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PubMed1983

Influence of lead poisoning on ultrastructural changes in the body wall of Eisenia foetida (Savigny), Oligochaeta. II. Long action of different concentration of lead on ultrastructural changes in the cells of the body wall.

The studies were performed on earthworms collected from March to September in the vicinity of Katowice. The earthworms were breed in Petri dishes on soil to which lead nitrate was added in the following concentrations 0.025, 0.10, 0.50 mg/g of soil. For the performed studies small specimen were taken from behind the citellum in which was lead histochemically evaluated. Tissue specimen taken from the citellum of the experimental animals were investigated in electronmicroscope. It has been found that lead accumulates in the sarcoplasm of the muscle fibres but not in the cell organells. Lead concentrations in the cells appear as regular crystals with membranaceous cover. The lead compounds used in the experiments does not provoke structural changes in the contractile elements of the muscle fibres, they induce only some deformations of mitochondria and hyperactivity of the glandular cells of the epithelium.

Animals↗
PubMed1975

Ultrastructure of the contractile system of striated skeletal muscle and the processes of muscular contraction. I. Ultrastructure of the myofibril and source of energy.

1) The contractile system consists of thick and thin filaments arranged side by side in a double network of hexagonal cross-section. 2) The thick filaments are principally made up of myosin and the thin ones of actin, tropomyosin and troponin. 3) Myosin is an enzyme catalysing the hydrolysis of ATP; actin increases the specific activity of this enzyme, converting it from a Ca+2 sensitive ATPase to a Mg+2 sensitive ATPase. 4) Hydrolysis of the last phosphoryl group of adenosine triphosphate (ATP) salts is the energy source for muscle contraction. 5) The adenosine diphosphate (ADP) salts, formed by ATP splitting, are rephosphorylated and reinjected into the myofibril.

Actins↗
PubMed1976

[Development of the internal ear in albino rat embryos subjected to transverse acceleration at + 3 G. Note 3: First observations on the ultrastructural picture of the labyrinth. 1st ultrastructural studies of the labyrinth].

Marked body size reduction (minus 50.5%), and delayed head and body skeletal development were noted in albino rat embryos following exposure of the mother to +/- 3 G acceleration for 3 hr/day between the 10th and 19th day of pregnancy. In addition, electron microscope examination of the inner ear showed signs of greater functional activity of the labyrinth, unaccompanied by reduction of development. Semicircular canal cells and size, in fact, were normal in the crests and at a distance from the latter. There was a marked increase in the number of mitochondria in the cells, in ER area and volume, and A and B glycogen granule richness compared with the controls, these being all signs of considerable activity. The findings substantiate prior histological and histochemical observations: the physiological stimulus offered by acceleration is highly specific for the inner ear structure, particularly that of the labyrinth, to the point where the handicap imposed by the circulatory hypoxia caused by such acceleration, by disturbing the mother-foetus circulation, is overcome.

Acceleration↗
PubMedDate not supplied

Ultrastructural changes in the myocardial myocytic mitochondria: crucial step in the development of oxygen radical-induced damage in isolated rat hearts?

The present study focuses on the sequential development of myocardial ultrastructural changes produced by oxygen radicals. Isolated rat hearts were perfused with oxygen radicals, generated by hypoxanthine and xanthine oxidase, for 5 and 10 min followed by a 35-min recovery period. The frequency of, and the association between, ultrastructural changes were examined by semiquantitative morphometry using the micrograph as unit. In each micrograph sarcolemmal, myocytic mitochondrial and myofilamental alterations were observed and graded as slight, moderate or severe. The myocytic nucleus and the endothelial cells were scored as normal or altered. Five min group: Among the cellular organelles examined, the myocytic mitochondria showed the highest frequency of alteration (in 15.3% of the micrographs). Among the grades of myocytic mitochondrial ultrastructural changes, slight alterations predominated (12.5%). Slight myocytic mitochondrial alterations were not significantly associated with the occurrence of ultrastructural changes of other cellular organelles. Endothelial ultrastructural alterations were sparse (1.5%). Ten min group: The frequency of altered organelles was greater when compared to the 5 min group. The myocytic mitochondria were still the most frequently altered component (61.7%), and myocytic mitochondrial ultrastructural alterations of all grades were strongly associated with the occurrence of other myocytic ultrastructural changes. In conclusion, the present study showed that myocytic mitochondrial changes predominated after both 5 and 10 min of oxygen radical exposure followed by recovery. In the 5 min group slight myocytic mitochondrial changes appeared independent of other myocardial changes, but in the 10 min group, however, myocytic mitochondrial changes were strongly associated with other myocardial ultrastructural changes. These results indicate that myocytic mitochondria are especially vulnerable to oxygen radicals, and further that myocytic mitochondrial ultrastructural changes may be a crucial step in the development of oxygen radical-induced myocardial damage.

