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Biomedical subjects

C S Schneider

Publications and source records attributed to C S Schneider.

7 recordsLinked to original sources
PubMed1999

Relationship between bull field fertility and in vitro embryo production using sperm preparation methods with and without somatic cell co-culture.

Experiments were designed to compare rates of embryonic development following oocyte exposure to cryopreserved spermatozoa from bulls of varying proven fertility, utilizing 3 different sperm preparation methods prior to oocyte introduction. These included 1) sperm co-culture with bovine oviductal epithelial cells (BOEC); 2) sperm co-culture with buffalo rat liver cells (BRLC); or 3) control culture in a routine, cell-free culture system. Semen from 9 bulls was classified by lifetime 60- to 90-d nonreturn rates as having either (mean +/- SEM) high (n=3) 73.2 +/- 3a, medium (n=3) 70.3 +/- 2b or low (n=3) 65.8 +/- 3c field fertility ((ac)p< 0.01; (bc)p< 0.05). There was no difference in embryo cleavage rates for spermatozoa from the high (58 +/- 18%), medium (57 +/-23%) or low (57 +/- 18%) fertility groups. Development to morula or beyond of oocytes fertilized with high (53 +/- 30%) or low (58 +/- 27%) fertility semen tended (P<0.10) to be higher than of those fertilized with medium fertility (33 +/- 28%) semen. This lack of relationship between in vivo fertility and in vitro embryo outcome was consistent across all sperm preparation methods. Therefore, pooled data were used to evaluate the effect of sperm preparation on embryo outcome. There was no difference in embryo cleavage rates between BOEC monolayers (51 +/- 22%), BRLC monolayers (60 +/- 20%) and the cell-free controls (60 +/- 17%). Subsequent embryonic development to compact morula and beyond was higher (P<0.01) with the BRLC monolayer treatment (61 +/- 28%) than with the BOEC monolayers (42 +/- 33%) or control culture (39 +/- 24%). In conclusion, these studies suggest that there is no predictive relationship between bull field fertility (in the ranges evaluated here) and in vitro embryo cleavage or development rates. However, oocytes inseminated with sperm cells co-cultured on BRLC monolayers develop to the morula stage or beyond at a higher rate than oocytes inseminated with spermatozoa from the BOEC or cell-free system.

Animals↗
PubMed1999

Higher-quality human sperm in a sample selectively attach to oviduct (fallopian tube) epithelial cells in vitro.

OBJECTIVE: To determine if sperm attachment to oviduct epithelial cells (OEC) in vitro is selective for higher quality sperm and if the system requires homologous species OEC. DESIGN: Controlled prospective study with outcomes assayed by a technician blind to sperm treatment groups. SETTING: An academic research laboratory. PATIENT(S): Experiment 1: normospermic donors with children (4 donors, 7 ejaculates). Experiment 2: cryopreserved donor samples (4 donors). INTERVENTION(S): Semen collection by masturbation after 48 hours of abstinence. MAIN OUTCOME MEASURE(S): Experiment 1: sperm assays of motility, morphology, membrane integrity, and capacitation status. Experiment 2: sperm chromatin (DNA) integrity and condensation. RESULT(S): Experiment 1: sperm not attaching to OEC had lower motility, more membrane disruptions, and more acrosome reactions than did control sperm. This selectivity was equivalent for sperm in coculture with all OEC types. Experiment 2: sperm attached to OEC had fewer abnormalities in chromatin structure compared with sperm that were not attached. CONCLUSION(S): Selective attachment of functionally superior sperm to OEC is likely important during sperm reservoir formation in vivo and may be exploitable in vitro as a method to isolate high-quality sperm for clinical procedures. Such a system does not require human origin OEC.

Cryopreservation↗
PubMed1998

Human sperm function in co-culture with human, macaque or bovine oviduct epithelial cell monolayers.

Human sperm function was compared in co-culture with monolayers of oviduct epithelial cells (OEC) from three species, human, macaque and bovine. For all species, freeze-thawed and passaged OEC from females in the periovulatory phase were used. OEC cultured on an extracellular matrix (Matrigel) formed a monolayer which supported human sperm attachment to OEC from all three species. Spermatozoa in co-culture with OEC from all three species showed prolonged survival and improved motility characteristics over those cultured in medium alone. This paper describes an efficient, repeatable co-culture system for human spermatozoa which supports sperm attachment to OEC and subsequently improves sperm function over that seen in control medium cultures. Because the improved sperm function in co-culture did not differ significantly between human and bovine OEC for those attributes studied, it is proposed that bovine OEC could be used as an alternative to human OEC in certain human sperm coculture studies. Follicular phase bovine OEC from reproductively normal donors are far more accessible than their human counterparts, thus making this co-culture system more widely available for the study of human spermatozoa-female tract interactions.

Animals↗
PubMed1987

Dopamine autoreceptor agonists: resolution and pharmacological activity of 2,6-diaminotetrahydrobenzothiazole and an aminothiazole analogue of apomorphine.

The enantiomers of the aminothiazole analogues of the known dopaminergic agonists apomorphine (1) and 2-aminohydroxytetralin (2) have been prepared. The absolute configurations of the enantiomers of 2,6-diaminotetrahydrobenzothiazole have been established by X-ray crystallographic analysis. Dopamine (DA) autoreceptor agonist activities of the compounds were evaluated. Testing revealed (-)-5, the S enantiomer, to be the most active compound tested (inhibition of GBL accelerated dopamine synthesis and inhibition of alpha-methyltyrosine-induced decline of DA). In addition (-)-5 does not exhibit stereotyped behavior, suggesting a pronounced selectivity for DA autoreceptors.

Animals↗
PubMed1984

Synthesis and antidepressant activity of 4-aryltetrahydrothieno[2,3-c]pyridine derivatives.

A series of substituted 4-aryltetrahydrothieno[2,3-c]pyridines was prepared by acid-catalyzed cyclization of 1-aryl-2-[(2-thienylmethyl)amino]ethanol derivatives. The compounds were examined for their antidepressant activity, as demonstrated by their ability to inhibit the uptake of norepinephrine (NE) and serotonin (5-HT) and to prevent tetrabenazine-induced ptosis (TBZ) in mice. Significant inhibition of both neurotransmitters is observed for several of the tested compounds, while some of them are selective inhibitors of either NE or 5-HT uptake. Optimal activity is associated with the introduction of lipophilic substituents into the 4-position of the phenyl ring and less lipophilic substituents into the 2-position of the thiophene ring (11, 23). Compound 33 bearing substituents in positions 2 and 6 of the phenyl ring is inactive. This might be a consequence of an out of plane conformation of this compound.

Animals↗
PubMedDate not supplied

Radiographic findings in commercial divers.

The primary method of detecting and recording the changes of dysbaric osteonecrosis is bone and joint radiographic survey. This is not the routine medical and orthopedic roentgen technique, but is a special purpose examination with special technical requirements. The findings indicate selective sites of damage and each should have meticulous study. Fine detail and heavily penetrated radiographs produce needed bony, especially trabecular, and detail and allow the film reviewers to exlude simulating lesions. The incidence of osteonecrosis in American commercial divers has been found to be quite low and considerably less than in other types of compressed gas workers and shell divers. The major radiographic observation is an area of sclerosis, but other changes occur. Juxta-articular lesions can lead to joint damage and are, therefore, potentially disabling. The immediate significance of a lesion in the shaft of a long bone is in its value as a basis for disqualification of an individual for further work in dysbaric environments.

Decompression Sickness↗