Ultrastructural pathological changes in mice kidney caused by Plasmodium berghei infection

Malaria, a common health problem in certain parts of the world, has a considerable morbidity and mortality. This work reports under electron microscopy studies serious ultrastructural kidney damage such as extensive cytoplasmic vacuolation, vesiculation and autophagic vacuoles in proximal tubular cells. A thickened endothelial wall on peritubular capillary, interdigitation disorganization and significant decrease of their number in some areas were detected. Swollen rough endoplasmic reticulum, swollen mitochondria, and parasitized erythrocytes were observed. Many epithelial cells exhibited cytoplasmic areas of autophagia and a myelin-like form. A tubular cell presented severe cytoarchitecture alterations. Abundant lipid droplets were noticed. Almost total loss of interdigitations, rough endoplasmic reticulum vesiculation, peritubular capillaries with endothelial cells thickened cytoplasm, papillary processes projected to the lumen, and an inflammatory infiltrate of macrophages were also observed. These ultrastructural kidney changes could cause, on the basis of their clinical and pathologic expressions, a fat accumulation, an acute temporary reversible glomerulonephritis, a chronic progressive irreversible glomerulonephritis, and an acute renal failure (ARF).

Effects of herbicide on the kidneys of two Venezuelan cultured fish: Caquetaia kraussii and Colossoma macropomum (Pisces: Ciclidae and Characeae)

The use of chemical pesticides and herbicides has increased environmental pollution and affected ichthyofauna in the watersheds where they are used. We studied the effect of an herbicide, triazine, on the kidneys of two species (Caquetaia kraussii and Colossomna macropomum) widely found in Caribbean and South American rivers. In Venezuela, these species are abundant and have a high aquaculture potential because they may be cultured and reproduced in captivity. Four kidney samples from juveniles of each species exposed to the herbicide were examined by Transmission Electron Microscopy. Kidney tubule alterations included loss of plasmalemma and cell interdigitations, misshaped mitochondria, decrease in rough endoplasmic reticulum and free polysomes, and the presence of autophagic vacuoles and primary lysosomes. These alterations at the cellular level may explain fish behaviour in terms of kidney tubule pathology, and relative amounts and conditions of organelles within affected cells.

Trypanosoma rangeli: ultrastructure and activity of the mitochondrion

Axenic cultures of pure Trypanosoma rangeli were used to investigate the relation between ultrastructure and activity in the mitochondrion. Every other day, ultrathin sections were obtained from cultivated flagellates and, subsequently, observed in order to register changes in the cytoarchitecture of the organelle. Culture samples were incubated in tetrazolium salts to determine the mitochondrion's metabolic state. The results show a high correspondence between mitochondrion ultrastructural shape and function of the same organelle in populations of T. rangeli maintained under in vitro conditions.

Inflammation and nitric oxide production in skeletal muscle of type 2 diabetic patients

An inflammatory process may be involved in nitric oxide production in skeletal muscle of type 2 diabetic patients. Nitric oxide generation in skeletal muscle was assessed in 14 non-complicated type 2 diabetic patients and in 12 healthy subjects. In samples of quadriceps femoris muscle, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), nitrite, nitrate and nitrotyrosine were determined. The macrophage-specific antigen CD163, the T-cell membrane factor CD154 and tumour necrosis factor-alpha (TNF-alpha) were also assayed. In six patients, ultrastructural analysis of muscle was performed. Nitrites and nitrates were increased in patients as compared to controls (22.7+/-4.5 and 32.7+/-7.0 vs 16.0+/-2.9 and 22.8+/-4.0 micromol/mg protein; P<0.001, Mann-Whitney U test). Endothelial NOS was similar in diabetic and control subjects (36.4+/-13.8 vs 36.3+/-6.8 ng/mg protein), contrasting with the significant increase of iNOS recorded in patients (34.3+/-13.0 vs 8.5+/-2.8 ng/mg protein, P<0.00002). Nitrotyrosine levels were higher in the patient than in the control group (42.1+/-24.4 vs 10.3+/-2.5 ng/mg protein, P<0.00002), as were CD163 (10-fold) and TNF-alpha (fourfold) levels. Furthermore, CD154 levels were detectable only in the patient samples (10.2+/-5.3 ng/mg protein). By multiple-regression analysis, changes in glycated haemoglobin values could predict 96% variation in nitrotyrosine. Macrophages were present in all muscle samples analysed by electromicroscopy. The increased levels of CD163, CD154 and TNF-alpha indicate that an inflammatory process occurs in skeletal muscle of type 2 diabetic patients. This may contribute to iNOS induction, muscle damage and insulin resistance.

