined, with family 1.5 and population 2 showing type A and family 1.6 showing type B. After scoring 73 bands obtained with six different RAPD primers, the percentage of polymorphic bands was: 55% for families 1.5 and 1.6 of population 1, 48% for population 2, and 77% for population 4, suggesting that population 4 is the most polymorphic of all three populations. The allozymic variation at 30 loci showed no fixed differences in isozyme genotypes between families 1.5 and 1.6. The percentage of polymorphic loci, under the criterion that the frequency of the most common allele was less than 0.95 in each population, was 6.67%, 3.33% and 16.67% for family 1.5 of population 1, family 1.6 of population 1, and population 2, respectively. Mean heterozygosities (+/- SE) were 0.023 +/- 0.017, 0.018 +/- 0.016, and 0.064 +/- 0.026, respectively. The low levels of allozyme polymorphisms indicate that mitochondrial DNA and nuclear DNA techniques are more useful for examining genetic diversity in order to follow individual stocks within a breeding program and to correlate genotypes with desirable growth and reproductive performance of SPF P. vannamei stocks.

Induction of human tissue plasminogen activator in the mammary gland of transgenic goats

Three transgenic females from a first generation transgenic male were induced to lactate between 11 and 12 months of age using a series of estrogen and progesterone injections. The milk contained human longer acting tissue plasminogen activator (LAtPA) at comparable concentrations (1-3 mg/ml) as occurred in the original founder female. In addition, the transgenic male was induced with a hormonal regime and was shown to produce 0.85 mg/ml of LAtPA. Milk protein gels indicated that the milk products (casein, IgG) were essentially normal. These experiments show that expression data for this vector can be evaluated in a shorter period of time in dairy goats than would be required through normal gestation and lactation schedules and can be used to identify the relative expression of transgenes in mammary tissue that would occur during normal lactation.

The rat proenkephalin germ line promoter contains multiple binding sites for spermatogenic cell nuclear proteins

Rat and mouse spermatogenic cells contain a family of 1700-nucleotide (nt) proenkephalin mRNAs that are generated from an alternate, germ cell-specific promoter. This promoter is located approximately 350 base pairs (bp) downstream of the promoter used in somatic cells, within the first intron for the somatic transcript. In a previous study, rat proenkephalin-chloramphenicol acetyltransferase fusion genes containing both promoters were shown to be transcribed selectively from the germ cell promoter and in the correct developmental pattern in spermatogenic cells of transgenic mice. In the present study it was found that spermatogenic cell-specific transgene expression was maintained after deletion of the upstream somatic promoter. This result establishes that the rat proenkephalin germ-line promoter is capable of functioning independently of transcriptional elements associated with the somatic promoter and localizes the requisite spermatogenic cell cis-elements to a 500-bp region encompassing the germ cell initiation sequences. A comprehensive analysis of binding sites for rat spermatogenic cell nuclear factors within this 500-bp region was performed using gel-shift and DNAse I footprinting techniques. Eight distinct binding regions were identified, each of which formed one or more cell-specific complexes with nuclear proteins from rat spermatogenic cells. These results suggest that multiple cis-acting elements may cooperate in the cell-specific and developmental regulation of rat proenkephalin gene transcription during spermatogenesis.

Production of cystic fibrosis transmembrane conductance regulator in the milk of transgenic mice

Here we describe the production of cystic fibrosis transmembrane conductance regulator (CFTR), the product of the gene associated with cystic fibrosis, in the milk of transgenic mice. Mammary specific expression was achieved by placing the CFTR cDNA under the control of the goat beta-casein gene promoter. By fractionation, CFTR was shown to be associated with the membranes that envelop milk fat globules as they are discharged from the apical surface of the mammary epithelia. Since milk fat globules may comprise up to 10% of whole milk, this represents a novel, inexpensive and efficient approach to produce CFTR and possibly other membrane-associated proteins. The availability of large quantities of CFTR could have important implications for the development of new therapies for cystic fibrosis.

