Effects of dehydration and arginine vasopressin infusions on the production of milk and the morphology of the goat udder

1990 ◽  
Vol 57 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Kristina Dahlborn ◽  
Jamal Hossaini Hilali ◽  
Heriberto Rodriguez-Martinez

SummaryLactating goats were subjected to dehydration and to infusions of arginine vasopressin (AVP). Dehydration decreased milk production significantly but no changes were observed on the day of AVP infusion. The levels of AVP in plasma reached the same magnitude during both experimental procedures. AVP-immunoreactivity was immunocytochemically detected by light (peroxidase-antiperoxidase technique) and electron microscopy (immuno-Au technique on to glutaraldehyde-fixed, resin-embedded sections) in the mammary gland but not in the control experiments. In addition the cisternae of the rough endoplasmic reticulum in the secretory alveolar cells underwent significant swelling in response to the experimental procedures.

Author(s):  
R. A. Turner ◽  
A. E. Rodin ◽  
D. K. Roberts

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.


1990 ◽  
Vol 68 (7) ◽  
pp. 1454-1467 ◽  
Author(s):  
K. M. Fry ◽  
S. B. McIver

Light and electron microscopy were used to observe development of the lateral palatal brush in Aedes aegypti (L.) larvae. Development was sampled at 4-h intervals from second- to third-instar ecdyses. Immediately after second-instar ecdysis, the epidermis apolyses from newly deposited cuticle in the lateral palatal pennicular area to form an extensive extracellular cavity into which the fourth-instar lateral palatal brush filaments grow as cytoplasmic extensions. On reaching their final length, the filaments deposit cuticulin, inner epicuticle, and procuticle sequentially on their outer surfaces. The lateral palatal crossbars, on which the lateral palatal brush filaments insert, form after filament development is complete. At the beginning of development, the organelles involved in plasma membrane and cuticle production are located at the base and middle of the cells. As the filament rudiments grow, most rough endoplasmic reticulum, mitochondria, and Golgi apparatus move to the apex of the epidermal cells and into the filament rudiments. After formation of the lateral palatal brush filaments and lateral palatal crossbars, extensive organelle breakdown occurs. Lateral palatal brush formation is unusual in that no digestion and resorption of old endocuticle occurs prior to deposition of new cuticle. No mucopolysaccharide secretion by the lateral palatal brush epidermis was observed, nor were muscle fibres observed to attach to the lateral palatal crossbars, as has been suggested by other workers.


2001 ◽  
Vol 84 (1) ◽  
pp. 241-255 ◽  
Author(s):  
B.J. Bequette ◽  
C.E. Kyle ◽  
L.A. Crompton ◽  
V. Buchan ◽  
M.D. Hanigan

2000 ◽  
Vol 83 (4) ◽  
pp. 765-775 ◽  
Author(s):  
B.J. Bequette ◽  
M.D. Hanigan ◽  
A.G. Calder ◽  
C.K. Reynolds ◽  
G.E. Lobley ◽  
...  

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
L Hille ◽  
T Nuehrenberg ◽  
M Lenz ◽  
A Vlachos ◽  
D Trenk

Abstract Reticulated platelets (RP) are the youngest circulating platelets in blood. Compared to older platelets, RP represent a highly active prothrombotic platelet population associated with an increased risk for cardiovascular events, mortality and impaired response to antiplatelet drugs compared to older platelets (non-RP). The underlying mechanisms for these characteristics of RP are so far poorly understood. This study aimed to characterize ultrastructural properties of RP and non-RP by transmission electron microscopy (TEM) of FACS-sorted human platelets using a novel staining method for RP. Washed platelets from three healthy donors were stained by SYTO™13, a nucleic acid binding fluorescent dye, which enables determination of RP and non-RP based on their RNA-content. 8×106 platelets were fixed, sorted and sandwiched between two layers of agarose gel. Samples were further processed for visualization by TEM. In total, 1047 platelets, i.e., electron micrographs of individual cross-sections, were analysed by an investigator blinded concerning experimental condition. Sizes, numbers of α-granules, dense granules, mitochondria and open canalicular system openings were assessed in RP and non-RP, respectively. Furthermore, platelets were screened for pseudopodia formation as an indicator for activation. Cross-sectional area was significantly different between RP and non-RP (2.44 [1.80–3.22] vs. 1.34 [1.04–1.89] μm2; p<0.0001; median with IQR). α-granule and mitochondria amounts were higher in RP which persisted even after adjustment for platelet size (α-granules: 4.64 [3.46–5.86]/μm2 vs. 4.15 [2.87–5.26]/μm2; p<0.0001; mitochondria: 0.33±0.02 /μm2 vs. 0.12±0.01/μm2; mean ± SEM). In contrast, the amount of open canalicular system openings per square μm was higher in the non-RP group (5.82 [4.34–7.68] /μm2 vs. 5.52 [4.01–7.11] /μm2; p=0.009). Dense granule content per square μm was similar in both RP and non-RP. Pseudopodia were present in 38% (RP) respective 37% (non-RP) of platelets. Notably, golgi apparatus and rough endoplasmic reticulum which are rarely seen in platelets were detected in several RP. Analysis of TEM pictures revealed an almost 2-fold higher cross-sectional area in RP compared to non-RP. Even after adjustment for differences in size, α-granule content remained significantly higher in RP indicating a higher storage pool for prothrombotic constituents like p-selectin or von Willebrand factor. Although the relative amount of dense granules per area did not differ between the two groups, a higher absolute number of dense granules per platelet in the RP group is indicative for higher amounts of stored small molecules such as ADP, calcium or serotonin. Despite the anucleate nature of platelets, the presence of golgi apparatus and rough endoplasmic reticulum suggests the capability of protein biosynthesis in RP. These comprehensive findings provide new important insight into the ultrastructural properties of human RP. Acknowledgement/Funding PharmCompNet Baden-Württemberg: Kompetenznetzwerk Pharmakologie Baden-Württemberg