Effects of Azadirachta indica and Melia azedarach (Meliaceae) extracts from leaves on Trypanosoma cruzi growth and ultrastructure

The chloroformic extracts from dried fresh leaves ofAzadirachta indica A. Juss. and Melia azedarach L. (Meliaceae) showed marked inhibitory activity on epimastigotes growth of Trypanosoma cruzi, evidenced by 96-wells microtiter plate bioassay and radioactive thymidine incorporation experiment. Each chloroformic extract was separated using silica gel and alumina column. In transmission electron microscopy the bioactive chromatographic fractions caused ultrastructural changes in epimastigotes such as vacuolization probably induced by degeneration of the kinetoplast-mitochondrion complex, organelle degeneration, and cell division disruption. In spectral analysis these bioactive fractions seemed to be composed mainly of fatty acid mixtures.

Cellular and subcellular changes in muscle, neuromuscular junctions and nerves caused by bee (Apis mellifera) venom

Biopsy specimens of cervico-scutular muscles obtained from animals injected with bee crude venom were prepared for electron microscopy studies. At 6 h from Apis mellifera venom injection, in mice under transmission electron microscopy, the muscular fibres presented different atrophy levels with increment of the intermyofibrillar spaces. Tubules and sarcoplasmic reticulum elements were altered, in some places only tubular fragments and an increment of the intermyofibrillar spaces were noticed as well as loss of fibre regularity and prominent triads. In subsarcolemma region, areas lacking myofibrils and mitochondria damages were observed. Muscular segmental necrosis and atrophy areas were observed. Neuromuscular junctions were altered. The number of synaptic vesicles was very variable and synaptic clefts showed irregularities. A decrease in the number and arrangement of the synaptic clefts, as well as free polysomes, suggesting regeneration processes, were also observed. The myelinic nerves exhibited in the axon or in the wall vacuolisation areas. The presence of severe muscular lesions, the finding of venom activities in the presynaptic region and the detection of damages in the neuromuscular junctions at different chronological stages of our experiments indicate that the bee venom is highly toxic for neuromuscular structures.

Ultrastructural alterations in cortex of adrenal gland caused by the toxic effect of bee (Apis mellifera) venom

Bee accidents incidence is underestimated because many people do not consult to the physicians. Here it is described for the first time the severe mice adrenal gland damage induced by Apis mellifera venom. Biopsy specimens were obtained from mice adrenal gland and after sample preparation observed in Hitachi H-7100 electron microscope. In this work the ultrastructural analysis showed, 6 h after injection, a non homogeneous smooth endothelial reticulum, and in some places loss of plasma membrane. The fenestrae spaces were bigger and detritus in the capillary lumen were observed. Erythrocytes were seen in a cortical cell. After 48 h of venom injection, expanded fenestrae were observed. Capillary basal membrane was interrupted. Myelin-like figures and autophagic vacuoles were noticed. Swollen smooth endoplasmic reticulum elements and endothelial unfolding to the light were seen. Moreover, swollen Golgi and mitochondria were observed, in some places forming myelinic-like figures. At 144 h after venom injection, widened spaces were noticed in capillary fenestrae. Cellular section showed swollen and lost smooth endoplasmic reticulum elements. Smooth endoplasmic reticulum tubules disappearance suggested non steroidogenesis. In conclusion, we suggest that some of the bee envenoming human clinical manifestations, as is observed in mice, are determined by suprarenal gland damage produced by toxins present in this venom.

Kidney structural and ultrastructural pathological changes induced by uracoan rattlesnake (Crotalus vegrandis Klauber 1941) venom

Acute renal insufficiency related to acute tubular necrosis is the most important complication caused by crotalid bite. For structural and ultrastructural studies of renal tissue, mice injected with crude venom or C. vegrandis haemorrhagic fraction, and controls were tested. Light microscopy analysis of kidneys at 24 h after injection of crude venom showed only moderate alterations such as tubular epithelia microvacuolisation. After 120 h marked glomerular and tubular capillaries congestion and interstitial oedema were observed. At 24 h after Uracoina-1 i.p. injection, intense glomerular and peritubular capillaries congestion was observed. Electron microscopic analysis of kidneys 24 h after i.p. injection of crude venom showed, capillary endothelial cell debris and pleomorphic mitochondria. Loss of interdigitations regularity, abundant dense bodies and light widening of the basal membrane were observed. Autophagic vacuoles were present as well as endothelia unfolding to the lumen and altered forms of podocytes. At 48 h, augmented endothelia without fenestrae formation with sequestration of low optical density debris inside the protrusions were noticed. At 120 h, capillary residues with loss of the endothelium were present and the basal membrane was widened. At 15 days, the number of vesicles and vacuoles in the tubules was increased and only few interdigitations were noticed. Autophagic vacuoles and mitochondrial matrix low electron density were observed. At 120 h after injection of crude venom, vascular damage with loss of capillary cell structures and collagen fibres were observed. At 24 h of haemorrhagic fraction injection, presence of autophagic vacuoles and myelinic figures were noticed.

