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W F Neiss

Publications and source records attributed to W F Neiss.

64 records · Page 4Linked to original sources
PubMed1984

Electron staining of the cell surface coat by osmium-low ferrocyanide.

In aldehyde-fixed liver and renal cortex of rat and mouse several variations of postfixation with osmium tetroxide plus potassium ferrocyanide ( FeII ) were tried. Depending on the ferrocyanide concentration different staining patterns were observed in TEM. -Osmium-High Ferrocyanide [40 mM (approximately 1%) OsO4 + 36 mM (approximately 1.5%) FeII , pH 10.4], stains membranes and glycogen. Cytoplasmic ground substance, mitochondrial matrices and chromatin are partially extracted, cell surface coats remain unstained. Membrane contrast, but extraction too, are higher with solutions containing cacodylate- than phosphate-buffer. -Osmium-Low Ferrocyanide [40 mM (approximately 1%) OsO4 + 2 mM (approximately 0.08%) FeII , pH 7.4], stains cell surface coats and basal laminae, but not glycogen, except for special cases. The trilaminar structure of membranes is poorly delineated. Signs of cytoplasmic extraction are not visible. The surface coat staining is stronger and more widespread with solutions containing phosphate- instead of cacodylate-buffer; it is enhanced by section staining with lead citrate. The cell surface coat stain does not traverse tight junctions nor permeate membranes.

Animals↗
PubMed1984

A coat of glycoconjugates on the inner surface of the lysosomal membrane in the rat kidney.

After perfusion fixation of the rat kidney with glutaraldehyde, and postfixation of the renal cortex with osmium-low ferrocyanide (40 mM OsO4 +6 mM K4Fe(CN)6 in 0.135 M phosphate buffer, pH 8.0), secondary lysosomes of proximal tubule cells carry a coat of electron dense material on the inner surface of the lysosomal membrane. This coat separates matrix and membrane of lysosomes, and corresponds in location and width to the electron translucent halo of conventionally processed lysosomes in TEM. The material which forms the coat, is stained by phosphotungstic acid at pH 0.3, and by periodic acid - thiocarbohydrazide - silver proteinate more intensively than the cell surface coat of the same cell; it contains a high concentration of hydroxyl, vicinal-glycol and alpha-aminoalcohol groups.

Animals↗
PubMed1983

Extraction of osmium-containing lipids by section staining for TEM.

Postfixation with osmium-ferrocyanide or OSO4 renders lipid droplets in rat liver and kidney homogeneously electron dense without additional section staining. In sections of the same block that have been single stained by uranyl acetate or lead citrate, lipid droplets show a more electron translucent center surrounded by a dense rim. In sections double stained with uranyl acetate and lead citrate, lipid droplets frequently appear as empty vacuoles, from which the electron dense content has been completely extracted.

Animals↗
PubMed1983

The electron density of light and dark lysosomes in the proximal convoluted tubule of the rat kidney.

The present paper deals with the electron density of the lysosomal matrices in the renal proximal-convoluted-tubule cells of Wistar rats (20-60 days of age). Its purpose was to determine which physicochemical factors influence the electron density of lysosomes, and how their electron density is affected by various methods of fixation.--3 types of lysosomes can be distinguished in the proximal-convoluted-tubule cell; namely light, intermediate and dark lysosomes, which have an electron density lower, equal to or higher than the surrounding cytoplasm. All 3 types of lysosomes were invariably present after all methods of fixation tested. Light, intermediate and dark lysosomes differ in several respects. Staining intensity with uranyl acetate, lead citrate and potassium permanganate, osmiophilia, basophilia (in semithin sections) and --probably most importantly--the physical mass density of the lysosomal matrix are all low in light lysosomes, higher in intermediate lysosomes and highest in dark lysosomes. Light, intermediate and dark lysosomes of the proximal convoluted tubule do not form discrete classes, but one continuous spectrum of lysosomes of increasing electron density.

Animals↗
PubMed1982

[Ossification of the sheep skeleton].