Selective transcription of rat proenkephalin fusion genes from the spermatogenic cell-specific promoter in testis of transgenic mice

The rat and mouse proenkephalin genes each contains two distinct promoters, one of which is utilized exclusively by spermatogenic cells. The germ cell-specific promoter lacks TATA sequences, is G+C rich, and contains multiple initiation sites. To investigate the nature of the cis-acting elements that determine selective transcription of the proenkephalin gene in male germ cells, two rat proenkephalin-chloramphenicol acetyltransferase fusion genes containing the two different promoter regions as well as 1.6 or 0.3 kilobases, respectively, of 5'-flanking sequence were expressed in transgenic mice. Multiple transgenic lines were developed which expressed the fusion genes in testis, brain, and heart but not in tissues that do not normally express the proenkephalin gene. Fusion gene transcripts in transgenic mouse testes were localized to those spermatogenic cell types that utilize the spermatogenic cell promoter and were selectively and accurately initiated from the multiple rat germ cell start sites. Transgenic mice thus provide a useful model for the localization and characterization of cis-acting elements mediating transcription of the proenkephalin gene from its germ cell-specific promoter.

Transgenic expression of a variant of human tissue-type plasminogen activator in goat milk: purification and characterization of the recombinant enzyme

A glycosylation variant of human tissue-type plasminogen activator (tPA) designated longer-acting tissue-type plasminogen activator (LAtPA) was extensively purified from the milk of a transgenic goat by a combination of acid fractionation, hydrophobic interaction chromatography and immunoaffinity chromatography. This scheme provided greater than 8,000-fold purification of the protein, a cumulative yield of 25% and purity greater than 98% as judged by SDS gel electrophoresis. SDS gel electrophoresis revealed that the transgenic enzyme was predominantly the "two chain" form of the protease. The specific activity of the purified transgenic protein, based on the average of the values obtained for three different preparations, was 610,000 U/mg as judged by amidolytic activity assay. This was approximately 84% of the value observed for the recombinant enzyme produced in mouse C127 cells. Analysis of the transgenic protein indicated that it had a significantly different carbohydrate composition from the recombinant enzyme produced in C127 cells. Molecular size analysis of the oligosaccharides from the transgenic and C127 cell-derived LAtPA preparations confirmed their differences and showed that the mouse cell-derived preparation contained larger, complex-type N-linked oligosaccharide structures than the material produced in goat mammary tissue.

Transgenic Production of a Variant of Human Tissue-Type Plasminogen Activator in Goat Milk: Generation of Transgenic Goats and Analysis of Expression

We report the first successful production of transgenic goats that express a heterologous protein in their milk. The production of a glycosylation variant of human tPA (LAtPA--longer acting tissue plasminogen activator) from an expression vector containing the murine whey acid promoter (WAP) operatively linked to the cDNA of a modified version of human tPA was examined in transgenic dairy goats. Two transgenic goats were identified from 29 animals born. The first animal, a female, was mated and allowed to carry the pregnancy to term. Milk was obtained upon parturition and was shown to contain enzymatically active LAtPA at a concentration of 3 micrograms/ml.

Culture of 5-day horse embryos in microdroplets for 10 to 20 days

Embryos were recovered from the uteri of mares 5 d after ovulation. Six embryos, all morulae, were placed singly in 200-ul droplets of Ham's F-12 with 10% fetal calf serum and cultured at 37 degrees C in a 5% CO(2) atmosphere. The embryos expanded to form blastocysts by the third day of culture. The blastocysts hatched from their zona pellucida, rather than the zona thinning and flaking off, as occurs in vivo. Hatching from the zona pellucida began on the third day of culture and was complete in five of six embryos by the sixth day. The embryonic capsule, normally present in equine embryos after Day 6, was not seen in the cultured embryos. The blastocysts continued to expand until 15 to 17 d of age (10 to 12 d in culture), reaching an average diameter (+/- SD) of 2052 +/- 290 um, after which time they either collapsed or contracted. These results demonstrate that equine embryos can be maintained in long-term culture in vitro, exhibiting continued growth and expansion in the absence of the embryonic capsule.

