The Z-chromosome is involved in the regulation of H-W (H-Y) antigen gene expression in Xenopus.

H-W (H-Y) antigen was investigated in diploid, triploid, and tetraploid Xenopus hybrids. These hybrids differ from each other with respect to their sex chromosome constitution-they all have a single W chromosome but one to three Z chromosomes. The H-W antigen concentration is reduced with increasing numbers of Z chromosomes.

Silver staining of nucleolus organizer regions during human spermatogenesis.

The sizes and staining intensities of the nucleolus organizer regions (NORs) in human spermatogenesis were studied qualitatively and quantitatively with the silver (Ag)-staining technique. The Ag-stainability of the NORs is a measure of the transcriptional activity of the ribosomal RNA genes. Ag-stained NORs are present during the whole period of meiotic prophase up to pachytene and totally absent in the two meiotic metaphases.

Proacrosin/acrosin activity during spermiohistogenesis of the bull.

Acrosin and its zymogen form, proacrosin, were extracted from early and late spermatids, from ejaculated and epididymal spermatozoa (caput, corpus, and cauda) of the bull. Activity of proacrosin/acrosin and the time course of proacrosin activation were studied. It turned out that proacrosin/acrosin activity is first demonstrable in haploid spermatids, increases during spermiohistogenesis in the testis, and remains nearly constant in epididymal and ejaculated spermatozoa.

Acrosin and the acrosome in human spermatogenesis.

Using the indirect immunofluorescent staining technique, the developmental patterns of (pro) acrosin and the outer acrosomal membrane were studied in human spermatogenesis. Specific antibodies against purified acrosin and outer acrosomal membranes from boar spermatozoa were raised in the rabbit and were found to crossreact with (pro)acrosin and outer acrosomal membrane from human spermatogenic cells. It was concluded that (pro)acrosin as well as the molecules building up the outer acrosomal membrane have been highly conserved during mammalian evolution.

Acrosin in the spermiohistogenesis of mammals.

Using the indirect immunofluorescence staining technique, the developmental pattern of acrosin during spermatogenesis of boar, ram, rabbit, mouse, rat, and Russian hamster (Phodopus sungorus) was studied. Specific antibodies against purified boar acrosin raised in rabbits cross-reacted with the acrosin of all species investigated thus suggesting that the antigenic determinants of the acrosin molecule cross-reacting with anti-boar acrosin antiserum have been highly conserved in mammalian evolution. During spermatogenesis acrosin was first demonstrable in haploid spermatids and increased in the course of the differentiation of the spermatids to spermatozoa.

A direct demonstration of somatically paired heterochromatin of human chromosomes.

Human lymphocyte cultures were treated with different concentrations of 5-azacytidine for various lengths of time. This cytosine analog induces very distinct undercondensation in the heterochromatin of chromosomes 1, 9, 15, 16, and Y if applied in low doses during the last hours of culture. These regions are further distinguished by their intense distamycin A/DAPI-staining and highly methylated DNA.

Quantification of acute phase reactants after muscle biopsy.

Blood concentrations of six acute phase reactants (ESR, neutrophil count, fibrinogen, haptoglobin, alpha 1-antitrypsin, and ferritin), parameters of muscle necrosis (myoglobin, CK, ALT, and AST) as well as hemopexin, iron, and TIBC were determined before and for 7 consecutive days after muscle biopsy in patients and in a control group. A muscle biopsy was chosen as a standardized surgical procedure that induces a mild transient inflammatory response. After muscle biopsy, a significant increase occurred in five (ESR, neutrophil count, fibrinogen, haptoglobin, and alpha 1-antitrypsin) of the six acute phase reactants.

Single cholinergic receptor channel currents in cultured human muscle.

Single cholinergic channel currents were recorded in adult human muscle tissue culture. The agonists suberyldicholine and carbamylcholine produce channels with the same conductance as channels produced by acetylcholine but with different closing kinetics. The antagonist tubocurarine, alone or mixed with suberyldicholine, activates channels which close very rapidly.

Effect of heme administration on hemopexin metabolism in the rhesus monkey.

Clinical conditions such as hemolytic anemias and certain neuromuscular diseases in which serum hemopexin levels are either increased or decreased were simulated in rhesus monkeys by administering heme intravenously daily at three dose levels over a period of 10 days. At the lower dose of heme (0.02 to 0.