1979 ◽  
Vol 13 (2) ◽  
pp. 75-80 ◽  
Author(s):  
David J. Lewis ◽  
David E. Prentice

Summary The fine structure of rhesus monkey renomedullary interstitial cells was studied by electron microscopy. These stellate cells contained variable numbers of lipid droplets, moderate numbers of mitochondria, moderate amounts of rough endoplasmic reticulum, and prominent Golgi zones. In rare instances, apparent release of lipid droplets into the interstitium was observed. The most prominent feature of the interstitial cells was large nuclear pseudoinclusions which were observed in a high proportion of the animals examined.


2021 ◽  
Vol 8 ◽  
Author(s):  
Meilin He ◽  
Xintian Nie ◽  
Huanhuan Wang ◽  
Shuping Yan ◽  
Yuanshu Zhang

Chinese dairy industries have developed rapidly, providing consumers with high-quality sources of nutrition. However, many problems have also appeared during the development process, especially the low quality of milk. To improve milk quality, a large amount of concentrated feed is usually added to the diet within a certain period of time, which increases the milk production to a certain extent. However, long-term feeding with high-concentration feed can lead to subacute rumen acidosis. Therefore, the present study aimed to determine the effect of adding a buffer on subacute rumen acidosis, and the improvement of milk production and milk quality. We also aimed to study the mechanism of promoting mammary gland lactation. A total of 12 healthy mid-lactating goats were randomly divided into two groups, they were high-grain diet group (Control) and buffering agent group. To understand the effects of high-grain diets with buffers on amino acids in jugular blood and the effects of amino acids on milk protein synthesis, Milk-Testing™ Milkoscan 4000, commercial kits, and high-performance liquid chromatography (HPLC) measurements were integrated with the milk protein rate, the amino acid concentration in jugular venous blood samples, quantitative real-time PCR, comparative proteomics, and western blotting to study differentially expressed proteins and amino acids in mammary gland tissues of goats fed high-grain diets. Feeding lactating goats with buffering agent increased the percentage of milk protein in milk, significantly increased the amino acid content of jugular blood (p &lt; 0.05), and increase the amino acid transporter levels in the mammary gland. Compared with the high-grain group, 2-dimensional electrophoresis technology, matrix-assisted laser desorption/ionization-time of flight/time of flight proteomics analyzer, and western blot analysis further verified that the expression levels of beta casein (CSN2) and lactoferrin (LF) proteins in the mammary glands of lactating goats were higher when fed a high-grain diets and buffers. The mechanism of increased milk protein synthesis was demonstrated to be related to the activation of mammalian target of rapamycin (mTOR) pathway signals.


Author(s):  
T. N. Tahmisian ◽  
E. J. Ainsworth

Studies are in progress to characterize a transmissible leukemia and the causal agent which is presumably viral. The neoplasm, originally isolated from an aged irradiated B6CF1, mouse, has been transmitted in irradiated (200 R; 250 kVp X rays) weanling mice by intraperitoneal injection of millipore filtered (0.45μ) supernatant from spleen cell suspensions. At 22 days after filtrate injection in syngeneic mice, spleen, lymph nodes, and thymus were removed and prepared for electron microscopy to determine the presence of virus and morphology of viral development.The ultrastructure of cells from the above organs showed viral infection by a murine type leukemia virus with many “C” type buds 90 to 110nm formed in the cisternae of the rough endoplasmic reticulum (Fig. 1). The limiting membrane of the “C” type virus, apparently isolating it from the cytoplasm, is the unit membrane from the rough endoplasmic reticulum. The viral membrane is not invariably intact.


Sign in / Sign up

Export Citation Format

Share Document