The ossification of sheep skeleton was investigated from 4th to 10th week of gravidity by means of cryostat and paraffin serial sections, cleared specimens and grenz ray radiographs. Significant decalcification occurred in paraffin sections and cleared specimens. These artifacts were not observed in cryostat sections and grenz ray radiographs of silver impregnated specimens. The Clavicle being the oldest bone of sheep embryo contains calcium deposits for the first time at a crown rump length (CRL) of 20.5 mm. During the further development of limbs Radius (at 28 mm CRL) and Tibia (at 30 mm CRL) ossify slightly earlier than Humerus and Ulna or Femur and Fibula respectively. The ossification of the diaphyses of all parallel pairs of long bones starts always at the median sides of these bones which are iuxtaposed to each other. The ossification of the vertebral column starts at C2 (vertebral arch, 45 mm CRL) and at Th1 (vertebral body, 49 mm CRL). During the course of course of development (up to 68 mm CRL) arches and bodies ossify at the same time descending and ascending from a cervical and a lumbar starting point in the vertebral column. The ossification of ribs starts at one point and spreads evenly in all directions over the cartilagineous primordium of the thoracic wall. Mandible and Maxilla are the first bones of skull to appear. They ossify with particular regularity at a CRL of 26.5 mm or 27 mm respectively. During the further development of skull the sequence of ossification of Parietal bone and Temporal bone and of Nasal bone and Zygomatic bone varies. The hypothesis is suggested that the observed variations in the development of sheep skeleton are caused by racial differences of the material investigated.

Animals↗
PubMed1981

The postnatal development of the rat kidney, with special reference to the chemodifferentiation of the proximal tubule.

New nephron anlages appear in the renal cortex up to the 4th postnatal day (PD). The last anlages to be formed develop into functional nephrons by PD 10, and the cortex appears mature at PD 12 after formation of the cortex corticis. The renal medulla develops by the longitudinal growth of loops of Henle and collecting ducts. The immature medulla cannot be divided into different zones and corresponds structurally to the later inner stripe of the outer zone. The inner zone is formed by PD 8, and the outer stripe of the outer zone by PD 12. The renal medulla is mature at PD 21. From the start of its development, the renal proximal tubule consists of the pars convoluta and pars recta. In both parts the formation of the brush border is accompanied by the simultaneous appearance of brush border enzymes (alkaline phosphatase, gamma-glutamyltranspeptidase, dipeptidylaminopeptidase IV) and lysosomal enzymes (acid phosphatase, acid beta-galactosidase, N-acetylglucosaminidase, dipeptidylaminopeptidase II) over the full length of the proximal tubule. During the course of proximal tubule maturation, however, the lysosomal enzyme activities decline in the pass convoluta (with constant brush border enzyme activities), while the brush border enzyme activities increase in the pars recta (with constant lysosomal enzyme activities). The two parts further differ in that they exhibit different lysosomal patterns from the outset, the pars convoluta containing numerous large, highly enzyme-active lysosomes arranged in groups, and the pars recta containing only a few very small lysosomes with low enzyme activity. Thus, even in the newborn rat, the lysosomal pattern of the pars recta already corresponds to that of the mature S3 segment. The S1 and S2 segments of the pars convoluta first differentiate between PD 10 and 21, as the groups of large lysosomes are progressively broken up and the extent of the lysosomal apparatus is diminished, this proceeding in a retrograde direction from the end of the immature pars convoluta.

Aging↗
PubMedDate not supplied

Slow axonal regrowth but extreme hyperinnervation of target muscle after suture of the facial nerve in aged rats.

Unilateral transection and suture of the facial nerve was performed in 60 old rats (20 months of age). The time course of mimetic reinnervation was studied by counting all retrogradely labeled motoneurons in the facial nucleus after injection of HRP into the whiskerpad muscles for 14-112 days post operation. The comparison between these neuron counts and data for young rats yielded four conclusions. First, the qualitative equivalent of the phenomenon "misdirected reinnervation" in aged rats was the same as in young adults: HRP-labeled motoneurons were scattered throughout the facial nucleus lacking myotopic organization from 18 until 112 days post operation. Second, no age-related loss of motoneurons was detected. Third, the axonal regrowth was delayed in aged rats. Fourth, the postoperative hyperinnervation (the projection of more motoneurons into a muscle than under normal conditions, i.e., the quantitative aspect of misdirected reinnervation) was more than two times higher than in young rats. These data may provide reasonable explanations for the poor functional recovery after reconstructive surgery on the facial nerve in old patients.

Aging↗