Cryptic human growth hormone gene sequences direct gonadotroph-specific expression in transgenic mice

Our laboratory reported previously that chimeric genes encoding either rat somatostatin (SS) or human GH (hGH), but containing the identical mouse metallothionein-I (MT) promoter/enhancer sequences and hGH 3'-flanking sequences, were selectively expressed in the gonadotrophs of transgenic mice. The experiments reported here were designed to identify the DNA sequences responsible for this unexpected cell-specific expression within the anterior pituitary. We produced new transgenic mice expressing fusion genes that tested separately the requirement of the MT or 3'-hGH sequences for gonadotroph expression. A fusion gene that retained the original MT and SS sequences, with a simian virus 40 polyadenylation signal exchanged for the 3'-hGH sequences, no longer directed strong pituitary expression, but was active in the liver. In contrast, a cytomegalovirus promoter/enhancer-SS-hGH fusion gene was expressed at the same high level in the anterior pituitaries of transgenic mice as the originally studied MT-SS-hGH gene. Immunohistochemical analysis indicated that pituitary expression of the cytomegalovirus promoter/enhancer-SS-hGH fusion gene was also restricted to gonadotroph cells in adult mice. These studies indicate that sequences within the 3'-flanking region of the hGH gene can direct expression of chimeric genes to pituitary cells that do not normally produce growth hormone.

In vivo culture of embryos in the immature mouse oviduct

In-vitro culture of mammalian preimplantation embryos is associated with subsequent decreased viability. This phenomenon is more pronounced with the domestic species embryos as culture conditions are at present unable to sustain cleavage of early preimplantation embryos for more than one or two cell divisions. In this study, the immature mouse oviduct is shown to be capable of supporting cleavage and morphological development of rabbit and porcine embryos. The immature mouse oviduct was shown to be comparable to in vitro culture as 76% and 60% of the transferred zygotes developed to the morula stage after 2 and 3 d respectively. The porcine zygotes, however, failed to develop beyond the 4-cell stage in either the immature mouse oviduct or in vitro. Porcine morula showed better tolerance of the oviduct environment and when recovered after 2 d contained an average of 64 cells, which was significantly more than in in vitro cultured morulae (40 cells). Early porcine blastocysts transferred to the mouse oviduct had over a two-fold increase in cell division (104 cells) over comparable blastocysts grown in vitro (57 cells). The immature mouse oviduct is, therefore, a potential surrogate environment for short-term storage of embryos of other species.

Mouse zygotes injected with mitochondria develop normally but the exogenous mitochondria are not detectable in the progeny

A microinjection procedure to introduce "paternal" mitochondria from a source other than spermatozoa into fertilized mouse eggs is described. When a mitochondrial suspension isolated from the testes or liver of Mus molossinus mice was microinjected into fertilized eggs of CD1 mice, the microinjected zygotes survived, developed normally, and offspring were produced. Mus molossinus mitochondrial DNA can be distinguished from CD1 mitochondrial DNA by Southern blot analyses using restriction enzymes such as Eco R1, Xba 1, or Spe 1. Although up to 120 viable mitochondria were injected, no exogenous mitochondrial DNA was detected in fetal samples or in the brain, liver, heart, testis, or ovary of the mature progeny. Under the experimental conditions used, similar results were obtained when mitochondria from the testes of New Zealand black mice or from testes of Syrian hamsters were microinjected into fertilized CD1 mouse eggs. Failure to detect the exogenous mitochondrial DNA under our assay conditions suggests that microinjected mitochondria from testis or liver did not selectively replicate during embryonic development. The "foreign" mitochondria appear to have the same fate during early embryogenesis as the mitochondria of the spermatozoon.

The preimplantation pig embryo: cell number and allocation to trophectoderm and inner cell mass of the blastocyst in vivo and in vitro

Total cell number as well as differential cell numbers representing the inner cell mass (ICM) and trophectoderm were determined by a differential staining technique for preimplantation pig embryos recovered between 5 and 8 days after the onset of oestrus. Total cell number increased rapidly over this time span and significant effects were found between embryos of the same chronological age from different females. Inner cells could be detected in some but not all embryos of 12–16 cells. The proportion of inner cells was low in morulae but increased during differentiation of ICM and trophectoderm in early blastocysts. The proportion of ICM cells then decreased as blastocysts expanded and hatched. Some embryos were cultured in vitro and others were transferred to the oviducts of immature mice as a surrogate in vivo environment and assessed for morphology and cell number after several days. Although total cell number did not reach in vivo levels, morphological development and cell number increase was sustained better in the immature mice than in vitro. The proportion of ICM cells in blastocysts formed in vitro was in the normal range.

