ULTRASTRUCTURAL CHANGES IN THE ADENOHYPOPHYSIS OF CASTRATED RABBITS

SUMMARY The ultrastructure of the rabbit adenohypophysis is described at increasing time-intervals after castration. An early effect of castration was the appearance of large numbers of degranulated or partially degranulated cells in both the pars distalis proper and the zona tuberalis. These cells were similar in general shape and granule size to the type 3 and 3z cells of the normal rabbit adenohypophysis. Characteristically these cells show a dilatation of the cisternae of the ergastoplasm and a prominent Golgi zone. 284 days after castration the partially degranulated cells were very large and their dilated cisternae were up to 1·3 μ in diameter and more spherical in form. Since the cells most affected by castration were similar in all respects to the type 3 and 3z cells described in normal rabbits, they are considered to be the gonadotrophs.

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ULTRASTRUCTURAL CHANGES IN THE ADENOHYPOPHYSIS OF HYPOTHYROID RABBITS

Journal of Endocrinology ◽

10.1677/joe.0.0440273 ◽

1969 ◽

Vol 44 (2) ◽

pp. 273-277 ◽

Cited By ~ 5

Author(s):

C. L. FOSTER ◽

E. CAMERON ◽

B. A. YOUNG

Keyword(s):

Endoplasmic Reticulum ◽

Stellate Cells ◽

Granular Endoplasmic Reticulum ◽

Ultrastructural Changes ◽

Pars Distalis ◽

Type 3

SUMMARY The ultrastructure of the adenohypophysis of the rabbit, after treatment with propylthiouracil, is described. All cells in the zona tuberalis and pars distalis proper, with the exception of the prolactin producing (type 1) and stellate cells (type 5), were affected. However, the only ones which presented some evidence of sequential changes were the type 4 cells. These became markedly degranulated and sometimes showed vesiculation of the cisternae of the granular endoplasmic reticulum, similar to that observed in the 'thyroidectomy' cells in some other species. Although changes occurred in the somatotrophs (type 2) and in the gonadotrophs (type 3) the evidence suggests that it is the type 4 cells which have a thyrotrophic function.

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Prolonged Fixation Studies For Spaceflight

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072101 ◽

1973 ◽

Vol 31 ◽

pp. 332-333

Author(s):

Robert Corbett ◽

Delbert E. Philpott ◽

Sam Black

Keyword(s):

High Pressure ◽

Living Systems ◽

Prolonged Storage ◽

Time Intervals ◽

Early Signs ◽

Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

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Stereological Analyses of Hepatocyte Ultrastructure Monitor Arsenic Liver Burdens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001896 ◽

1980 ◽

Vol 38 ◽

pp. 442-443

Author(s):

E. M. B. Sorensen ◽

R. R. Mitchell ◽

L. L. Graham

Keyword(s):

Drainage System ◽

Water Levels ◽

Ultrastructural Changes ◽

Hepatocyte Ultrastructure ◽

Lepomis Cyanellus ◽

Large Numbers ◽

Activation Data ◽

Water Analyses ◽

Municipal Lake ◽

Green Sunfish

Endemic freshwater teleosts were collected from a portion of the Navosota River drainage system which had been inadvertently contaminated with arsenic wastes from a firm manufacturing arsenical pesticides and herbicides. At the time of collection these fish were exposed to a concentration of 13.6 ppm arsenic in the water; levels ranged from 1.0 to 20.0 ppm during the four-month period prior. Scale annuli counts and prior water analyses indicated that these fish had been exposed for a lifetime. Neutron activation data showed that Lepomis cyanellus (green sunfish) had accumulated from 6.1 to 64.2 ppm arsenic in the liver, which is the major detoxification organ in arsenic poisoning. Examination of livers for ultrastructural changes revealed the presence of electron dense bodies and large numbers of autophagic vacuoles (AV) and necrotic bodies (NB) (1), as previously observed in this same species following laboratory exposures to sodium arsenate (2). In addition, abnormal lysosomes (AL), necrotic areas (NA), proliferated rough endoplasmic reticulum (RER), and fibrous bodies (FB) were observed. In order to assess whether the extent of these cellular changes was related to the concentration of arsenic in the liver, stereological measurements of the volume and surface densities of changes were compared with levels of arsenic in the livers of fish from both Municipal Lake and an area known to contain no detectable level of arsenic.

