Zinc is sufficiently abundant within mammalian sperm nuclei to bind stoichiometrically with protamine 2.

Although studies have demonstrated that zinc can bind to sperm nuclear proteins, specifically protamine 2, it has not been shown that the metal is sufficiently abundant inside the sperm nucleus to interact stoichiometrically with these proteins. In this study proton-induced X-ray emission (PIXE) has been used to measure the amount of sulfur and zinc within the nuclei of individual sperm cells to infer the stoichiometry of zinc binding to protamine 2 in six species of mammal: bull, chinchilla, stallion, hamster, human, and mouse (protamine 2 comprises from 0% (bull) to 67% (mouse) of the protamine present in the sperm of these animals). Using the sulfur mass and electrophoretic data on the relative proportion of protamine 1 and protamine 2 in the sperm chromatin of these species, the protamine 1, protamine 2, and total protamine contents within each species sperm nuclei have been determined. The PIXE measurements reveal that the zinc content of the sperm nucleus varies proportionately with the protamine 2 content of sperm chromatin. PIXE analyses of hamster protamines extracted under conditions that appear to at least partially preserve zinc binding also confirm that the majority of the metal is bound to protamine. In five of the species examined, sufficient zinc is present for each protamine 2 molecule to bind one zinc. The results obtained for chinchilla sperm, conversely, indicate the chinchilla protamine 2 molecule may interact differently with zinc. Chinchilla sperm only contain enough zinc for one atom to be bound to two protamine 2 molecules.

Noninvasive glucose determination by oscillating thermal gradient spectrometry.

BACKGROUND: Several noninvasive measurement approaches for the determination of blood glucose levels have been pursued over the past two decades. There is worldwide recognition that an unobtrusive and noninvasive measurement technique will better enable the patient with diabetes to obtain information for appropriate disease management. Many challenges have so far prevented any noninvasive technology from meeting the requirements. METHOD: In this article, we describe a novel optical technology that when applied to the human body, provides both the sensitivity and the specificity required for acceptance. For human tissue, specific wavelength bands in the mid- infrared (IR) region offer predominantly single component absorbances and thus, provide the basis for the required specificity of an in vivo determination of glucose. It is highly desirable to utilize these bands for the development of a practical spectroscopic technique. The use of mid-IR absorbance bands requires a methodology that accommodates relatively short optical transmission pathlengths. Thermal gradient spectroscopy is one suitable methodology. We describe the utilization of optical phenomena, which arise during a thermal gradient, in the development of a practical instrument. The prototype apparatus is described and results obtained from aqueous samples and tissue phantom studies are presented. Furthermore, a mathematical derivation is presented in the Appendix, that defines the relationship between the optical signals produced and the properties of the tissue under analysis.

Nucleoli in low-grade prostate adenocarcinoma and adenosis.

This study compares the frequency of prominent nucleoli in low-grade adenocarcinoma with that of its frequent mimicker, adenosis. One hundred thirteen transurethral resection specimens of stage A purely low-grade adenocarcinoma (only Gleason score 1 or 2) were evaluated. Eighteen cases of adenosis were evaluated for comparison. Prominent nucleoli were defined as those with a greatest dimension more than 1.6 microns as measured with an ocular micrometer. The frequency of prominent nucleoli in each focus was estimated as (1) none, (2) rare (< 5% of epithelial cells), (3) occasional (5% to 50% of epithelial cells), and (4) frequent (> 50% of epithelial cells). Twenty percent of cases of adenocarcinoma had, at most, rare prominent nucleoli. Eight percent of adenocarcinoma cases had no prominent nucleoli. Twenty-eight percent of cases of adenosis had at least one focus of occasional or frequent prominent nucleoli. We conclude that a small but significant subset of low-grade prostatic adenocarcinomas lack prominent nucleoli and, likewise, a significant proportion of cases of adenosis have prominent nucleoli. Like many other histologic features of these lesions, we feel there is a spectrum of frequency of prominent nucleoli, with overlap between the two. The significance of nucleoli should be taken in context with other cytologic and architectural features characteristic of prostatic adenocarcinoma and adenosis. In difficult cases basal cell-specific immunohistochemical stains may be helpful.

Evaluation of radical prostatectomy specimens. A comparative analysis of sampling methods.

We evaluated 104 radical prostatectomies for clinical stage B (n = 93) and stage A (n = 11) prostate cancer. Seven (8%) stage B cases had no gross cancer. By submitting only gross stage B cancer along with standard sections of proximal and distal margins, base of seminal vesicles, and most apical section (next to distal margin), we identified 91% of capsular penetration and 96% of positive margins as compared with identification by complete microscopic examination. Although this method identified 100% capsular penetration and positive margins in stage A cases, 28% of all the cases were grossly normal. Stage A tumor was often difficult to identify because of its heterogeneous location, its gross similarity to nodular hyperplasia, and the confounding presence of post-transurethral resection scarring. In 98% of all stages B and A cases, this method identified to within 1, the Gleason sum of the totally embedded radical prostatectomy. Using this sampling method, key pathologic parameters were identified with an average of 13 blocks (range 7-36) as compared with totally embedding the prostate, using an average of 42 blocks (range 21-81). Based on our study and our understanding of stages A and B disease, we recommend that in grossly normal glands, alternate posterior sections (stage B) and alternate entire sections (stage A) be submitted. Use of this sampling method will achieve a greater uniformity in the processing of specimens and a more accurate pathologic analysis of radical prostatectomy specimens.