Skeletal muscle microvascular alterations in euthyroid and hypothyroid patients with autoimmune thyroid disease

An electron microscopic study of skeletal muscle biopsies from euthyroid and hypothyroid patients with autoimmune thyroid disease (ATD) showed the existence of capillary alterations and a mononuclear cell infiltrate. Microvascular abnormalities included thickening and lamination of basement membrane, endothelial proliferation with progressive lumen occlusion, and hypertrophied pericytes. Capillary degeneration was also observed. Macrophages, and scarce lymphocytes and mast cells formed the cell infiltrate. This pathological picture is similar to that found in the muscular compromise of other autoimmune diseases, particularly Graves' hyperthyroidism. This study shows that patients with ATD may have skeletal muscle capillary abnormalities that could probably be related to autoimmunity and are independent of thyroid functional status.

Extraocular muscle ultrastructural pathology in the paraneoplastic phenomenon associated with retinoblastoma

Extraocular muscle biopsies were obtained during enucleation because of advanced intraocular retinoblastoma in four patients admitted to the Service of Ophthalmology at the Caracas University Hospital. Slight limitations of ocular movements and strabismus were present in all cases. The electron microscopical analysis showed muscle fibres with slight to severe atrophy exhibiting myopathic structures as nemaline, filamentous and zebra bodies. Fibre necrosis was also observed characterized by sarcomeric hypercontraction, autophagia, sarcolemmal disruption, and mitochondrial swelling. Capillary alterations included endothelial proliferation with intraluminal infoldings and, in some cases, capillary degeneration and necrosis. A mononuclear cell infiltration formed by macrophages and scarce mast cells located next to atrophic fibres and altered capillaries was observed. Additionally, neutrophils were found around capillaries and in their wall. Cancer cells invading muscle tissue were not seen. Two different ethiopathogenic mechanisms for muscle damages seem to be present. Because of the similarity between the microvascular changes we observed and those found in the muscle compromise of several autoimmune diseases, an autoimmune component in the ethiopathogenesis of the observed capillary alterations is proposed. On the other hand, abnormalities observed in muscle fibres are very similar to those in neurogenic atrophy. This study represents the first report on an extraocular muscle paraneoplastic phenomenon associated with orbital tumours.

Skeletal muscle ultrastructural pathology in mice infected with Trypanosoma evansi

An ultrastructural study of skeletal muscle alterations wascarried out in mice experimentally infected with Trypanosoma evansi. Manifested anomalies were found, in both muscle fibre and microvasculature. Muscle fibre changes included atrophy, autophagic vacuoles formation, mitochondrial degeneration, nuclei pyknosis and segmental necrosis. In another direction, the cytoplasm of capillary endothelial cells showed rough endoplasmic reticulum and mitochondrial swelling, as well as luminal infoldings; parasites were found in the endothelial cell cytoplasm. A mononuclear infiltrate, formed by macrophages and neutrophils, was also observed. This work shows that skeletal muscle is an important target tissue for Trypanosoma evansi.

Salivary gland ultrastructural alterations in mice inoculated with Tityus discrepans (Buthidae) venom

In this work we have studied the possible relationships between clinical manifestations such as sialorrhea, appearing in response to the toxic aggression by Tityus discrepans venom, and the alterations or changes at cellular or subcellular levels in sub-maxillary salivary glands in the murine model. To evaluate salivary gland subcellular response to Tityus discrepans venom, male C57/Bl adult mice were randomised into two groups: a group of mice were intraperitoneally injected with Tityus discrepans venom at a dose of 5 mg/Kg of weight and controls received saline solution. In the salivary glands from the envenomed animals sub-cellular changes such as hyperchromatic nucleus, swollen rough endoplasmic reticulum, granules of different electron density, some of them practically transparent, nucleolus of low density and big size and electron-transparent cisterns were observed. Capillary wall was augmented in certain areas and thin in others. Endothelial cell infolding to the lumen was seen. The distribution of the vesicles and its density varied. Macrophages and plasmocytes were observed next to the damaged capillaries. Different electron density of cytoplasm was noticed. In conclusion, we suggest that sialorrhea is determined by salivary gland damage produced by toxins present in this venom.

Hepatocyte ultrastructural alterations in cocaine users

The ultrastructural examination of liver biopsies from five male cocaine users showed hepatocytes presenting diverse alterations in rough and smooth endoplasmic reticulum, mitochondria, nuclei and microvilli. Lipid deposition and an increase of autophagic vacuoles were also observed. This study demonstrates that the hepatocyte is an important target cell for cocaine toxic effects in some patients.

