Development of the ovarian surface and associated germ cells in the human fetus

Summary The ovarian surface and associated germ cells have been studied in human fetuses from 12 weeks of age until near term, using light, TEM and SEM techniques. The surface epithelium and related cords proliferate extensively, especially at midterm. The cords in the ovarian cortex appear to be linked with ingrowths from the surface epithelium, and both structures have a common basal lamina. Germ cells are always interspersed among the somatic cells of the surface epithelium and associated cords. These results indicate that both the proliferating cords and surface epithelium may contribute to the formation of early follicles. Furthermore, the occurrence, of elements having some of the features of primitive steroidogenic cells in the regions of cordsurface epithelium continuity, suggests that both structures (surface epithelium and cords) contribute somatic cells, which in addition to becoming granulosa cells, might also contribute to the provision of primitive interstitial cells.Gonocytes tend to migrate through the developing ovarian tissue towards the surface where they become extruded into the peritoneal cavity. This phenomenon might contribute to the reduction in the number of germ cells at birth and parallels the atretic processes within the ovary.     

Immobilized hydroxysteroid dehydrogenases for the transformation of steroids in water--organic solvent systems.

The hydroxysteroid dehydrogenases: beta-HSDH, 20 beta-HSDH, and 3 alpha-HSDH, were immobilized on CNBr-activated Sepharose. The effect of various immobilization conditions on the activity recovery and stability were examined. The presence of cofactor during the immobilization reaction increased the activity recovery (40--60% of the total) and also led to materials highly stable in the presence of organic solvents. For example, beta-HSDH maintained 60% of its original activity two months after continuous use in the water--ethyl-acetate system. Kinetic experiments showed that the increase of the apparent Km values is poor and demonstrated that the organic solvent behaves as a weak inhibitor (ki greater than 0.2M) for the substrate. The immobilized enzymes lyophilized in the presence of sucrose had full activity restored even after several months storage at room temperature. Immobilized hydroxysteroid dehydrogenases were shown to be suitable for preparative transformation of steroids in water--organic solvent systems.     

Interrelationship between oxygen consumption,superoxide anion and hydrogen peroxide formation in phagocytosing guinea pig polymorphonuclear leucocytes

The paper presents an experimental procedure for a simultaneous assay of oxygen consumption, O2- release and H2O2 accumulation at a very early stage of the respiratory burst that is induced by phagocytosis in guinea pig polymorphonuclear leucocytes. The main findings are as follows: (a) The oxygen consumption that is measurable does not correspond to all oxygen that is reduced. The relationship between the actual oxygen consumed and the amount that is reduced depends on the fate of the intermediate products O2- and H2O2. (b) O2- is measurable extracellularly by the reduction of cytochrome c. When cytochrome c oxidizes the extracellular O2-, molecular oxygen is formed. This fact is shown by a decrease of oxygen consumption. The molar ratio between the O2- detected and the oxygen given back is 1. (c) The amount of O2- released from the cells accounts for only a small part of oxygen actually reduced. (d) H2O2 is detectable only in the presence of NaN3. In this condition almost all oxygen consumed is recovered in the form of H2O2. The molar ratio O2/H2O2 is near unity. The amount of H2O2 derived from dismutation of O2- released is only an aliquot of the total H2O2 accumulated. Thus, most of H2O2 is derived from intracellular sources. (e) In the absence of inhibitors of H2O2 degrading reactions, no detectable accumulation of peroxide occurs. Under these conditions, the main part of H2O2 formed is degraded in almost equal amount by catalase and myeloperoxidase, while only a small aliquot is degraded by NaN3 insensitive reactions.     

Three dimensional organization of mammalian adrenal cortex

Summary The adrenal cortex of different mammals was studied by SEM in order to demonstrate its actual three-dimensional organization. In the rat, as well as in the cat and pig, the adrenal cortex appeared as a tunnelled continuum of polyhedral cells arranged in plate-like structures (laminae). This laminar arrangement was more evident in the inner fasciculate and reticular zones where the cortex revealed a striking similarity to liver tissue. The polyhedral cells of all cortical zones possessed regular facets populated by small pits, larger invaginations and numerous microvilli with the exception of very short and smooth areas probably corresponding to attachment zones and/or gap junctions. This cellular architecture produced a labyrinthic system of intercellular channels or lacunae in which the capillaries were suspended.The pericapillary areas of this labyrinth contained microvilli, amorphous material, a delicate net of fibrils and occasional cells. The intercellular compartment of this lacunar system was mainly bordered by numerous microvilli arising from endocrine cells.The luminal surface of the capillary wall showed not only irregularly protruding margins (interpretable as endothelial junctions) but also clearly overlapping and flattened endothelial extensions.In all the animals and areas of the adrenal cortex examined, the endothelial wall was provided with abundant clusters of small fenestrations (about 50 nm in diameter) generally arranged in sieve plates. Larger fenestrations were noted mainly in the fasciculate and reticular zones of the cat and pig and occasionally in the rat.A final point related to the nature and significance of sinusoidal fenestrations was the occurrence of irregularly shaped and intracapillary located cells mainly noted in the deeper zones of the fasciculate and reticular zones of the gland. These elements — possessing the surface characteristics of macrophages — were observed, with their irregular and slender evaginations, in close proximity to the large fenestrations in a manner reminiscent of Kupffer cells within the lumen of liver sinusoids.     

