51 research outputs found
The effect of fasting on the ultrastructure of the hypothalamic arcuate nucleus in young rats
In the present study, we described ultrastructural changes occurring in the
neurons of the hypothalamic arcuate nucleus after food deprivation. Young
male Wistar rats (5 months old, n = 12) were divided into three groups. The
animals in Group I were used as control (normally fed), and the rats in Groups
II and III were fasted for 48 hours and 96 hours, respectively. In both treated
groups, fasting caused rearrangement of the rough endoplasmic reticulum forming
lamellar bodies and membranous whorls. The lamellar bodies were rather
short in the controls, whereas in the fasting animals they became longer and
were sometimes participating in the formation of membranous whorls composed
of the concentric layers of the smooth endoplasmic reticulum. The whorls
were often placed in the vicinity of a very well developed Golgi complex. Some
Golgi complexes displayed an early stage of whorl formation. Moreover, an
increased serum level of 8-isoprostanes, being a reliable marker of total oxidative
stress in the body, was observed in both fasting groups of rats as compared
to the control
Ultrastructural observations on the hypothalamic arcuate nuclei of aged rats in the fasting/refeeding model
The arcuate nucleus of the hypothalamus (ARH) is involved in the control of
energy homeostasis. This is the first study on the ultrastructural response of ARH
neurons in aged rats after short-term fasting and subsequent refeeding. Male
Wistar rats (24 weeks old) were fasted for 48 or 96 hours and were then refed for
24 hours. The controls were normally fed. The rats received water ad libitum. In
both groups of fasting animals, we observed a rearrangement of the arcuate
rough endoplasmic reticulum (RER) and Golgi complexes to form membranous
whorls. Moreover, refeeding for 24 hours did not reverse this process. The RER
was frequently found to be well organized into lamellar bodies composed of
several cisternae. The membranous whorls were composed of concentric layers
of endoplasmic reticulum and Golgi complexes. In addition, multiform lipofuscin
granules were observed in close relationship with Golgi complexes and membranous
whorls. Lipofuscin granules within the neurons of the arcuate nucleus are
assumed to be a morphological manifestation of oxidative stress phenomena,
which are presumably implicated in the formation of membranous whorls in
both fasting and fasting/refed animals. This observation correlates with a significant
increase in 8-isoprostane serum levels in the fasting and fasting/refed animals
as compared to the fed control rats
Myocardial necrosis due to vitamin D3 overdose - scanning electron microscopic observations
Our studies were carried out on the hearts of virgin female Wistar rats treated
with 100.000 i.u. of vitamin D3 (calciol) per os for 3 consecutive days. Multifocal
cardionecrosis was established macroscopically in 70% of the vitamin D-treated
rats on the 7th day of the experiment when the rats were in the acute phase of
intoxication.
Using a scanning electron microscopy (SEM), we received three-dimensional information
about the structural changes to the rat myocardium damaged by
high doses of vitamin D3. The images of necrotic hearts revealed significant
disruption of the structural integrity of the myocardium linked to fragmentation
of the cardiac muscle bundles and a visible disruption of the extracellular matrix
(ECM) components. In healthy hearts, the structural integrity of the myocardium
and the dense network of the extracellular matrix were well preserved. In parallel,
the effect of an increasing concentration of free Ca2+ on the total proteolytic
activity of the heart muscle homogenate of the healthy and necrotic rats was
investigated at neutral pH. These data showed that following vitamin D3 intoxication,
the proteolytic processes in the rat hearts occurred in Ca2+ overload or
saturation. On the basis of our morphological and biochemical results we can
suggest that calcium-activated neutral proteinases may have contributed to the
structural alteration of the extracellular matrix components and were in this way
involved in vitamin D-induced cardionecrosis
The growth and differentiation of aortal smooth muscle cells after calcitriol treatment are associated with microtubule reorganisation - an in vitro study
The smooth muscle cells (SMCs) of the arterial media play a predominant role
in functional and structural alterations of the arterial wall. The transition from
the “contractile” to the “synthetic” phenotype appears to be an early critical
event in the development of atherosclerotic disease. A number of observations
suggest that 1,25(OH)2D3 (calcitriol) is of importance in maintaining normal
cardiovascular function through its receptors in cardiac myocytes or aortal
SMCs. The present study has focused on the microtubular (MT) network reorganisation
after exposure to calcitriol. SMCs isolated by enzymatic digestion
from the aortal media of neonatal rats were cultured on glass cover slips.