Capillary changes in skeletal muscle of patients with essential hypertension

Arterial hypertension produces changes along the vascular tree. However, there are few reports on its effect on human muscle capillaries. This study demonstrates the effects of essential hypertension on the capillaries of human quadriceps muscle. Muscle biopsy was taken from quadriceps femoris in eight men with recent diagnosis of essential hypertension, without treatment. Biopsies were also taken from eight normotensive men and were used as controls. Fiber types were classified by ATPase reaction, capillaries counted in alpha-amylase-PAS stained sections and ultrastructure studied by conventional methods of transmission electron microscopy. No changes were found in capillaries or muscle fiber types by histochemical methods. However, electron microscopy revealed abnormal capillaries with endothelial cells infoldings into the lumen, as well as occluded or degenerated capillaries. In some cases the endothelial cell area covered by pericytes was increased. Basement membrane of capillaries was frequently increased in width, sometimes irregularly, and in other instances it was reduplicated. In transversely sectioned capillaries lumen diameter was reduced and wall thickness was increased, although total diameter was unchanged. In hypertensive patients the finding of some degenerated capillaries adjacent to muscle fibers could be interpreted as the beginning of a process of rarefaction. Some capillaries showed morphological changes, and the ratio wall thickness/lumen was increased.

Ultrastructural alterations in the adrenal gland cortex of mice experimentally infected with a Venezuelan isolate of Trypanosoma evansi

The ultrastructural study of adrenal gland from mice experimentally infected with Trypanosoma evansi, in addition to intravascular and intracellular trypanosomes, showed different degrees of cortical cell alterations and capillary wall modifications. Beside its biological scope, these results suggest a role for the adrenal cortex to partake in Surra's etiopathogenesis and describe for the very first time a T. evansi intracellular stage.

Ultrastructural pathology in skeletal muscle of mice envenomed with Crotalus vegrandis venom

In this ultrastructural study we examined skeletal muscle fibres from mice intraperitoneally inoculated with a sublethal dose of Crotalus vegrandis (rattlesnake) venom. The group of mice inoculated presented neurological symptoms characterised by respiratory failure and hind limbs paralysis. Skeletal muscle fibres showed different degrees of alterations. Most of them presented the characteristic pattern of necrosis in progress. Atrophied and hypercontracted fibres were frequently seen. Some atrophied and necrotic fibres showed several nucleoli-like bodies in the nucleus. In the atrophic and hypercontracted fibres, sarcoplasmic vacuolation and abnormal mitochondria with stacked cristae were observed. Areas of segmental necrosis were also frequently found. In connection with these altered muscle fibres, capillary abnormalities were detected. This study suggests that in envenomed mice respiratory failure symptoms may be related with muscle damage caused by Crotalus vegrandis venom components.

Liver ultrastructural pathology in mice envenomed with Uracoan rattlesnake (Crotalus vegrandis) venom

In South America rattlesnake venom activities have not been entirely characterised. Some studies have shown haemorrhagic, myotoxic, and neurotoxic effects as manifestations of envenoming in experimental animals and humans. Biopsy specimens were obtained from liver and immediately fixed in situ and observed in Hitachi H-500 and H-7100 electron microscopes. In this work the ultrastructural analysis of experimental mice liver showed hepatocytes with increased lipid droplets content and significant vacuolation in areas of their cytoplasm limiting with the Disse space. Lysosomes and altered peroxisomes exhibiting a very dense electron content were also evident. Mitochondrial pleomorphism including cup-shaped and ring-shaped mitochondria were frequently found. The cristae were scarce or absent in the majority of mitochondria observed. The rough endoplasmic reticulum showed a preferentially disposition lining the outer mitochondrial membranes. In some section glycogen particles were scarce and lipofuchsin granules could be observed. Red blood cells showed endothelial cell adherence and, in many instances, the liver sinusoids were observed plugged with aggregated red blood cells. In conclusion, using an animal model that probably correlates well with the pathological effects found in envenomed humans, we have shown the severe hepatocellular alterations caused by this venom.

Ultrastructure of hepatocyte abnormalities in perimetastatic areas

The ultrastructural pathology of non-invaded hepatocytes located in close proximity to metastases from diverse gastrointestinal carcinomas was studied. Observed abnormalities included swelling of rough and smooth endoplasmic reticulum, proliferation of lysosomes, and mitochondrial alterations as presence of granules and paracrystalline inclusions, marked pleomorphism, and lack of cristae. These results show that, contrary to the classical conception, the non-invaded cells surrounding primary tumours or their metastases could be abnormal.