Animals↗
PubMed1993

Ciliary ultrastructure in nasal brushings.

Normal ciliary ultrastructure is thought to be necessary for effective function. There has been little or no attempt to quantify ultrastructural abnormalities in nasal disease and assess their significance. In this study we measured nasal ciliary function and examined ciliary ultrastructure in nasal brushings from 35 patients with perennial nasal symptoms refractory to treatment. Ultrastructural defects included microtubular abnormalities, compound cilia and ciliary 'blebs'. The incidence of abnormal cilia was 16.7%, compared with 9% in controls, but there was only a poor correlation between ultrastructural defects and ciliary beat frequency. One patient had primary ciliary dyskinesia (PCD) with a typical clinical history and immotile cilia. However, only secondary ultrastructural abnormalities were seen. We have been unable to show that ciliary ultrastructural defects form the basis of impaired function. In patients with suspected PCD, nasal brushings should be taken for functional and ultrastructural studies; ideally, a further sample should be obtained for examination of possible primary ultrastructural abnormalities.

Cilia↗
PubMed1980

Comparative ultrastructure of certain Actinomyces species, Arachnia, Bacterionema and Rothia.

A comparative ultrastructural study was carried out on several species of Acinomyces and related Gram-positive rods including Arachnia, Bacterionema, Rothia and Leptotrichia. A total of 52 well characterized strains were examined by transmission electron microscopy. Particular attention was paid to the ultrastructure of the cell periphery, that is the plasma membrane, periplasmic space, the cell wall per se and extramural structures, including surface "fuzz". In addition, the ultrastructure of various features of the cytoplasm were also examined. A good correlation appeared to exist between certain ultrastructural characteristics of the microorganisms and their taxonomic position as determined by other criteria. It should be noted, however, that the ultrastructure of certain strains differed markedly from that of the remaining strains of the species. This observation raises some doubt on the appropriateness of the current classification for these particular strains. The ultrastructural features of the cell periphery were found to be particularly stable for all strains grown under standard conditions. For this reason, ultrastructural features of the cell wall and associated structures are probably a more reliable source of morphological criteria for identification purposes than the ultrastructural characteristics of the cytoplasmic components which tend to be more variable. The results suggest that certain ultrastructural features are useful criteria for the identification and classification of these Gram-positive rods.

Actinomyces↗
PubMed1983

[Histological and ultrastructural analysis of infiltrative tumors of the human breast].

The ultrastructural analysis of the three main histological forms (adenocarcinoma, scirrhous carcinoma, and solid carcinoma) of infiltrative mammary gland carcinomas with regard to the histological grades of malignancy (I, II, III) has revealed that with the increase of the histological grade of malignancy the number of ultrastructurally differentiated cells decreased. No correlation between histological and ultrastructural findings has been found, however. In histologically highly differentiated adenocarcinomas of grade I of malignancy ultrastructurally nondifferentiated cells could mainly be found, but ultrastructurally differentiated cells predominated in a number of cases of histologically nondifferentiated scirrhous and solid carcinomas of grade III of malignancy. Some cases of histologically similar carcinomas showed predominance of ultrastructural differentiated cells, others of ultrastructurally nondifferentiated cells. These results should be taken into account in ultrastructural diagnosis and evaluation of prognostic significance of electron microscopic findings.

Adenocarcinoma↗
PubMed1984

Ultrastructure of cultured atrial cardiac muscle cells from adult rats.