Chemical and physical properties of the human urinary glycoprotein with gastric antisecretory activity.

The chemical and physical properties of the high-molecular-weight glycoprotein (SO20, w = 8S; Ve=Vo on Sephadex G-200) with gastric antisecretory activity extracted from the urine of pregnant women were studied. Gel filtration in the presence of sodium dodecyl sulphate and sodium dodecyl sulphate/polyacrylamide-disc-gel electrophoresis indicated subunit mol.wts. of 16 000 +/- 1500 and 13 000 +/- 1000 respectively. Reaggregation of the subunits and partial recovery of the biological activity were observed on removal of the detergent. The partial C-terminal sequence was found to be Phe-Tyr-Leu-Val-OH, whereas glycine appears to be the N-terminal amino acid. The carbohydrate composition was examined; all galactosamine was found to be O-glycosidically linked to the polypeptide chain.     

Chromosome constitution of in vitro segregated haploid and diploid cells of the mouse

The composition in segregated haploid sets of paternal and maternal chromosomes has been studied in order to verify whether their composition is uniparental of mixed, fixed or variable. Primary cultures where prepared using kidneys from hybrids of strains of Mus musculus in which the parental chromosomes are distinguishable; the maternal set consists of 20 teleocentric chromosomes, the paternal set of 9 metacentric chromosomes, derived by Robertsonian fusion and 2 telocentrics. Applying Seabright's banding technique, an analysis of segregated haploid and diploid cells, which have originated spontaneously through polyploidisation-segregation processes was carried out. It was concluded that the haploid sets have a variable composition of paternal and maternal chromosomes.     

Studies on photosystem I. Characteristics of "310 material" isolated from spinach chloroplasts

Exposure of osmotically shocked chloroplasts to dilute pyridine and sonic oscillation results in the extraction of a small molecular-weight factor. Purification of the factor was accomplished using gel filtration chromatography. Due to the spectral nature of the purified species (λ_max at 310 nm) the factor was named “310 material.”Physiologically, the 310 material was found to inhibit a variety of ferredoxin-dependent photoreductions catalyzed by isolated spinach chloroplasts but stimulate both pseudocyclic photophosporylation and the ferredoxin-independent photoreduction of mammalian cytochrome c. The latter reaction was found to involve, at least partially, the formation of a Superoxide radical. Dark-reduction studies have further established that the 310 material is an autooxidizable electron carrier.Chemically, the 310 material is a water-soluble, low molecular-weight phenolic-type compound; possibly a derivative of coumaric acid. No proteinaceous material is observed in physiologically active preparations of 310 material.Based on these findings, it is concluded that the isolated 310 material acts on the reducing side of Photosystem I at or near the site of reduction of ferredoxin and competes with ferredoxin for the reducing power generated by the Photosystem I reaction center. The exact physiological role of the 310 material in the intact photosynthetic system, however, remains unknown.The similarities between the 310 material and a variety of other factors previously isolated from chloroplasts are discussed.     

Nusinersen treatment and cerebrospinal fluid neurofilaments: An explorative study on Spinal Muscular Atrophy type 3 patients

The antisense oligonucleotide Nusinersen has been recently licensed to treat spinal muscular atrophy (SMA). Since SMA type 3 is characterized by variable phenotype and milder progression, biomarkers of early treatment response are urgently needed. We investigated the cerebrospinal fluid (CSF) concentration of neurofilaments in SMA type 3 patients treated with Nusinersen as a potential biomarker of treatment efficacy. The concentration of phosphorylated neurofilaments heavy chain (pNfH) and light chain (NfL) in the CSF of SMA type 3 patients was evaluated before and after six months since the first Nusinersen administration, performed with commercially available enzyme-linked immunosorbent assay (ELISA) kits. Clinical evaluation of SMA patients was performed with standardized motor function scales. Baseline neurofilament levels in patients were comparable to controls, but significantly decreased after six months of treatment, while motor functions were only marginally ameliorated. No significant correlation was observed between the change in motor functions and that of neurofilaments over time. The reduction of neurofilament levels suggests a possible early biochemical effect of treatment on axonal degeneration, which may precede changes in motor performance. Our study mandates further investigations to assess neurofilaments as a marker of treatment response.