1 μM of 1,25(OH)2D3 was added to the culture medium every second day. The
cytoskeletal features of SMCs after calcitriol were visualised by the immunofluorescence
staining of α-tubulin. The alterations in α-tubulin expression and
the distribution of microtubules related to the activities of the vascular smooth
muscle cells, namely adhesion, migration, multilayer formation and cell division,
were observed. A spindle shape, decreased cell adhesion, low expression
of α-tubulin and a longitudinally arranged microtubular network manifested
the high rate of SMC differentiation in the calcitriol-treated culture. A flat
stellate morphology, high expression of α-tubulin and a radially distributed
three-dimensional microtubular network were observed in the SMCs of the
control culture. Destructive changes in the microtubular architecture which
altered the cellular shape were evident in SMCs undergoing apoptosis. Cells
with apoptotic features were more frequent in calcitriol-exposed culture. In
contrast to the regular SMC divisions observed in the control culture, some of
the mitotic cells exposed to calcitriol contained broader bipolar, multipolar or
disordered spindles.
These alterations in the SMCs’ microtubular cytoskeleton after calcitriol treatment
were concomitant with changes in cell growth, differentiation and apoptosis,
and may suggest a similarity to atherosclerotic plaque formation
A scanning electron microscopic study of phenotypic plasticity and surface structural changes of aortal smooth muscle cells in primary culture
Phenotypic modulation of smooth muscle cells (SMCs) from a contractile to
a synthetic state characterised by active proliferation appears to be an early event
in the pathogenesis of atherosclerosis. A similar transition occurs when SMCs are
established in culture. In this study the phenotypic plasticity and surface structural
changes of aortal smooth muscle cells during the transition from the contractile to
the synthetic state and during maturation have been structurally assessed by scanning
electron microscope (SEM). The experiments were performed on SMCs obtained
from aorta of neonatal rats after enzymatic digestion and then cultured on
glass cover slips. SEM observations revealed a three-dimensional appearance characteristic
for different stages of SMCs. Intensively proliferating cells from monolayer
region were large, polygonal in shape with lamellipodia and well spread. Long,
uniform in diameter, finger-like microvilli were densely arranged on the surface of
these cells. In the thickened region of culture, the cells were rather small, generally
spindle-shaped, not well spread, with low density of short, bubble-like microvilli
on the surface. Numerous plasma membrane structural alterations in apoptotic
cells were observed by SEM: loss of cellular adhesion, smoothing, shrinkage and
outpouching of membrane segments have been recognised as markers associated
with the cell injury and death. It was concluded that scanning microscopy
observations would allow a more complete understanding of SMCs and their changes
in culture and atherosclerotic disease
The effect of angiogenesis inhibitor TNP-470 on the blood vessels of the lungs, kidneys and livers of treated hamsters
The growth of solid tumours and their metastases is dependent on the development
of new blood vessels (angiogenesis). Therefore angiogenesis inhibitors are
potential antitumour drugs.
In our previous studies it was found that the angiogenesis inhibitor TNP-470
given to transplantable melanoma-bearing hamsters can decrease the rate of
the tumour growth, although the survival time of the animals treated was not
significantly affected. It was found finally that TNP-470 given in the vicinity of
the growing tumour can cause complete remission of the melanoma in hamsters
treated in this way. To check what side-effects could be evoked by such
treatment, an examination of the morphology of the blood vessels of the lungs,
kidneys and livers of the treated animals was carried out. It was found that the
angiogenesis inhibitor applied did not cause any changes which could be observed
by light and electron microscopes in the structure of the examined blood
vessels of the treated animals
Diagnostyka różnicowa: opis przypadku wola Riedla z cechami choroby Hashimoto
Riedel’s disease (RD) is a rare form of chronic thyroiditis, predominantly characterised by fibrosis which may involve neighbouring tissues
and organs. Hashimoto’s disease (HD), on the other hand, is fairly common. Clinical differentiation between these diseases is often difficult,
and the results of diagnostic imaging, laboratory tests and cytology studies are often similar. We report the case of a female patient
with Riedel’s thyroiditis displaying clinical, laboratory and radiological traits of both diseases.