Atrial cardiac muscle cells enzymatically isolated from adult rats were maintained in culture for 0-17 days and examined by transmission electron microscopy (TEM). Cells were stained with conventional TEM stains as well as with osmium ferrocyanide and tannic acid. Our results show that cultured adult atrial cells are capable of in vitro ultrastructural reorganization and possess differentiated ultrastructural characteristics including specific atrial granules, sarcomerically arranged myofilaments, appropriately organized sarcoplasmic reticulum (both junctional and nonjunctional), and intercalated disc components. In addition, the cultured atrial cells also possess rare, but ultrastructurally typical, elements of the transverse tubular system. These can be identified on the basis of size, location, association with internal junctional sarcoplasmic reticulum, and accumulation of extracellular tracer. Atrial muscle cells are capable of reestablishing a myotypic ultrastructure, although they have a considerably less complex and organized in vitro ultrastructure than similarly cultured adult ventricular myocytes. This lessened in vitro ultrastructural specialization is in accord with the in vivo comparative ultrastructure of atrial vs. ventricular myocytes.

Animals↗
PubMed1995

Ultrastructural changes during continuous retrograde warm and mild hypothermic blood cardioplegia for coronary bypass operations.

Ultrastructural changes in myocardial tissue were studied in 21 patients undergoing elective aorta-coronary bypass operation. The patients were randomized into two groups, with 10 of them receiving continuous retrograde warm and 11 continuous retrograde mild hypothermic blood cardioplegia. Biopsy specimens for electron microscopy were taken from the apical part of the left ventricle before and at the end of the aortic crossclamp period and after reperfusion of the myocardium. The ultrastructural changes were analyzed with use of a semiquantitative scoring system and classified as mild, moderate, or severe. Slight ultrastructural changes were found in both groups even before the aortic crossclamp period. At the end of the aortic crossclamp period the most prominent ultrastructural changes were mitochondrial swelling, damage of capillary endothelium, and clearing of the nucleoplasm or margination of chromatin, but some enlargement in intercalated discs was also discernible. Reperfusion of the myocardium for 15 minutes somewhat further increased the overall score of the ultrastructural changes. Two patients in the warm cardioplegia group had a perioperative myocardial infarction, and this may be one reason for the higher postoperative creatine kinase MB efflux in this patient group. Despite this finding, no major differences in the ultrastructural changes between the two cardioplegia groups could be observed. We conclude that only mild to moderate and principally reversible ultrastructural changes occur in myocardium during continuous retrograde warm and mild hypothermic blood cardioplegia for coronary bypass operation.

Aged↗
PubMedDate not supplied

The initial phase of myocardial reperfusion is not associated with aggravation of ischemic-induced ultrastructural alterations in isolated rat hearts exposed to prolonged global ischemia.

The present study focuses on the qualitative and sequential development of myocardial ultrastructural changes during the first 10 min of reperfusion in isolated rat hearts exposed to 60 min of global ischemia. The frequency of and the association between ultrastructural changes were examined by semiquantitative morphometry using the micrograph as unit. In each micrograph the subcellular components of the myocytes (sarcolemma, mitochondria, myofilaments and nucleus) and the endothelial cells were evaluated and graded as slightly, moderately, or severely altered. Ischemia alone induced moderate to severe ultrastructural alterations. The myocytes revealed sarcolemmal disattachment or rupture. The myocytic mitochondria had a clear matrix with abundant broken cristae and amorphous matrix densities. The myofilamental pattern was irregular or even disrupted, and most nuclei had reduced density and showed margination of chromatin. The endothelium showed vacuolization, rupture of the plasma membrane, and extracellular accumulation of cellular debris. During the first 2 min of reperfusion severe ultrastructural alterations were partly reversed. After 10 min of reperfusion both the frequency and grade of myocardial ultrastructural alternations were similar to that observed after ischemia. Cristal adhesions occurred predominately during reperfusion and were associated with moderately and severely altered myocytic mitochondrial alterations. In conclusion, the results showed that ischemic-induced ultrastructural alterations were transiently improved upon reperfusion. With exception of the development of cristal adhesions, the acute phase of reperfusion was not associated with additional ultrastructural changes in isolated buffer-perfused rat hearts exposed to prolonged ischemia.

Animals↗
PubMed1983

Normothermic ischemic cardiac arrest of the isolated working rat heart. Effects of time and reperfusion on myocardial ultrastructure, mitochondrial oxidative function, and mechanical recovery.