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A ROLE OF POLYMORPHONUCLEAR LEUKOCYTES AND COMPLEMENT IN NEPHROTOXIC NEPHRITIS

Journal of Experimental Medicine ◽

10.1084/jem.122.1.99 ◽

1965 ◽

Vol 122 (1) ◽

pp. 99-116 ◽

Cited By ~ 265

Author(s):

Charles G. Cochrane ◽

Emil R. Unanue ◽

Frank J. Dixon

Keyword(s):

Polymorphonuclear Leukocytes ◽

Basement Membranes ◽

Ultrastructural Changes ◽

Glomerular Injury ◽

Large Numbers ◽

Secondary Stage ◽

Vascular Beds ◽

Nephrotoxic Nephritis ◽

Glomerular Damage

In acute nephrotoxic nephritis, polymorphonuclear leukocytes (polymorphs) accumulated in large numbers in the glomeruli in the first 12 hours. The endothelial cells were dislodged by the polymorphs which then came to lie immediately adjacent to the glomerular basement membranes. Ultrastructural changes in neither polymorphs nor basement membranes were observed. Depletion of polymorphs in both rats and rabbits prevented the development of proteinuria. This occurred when doses of nephrotoxic globulin were employed that produced proteinurias of as much as 1800 mg/kg/24 hours in intact rabbits, or enough to yield near maximal immediate proteinuria in intact rats. In addition, measurable glomerular damage was frequently averted until the onset of the secondary stage of NTN. Controls indicated that the polymorph depleted animals exhibited minimal non-specific changes in the blood, that the ability of their vascular beds to react to stimuli was not affected, and that deposition of nephrotoxic antibody and C' in the glomeruli was not inhibited. Elimination of polymorphs from the circulation was only partially effective in preventing glomerular damage when large doses of nephrotoxic globulin were used. This indicated that under these circumstances, a polymorph independent glomerular injury may also take place in first stage nephrotoxic nephritis. An indirect role of C', i.e., the accumulation of polymorphs, in bringing about glomerular injury in first stage nephrotoxic nephritis was apparent. When rabbit nephrotoxic globulin was injected into rats depleted of C', or when duck nephrotoxic globulin that fixed C' poorly was injected into normal rats, C' failed to bind with the antibody along glomerular basement membranes and polymorphs did not accumulate.

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The initial stages in the action of an insecticidal delta-endotoxin of Bacillus thuringiensis var. israelensis on the epithelial cells of the malpighian tubules of the insect, Rhodnius prolixus

Journal of Cell Science ◽

10.1242/jcs.90.1.131 ◽

1988 ◽

Vol 90 (1) ◽

pp. 131-144

Author(s):

S.H. Maddrell ◽

N.J. Lane ◽

J.B. Harrison ◽

J.A. Overton ◽

R.B. Moreton

Keyword(s):

Bacillus Thuringiensis ◽

Intercellular Junctions ◽

Fluid Secretion ◽

Malpighian Tubules ◽

Ultrastructural Changes ◽

Cytoplasmic Vacuolization ◽

Large Numbers ◽

Delta Endotoxin ◽

High Concentrations ◽

Very High

The effects of the 27 X 10(3) Mr insecticidal delta-endotoxin from Bacillus thuringiensis var. israelensis have been studied using, as a model system, isolated insect Malpighian tubules. At all concentrations of the toxin higher than 1 microgram ml-1 (4 X 10(−8) moll-1) applied to the outer surface of the tubules, fluid secretion failed within about 30 min. Except at very high concentrations, where failure always takes at least 30 s, there was an inverse relationship between the concentration of toxin and the time of failure of toxin-treated tubules. During exposure to toxin, the tubules were initially unaffected for a relatively long period and then rapid failure occurred. If the tubules were removed into toxin-free saline just before failure would have occurred, fluid secretion remained normal for at least 2 h, but on return to the origin toxin-containing saline failure was almost immediate. The toxin was found not to bind to the basement membrane. Ultrastructural changes became evident as tubule failure occurred. These initially involved modifications to the basal side of the cells, but later also to the luminal microvilli. Intercellular junctions became disassociated and cytoplasmic vacuolization occurred. The population of intramembranous particles in the basal membranes became reduced with time. Our findings suggest the following hypothesis for the initial stages in the interaction of the toxin with the tubules. Toxin molecules attach to the accessible cell membranes progressively and irreversibly. They do not readily associate by diffusing laterally in the membrane, so that toxic effects develop only when sufficiently large numbers of them attach close together. The molecules may then associate in some way as a complex, perhaps forming a pore in the membrane. Relatively few such pores lead rapidly to cell failure and death.

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HISTOLOGICAL AND ULTRASTRUCTURAL CHANGES IN THE PARS DISTALIS OF THE RABBIT PITUITARY IN ORGAN CULTURE

Journal of Endocrinology ◽

10.1677/joe.0.0600155 ◽

1974 ◽

Vol 60 (1) ◽

pp. 155-NP ◽

Cited By ~ 4

Author(s):

S. PATHAK ◽

A. FISK

Keyword(s):