A 44 year-old Caucasian female was diagnosed with hypothyroidism. A fine-needle aspiration biopsy was performed; the findings were
suggestive of an exacerbated chronic inflammatory process. However, a small lymphocyte-derived malignancy could not be ruled out with
certainty, and so the patient was referred for elective thyroidectomy. The microscopic features of both specimens did not meet the criteria of
Hashimoto’s thyroiditis. The immunohistochemical studies revealed few scattered B lymphocytes (CD20 positive) and numerous scattered
T lymphocytes (CD3 positive). Finally, Riedel’s thyroiditis with an intense inflammatory infiltrate composed of lymphocytes was diagnosed.
Reaching a diagnosis was particularly difficult in this patient, since Riedel’s thyroiditis, the fibrosing form of Hashimoto’s disease and malignant
tumours of the thyroid can show similar traits upon physical and histopathological examination. As the clinical data was indicative
of Hashimoto’s thyroiditis and there were partial histological criteria of two forms of thyroiditis, namely Hashimoto’s and Riedel’s, the very
rare diagnosis of a combined disease was made. Dense B and T lymphocytes and some plasma cell infiltrates, as well as the destruction of
thyroid follicles by fibrosis extending into surrounding tissues, were supportive of the eventual diagnosis.
Differentiating between the histopathological and clinical presentation of both diseases in one patient is difficult, primarily due to the
partial overlapping of their histopathological traits. In order to avoid a diagnostic error, close cooperation between the endocrinologist
and pathologist is mandatory. It is our opinion that in our patient the two diseases existed separately, and their coexistence was most likely
coincidental. (Pol J Endocrinol 2011; 62 (4): 351–356)Wole Riedla jest rzadką postacią przewlekłego zapalenia tarczycy, w której dominuje włóknienie mogące obejmować sąsiednie tkanki.
Choroba Hashimoto jest stosunkowo częstym schorzeniem. Różnicowanie tych schorzeń bywa trudne, gdyż wyniki badań laboratoryjnych,
obrazowych i cytologicznych bywają podobne. Autorzy przedstawiają przypadek pacjentki z wolem Riedla prezentującym kliniczne,
laboratoryjne i obrazowe cechy obu tych chorób. U 44-letniej kobiety rozpoznano niedoczynność tarczycy. W preparatach z wykonanej
biopsji aspiracyjnej cienkoigłowej rozpoznano zaostrzony przewlekły proces zapalny, ale jednocześnie nie można było wykluczyć
chłoniaka. Pacjentkę poddano tyreoidektomii. W badaniu histopatologicznym nie potwierdzono jednoznacznie choroby Hashimoto.
Badanie immunohistochemiczne wykazało nieliczne limfocyty B (CD20) i liczne limfocyty T (CD3). Ostatecznie rozpoznano wole Riedla
z naciekiem limfocytarnym.
Diagnostyka u tej pacjentki była utrudniona, gdyż wole Riedla, włókniejąca forma choroby Hashimoto oraz guz złośliwy mają podobne
cechy w badaniu fizykalnym i histopatologicznym. Jeżeli występują kliniczne cechy choroby Hashimoto oraz histologiczne cechy obu form
zapalenia, można rozpoznać rzadką kombinację choroby Hashimoto i wola Riedla. Naciek limfocytów B i T oraz komórek plazmatycznych,
jak również niszczenie pęcherzyków tarczycy przez włóknienie, które przechodzi na sąsiednie tkanki, może pomóc w postawieniu ostatecznego
rozpoznania. Różnicowanie pomiędzy histopatologicznym i klinicznym obrazem obu chorób bywa trudne szczególnie z powodu
nakładania się cech histopatologicznych. Konieczna jest ścisła współpraca patologa i klinicysty w celu uniknięcia pomyłki diagnostycznej.
Zdaniem autorów u badanej pacjentki występowały obie te choroby, ale związek pomiędzy nimi był jedynie przypadkowy.