The ischemic state of the myocardium of the isolated working rat heart after induction of normothermic ischemic cardiac arrest was assessed by the interrelationship among changes in myocardial ultrastructure, mitochondrial oxidative phosphorylation, and tissue high energy phosphate contents. At all time intervals (10-40 minutes) studied, the ultrastructural changes were more severe in the subendocardium than in the subepicardium. After 25-40 minutes of normothermic ischemic cardiac arrest, the mitochondrial oxygen uptake (state 3) became increasingly depressed, particularly in mitochondria isolated from the subendocardium. Mitochondrial oxidative function, as measured in vitro, did not correlate well with mitochondrial ultrastructural damage. In addition, the effects of coronary reperfusion on the ability of the ischemic heart to recover in terms of ultrastructure, mechanical, and metabolic function were evaluated. Hearts subjected to 10-40 minutes of normothermic ischemic cardiac arrest showed almost complete ultrastructural recovery of the subepicardium upon reperfusion; regression of ultrastructural changes occurred to a lesser extent in the subendocardium. Reperfusion for 30 minutes did not alleviate the depression in mitochondrial oxidative function, while tissue ATP levels did not return to control, preischemic levels. After 20 minutes of normothermic ischemic cardiac arrest, the mechanical performance of the working heart during reperfusion was significantly depressed, compared with pre-ischemic control values. Normal ultrastructure of the subendocardium always accompanied mechanical recovery, while improvement of mitochondrial oxidative function was not essential.

Adenosine Triphosphate↗
PubMed1992

Ultrastructural non-radioactive in situ hybridization of GH mRNA in rat pituitary gland: pre-embedding vs ultra-thin frozen sections vs post-embedding.

In situ hybridization at the ultrastructural level can be carried out using three different methods: on vibratome sections before embedding in epoxy resin, on ultra-thin frozen sections, or on ultra-thin sections of tissues embedded in hydrophilic resin such as Lowicryl. With the purpose of comparing the sensitivity, resolution, and ultrastructural preservation of these three methods, we examined the expression of the growth hormone (GH) gene in anterior pituitary cells by in situ hybridization at the ultrastructural level, using a synthetic oligonucleotide complementary to the codons of the mRNA from Gln 45 to Ser 54 labeled at the 3' end of biotin-21dUTP. All these methods gave similar results: mRNA was located on the lamellar endoplasmic reticulum of somatotrophs. The pre-embedding method gave the best ultrastructural preservation, with low resolution with the enzymatic detection system and an intermediate sensitivity. A probe concentration of 10 pmol/ml was sufficient to obtain a signal. With this method gold particles could not be used without pre-treatment. The frozen section method gave the best sensitivity (a signal was observed with 4 pmol/ml of probe) but the lowest ultrastructural preservation. On ultra-thin Lowicryl sections, resolution was as high as with the frozen-section method, ultrastructural conservation was intermediate, and sensitivity was low. These results indicate that the last method seems to be a good compromise between sensitivity and ultrastructural preservation.

Animals↗
PubMed2006

A study on blood-brain barrier ultrastructural changes induced by cerebral hypoperfusion of different stages.

OBJECTIVES: To evaluate the ultrastructural changes in the blood-brain barrier (BBB) induced by cerebral hypoperfusion of different stages, which may predispose the brain to the formation of vasogenic edema and hemorrhage under cerebral luxury perfusion. METHODS: Twenty cerebral steal models with left neck arteriovenous fistula (AVF) were surgically created in Wistar's rats, leading to a noninfarctional reduction in the cerebral blood flow (CBF) by between 25 and 50%, resulting in cerebral hypoperfusion in the AVF side for 3 days (acute stage), 3 weeks (subacute stage) and 3 months (chronic stage), respectively. Another six sham-operated models were made in age-matched rats as control. The BBB ultrastructural changes were assessed by transmission electron microscopy. Ridit analysis was conducted to compare the positive ratio of ultrastructural changes among multiple groups. RESULTS: Electron microscopy demonstrated no ultrastructural change at the acute stage, however, at the subacute stage, slight vacuolar degeneration was found in the astrocytic foot process layer encircling the capillaries; furthermore, at the chronic stage, the astrocytic foot processes expressed marked vacuolization associated with the adjacent astrocytic degeneration. Meanwhile, in both capillary endothelium and basal lamina layers, no abnormal ultrastructures similar to those in the astrocytic foot processes layer were identified. After cerebral luxury perfusion took place, BBB was disrupted where astrocytic foot processes vacuolization was most distinguished. CONCLUSION: Astrocytes generate ultrastructural abnormality as a result of chronic cerebral hypoperfusion. Astrocytic foot process vacuolization, which constitutes the major ultrastructural change in the BBB, is the extension of the degeneration of astrocyte body. It is inferred that BBB is prone to structure weakness and function instability, which forms the morphological basis of cerebral luxury perfusion.

