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There is evidence that the mammalian ejaculate contains distinct subpopulations of spermatozoa and that the variability among these subpopulations may have adaptive and functional significance. This study investigated the precision, reproducibility and operating characteristics of a novel automated sperm morphology analysis system, the Hobson Morphology package, establishing protocols to investigate boar sperm characteristics. Five ejaculates were collected from each of three boars from different genetic lines: Landrace-Meishan introgression, Sireline Large White and Damline Large White. Five semen smears per ejaculate were stained with haematoxylin and eosin. Two hundred spermatozoa per slide were analysed. No significant differences among slides within an ejaculate were detected for sperm tail length (P = 0.770), head width (P = 0.736) and head length (P = 0.615), indicating that both staining and morphology analysis were precise and reproducible. Among the boars, variability in tail length was detected (P = 0.001), but head width (P = 0.114) and length (P = 0.069) did not differ significantly. Multivariate pattern analysis (PATN computer package) highlighted three sub-populations of spermatozoa objectively on the basis of tail length (10.0-22.0 microns, 22.1-73.0 microns and 73.1-130.0 microns). The Landrace-Meishan introgression boar possessed more spermatozoa (P < 0.0001) with tails 73.1-130 microns long. Subsequent analysis of morphology parameters in a pure-bred Meishan boar showed similar measurements for tail length (mean +/- SD; 66.36 +/- 24.70 microns) to the Landrace-Meishan introgression boar (mean +/- SD; 67.09 +/- 21.80 microns). Sperm subpopulations originate during spermatogenesis, when heterogeneous genotypic effects determine the structural features of spermatozoa. The findings of this study confirm that tail length differs between boars and that subpopulations of spermatozoa can be detected within a single ejaculate.

The decision to provide a child with a cochlear implant is quite complex, as it must include consideration not only of the implant itself but also of the habilitative services necessary following the surgical procedure. To provide a systematic means of selecting hearing-impaired children for cochlear implants, a team at Children's Hearing Institute, Manhattan Eye, Ear and Throat Hospital, developed the Children's Implant Profile (ChIP). There is no one profile of a successful implant user--at least 11 factors appear to contribute to successful implantation. In the ChIP, each factor is evaluated on a three-point scale: (1) no concern, (2) mild-to-moderate concern, and (3) great concern. A profile showing "no concern" on all 11 factors denotes clear acceptability of the child as an implant candidate. A profile including several ratings in the "mild-to-moderate concern" category suggests a need for further study to determine if improvements could be made in projected outcomes before initiating surgical procedures. Finally, ratings of "great concern," especially on more than one factor, indicate a very limited probability of successful implant outcomes, at least at the time of evaluation. A case study is presented to demonstrate the relationship between the evaluated factors and to show how the profile is used to address and remedy areas of concern.

Angiotensin III is formed by removal of the N-terminal Asp residue of angiotensin II in a reaction catalyzed by glutamyl aminopeptidase (aminopeptidase A EC 3.4.11.7). Thiol derivatives of glutamate and aspartate in which the alpha-COOH group was replaced by -CH2SH were synthesized as inhibitors of glutamyl aminopeptidase. Glutamate thiol was a potent inhibitor of glutamyl aminopeptidase (Ki = 4 x 10(-7) M) but even more potently inhibited microsomal alanyl aminopeptidase (Ki = 2.5 x 10(-7) M). Aspartate thiol (beta-homocysteine) was a less potent but more selective inhibitor of glutamyl aminopeptidase (glutamyl aminopeptidase: Ki = 1.2 x 10(-6) M; microsomal alanyl aminopeptidase: Ki = 7.5 x 10(-6) M). Neither compound inhibited cytosolic leucyl aminopeptidase. Aspartate thiol blocked the conversion of angiotensin II to angiotensin III. These derivatives are more selective than amastatin and may be of value in studies probing the biological significance of angiotensin III.

A principal mechanism of action of the clinical antitumor drugs etoposide (1) and teniposide (2) is the inhibition of catalytic activity of type II DNA topoisomerase and concurrent enzyme-mediated production of lethal DNA strand breaks. Substitution of the glycosidic moiety of 1 or 2 by ester and ethers, as well as the esterification and etherification of alpha-peltatin (4) including its glucosidic ethylidene and thenylidene cyclic acetals (25 and 26), has afforded compounds of much less activity than that of 1. The in vitro cytotoxicity (KB) appears to have no correlation with the inhibitory activity of the human DNA topoisomerase II.

A method is described for the determination of pentachlorophenol (PCP) in gelatin. The method employs acid and heat to hydrolyze the gelatin matrix, a base partition and wash for separation and cleanup, and a reacidification and extraction with hexane for direct determination of PCP, without preparation of a derivative, using gas chromatography (GC) with a 1% SP- 124ODA liquid phase and a 63Ni electron capture detector. Recoveries averaged 106% for fortifications between 0.02 and 1.0 ppm. The limit of quantitation is 20 ppb. The limit of detection is 4-6 ppb. The method, which has undergone a successful intralaboratory trial, is simple and rapid, and requires only general laboratory reagents and equipment. GC of the acetate derivative of PCP is used for confirmation of identity.

It has been reported that the action of etoposide (VP-16) (14) as an antitumor agent is mediated through its interaction with DNA topoisomerase II which results in DNA breakage inside the cell. In order to understand the mechanism of action as well as structure-activity relationships of 14, several novel, synthetic and some naturally occurring analogues related to podophyllotoxin were examined for inhibition of the DNA topoisomerase II activity. Compound 2 exhibited enhanced activity and compound 5 slightly diminished activity relative to 14. A 4 beta-substituted ether at the C ring and O-demethylation at the E ring appear to enhance activity.

A series of analogues of etoposide, the C-4 amino- and alkylamino-substituted 4'-demethyl-epipodophyllotoxins, have been synthesized and studied for their activity to inhibit type II human DNA topoisomerase as well as their activity in causing cellular protein-linked DNA breakage. Substitution of the glycosidic moiety of 1 by a 2"-hydroxyethylamino or 2"-methoxyethylamino chain at the C-4 beta position resulted in potent inhibitors of the human DNA topoisomerase II. This inhibitory activity correlates reasonably well with their activity in causing protein-linked DNA breakage in KB cells. The in vitro cytotoxicity (KB) appears to have no correlation with the inhibitory activity of the human DNA topoisomerase II.