Flow cytometric sperm sorting: effects of varying laser power on embryo development in swine

This study was conducted to determine fertilization rate and embryo development using the Beltsville Sperm Sexing Technology with two different laser power outputs, 25 and 125 milliwatts (mW). Freshly ejaculated boar semen was diluted; one aliquot was not stained or sorted (nonsort) and a second aliquot was stained with Hoechst 33342 and sorted as a complete population, not separated into X and Y populations (all-sort). Ovulation controlled gilts were surgically inseminated with 2 x 10(5) spermatozoa (44-46 hr after human chorionic gonadotropin (hCG)) into the isthmus of each oviduct, one oviduct receiving nonsort and the other all-sort at 25 or 125 mW. A total of 426 embryos were flushed from oviducts at slaughter 43 hr after laparotomy and prepared for determination of fertilization and cleavage rates using confocal laser microscopy for analysis of actin cytoskeleton and chromatin configuration. The percentage of fertilized eggs and embryos was less for the 25 mW all-sort compared to nonsort or the 125 mW all-sort (77.9 vs. 96.3 and 96.2%, P < 0.05). The percentage of fragmented embryos was greater for the 25 mW all-sort than the nonsort (15.2 vs. 4.5%, P < 0.05), but did not differ significantly from 125 mW all-sort mean (7.2%). The percentage of normal embryos (80.4% overall) did not differ (P > 0.05) among treatments. However, the rate of embryo development was slower (P < 0.05) after insemination with the 25 mW all-sort spermatozoa compared to nonsort spermatozoa. Embryos in the 3-4 and 5-9 cell stages for the 25-mW all-sort and nonsort were 78 and 20% vs. 49 and 50%, respectively. The embryo percentages for the 125 mW (3-4 and 5-9 cell stages, 59 and 35%) did not differ significantly (P > 0.05) from the nonsort or 25 mW all-sort. We conclude that the use of 125 mW laser power for sorting boar spermatozoa is advantageous to maintain high resolution separation and has no detrimental effect on embryo development compared to 25 mW.

The Emergency Medical Treatment and Labor Act as a federal health care safety net program

Despite the greatest economic expansion in history during the 1990s, the number of uninsured U.S. residents surpassed 44 million in 1998. Although this number declined for the first time in recent years in 1999, to 42.6 million, the current economic slow-down threatens once again to increase the ranks of the uninsured. Many uninsured patients use hospital emergency departments as a vital portal of entry into an access-impoverished health care system. In 1986, Congress mandated access to emergency care when it passed the Emergency Medical Treatment and Labor Act (EMTALA). The EMTALA statute has prevented the unethical denial of emergency care based on inability to pay; however, the financial implications of EMTALA have not yet been adequately appreciated or addressed by Congress or the American public. Cuts in payments from public and private payers, as well as increasing demands from a larger uninsured population, have placed unprecedented financial strains on safety net providers. This paper reviews the financial implications of EMTALA, illustrating how the statute has evolved into a federal health care safety net program. Future actions are proposed, including the pressing need for greater public safety net funding and additional actions to preserve health care access for vulnerable populations.

Determination of an acute no-observed-adverse-effect level (NOAEL) for copper in water

A prospective, double-blind controlled study was designed to determine the acute no-observed-adverse-effect level (NOAEL) of nausea in an apparently healthy population of 179 individuals who drank copper-containing water as the sulfate salt. Subjects were recruited at three different international sites and given a blind, randomly selected dose (0, 2, 4, 6, or 8 mg Cu/L) in a bolus of 200 ml (final total copper dose was equivalent to 0, 0.4, 0.8, 1.2, and 1.6 mg) once weekly over a consecutive 5-week period. Gastrointestinal (GI) symptoms of nausea, abdominal pain, vomiting, or diarrhea were screened for a period of up to 24 h. Nausea was the most frequently reported effect and was reported within the first 15 min of ingestion. For the combined trisite population (n=179), 8, 9, 14, 25, and 44 subjects responded positively to one or more GI symptoms at 0, 2, 4, 6, and 8 mg Cu/L, respectively. Analysis of the data demonstrated a clear dose response to the combined positive GI effects and to nausea alone. Statistically significant greater reporting of effects occurred at 6 and 8 mg Cu/L. Therefore, an acute NOAEL and lowest-observed-adverse-effect level of 4 and 6 mg Cu/L (0.8 and 1.2 mg Cu), respectively, were determined in drinking water for a combined international human population.