A Moloney MLV-rat somatotropin fusion gene produces biologically active somatotropin in a transgenic pig

Expression of a Moloney murine leukemia virus (MLV) rat somatotropin fusion gene was examined in a transgenic pig. The fusion gene was integrated in a single site within the genome in a tandem array with approximately eight copies per cell. The integrated in a single site within the genome in a tandem array with approximately eight copies per cell. The integrated MLV-rat somatotropin fusion gene produced high levels of circulating rat somatotropin and resulted in an elevation in the circulating levels of insulin-like growth factor I. Although there was no increase in the rate of growth of the transgenic animal during the rapid growth phase, several phenotypic changes were evident. Skeletal growth was markedly increased and fat deposition was reduced throughout the animal. Blood glucose levels were elevated without ketosis. Northern blot analyses of rat somatotropin RNA revealed that expression of the fusion gene was highest in the spleen, lung, intestine, lymph nodes, and bone marrow. These results show that the MLV promoter can be used to express high levels of biologically active rat somatotropin in transgenic swine.

Mitochondrial DNA in the mouse preimplantation embryo

Total DNA was extracted from mouse embryos that were collected from CD-1 random-bred females on Day 1 of pregnancy and cultured for up to 4 days in vitro, or from the reproductive tracts of pregnant females on Days 1, 3, 4 and 5 of pregnancy. Southern blot analyses with a cloned mouse mitochondrial DNA probe were performed to determine the relative levels of mitochondrial DNA in the zygote, morula, blastocyst and early egg cylinder stage embryos. The results indicated that the total amount of mitochondrial DNA does not change during development of the mouse embryo up to the egg cylinder stage and is not altered during in-vitro culture of the fertilized one-cell embryo to the blastocyst stage.

Changes in the organization of the actin cytoskeleton during preimplantation development of the pig embryo

The organization of the actin cytoskeleton was studied in unfertilized porcine oocytes and preimplantation stage embryos from Day 1 through Day 8 of development. Fixed and detergent-extracted oocytes and embryos were analyzed by fluorescence microscopy after staining with either rhodamine-phalloidin to localize filamentous actin or with affinity-purified anti-actin antibodies to localize the total immunodetectable actin. Whereas unfertilized oocytes contain immunoreactive cytoplasmic actin, rhodamine-phalloidin binding is not detected until fertilization when a prominent cortical staining pattern becomes apparent. In early cleavage stage embryos, filamentous actin is concentrated in the cell cortex of blastomeres especially at sites of cell-cell contact. Compacting morulae exhibit a marked accumulation of actin at the margins of blastomeres where numerous interdigitating cell processes are located. The predominantly pericellular distribution of actin becomes a distinguishing feature of trophectodermal cells in the expanding blastocyst at Day 6 of development; these cells form a prominent actin-limited zone circumscribing the inner cell mass. In Day 8 blastocysts, three cell types are present that are readily distinguishable based upon their actin displays among other cytological features. Trophectodermal cells exhibit continuous actin-rich lateral borders and stress fibers along their basal surface. Inner cell mass cells contain a discontinuous actin boundary and prominent foci of actin along their blastocoelic surface. Lining the blastocoel are patches of endodermal cells in which the actin is exclusively cortical. The data are discussed with respect to differences between species and the chronology of actin rearrangements during preimplantation development of the porcine embryo.

Development of fertilized embryos transferred to oviducts of immature mice

The in-vitro culture of fertilized 1-cell mouse embryos to the blastocyst stage is associated with subsequent decreased viability. In this study, 1-cell embryos were cultured for 3 days in the reproductive tract of immature female mice as an alternative to in-vitro culture. Embryos that spent 3 days in immature females were developmentally more advanced, had higher cell numbers and better viability, as measured by development to mid-gestation, after transfer to pseudopregnant recipient females than did embryos maintained for the same period in culture. Embryos that developed in immature females had lower cell numbers but comparable rates of development and subsequent viability when compared with embryos transferred to synchronous pseudopregnant females for the same preimplantation period. The immature mouse oviduct is therefore a suitable alternative environment to in-vitro culture or a pseudopregnant host for complete preimplantation development and has the additional advantage that synchrony between embryo and temporary host is not necessary. This method will allow for evaluation of manipulation procedures while maintaining viability before the embryos are finally committed to a foster mother for development to term.

