Worcester Foundation for Biomedical Research

About: Worcester Foundation for Biomedical Research is a based out in . It is known for research contribution in the topics: Estrone & Estrogen. The organization has 2195 authors who have published 2646 publications receiving 115809 citations. The organization is also known as: Worcester Foundation for Experimental Biology.

Transplantation of fertilized rabbit ova; the effect on viability of age, in vitro storage period, and storage temperature.

Abstract: IN 1890 and 1897, Heape1 demonstrated the unimportance of somatic tissue to the germ cells by his successful transplantation of rabbit ova to a uterine foster mother. In 1934, Pincus and Enzmann2 obtained normal young by transplanting rabbit ova fertilized or cultured in vitro. Recently3, I reported normal development of ova stored at low temperature, and an optimal temperature for storage. I now have data on the probability of normal development after various treatments.

Superovulation in the immature rat as a possible assay for LH and HCG.

Abstract: It has been demonstrated that superovulation can be used as a quantitative assay for LH and HCG. The use of PMS to induce maximal growth and number of Graafian follicles results in an increase in the magnitude of the response. Treatment with a single dose of PMS failed to induce ovulation; however, injection of high dosages of PMS (10 to 20 I.U.) in immature rats pretreated with PMS caused 20 to 60% of the animals to ovulate. The intravenous injection of both HCG and LH increased the sensitivity of the assay by a factor of 10, as compared to the subcutaneous route of administration. A minimal response was obtained with 0.025 I.U. of HCG and 0.1 µg. of the Armour's standard LH given i.v. In the latter instance this test appeared to be 150-fold more sensitive than the test involving increase in weight of the prostate. A statistical analysis of the assay is given indicating a high precision for the average response. The λm for HCG and LH was 0.21 when given subcutaneously and 0.07 when given i.v. Preliminary...

Androstenedione and testosterone in ovarian venous and peripheral plasma during ovariectomy for breast cancer.

Abstract: Recent evidence has been presented that a major fraction of plasma testosterone in the adult female is derived from peripheral conversion of plasma androstenedione. This conclusion is based upon the demonstration of a considerable conversion ratio (15%) from infused 3H-androstenedione to its conversion product testosterone and the finding of relatively large amounts (0.140 μg/100 ml) of androstenedione in female plasma (1). The back conversion of both dehydroisoandrosterone and testosterone to plasma androstenedione is minimal (2), suggesting that androstenedione must be a major secretory product of the ovary and/or adrenal cortex. It has been calculated that, since no more than one third of testosterone in female plasma can arise from direct secretion, the ratio of androstenedione to testosterone in ovarian venous plasma should be about 20:1 (1).

Outer-arm dynein from trout spermatozoa: substructural organization.

Abstract: Outer-arm dynein purified from trout spermatozoa was disrupted by low-ionic-strength dialysis, and the resulting subunits were separated by sucrose density-gradient centrifugation. The intact 19 S dynein, containing the alpha- an beta-heavy chains, intermediate chains (ICs) 1-5 and light chains (LCs) 1-6, yielded several discrete particles: a 17.5 S adenosine triphosphatase (ATPase) composed of the alpha- and beta-chains ICs 3-5 and LC 1; a 9.5 S complex containing ICs 1 and 2 together with LCs 2, 3, 4, and 6; and a single light chain (LC 5), which sedimented at approximately 4 S. In some experiments, ICs 3-5 also separated from the heavy chain complex and were obtained as a distinct subunit. Further dissociation of the 17.5 S particle yielded a 13.1 S ATPase that contained the beta-heavy chain and ICs 3-5. The polypeptide compositions of the complexes provide new information on the intermolecular associations that occur within dynein. Substructural features of the trout dynein polypeptides also were examined. The heavy chains were subjected to vanadate-mediated photolysis at the V1 sites by irradiation at 365 nm in the presence of Mg2+, ATP, and vanadate. Fragment pairs of relative molecular mass (Mr) 245,000/185,000 and 245,000/170,000 were obtained from the alpha- and beta-heavy chains, respectively. Photolysis of these molecules at their V2 sites, by irradiation in the presence of vanadate and Mn2+, yielded fragments of Mr 160,000/270,000 and 165,000/250,000, respectively. These values confirm that the alpha- and beta-heavy chains have masses of 430,000 and 415,000 daltons, respectively. Immunological analysis using monoclonal antibodies revealed that one intermediate chain from trout dynein (IC 2) contains epitopes present in two different intermediate chains from Chlamydomonas dynein. This indicates that specific sequences within the dynein intermediate chains have been highly conserved throughout evolution.

Flagellar movement of intact and demembranated, reactivated ram spermatozoa.

Abstract: The flagellar movement of intact ejaculated ram sperm, and of demembranated models reactivated with ATP, has been studied using high-speed, high-resolution video microscopy. Intact sperm attached to the coverslip by their heads had an average beat frequency of 20.9 Hz and an average wave amplitude of 20.2 micron. There was little difference in the beat frequency or waveform of these sperm and sperm swimming freely near the coverslip or captured by their heads with a micropipette and held far from the coverslip, indicating that the flagellar waveform of ram sperm is relatively resistant to distortion as a result of immobilization of the head or proximity to a surface. The beat envelope was nearly planar as determined by observations of free-swimming sperm and sperm captured by their head and oriented so they were beating either parallel or perpendicular to the plane of focus. The effect of various conditions for demembranation and reactivation of the sperm were examined. Treatment of sperm with 0.2% Triton X-100 removed most of their plasma membrane. Under optimal conditions, nearly 100% of the demembranated sperm reactivated at MgATP2- concentrations ranging from approximately 4 microM to approximately 20 mM. From approximately 1 mM to approximately 10 mM MgATP2-, their beat pattern closely resembled that of intact sperm; beat frequency depended on MgATP2- concentration. Percent motility was maximal between pH 7.5 and 8.0 and decreased sharply below pH 7.0 and above pH 8.5. The addition of 50 microM cAMP to the reactivation medium had no effect on percent motility or the beat pattern and did not accelerate the initiation of movement.