Liver ultrastructural pathology in mice infected with Plasmodium berghei

As liver can be an important target organ in malaria, we performed an ultrastructural study of hepatic alterations in the final stage of Plasmodium berghei infection in mice. Significant hepatocyte abnormalities were found. An elevated number of cells showed mitochondria with a high electron-dense matrix and multiple changes in shape and size, alterations in the structure of Golgi complex, swelling and disorganisation of both rough and smooth-surfaced endoplasmic reticulum, differently shaped peroxisome nucleoids, and disappearance of glycogen granules. In other areas the hepatocytes were significantly altered with diminished microvilli and exhibited myelin-like figures, autophagic vacuoles, abundant lipid droplets, and swollen mitochondria in their cytoplasm. Necrotic and atrophied hepatocytes with scarce microvilli in the Disse space and biliary canaliculi could be seen. Parasitised red blood cells and parasite debris were found inside degenerated hepatocytes. Alterations were also noticed in microvasculature, including thickened endothelial cells with swollen mitochondria, lysosomes and autophagic vacuoles in their cytoplasm. Our results demonstrate that hepatocyte damage is an important finding associated with the advanced stages of P. berghei malarial infection, which may lead to liver dysfunction in this disease.

Histochemical and ultrastructural study of skeletal muscle in patients with sepsis and multiple organ failure syndrome (MOFS)

Muscle biopsies for histochemical and ultrastructural analysis were obtained from seven critically ill patients admitted to the Intensive Care Unit of the "Domingo Luciani" Hospital, Caracas, Venezuela. The sample included two patients with sepsis of abdominal origin, and five that presented sepsis/MOFS, with renal, hepatic, and respiratory disturbances and muscular weakness. Sections were examined for myosin adenosine triphosphatase (ATPase) after pre-incubation with both acid buffer (pH 4.37 and 4.6) and alkaline buffer (pH 10.3), for reduced nicotinamide dinucleotide diaphorase (NADHd), and for alpha-glycerophosphate dehydrogenase (alpha-GPDH). Sections were stained with hematoxilin and eosin to look for pathological changes and examined with a transmission electron microscope. Skeletal muscle of patients in early stage of sepsis showed a normal aspect with light microscopy, but at the ultrastructural level some of the fibres showed atrophy and some capillaries looked altered. Patients with sepsis/MOFS exhibited an evident muscle disorder with oedema, infiltrate, atrophy and segmental necrosis. All fibre types showed decrease in diameter; specially fibre types IIA and IIB. Intramuscular capillaries were thickened and occluded, indexes of capillarity were slightly reduced, and fibre oxidative activity was decreased. At ultrastructural level fibres showed severe atrophy, contractile system disorganization and segmental necrosis. Capillaries were also altered and the mononuclear cell infiltrate was abundant and represented by macrophages, lymphocytes and mastocytes.

Ultrastructure of hepatic metastases from a colon leiomyosarcoma

The electron microscopic examination of biopsies from liver metastases of a colon leiomyosarcoma showed the existence of alterations not previously reported in primary tumors of that kind. Those abnormalities included proliferation of lysosomal structures as multivesicular bodies, myelin-like figures, lipofuscin granules and autophagic vacuoles, along with mitochondrial changes as concentric and vesiculated cristae, and presence of dense granules and elongated inclusions. This study suggests that, in this tumor and host tissue, the so-called invasive phenotype, which is supposed to form the metastases, could have a distinct morphological picture at the ultrastructural level.

Anopheles aquasalis eggs from two Venezuelan localities compared by scanning electron microscopy

Anopheles (Nyssorhynchus) aquasalis, is the main coastal vector of malaria from northeastern Venezuela to southeastern Brazil. Several authors have argued that An. aquasalis is a highly polymorphic species while others indicated that it is a complex of closely related species. This investigation compared the morphology of An. aquasalis eggs from Sinamaica (Zulia State) and Yaguaraparo (Sucre State), the west and east of Venezuela, respectively. We were able to separate eggs from the two localities using discriminant analyses based on ratios and percentages of anterior and posterior tubercles measured by scanning electron microscopy. The results of this work suggest that An. aquasalis has high intraspecific variation.

Microvascular pathology in the skeletal muscle paraneoplastic phenomenon

An electron microscopic investigation was made in order to study capillary alterations in the muscle paraneoplastic phenomenon associated with different malignant tumours. Several abnormalities were found including basement membrane widening and lamination, endothelial hypertrophy, a varied degree of lumen occlusion, and proliferative changes in pericytes. A degenerative process leading to capillary necrosis was also observed. A mononuclear cell infiltrate formed by macrophages, lymphocytes and mast cells was seen. The capillary changes observed suggest the existence of an autoimmune vascular factor in the etiopathogenesis of muscle damage in this phenomenon.