Production of transgenic rabbits, sheep and pigs by microinjection

Direct microinjection has been used to introduce foreign DNA into a number of terminally differentiated cell types as well as embryos of several species including sea urchin, Candida elegans, Xenopus, Drosophila and mice. Various genes have been successfully introduced into mice including constructs consisting of the mouse metallothionein-I (MT) promoter/regulator region fused to either the rat or human growth hormone (hGH) structural genes. Transgenic mice harbouring such genes commonly exhibit high, metal-inducible levels of the fusion messenger RNA in several organs, substantial quantities of the foreign growth hormone in serum and enhanced growth. In addition, the gene is stably incorporated into the germ line, making the phenotype heritable. Because of the scientific importance and potential economic value of transgenic livestock containing foreign genes, we initiated studies on large animals by microinjecting the fusion gene, MT-hGH, into the pronuclei or nuclei of eggs from superovulated rabbits, sheep and pigs. We report here integration of the gene in all three species and expression of the gene in transgenic rabbits and pigs.

Translation and stability of ovalbumin messenger RNA injected into growing oocytes and fertilized ova of mice

Growing mouse oocytes and fertilized ova were injected with chicken ovalbumin messenger RNA (mRNAov) and chicken conalbumin mRNA (mRNAcon) and cultured in vitro. Estimation of mRNAov and mRNAcon stability by hybridization of cDNAov and cDNAcon to extracted mRNA from injected oocytes and fertilized ova indicated a half-life of 147 and 366 h in the oocyte and 5 and 3 h in the fertilized ovum respectively. Stability of mRNAov was similar in the fertilized and unfertilized ovum. Oocytes injected with chicken ovalbumin mRNA were also labelled with [3H]leucine and ovalbumin synthesis was measured by immunoprecipitation. The amount of ovalbumin synthesized during the initial 7 h was less than during the period of 18-25 or 66-73 h postinjection. The greatest percentage of ovalbumin to total protein synthesis occurred between 66-73 h. Oocytes secreted 12% of the synthesized ovalbumin during each of the 7 h periods (0-7, 18-25 and 66-73 h) indicating a stable mechanism for secretion throughout the culture period. These studies demonstrate: a dramatic difference in stability of injected mRNA between the growing oocyte and the unfertilized or fertilized ovum, and a gradual increase in the translation of injected mRNA by the growing oocyte during in vitro culture.

Rabbit alpha-globin messenger RNA translation by the mouse ovum

Fertilized mouse ova were injected with messenger RNA for rabbit globin. The ova were labelled with [3H]leucine and the synthesized rabbit alpha-globin measured by immunoprecipitation. Injection of rabbit globin mRNA from 4.0 to 15.8 pg/ovum resulted in the synthesis of approximately 1200 dpm/ovum of alpha-globin during an 18 h incubation. A concentration of mRNA that was translated below the maximum level of globin synthesis was used to determine translation efficiency. The efficiency of translation was 14.1 molecules of alpha-globin synthesized/cell/h for each molecule of alpha-globin mRNA injected. The radioactivity in alpha-globin was 1% of the total incorporation in acid-precipitable material. Total incorporation of control and injected ova was not significantly different. This study shows that the fertilized mouse ovum can translate an injected foreign message with essentially the same efficiency as that reported for the Xenopus oocyte but substantially lower than the reticulocyte and that the translational capacity of the mouse fertilized ovum for injected mRNA is limited with little if any spare translational ability.

Synthesis and secretion of ovalbumin by mouse-growing oocytes following microinjection of chick ovalbumin mRNA

Mouse-growing oocytes were injected with chick ovalbumin mRNA. The oocytes were cultured for 18 h in the presence of [3H]leucine and the labeled ovalbumin was measured by immunoprecipitation. Two types of ovalbumin were precipitated by antibody to ovalbumin; one co-migrated with authentic, glycosylated ovalbumin in an 18% polyacrylamide gel and was estimated to be 45 000 D, whereas the other migrated faster with an apparent MW of 41 500 D. Both types of ovalbumin were also detected in the culture medium. This study demonstrates that mouse-growing oocytes can translate exogenous mRNA coding for a secreted protein and secrete two forms of the product.