An X-Y paint set and sperm FISH protocol that can be used for validation of cattle sperm separation procedures

X and Y chromosome paints were developed from sorted yak chromosomes for sexing cattle spermatozoa. Clear hybridization signals were obtained for every spermatozoon using a modified sperm decondensation protocol and fluorescence in situ hybridization (FISH). The procedure was evaluated using the established Beltsville sperm sexing technology, which separates spermatozoa by flow cytometry into X- and Y-bearing fractions. Close agreement was found between the assessment of sperm separation by flow cytometry and by FISH with the X-Y paint set. The FISH method is a simple, reliable and robust procedure for assessing the effectiveness of separation of X and Y spermatozoa.

An X-Y paint set and sperm FISH protocol that can be used for validation of cattle sperm separation procedures

X and Y chromosome paints were developed from sorted yak chromosomes for sexing cattle spermatozoa. Clear hybridization signals were obtained for every spermatozoon using a modified sperm decondensation protocol and fluorescence in situ hybridization (FISH). The procedure was evaluated using the established Beltsville sperm sexing technology, which separates spermatozoa by flow cytometry into X- and Y-bearing fractions. Close agreement was found between the assessment of sperm separation by flow cytometry and by FISH with the X-Y paint set. The FISH method is a simple, reliable and robust procedure for assessing the effectiveness of separation of X and Y spermatozoa.

Complete nucleotide sequence and analysis of the locus of enterocyte Effacement from rabbit diarrheagenic Escherichia coli RDEC-1

The pathogenicity island termed the locus of enterocyte effacement (LEE) is found in diverse attaching and effacing pathogens associated with diarrhea in humans and other animal species. To explore the relation of variation in LEE sequences to host specificity and genetic lineage, we determined the nucleotide sequence of the LEE region from a rabbit diarrheagenic Escherichia coli strain RDEC-1 (O15:H-) and compared it with those from human enteropathogenic E. coli (EPEC, O127:H6) and enterohemorrhagic E. coli (EHEC, O157:H7) strains. Differing from EPEC and EHEC LEEs, the RDEC-1 LEE is not inserted at selC and is flanked by an IS2 element and the lifA toxin gene. The RDEC-1 LEE contains a core region of 40 open reading frames, all of which are shared with the LEE of EPEC and EHEC. orf3 and the ERIC (enteric repetitive intergenic consensus) sequence present in the LEEs of EHEC and EPEC are absent from the RDEC-1 LEE. The predicted promoters of LEE1, LEE2, LEE3, tir, and LEE4 operons are highly conserved among the LEEs, although the upstream regions varied considerably for tir and the crucial LEE1 promoter, suggesting differences in regulation. Among the shared genes, high homology (>95% identity) between the RDEC-1 and the EPEC and EHEC LEEs at the predicted amino acid level was observed for the components of the type III secretion apparatus, the Ces chaperones, and the Ler regulator. In contrast, more divergence (66 to 88% identity) was observed in genes encoding proteins involved in host interaction, such as intimin (Eae) and the secreted proteins (Tir and Esps). A comparison of the highly variable genes from RDEC-1 with those from a number of attaching and effacing pathogens infecting different species and of different evolutionary lineages was performed. Although RDEC-1 diverges from some human-infecting EPEC and EHEC, most of the variation observed appeared to be due to evolutionary lineage rather than host specificity. Therefore, much of the observed hypervariability in genes involved in pathogenesis may not represent specific adaptation to different host species.

Antepartum bed rest: effect upon the family

OBJECTIVE

To identify the effects of antepartum bed rest upon the family.

DESIGN

Descriptive, retrospective survey.

PARTICIPANTS

A national random selection of 89 women who had been prescribed antepartum bed rest in the hospital or at home and who contacted a high-risk pregnancy support group for information.

MAIN OUTCOME MEASURE

An open-ended questionnaire.

RESULTS

Families experienced difficulty assuming maternal responsibilities, anxiety about maternalfetal outcomes, and adverse emotional effects on the children. Child care was managed by various people across time. Child care problems included negative reactions from the children, concern about the quality of the provider, and maternal worry about care. Families also experienced financial difficulties, the majority of which were not compensated by insurance or work benefits. Almost all, 96.6%, families received some type of support during bed rest. Instrumental support was the most commonly received; however, emotional support was considered the most helpful. The least helpful type of support was that which was unreliable. The primary providers of support to the family were parents and family, followed by friends. The women reported that health care providers offered minimal support to the family.

CONCLUSION

Despite support, antepartum bed rest creates difficulties that affect the entire family and its finances.

Development of neuronal circuits and behaviors in the medicinal leech

We are studying the neuronal mechanisms responsible for establishing circuitry underlying the local bending response in the medicinal leech. Local bending replaces an embryonic behavior, circumferential indentation, during the time of initial chemical synaptogenesis in leech embryos. We found that the electrical connections among the motor neurons are established first, about 5% of embryonic time (almost 2 full days) before chemical connections form. The inhibitory connections from muscle inhibitors to muscle excitors are, we hypothesize, responsible for the emergence of local bending. We have also found that the central processes of the excitors--but not the inhibitors--have much longer central processes when their peripheral processes are kept from contacting their target muscles. This system should allow us to test ideas about how individual neurons find their appropriate targets to form functional neuronal circuits.