Adrenal cortex alterations in mice infected with Plasmodium berghei

The ultrastructural study of adrenal cortex from Plasmodium berghei infected mice showed different degrees of capillary wall alterations including disruption and widening of the fenestrae, capillaries packed with parasitized erythrocytes, necrosis of cortical cells, parasitized erythrocytes outside capillaries and in some instances inside cortical cell cytoplasm. Lymphocytes were also observed in degenerated cortical cells. Our results suggest that adrenal cortex lesions may be relevant in the etiopathogenesis of severe malaria.

Skeletal muscle pathology in mice experimentally infected with Toxoplasma gondii

In two different groups of mice, the infection with Toxoplasma gondii was produced by intraperitoneal route, with 2 x 10(5) parasites (n = 8) and 14 x 10(5) parasites (n = 3). Five days after infection animals were killed to examine skeletal muscles by light and transmission electron microscopy. Severity of muscle alterations depended upon concentration of parasites. Parasite cysts were not identified in muscle sections. Ultrastructural features revealed different degrees of fibre atrophy, alterations in the sarcomeric structure and, in some cases, disorganization of contractile and sarcotubular systems. Changes in muscular capillaries included loss of the endothelial wall, occlusion of lumen and necrosis. Motor end-plates were abnormal and axonolysis was present. A mononuclear cell infiltrate consisted of macrophages, lymphocytes, mastocytes and eosinophils were observed. In this murine model it was demonstrated that the infection of non-immunocompromised hosts with Toxoplasma gondii produces an acute myositis.

Capillary and muscle fiber type changes in DOCA-salt hypertensive rats

BACKGROUND

Discrepancies concerning the effect of hypertension on capillaries and muscle fiber types in skeletal muscle have been reported. This study demonstrates the effects of hypertension produced by deoxicorticosterone acetate (DOCA) and salt load on the extensor digitorum longus (EDL) and soleus muscles of the rat.

METHODS

Hypertension was produced by subcutaneous injections of DOCA and supplemented with drinking 1% NaCl solution. One group was treated for 7 weeks and another for 14 weeks. Fiber types were classified by ATPase reaction at pH 4.35, capillaries were counted in alpha-amylase-PAS-stained sections, and ultrastructure was studied by conventional methods of transmission electron microscopy.

RESULTS

In the 7-week group, a decrease in the percentage of IIA, with an increase in IIB and I fiber types, was found in the EDL muscle. Capillary density was not reduced, but endothelial cells showed surface infoldings into the lumen. Altered mitochondria and an infiltrate of macrophages was present in pericytes. In the 14-week group, a decrease in capillary to fiber index was found in both soleus and EDL muscles. EDL fiber type changes were the same as at 7 weeks. The soleus muscle showed an increased percentage of type I fibers. Some capillaries were degenerated, and others showed an increase in the endothelial cell area covered with pericytes, which resembled smooth muscle cells.

CONCLUSION

Hypertensive rats showed changes in the percentage of fiber types in the soleus and EDL muscles. Capillaries adjacent to muscle fibers were reduced and showed morphological changes that resembled arterioles.

Skeletal muscle ultrastructural pathology in Serinus canarius infected with Plasmodium cathemerium

Serinus canarius infected with Plasmodium cathemerium was used as an animal model in order to study the skeletal muscle compromise in malaria. Pectoral muscle biopsies were obtained from 7 infected female birds. The transmission electron microscopic study showed alterations of contractile and sarcotubular systems, mitochondrial abnormalities, lysosomal proliferation and nuclear pyknosis. The sarcolemma looked disrupted and separated from the necrotic fibres. Capillary abnormalities included endothelial degeneration with proliferation of lysosomal structures, penetration of endothelial cell by the parasites and necrosis. A mononuclear cell infiltrate formed by plasmocytes, lymphocytes and macrophages was observed. This investigation shows that skeletal muscle is an important target tissue for some malaria parasites.

Toxic and neurogenic factors in chloroquine myopathy fibre selectivity

Biopsies from soleus and extensor digitorum longus (EDL) muscles obtained in rats with an experimental chloroquine myopathy were studied ultrastructurally. Two different histopathological pictures were observed: type I fibres from soleus exhibited a vacuolar myopathy with an almost normal sarcomeric structure; type II fibres from EDL did not show vacuoles but changes similar to neurogenic atrophy. Our results suggest that chloroquine produces direct toxic effects in type I fibres and secondary neurogenic damage in type II fibres.

