Jeffrey J. Aalberg

Quantitative studies of changes in cortical granule number and distribution in the mouse oocyte during meiotic maturation

Cortical granules (CGs) undergo a substantial change in distribution in the mouse oocyte cortex during meiotic maturation. In order to determine the mechanism of their change in distribution near the time of ovulation, CG density, total number per oocyte, and domain areas were quantitated. CGs were visualized microscopically by Lens culinaris agglutinin-biotin and Texas red-strepavidin fluorescence as well as by electron microscopy. Immature germinal vesicle stage (GV) oocytes from adult mice had a continuous cortical localization with some interior granules. Mature oocytes had an asymmetric cortical distribution with a CG-free domain, overlying the meiosis II metaphase spindle, occupying 40% of the cortex. The mean CG densities of the granule-occupied cortex of mature oocytes and the entire cortex of GV oocytes were 43 and 34 CGs/100 micron 2, respectively. The mean total numbers of CGs/oocyte were 4127 (mature) and 7440 (GV), and staining was absent in fertilized oocytes with two pronuclei. Calcium ionophore (A23187)-activated mature oocytes had a mean total number of 1235 CGs, some of which may have been in the process of exocytosis. The first polar body had few CGs, and thus was unlikely to account for the difference in CG number between GV and mature oocytes. The smaller total number and higher density of CGs in mature mouse oocytes suggests that both exocytosis and redistribution are plausible mechanisms for the development of the CG-free domain. Prefertilization exocytosis could account for the locus of sperm penetration which others have reported to occur in the hemisphere opposite the meiotic spindle in the mouse.

The cytoplasmic filamentous network in cultured ovarian granulosa cells

We have utilized a cracking procedure followed by a rotary shadow technique to examine the ultrastructure of cultured ovarian granulosa cells. We have demonstrated that the structures observed are not artifacts of fixation or cracking by generating equivalent images following freezing and deep etching as well as by fixation prior to cracking. The cytoplasm of granulosa cells exhibits a complex cytoskeletal lattice composed of many 40-55 nm filaments. This filamentous network is continuous with the plasma membrane and appears to incorporate all formed elements within the cytoplasm. Filaments are organized in three ways: first, in large bundles, second, in individual filaments that are in direct association with organelles, and third, in a complex branching and anastomosing configuration. S-1 decoration revealed that the predominant filament species is action.

Cytological observations of dissociated rat corpus luteum.

Cells from 15- to 20-day corpora lutea of the pregnant rat can be divided into two classes based on their size and the amount of lipid in the cells and each can be conveniently separated by velocity sedimentation at unit gravity through BSA gradients. One class, which we have designated as D-cells, is about 30 μm in diameter and has numerous lipid inclusions. The other class, referred to as I-cells, varies from about 18 to 25 μm in diameter, contains relatively few lipid droplets, and is more typically steroidogenic in its ultrastructural morphology. In culture the I-cells lose their lipid through an apocrine-like secretory process that results in the removal of most lipid from the cell. In contrast, the D-cell retains its distinct lipid inclusions. The data suggest that our observations are related to continuing cell differentiation during regression of the rat corpus luteum.

Cell surface polarization, tight junctions, and eccentric inner cells characterize human teratocarcinoma embryoid bodies

These studies demonstrate that human embryoid bodies can develop in vitro from human teratocarcinoma cell line HT-H. Furthermore, scanning and transmission electron microscopy reveal that these embryoid bodies resemble the preimplantation embryo more than mouse embryoid bodies which are multilayered. This resemblance is based on (1) an eccentrically located group of inner cells within a thin-walled cyst, (2) apical junction complexes with tight, gap, and desmosomal junctions, as well as intermediate filaments associated with the outer cell layer and not the inner cells, and (3) mitochondria with an extremely dense matrix and few plate-like cristae. Observations of the cell surface indicate that microvilli have a polarized distribution and are localized to two areas (centrally and at intercellular borders) on the apical cell surface of compacted aggregates. Immunosurgery of cystic embryoid bodies indicates that at least half of them are characterized by inner cells enclosed by an impermeable outer cell layer. These developmental similarities with the preimplantation mouse embryo suggest that at least some HT-H teratocarcinoma cells express an embryo-like program for multicellular organization. HT-H embryoid body organization is characteristic of the preimplantation embryo in contrast to the organization reported for mouse embryoid bodies which resembles the postimplantation inner cell mass.

New 5-Factor Modified Frailty Index Using American College of Surgeons NSQIP Data

BACKGROUND The modified frailty index (mFI-11) is a NSQIP-based 11-factor index that has been proven to adequately reflect frailty and predict mortality and morbidity. These 11 factors, made of 16 variables, map to the original 70-item Canada Study of Health and Aging Frailty Index. In past years, certain NSQIP variables have been removed from the database; as of 2015, only 5 of the original 11 factors remained. The predictive power and usefulness of these 5 factors in an index (mFI-5) have not been proven in past literature. The goal of our study was to compare the mFI-5 to the mFI-11 in terms of value and predictive ability for mortality, postoperative infection, and unplanned 30-day readmission. STUDY DESIGN The mFI was calculated by dividing the number of factors present for a patient by the number of available factors for which there were no missing data. Spearmans rho was used to assess correlation between the mFI-5 and mFI-11. Predictive models, using both unadjusted and adjusted logistic regressions, were created for each outcome for 9 surgical sub-specialties using 2012 NSQIP data, the last year all mFI-11 variables existed. RESULTS Correlation between the mFI-5 and mFI-11 was above 0.9 across all surgical specialties except for cardiac and vascular surgery. Adjusted and unadjusted models showed similar c-statistics for mFI-5 and mFI-11, and strong predictive ability for mortality and postoperative complications. CONCLUSIONS The mFI-5 and the mFI-11 are equally effective predictors in all sub-specialties and the mFI-5 is a strong predictor of mortality and postoperative complications. It has credibility for future use to study frailty within the NSQIP database. It also has potential in other databases and for clinical use.