Demonstration of 2',3'-cyclic nucleotide 3'-phosphohydrolase in cultured human Schwann cells.

Schwann cell cultures were established from adult human sural nerve biopsies. 2'3'-Cyclic nucleotide 3'-phosphohydrolase (CNPase) activity was estimated in the homogenates of those cells by a sensitive isotope assay using [3H]2',3'-cyclic AMP as substrate. A high level of CNPase activity was observed in cultured Schwann cells, whereas cultured human muscle and skin fibroblasts contained negligible levels of CNPase activity.

Left ventricular relaxation, mitral valve prolapse, and intracardiac conduction in myotonia atrophica: assessment by digitized echocardiography and noninvasive His bundle recording.

Myotonia atrophica, a neuromuscular disease marked by autosomal dominant transmission and delayed relaxation of skeletal muscle, has been associated with cardiac failure, conduction abnormality and mitral prolapse (MVP). In order to determine the relaxation rate of cardiac muscle, left ventricular (LV) size and function, and the presence of MVP, 30 patients with myotonia atrophica were studied using digitized M-mode echocardiography (MME). Intracardiac conduction intervals were determined by noninvasive His bundle recording (HBR) from surface electrodes using a high-resolution, R-wave triggered, signal averaging computer.

Myosin isoenzymes in cultured human muscle.

Cultured human muscle grown aneurally and innervated by the ventral part of fetal rat spinal cord was examined using antimyosin antibodies specific for isomyosins from fast and slow mammalian skeletal muscle. Cultured muscle displayed multiple reactivity with antibodies against both types of myosins, with no evident compartmentalization of different forms of myosin into different muscle cells, such as seen in adult muscle. Innervation of cultured muscle resulted in better growth and longer survival of cultured muscle and its more advanced maturation, with a larger number of cross-striated muscle fibers.

Evolutionary conservation of a common pattern of activity of nucleolus organizers during spermatogenesis in vertebrates.

The patterns of activity of the nucleolus organizer regions (NORs) in the spermatogeneses of ten species of all non-mammalian classes of vertebrates and one species of the cephalochordates were investigated with the silver (Ag)-staining technique. The Ag-stainability of the NORs is a measure of the transcriptional activity of the ribosomal RNA genes. In all species, there is a very similar pattern of NOR-activity in the various stages of spermatogenesis.

Depth of information in photoelectron microscopy.

The depth of information is defined as the distance below the surface of a specimen from which information is contributed at a specific resolution. A simplified model of photoemission is used to explore the relationship between electron escape depths and depth of information in photoelectron microscopy (PEM or photoemission electron microscopy). The depth of information is equal to the escape depth when the escape depth is small relative to the instrument resolution.

Biochemical and morphological effects of 20,25-diazacholesterol on cultured muscle cells.

Effects of 20,25-diazacholesterol (DAC), a myotonia-inducing drug, were evaluated on certain biochemical and morphological properties of embryonic rat muscle cells grown in tissue culture. During DAC treatment, muscle fibers exhibited spontaneous contractions that changed from coarse twitches to finer fibrillation movements, The ultrastructural alterations produced by DAC were smeared Z-lines, disorganized myofibrils, occasional honeycomb appearance of membranes and large vacuoles connected to zipper-like structures. Biochemically, a microsomal fraction prepared from DAC-treated cells (compared to that of normal cells) showed a 30-45 per cent decrease in the isoproterenol-enhanced and the NaF-enhanced adenylate cyclase activity.

Patterns of cyclic AMP phosphodiesterases in the rat pineal gland: sex differences in diurnal rhythmicity.

Rat pineal cyclic AMP (cAMP) phosphodiesterases (PDEs) were studied during male development and in adult females by means of gel electrophoresis, kinetic analysis, and diurnal activity measurements. In both male and female rats, two molecular forms of PDE coexisted. In neonatal-infantile males (birth to day 20 of age) a third isozyme was detected.

Lysosomal abnormalities in cultured schwann cells from a patient with peripheral neuropathy and continuous muscle fiber activity.

Schwann cell cultures were established from a sural nerve containing large membrane-bound vacuoles in its Schwann cells, obtained from a patient with neuropathy and continuous muscle fiber activity. Cultured Schwann cells contained many large membrane-bound vacuoles, presumably lysosomes, resembling those present in the biopsied nerve. The acid phosphatase reaction was excessive in the patient's cultured Schwann cells but practically negative in normal cultured Schwann cells.