Ultrastructure of systemic sclerosis inflammatory myopathy

Muscle biopsies from 7 patients with systemic sclerosis (SS) and a slowly progressive proximal muscular weakness were studied ultrastructurally. In all cases an inflammatory myopathy was found exhibiting fibre atrophy, occasional fibre necrosis, connective tissue proliferation, filamentous bodies, concentric laminated bodies and a mononuclear cell infiltration formed by lymphocytes, macrophages and mast cells. Capillary abnormalities included alterations of endothelium, thickening and reduplication of basement membrane and the presence of cylindric confronting cisternae. The different associations between muscle diseases and SS are grouped. Our data suggest that SS inflammatory myopathy is a distinct clinical and pathological entity.

[Skeletal muscle ultrastructural pathology in bovine paraplegic syndrome]

This study reports the ultrastructural alterations found in biopsies taken from fast twitch gastrocnemius and slow twitch soleus muscles from bovines affected by the paraplegic syndrome. The abnormalities observed were contractile and sarcotubular systems disorganization, proliferation of autophagic vacuoles with mitochondrial material and glycogenosomes, decrease of nuclear chromatin electron density, and sacrolemmal damage in areas of segmental necrosis where macrophages were also seen. Capillary alterations were slight. Mentioned abnormalities are discussed in connection with mineral nutritional deficiences presented by the studied animals.

Muscular changes in Venezuelan wild horses naturally infected with Trypanosoma evansi

Skeletal muscle biopsy specimens were taken from 10 male horses naturally infected with Trypanosoma evansi and from 10 uninfected males. An indirect fluorescent antibody test was used to provide a rapid and reliable indication of infection. Histological, histochemical and transmission electron microscopical techniques were used to examine skeletal muscle. The ultrastructural features in muscle fibres were those usually seen in autoimmune disease, namely fibre and capillary necrosis and mononuclear cell infiltration, consisting of macrophages. Changes in fibre-type percentages did not occur in response to the parasite, but alterations in fibre size and capillary supply were found in the parasitized horses.

Effects of thyroidectomy on biochemical and ultrastructural aspects of rat slow and fast muscles

Thyroidectomy provoked the reduction of the oxygen consumption rate in state 3 respiration in both Extensor Digitorum Longus (EDL, fast twitch) and Soleus (slow twitch) muscles of rat, being the last one the most affected. Morphological alterations after 8 weeks of thyroidectomy were found in mitochondria. These organelles exhibited cristae swelling and formation of autophagic vacuoles in subsarcolemmal and intermyofibrillar spaces. Altered mitochondria were also seen in the axon terminal and the postjunctional region of motor end-plate.

Ultrastructure of an iguana fast twitch denervated muscle

This ultrastructural study was undertaken to investigate the morphological changes which occur in the fast twitch gastrocnemius muscle of the reptile Iguana iguana after nerve section. It was found that initial degenerative alterations appeared in muscle fibers two weeks after denervation and progressed along the two months of the investigative period. They consisted of disorganization of contractile and sarcotubular elements and the appearance of autophagic vacuoles with mitochondrial debris. However, even two months after nerve section some myofibrils and mitochondria looked normal. Our results suggest that although the general course of denervation atrophy in iguana gastrocnemius is similar to that in other twitch muscles of vertebrates, the chronology of the process shows that iguana fast twitch skeletal muscles exhibit an intermediary position among the vertebrates in relation to their velocity of response to denervation.

Ultrastructural pathology of skeletal muscle in systemic lupus erythematosus

Muscle biopsies from 12 patients with systemic lupus erythematosus (SLE) who presented with muscle weakness and myalgias were studied ultrastructurally. Two different alterations were present, myositis (11 cases), and vacuolar myopathy (1 case). The myositis exhibited muscle atrophy, microtubular inclusions, and a mononuclear cell infiltration. In one case, with increased serum creatine phosphokinase, fiber necrosis was evident. Capillary abnormalities included thickening and reduplication of basement membrane, alterations of endothelium and microtubular inclusions. The vacuolar myopathy also showed vacuolated muscle fibers and occasional zebra bodies. The different associations between muscle diseases and SLE are grouped. Our data suggest that SLE myositis is a distinct clinical and pathological entity. The SLE vacuolar myopathy is a pathological entity clinically undistinguishable from SLE myositis.

Ultrastructure of skeletal muscle in rheumatoid myositis

Muscle biopsies from 8 cases of rheumatoid myositis (5 females and 3 males) were studied by electron microscopy. All muscle fibers studied showed either necrosis or atrophy, the latter varying from slight to severe. Mononuclear cell infiltration was present in all cases, with 4 types of cells observed (lymphocytes, plasma cells, macrophages and mast cells). The capillary endothelium showed proliferation of organelles, occlusion of lumina, and thickening of the basement membrane. The pathogenesis of muscle damage in rheumatoid myositis is discussed.