Animals↗
PubMed1999

[Disjunction patterns: the morphological and ultrastructural bases of bladder instability in the male].

OBJECTIVE: To apply the new protocols and recent contributions on detrusor ultrastructural morphology in order to standardize criteria and evaluate our findings relative to the ultrastructural morphology, the presence of a dysfunction pattern, changes in nerve supply and formation of a chained cellular syncytium in hyperactive detrusor bladder instability in the male. METHODS: We studied 480 ultrastructural preparations of detrusor muscle from 32 male patients with bladder outlet obstruction with and without urodynamically demonstrated bladder hyperactivity. Bladder biopsies were obtained from the anterior aspect of the bladder and prepared according to the standard procedures for ultrastructural study. Semiquantitative nerve supply ultrastructural patterns, syncytial composition, and complete and incomplete disjunction were analyzed. RESULTS: Lower urinary tract obstruction was demonstrated in all patients; 6 of these patients had involuntary phasic detrusor contractions during filling. No significant decrease in nerve supply was found in isolated obstruction or in bladder hyperactivity. No axonal degeneration was observed in any of the patients and the myelin sheath structure was normal. Nerve effector endings were also normal. Four patients with hyperactive detrusor showed complete and two incomplete disjunction pattern. Incomplete disjunction pattern was also demonstrated in two patients with isolated obstruction. CONCLUSIONS: The change in the properties of the detrusor muscle in the unstable bladder is due to a complete reduction in excitatory nerve relation to smooth muscle. Having established the concept of common final myogenic pathway that explains involuntary detrusor contraction, complete dysfunction ultrastructural patterns have been defined with univocal relation to hyperactive detrusor. These patterns indicate the existence of a syncytium of chained muscle cells with changes in the excitation threshold that are absent in the normal stable detrusor. Two ultrastructural components sustain this hypothesis: 1) the major loss observed in intermediate cellular unions that are thought to mediate in the mechanical coupling of cellular contraction and 2) the presence in all the microscopic fields of abutments in the narrow cellular unions like gap-junctions, which mediate the electrical coupling. In the present study we have found this pattern in 4 out of 6 patients with hyperactive detrusor, and congruent with other studies, the incomplete disjunction pattern could be the prelude of bladder hyperactivity.

Aged↗
PubMed2000

Comparative quantitative ultrastructural study of pinealocytes in eight mammalian species.

OBJECTIVES: The studies related to quantitative ultrastructural features of mammalian pinealocytes, especially in comparative aspects, are relatively rare. Quantitative ultrastructural studies in many mammalian species are lacking. Because of the existence of differences in diurnal melatonin profiles in various species it seemed interesting to compare the ultrastructure of pinealocytes in various mammalian species, both laboratory and domestic animals. MATERIAL AND METHODS: The pineal glands of the following mammalian species have been examined: mouse, rat, Syrian hamster, gerbil, sheep, horse, pig and European bison. For each species 4 adult animals (2 males and 2 females) were used. Cross-sectional areas of the pinealocyte and its nucleus and the relative volumes of the following cytoplasmic organelles were analyzed: mitochondria, lysosomes, Golgi apparatus, granular endoplasmic reticulum, and lipid droplets. The relative volumes of membrane-bound bodies (MBB) in the pig pinealocytes, pigment granules in the horse pinealocytes, and calcareous concretions in the gerbil pineal gland were also analyzed. In addition, numerical density of dense-core vesicles and "synaptic" ribbons was estimated. RESULTS: Ultrastructure of pinealocytes in examined species shows many common features, and existing differences are of quantitative nature only. The observed qualitative differences include MBB in the pig, abundance of pigment granules in the horse, and calcareous concretions in the gerbil. Relative volumes or the numbers of some cell structures (mitochondria, Golgi apparatus, lipid droplets, dense-core vesicles and "synaptic" ribbons) show distinct interspecie differences, whereas those of other cell structures (granular endoplasmic reticulum, lysosomes) are similar in all studied species. CONCLUSIONS: The ultrastructural features of pinealocytes in all examined species confirm earlier suggestions of high activity of these cells. No distinct correlation has been found between the type of melatonin secretion and ultrastructural patterns of pinealocytes. It should be stressed, however, that the ultrastructure of pinealocytes in the present study was studied during the daytime, whereas differences in melatonin secretion are observed at night.

Journal Article↗