Detection and synthesis of a progestagen-dependent protein in human endometrium

Immunologiocal and biochemical methods were employed to demonstrate the presence of progestagen-dependent proteins in human endometrium. Cytosols were prepared from proliferative and secretory phase endometria of cycling women, from decidua and decidua-rich tissues of women in early pregnancy and from decidua of tubal pregnancy. Antisera were raised in rabbits against the antigens of decidua of tubal pregnancy and decidua-rich tissues. Immunoelectrophoresis, Ouchterlony's immunodiffusion test and polyacrylamide gel electrophoresis using native gels revealed 2 antigenic proteins, designated antigens A and B, in secretory endometria, decidua-rich tissues, decidua, and in decidua of tubal pregnancy. However, only 1 antigenic protein was detected by SDS-gel electrophoresis: antigens A and B may therefore be two different proteins or two forms of a single protein. The antigens could not be detected in non-pregnancy sera or in term placentae. Double isotopic labelling (incubation of tissues with [3H]- and [14C]leucine) followed by protein fractionation methods were used to compare the in-vitro synthesis rates of antigens in poroliferative tissues with those in decidua or secretory endometria. The rate of synthesis of antigens A and B was markedly higher in the decidua and secretory endometria than in the proliferative endometria. We conclude, therefore, that during progestagen-dependent transformation of proliferative phase endometria into secretory endometria and decidua in women, there is a selective stimulation of at least one species of pregnancy-associated protein.

Properties of the progestagen-dependent protein of the human endometrium

Antigens A and B, shown to be associated with the progestagen-dominated human endometrium, were partly purified and their properties studied. The antigens were recovered in the crude nuclei, the heavy particulate fraction and cytosol of decidua-rich tissue from early pregnancy. The antigens in cytosol were enriched by a combination of Concanavalin A-Sepharose chromatography and polyacrylamide gel electrophoresis. The immunological reactivity of the antigens after partial purification by Concanavalin A-Sepharose chromatography was retained after 30 min exposure to 4-85 degrees C at pH 7.4, or after 2 h to pH 2-12 at 22 degrees C. Trypsin, but not pepsin, RNase, DNase or neuraminidase, completely destroyed immunological reactivity of both antigens. The apparent molecular weight of both antigens determined by filtration on Sephadex G100 was 48 000. The isoelectric point of both antigens was approximately 4.9. The antigens were not immunologically related to transferrin, ceruloplasmin, alpha-1-antitrypsin, ferritin, uteroglobin, alpha-fetoprotein, human chorionic gonadotrophin, pregnancy-associated plasma proteins or pregnancy zone protein. Furthermore, the antisera to Antigens A and B did not react with the decidual cytosol of pregnant baboons or of pseudopregnant rats.

Effects of progesterone on labeling of soluble proteins and glycoproteins in rabbit endometrium

An in vitro test system was used to study in vivo effects of progesterone on synthesis and secretion of total proteins and glycoproteins in rabbit endometrium. Endometrial explants incubated in Eagle's minimal essential medium containing radioactive leucine and N-acetylglucosamine were found to synthesize soluble proteins readily, including glycoproteins. Furthermore, significant amounts of newly synthesized proteins, including blastokinin, were released by the tissues into the incubation medium. In addition, in vitro synthesis and release of labeled proteins by estrogen-primed endometrial tissue (E-primed tissue) was significantly enhanced by exposure of the tissues to progesterone in vivo. Double-labeling studies demonstrated qualitative as well as quantitative differences in peptide synthesis between E-primed tissues and E-primed, progesterone-treated tissues. Progesterone also stimulated both the synthesis and the release of glycoprotein by E-primed tissues. These studies, therefore, suggest that progesterone regulates qualitatively and quantitatively the synthesis and secretion of total proteins, including glyco-proteins, in rabbit endometrium.