Organ Culture ◽

Granular Cell ◽

Common Type ◽

Ultrastructural Changes ◽

Pars Distalis ◽

Prolactin Cells ◽

Dna And Rna ◽

Intranuclear Rodlets ◽

Maximum Proportion

SUMMARY Typical histological and ultrastructural changes that occur in the pars distalis of the rabbit pituitary after different periods of organ culture are described. The best technique for the maintenance of the maximum proportion of the explant was assessed by comparing cultures grown under different conditions. Explants in air with a medium buffered with N-2-hydroxyethylpiperazine-N1-2-ethanesulphonic acid (HEPES), not previously used in organ culture, proved more satisfactory than explants in carbogen with bicarbonate-buffered 199, and cultures were maintained for more than 3 weeks. The survival of cells was assessed on the basis of their cytological integrity; DNA- and RNA-fluorescence with acridine orange was a valuable indicator. Prolactin cells, which were few in uncultured controls, became the most common type of granular cell in long-term cultures. Cell modifications during culture included the development of a peripheral epithelioid layer and the appearance of numerous microvilli. Microfibrils, coated or smooth vesicles, lytic bodies, desmosomes and intranuclear rods became more common and intranuclear rodlets (fibrous or membranous structures) were identified. Cells often became more electron dense during long-term culture. Though there was an increase in the number of agranular cells during culture, identifiable granules were retained by many cells throughout culture.

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Early Events of Citrus Greening (Huanglongbing) Disease Development at the Ultrastructural Level

Phytopathology ◽

10.1094/phyto-100-9-0949 ◽

2010 ◽

Vol 100 (9) ◽

pp. 949-958 ◽

Cited By ~ 82

Author(s):

Svetlana Y. Folimonova ◽

Diann S. Achor

Keyword(s):

Middle Lamella ◽

Ultrastructural Level ◽

Citrus Greening ◽

Ultrastructural Changes ◽

Bacterial Cells ◽

Tissue Samples ◽

Large Numbers ◽

Presymptomatic Stage ◽

Candidatus Liberibacter ◽

Advanced Stages

Citrus greening (Huanglongbing [HLB]) is one of the most destructive diseases of citrus worldwide. The causal agent of HLB in Florida is thought to be ‘Candidatus Liberibacter asiaticus’. Understanding of the early events in HLB infection is critical for the development of effective measures to control the disease. In this work, we conducted cytopathological studies by following the development of the disease in citrus trees graft inoculated with ‘Ca. L. asiaticus’-containing material under greenhouse conditions to examine the correlation between ultrastructural changes and symptom production, with the main objective of characterizing the early events of infection. Based on our observations, one of the first degenerative changes induced upon invasion of the pathogen appears to be swelling of middle lamella between cell walls surrounding sieve elements. This anatomical aberration was often observed in samples from newly growing flushes in inoculated sweet orange and grapefruit trees at the early “presymptomatic” stage of HLB infection. Development of symptoms and their progression correlated with an increasing degree of microscopic aberrations. Remarkably, the ability to observe the bacterium in the infected tissue also correlated with the degree of the disease progression. Large numbers of bacterial cells were found in phloem sieve tubes in tissue samples from presymptomatic young flushes. In contrast, we did not observe the bacteria in highly symptomatic leaf samples, suggesting a possibility that, at more advanced stages of the disease, a major proportion of ‘Ca. L. asiaticus’ is present in a nonviable state. We trust that observations reported here advance our understanding of how ‘Ca. L. asiaticus’ causes disease. Furthermore, they may be an important aid in answering a question: when and where within an infected tree the tissue serves as a better inoculum source for acquisition and transmission of the bacterium by its psyllid vector.

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SOME OBSERVATIONS ON THE ULTRASTRUCTURE OF THE ADENOHYPOPHYSIS OF THE RABBIT

Journal of Endocrinology ◽

10.1677/joe.0.0310279 ◽

1965 ◽

Vol 31 (3) ◽

pp. 279-287 ◽

Cited By ~ 37

Author(s):

B. A. YOUNG ◽

C. L. FOSTER ◽

E. CAMERON

Keyword(s):

Granular Cell ◽

Pars Intermedia ◽

Pars Tuberalis ◽

Pars Distalis ◽

Cell Type ◽

Cytoplasmic Rna ◽

Large Numbers ◽

Predominant Cell Type ◽

Relationship Of ◽

The Relationship

SUMMARY The ultrastructure of the adenohypophysis of the rabbit is described preliminary to reporting changes after experimental procedures. Fixation by perfusing with gluteraldehyde enabled selected regions of the gland to be removed with accuracy. Separate descriptions of the pars distalis proper, zona tuberalis, pars tuberalis and pars intermedia are therefore included. In the pars distalis proper four types of granular cell were recognized although their function cannot be accurately determined. For convenience, therefore, they have been designated 1, 2, 3 and 4. In addition a fifth type of cell (type 5) is described which is also present in the other areas. This cell, as well as having possible phagocytic functions, appears to be concerned in the formation of a perivascular channel. Two types of cell are recognized in the zona tuberalis, which are similar in appearance to the 3 and 4 cells of the pars distalis, although not necessarily identical in function. The characteristic cells of the pars tuberalis are rich in cytoplasmic RNA and contain large numbers of intracellular fibrils. It is suggested that the ribosomes are concerned in the synthesis of a sedentary protein which may take the form of the microfibrils. The pars intermedia contains a predominant cell type with large granules of varying density. The relationship of these granules to the specific hormone is discussed.

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