Regulation of IFN-gamma production following 2B4 activation in human NK cells

IFN-gamma is a cytokine that regulates various functions of the immune system. The major producers of IFN-gamma are T cells and NK cells. 2B4 is a novel activating receptor expressed on all human NK cells, a subset of CD8+ T cells, monocytes and basophils. Activation of human NK cells through surface 2B4 enhances NK cell cytolytic function and secretion of IFN-gamma. We have examined the regulation of IFN-gamma production by the human NK cell line YT upon activation through surface 2B4. Our data indicate that ligation of surface 2B4 by mAb C1.7, that specifically recognizes 2B4, induces transcriptional activation of IFN-gamma. Partial inhibition of transcription did not prevent the transcriptional upregulation of IFN-gamma. S1 nuclease protection analysis indicated that transcriptional activation as well as mRNA stability may account for the increased production of IFN-gamma by human NK cells following 2B4 stimulation.

Storage of boar semen

The problems, aspects and methods of liquid storage and freeze-thawing of boar semen are discussed and a review is given on examination of spermatozoa by the recent fluorescent staining methods.

Sexing mammalian sperm for production of offspring: the state-of-the-art

Predetermination of sex in livestock offspring is in great demand and is of critical importance to providing for the most efficient production of the world's food supply. With the changes that have taken place in animal agriculture over the past generation the application of sex preselection to production systems becomes increasingly necessary. The current technology is based on the well-known difference in X- and Y-sperm in the amount of DNA present. The method has been validated on the basis of live births, laboratory reanalysis of sorted sperm for DNA content and embryo biopsy for sex determination. The technology incorporates modified flow cytometric sorting instrumentation to sort X- and Y-bearing sperm. Resulting populations of X or Y sperm can be used in conjunction with IVF in swine and in cattle for the production of sexed embryos to be transferred to eligible recipients for the duration of gestation. It can also be used for intratubal insemination and for deep-uterine and conventional insemination in cattle. This semipractical sexing method, though currently impractical for some production systems (where large numbers of sperm are required for fertilization) could be used to provide a more flexible progeny-producing option in many livestock operations. Improvements in the production rate of sexed sperm continue as new technology is developed. High-speed sorting is one of the newer technological advances and is being used in our laboratory to increase sorted sperm throughput. With our original technology we sorted 350,000 sperm/h. We now sort 6 million of each sex, under routine conditions. Sorting only the X population results in about 18 million sperm/h. Improvements in the technology will no doubt lead to much greater usage of sexed sperm, depending on the species involved. Insemination of lower sperm numbers in cattle has proven to be an effective means of utilizing the sexing technology. Solving the problems associated with inseminating low sperm numbers in the pig would be advantageous to the utilization of sexed sperm for some type of deep artificial insemination. Such a development would also enhance the economy of using lower sperm numbers with conventional artificial insemination (AI) and aid the swine industry worldwide. The use of sexed sperm for non-ordinary applications such as endangered species, laboratory animals, hobby or pet species is also of interest and will become a part of the move to be more reproductively efficient in the next millennium. Sexed sperm on demand over the next several years will provide livestock producers with many options in seeking to improve efficiency of production and improve quality of products to enhance consumer acceptability.

Simplified process for soybean glycinin and beta-conglycinin fractionation

A simplification of the pilot-plant scale modified Nagano method yielding two protein fractions, glycinin and beta-conglycinin, by pH adjustment and ultrafiltration membrane separation was developed and compared with our pilot-plant-scale modified Nagano procedure and with a soy protein isolate pilot-plant procedure as our reference process. Two protein fractions, glycinin and beta-conglycinin, were produced from our simplified process and compared to the three protein fractions, glycinin, beta-conglycinin, and an intermediate protein mixture, produced with the modified Nagano method. The pilot-plant yields of glycinin, beta-conglycinin, and intermediate mixture fractions from the modified Nagano method were 9.4, 10.3, and 4.8% [dry basis (db)], respectively. The yield of glycinin fraction of the simplified method was 9.7% (db), and it had a protein content and purity similar to those obtained with the modified Nagano method. The yield of the beta-conglycinin fraction was 19.6% (db), which was twice that of the modified Nagano process. The protein content of beta-conglycinin was 91.6% (db), and the purity was 62.6% of the protein content, which was 9% lower in purity than the modified Nagano method. Process optimization of the simplified method suggested the best operating conditions for the membrane filtration system were 20-25 psi inlet pressure and 200-250 L/min ultrafiltration recirculation speeds.