(Endokrynol Pol 2011; 62 (4): 351–356
Ultrastructural response of arcuate nucleus neurons to fasting in aged rats
The arcuate nucleus of the hypothalamus (ARH) is involved in the control of
energy homeostasis. Leptin - an adipocyte derived hormone - is known to
act on the hypothalamic nuclei and thus to control body weight by food intake
reduction. Oxidative stress is believed to be implicated in leptin signalling. However,
its relevance for leptin-induced signal transduction within ARH remains
unclear. The goal of the study was to investigate the effect of fasting on morphological
alterations of the neuronal endoplasmic reticulum/Golgi network as
well as on the expression of leptin receptors in the arcuate nucleus of aged
rats. Male Wistar rats, aged 24 months, were fasted for 96 hours. The control
animals were fed ad libitum. Membranous whorls in the ARH neurons were
visualized using the electron microscopy technique. Leptin receptors in the
membranes of ARH neurons were determined immunohistochemically (IHC),
and soluble leptin receptors in the plasma as well as plasma isoprostanes were
quantified immunochemically (ELISA). An intense formation of membranous
whorls was observed, directly associated with the cisternae of the rough endoplasmic
reticulum, as well as lamellar bodies. Interestingly, the whorls were
often localized near a well-developed Golgi complex. Moreover, some Golgi
complexes displayed an early stage of whorl formation. Groups of residual
lipofuscin granules were found in the immediate proximity of the whorls. An
increased immunoreactivity with neuronal leptin receptors suggests that hypersensitive
neurons may still effectively respond to the fasting serum levels of
leptin, mediating ultrastructural transformation of ARH neurons during short-term fasting. Having observed a significant accumulation of lipofuscin granules
and a marked increase of total 8-isoprostane serum level in the fasting rats, we
hypothesize that signal transduction within the neurons of ARH is dependent
on oxidative stress phenomena
Cellulose biosynthesis in plants – the concerted action of CESA and non-CESA proteins
Cellulose is the most abundant polysaccharide produced by plants. In the form of rigid microfibrils surrounding the cells,
cellulose constitutes the load-bearing cell wall element that controls cell growth and shape. Cellulose microfibrils are laid
down outside the cell by the multimeric plasma membrane-inserted cellulose synthase complexes (CSCs), which move
along underlying cortical microtubules (CMTs). In plants, CSCs are shaped as rosettes with six lobes symmetrically
arranged in a hexagonal structure. In Arabidopsis, the CSC is composed of at least three functionally non-redundant
cellulose synthase (CESA) glycosyltransferases in both primary and secondary cell walls. The number, organization,
and interactions of CESA proteins within the CSC have been debated for many years on the basis of numerous lines of
evidence provided by electron microscopy, biochemical and genetic approaches, spectroscopic techniques, as well as
computational modeling. The Arabidopsis thaliana model was extremely useful in elucidating the molecular composition
of CSC and enabled to elucidate the specialized functions of distinct AtCESA isoforms. Several additional, non-CESA
proteins involved in cellulose synthesis and its regulation were also identified in Arabidopsis. This review outlines the
latest findings on CSC organization, trafficking, and plant-specific proteins directly associated with the complex and
interconnecting CESAs with CMTs
Changes in the morphology of the acinar cells of the rat pancreas in the oedematous and necrotic types of experimental acute pancreatitis
Limited experimental models of the oedematous and necrotic types of acute
pancreatitis provide some understanding of the pathophysiology of this disease.
Wistar rats were treated with cerulein at 10 mg/kg of body weight or with
L-arginine at 1.5 or 3 g/kg of body weight in order to induce the oedematous or
necrotic type of acute pancreatitis. After the induction period we examined
samples of pancreata with light and electron microscopes. Morphological
examination showed profound changes in the histology of the pancreas and its
acinar cells and subcellular structures, especially in the group of rats which
received a higher dose of L-arginine, amounting to 3 g/kg body weight. These
included parenchymal haemorrhage and widespread acinar cell necrotic changes.
4-OH-TEMPO successfully prevented morphological deterioration as well as
amylase release, suggesting that the severity of the two types of disease strongly
depends on the intensity of the oxidative stress. Our results lend support to the
assumption that reactive oxygen species play an axial role in the pathogenesis of
both types of acute pancreatitis
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