The differential expression of lamin epitopes during mouse spermatogenesis

The presence of lamin proteins in mouse spermatogenic cells has been examined by using an anti-lamin AC and an anti-lamin B antisera which recognize somatic lamins A and C, and somatic lamin B, respectively. Anti-lamin B binds to the nuclear periphery of all cell types examined, including Sertoli cells, primitive type A spermatogonia, preleptotene, leptotene, zygotene and pachytene spermatocytes, and round spermatids. In sperm nuclei, the antigenic determinants are localized to a narrow domain of the nucleus. However, after removing the perinuclear theca, anti-lamin B localizes to the entire nuclear periphery in a punctate pattern, suggesting that it is binding to determinants previously covered by the theca constituents. On immunoblots anti-lamin B reacts with a ～ 68 kD polypeptide in all germ cells and, to a lesser extent, with four additional polypeptides present only in meiotic and post-meiotic nuclear matrices. Anti-lamin AC also reacts with the perinuclear region of the somatic cells in the testes, in particular, those of the interstitium and also the Sertoli cells of the seminiferous epithelium. In contrast to anti-lamin B, anti-lamin AC does not bind to the germ cells at any stage of spermatogenesis. In addition, nuclear matrix proteins from isolated spermatogenic cells do not bind anti-lamin AC on immunoblots, suggesting the lack of reactivity is not due to the masking of any antigenic sites. These data demonstrate that germ cells contain lamin B throughout spermatogenesis, even during meiosis and spermiogenesis when the nuclear periphery lacks a distinct fibrous lamina. © 1993 Wiley-Liss, Inc.     

Trace amines and Tourette's syndrome

There has been considerable interest in recent years in possible neurochemical abnormalities in Tourette's Syndrome (TS). In studies combining neuropsychological and neurochemical measurements, we have investigated the possible roles of trace amines in this disorder. Urinary levels of free -phenylethylamine (PEA) and plasma levels of its precursor amino acid phenylalanine were decreased in TS patients when compared to values in normal children. These urinary PEA levels in TS patients were inversely related to several scores from the Tourette's Syndrome Global Scale (TSGS). Further investigation of the group of subjects with low urinary PEA indicated that they also had low levels of MHPG, normetanephrine, 5-HT andm- andp-tyramine. Patients with low PEA were also compared on an extensive battery of neuropsychological measures and observed to perform significantly worse than TS patients with normal urinary PEA levels. Biochemical measurements also suggest a possible abnormality in tryptamine turnover in TS since urinary levels of indole-3-acetic acid (IAA; the acid metabolite of tryptamine) are significantly lower in TS patients than in normal controls.     

Mouse blastocyst immunosurgery with commercial antiserum to mouse erythrocytes

Summary Immunosurgery is a useful technique for the isolation of inner cell masses from murine blastocysts. Conventionally, rabbit antisera made ad hoc against murine splenic or fetal cells or fibroblasts have been used as antibody sources. We investigated the feasibility of using commercially available rabbit antiserum to murine erythrocytes (anti-RBC) and compared it with rabbit antiserum generated ad hoc to murine L-cells (anti-L-cell). Our results indicate that anti-RBC is at least as effective as anti-L-cell serum for the immunosurgical isolation of inner cell masses, which became either miniblastocysts (later forming outgrowths) or embryoid bodies (undergoing ectoderm-endodermlike differentiation within 48 h). Because anti-RBC is commercially available, the technical modification described herein increases the accessibility of the immunosurgical protocol for the isolation of murine inner cell masses.     

From aquatic science to ecosystem health: a philosophical perspective

The development of an ecosystem (social, economic, environmental) approach to water management is traced from its origins in the Great Lakes of North America. The focus on health and integrity of ecosystems is an outgrowth of the Lamarckian concept of The Biosphere as a global system of matter, life, and mind. The driving forces behind the development of an ecosystem approach have been negative feedback from excessive demotechnic growth and faith that we can maintain a healthy relationship with Mother Earth.     

High-performance liquid chromatographic determination of spectinomycin in swine, calf and chicken plasma

A rapid clean-up procedure based on ion-pair solid-phase extraction (SPE) for the high-performance liquid chromatographic (HPLC) determination of spectinomycin in swine, calf and chicken plasma at a limit of detection of 50 ng/ml is described. After dilution with water and adjustment of the pH to approximately 5.6, the plasma is applied to a high-hydrophobic C₁₈ SPE column treated with sodium dioctylsulphosuccinate. Spectinomycin is eluted with methanol and derivatized with 2-naphthalene sulphonyl chloride prior to chromatography. The HPLC set-up consists of a dual-column system using two Chromspher silica columns and dichloromethane—acetonitrile—ethyl acetate—acetic acid, in different ratios, as mobile phases. Detection is performed at 250 nm. Quantification is carried out using external standards prepared in blank cleaned plasma. Mean recoveries were 83 ± 3% (n = 5), 93 ± 6% (n = 5) and 92 ± 6% (n = 6) for swine, calf and chicken plasma, respectively, at the 0.1 μg/ml level.