High-affinity anti-ganglioside IgG antibodies raised in complex ganglioside knockout mice: reexamination of GD1a immunolocalization

Gangliosides, sialic acid-bearing glycosphingolipids, are highly enriched in the vertebrate nervous system. Anti-ganglioside antibodies are associated with various human neuropathies, although the pathogenicity of these antibodies remains unproven. Testing the pathogenic role of anti-ganglioside antibodies will be facilitated by developing high-affinity IgG-class complement-fixing monoclonal anti-bodies against major brain gangliosides, a goal that has been difficult to achieve. In this study, mice lacking complex gangliosides were used as immune-naive hosts to raise anti-ganglioside antibodies. Wild-type mice and knockout mice with a disrupted gene for GM2/GD2 synthase (UDP-N-acetyl-D-galactosamine : GM3/GD3 N-acetyl-D-glactosaminyltransferase) were immunized with GD1a conjugated to keyhole limpet hemocyanin. The knockout mice produced a vigorous anti-GD1a IgG response, whereas wildtype littermates failed to do so. Fusion of spleen cells from an immunized knockout mouse with myeloma cells yielded numerous IgG anti-GD1a antibody-producing colonies. Ganglioside binding studies revealed two specificity classes; one colony representing each class was cloned and characterized. High-affinity monoclonal antibody was produced by each hybridoma : an IgG1 that bound nearly exclusively to GD1a and an IgG2b that bound GD1a, GT1b, and GT1aalpha. Both antibodies readily readily detected gangliosides via ELISA, TLC immune overlay, immunohistochemistry, and immunocytochemistry. In contrast to prior reports using anti-GD1a and anti-GT1b IgM class monoclonal antibodies, the new antibodies bound avidly to granule neurons in brain tissue sections and cell cultures. Mice lacking complex gangliosides are improved hosts for raising high-affinity, high-titer anti-ganglioside IgG antibodies for probing for the distribution and physiology of gangliosides and the pathophysiology of anti-ganglioside antibodies.

2B4 stimulation of YT cells induces natural killer cell cytolytic function and invasiveness

2B4 is a surface molecule found on all human natural killer (NK) cells, a subset of CD8+ T cells, monocytes and basophils. It was originally identified on mouse NK cells and the subset of T cells that mediate non-major histocompatibility complex (MHC)-restricted killing. Recently,9 we have cloned the human homologue of 2B4 (h2B4) and found h2B4 to also mediate non-MHC-restricted cytotoxicity. In this study, we examine h2B4 in regulating various functions of NK cells using a human NK cell line YT, with monoclonal antibody (mAb) C1.7, an antibody that specifically recognizes h2B4. Ligation of surface 2B4 with mAb C1.7 increases YT's ability to destroy tumour cells. In the presence of mAb C1.7, the production of interferon-gamma (IFN-gamma) by YT cells is greatly enhanced. Engagement of surface 2B4 by mAb C1.7 downregulates the expression of h2B4 at the cell surface as well as the expression of h2B4 mRNA. Also, signalling through h2B4 causes the increased expression of matrix metalloproteinase-2, a member of the matrix degrading proteinase family. Thus, in addition to modulating cytolytic function and cytokine production of NK cells, activation through surface 2B4 may play a role in upregulating the machinery for degradation of extracellular matrices to promote invasion of the tumour by NK cells.

Disruption of peripheral target contact influences the development of identified central dendritic branches in a leech motor neuron in vivo

Retrograde signaling from target tissues has been shown to influence many aspects of neuronal development in a number of developmental systems. In these experiments using embryonic leeches (Hirudo medicinalis), we examined how depriving a neuron of contact with its peripheral target affects the development of the cell's central arborization. We focused our attention on the motor neuron cell 3, which normally stimulates dorsal longitudinal muscle fibers to contract. At different locations in the periphery and in embryos of several different stages, we cut the nerve containing the growing axon of cell 3. This surgery led to dramatic overgrowth of cell 3's central dendritic branches, which normally accept synaptic contacts from other neurons, including the inhibitory motor neuron cell 1. When cell 3's peripheral axon was cut relatively early in development, its overgrown central branches eventually retracted. However, cells that were disrupted later in development retained their overextended branches into adulthood. In addition, if the axon was cut close to the ganglion early in development, depriving the cell of contact with any dorsal tissues, the central branches failed to retract and were instead retained into adulthood. Unlike cell 3, the central branches of cell 1, which has the same peripheral target muscles as cell 3, remained unchanged following all axotomy protocols. These results suggest that in at least some neurons contact with peripheral targets can influence development of the central processes that normally mediate synaptic contacts.