Chronic stimulation modifies the isotonic shortening velocity of denervated rat slow-twitch muscle

Rat soleus muscles were denervated and stimulated in vivo for periods of up to 104 days. Stimuli used were trains of 1 ms pulses at 100 Hz delivered for periods of 1 s; trains were repeated every 10-100 s. In a majority of animals the tension of the muscles was maintained at about 10% of normal, equivalent to muscles denervated but unstimulated for 20 days. At the longest periods the stimulated muscles developed ten times more tension than ones that were denervated but not stimulated. In denervated and denervated-stimulated muscles twitch contraction and relaxation times were prolonged, compared with controls, for up to 3 weeks. Thereafter both sets showed a speeding of the isometric twitch that was greater in the stimulated muscles. At the longest periods the twitch was as short as that of a denervated fast muscle. Stimulation did not affect contralateral denervated muscles. Twitch: tetanus ratios remained high despite stimulation, and muscles showed little post-tetanic potentiation. Tension developed more rapidly in the tetani of the stimulated muscles, even allowing for larger final values. Maximum velocity of shortening was increased in many of the stimulated muscles, and there was a proportional flattening of the force-velocity curve, i.e. a/P0 increased. Maximum velocity and a/P0 increased reciprocally with twitch time to peak, so that those muscles that had twitches most changed by stimulation also had their isotonic properties modified to the greatest extent. Even at the longest period of stimulation, twitch time course and tetanic tension were not converted to those of normal fast muscle.

Ultrastructural abnormalities in muscular vessels of hyperthyroid patients

An electron microscope study of needle biopsies from the quadriceps muscle was carried out in 11 non-selected patients (ten females and one male), with clinically and laboratory-diagnosed hyperthyroid disease. Alterations of the normal structure of muscle fibres were found in all cases. Changes in capillaries were found in ten patients, and ranged from an increase in basement membrane thickness with reduplication, to total destruction of the capillaries. The importance of the vascular involvement in the muscles of patients with Graves-Basedow disease is stressed.

Glycogenosomes in fibres of human normal skeletal muscles. An electron-microscopic study

Analysis of muscle biopsies from five patients, with no clinical evidence of neuromuscular disorders, showed the presence of membrane-bound structures containing glycogen (glycogenosomes). Occurrence of these structures within human muscle fibres has been usually considered a pathological finding, common to various types of metabolic diseases. Our results provide evidence that glycogenosomes are a normal constituent of human muscle fibre, thereby emphasizing that any relationship between glycogenosomes and a specific pathological condition should be established with great care.

Ultrastructure of the branchial epithelium of an amphibious brackish-water crab

The ultrastructure of the branchial epithelium of the amphibious brackish-water crab Uca mordax (Smith) was investigated in relation to adaptation to the salinity of the medium. No distinct differences were observed in the epithelial structure of animals adapted to either 100% sea water or to 1% sea water. Thus any interpretation of the significance of particular structures in relation to specific transport processes should be regarded with caution. Apart from strict epithelial cells, pillar cells and glycogen (presumed) storage cells were found. The epithelial cells showed very well-developed apical microvilli or lamellae and basal interdigitations with adjacent cells. Well-developed junctional complexes were seen (band desmosomes, septate desmosomes, gap junctions). The cells are extremely rich in mitochondria. Microtubules, peroxisome-like bodies, multivesicular bodies and near-nuclear Golgi complexes were present.

The effects of denervation on contractile properties or rat skeletal muscle

1. Isometric contractions of fast and slow twitch muscles of rats were recorded 1-42 days after denervation. 2. The major changes occurred over the period from 2 to 6 days after denervation. These changes were qualitatively similar in the two types of muscle. The most important effects were on the twitch: times to peak and half relaxation were prolonged, active tension and peak rate of rise of tension were increased. Tetanic tension per unit cross-sectional area and the maximum rate of rise of tension decreased during this period but, in the second week, the tension recovered substantially and the maximum rate recovered completely. 3. Very small differences were seen between muscles denervated with short and long nerve stumps at day 4. 4. In the late stage of denervation (7-42 days) twitch and tetanic tension fell more than cross-sectional area, but this may have been due to greater atrophy of fibres compared with other muscle tissue. 5. Apart from this tension fall, there were only small changes in the fast muscle in the late stage of denervation. These were a fall in twitch-tetanus ratio and a prolongation of relaxation. 6. In more than half of the soleus muscles there was a late reversal of some of the denervation changes, and these muscles showed a greater degree of atrophy. The less atrophied soleus muscles maintained a prolonged twitch and a low rate of development of tension. 7. It is concluded that denervation affects the contractile properties of muscle as early and as abruptly as it does the membrane properties, and that most of the contractile changes are a direct consequence of changes in excitation-contraction coupling alone.