The morphology and location of atrial specific granules and the demonstration of atrial natriuretic factor in porcine,lapine and bovine heart by immunoelectronmicroscopy

The atrial specific granules (ASGs) were studied in samples collected from the right and left auricles of conventionally slaughtered cows (10), pigs (16) and rabbits (8). In addition, the presence of atrial natriuretic factor (ANF) was detected by immunocytochemistry. Mature ASGs, characterized by the presence of highly osmiophilic and electron-dense material surrounded by a membrane, were present in all atrial myoendocrine cells and their diameters ranged from 100 to 470 nm in pigs, from 100 to 235 nm in cattle, and from 125 to 275 nm in rabbits. Immunoelectronmicroscopical studies revealed the presence of ANF in the ASGs of pigs and cattle, whereas anti-ANF polyclonal serum failed to detect any significative reaction in lapine ASGs. The ultrastructural features of the ASGs of pigs, cattle and rabbits described may be useful in comparing the morphological picture of several cardiac endocrine pathological conditions.     

Morphometric quantitation of early autolytic changes in rat myocardial cells

Early autolytic changes in rat heart muscle were quantified using electron microscopical morphometry. Five different time groups with five rats in each group were used. All the rats were anaesthetised, and the hearts of the rats in one group were fixed by perfusion. The other rats were decapitated, and immersion fixation of the hearts performed one minute, five minutes, 10 minutes or 25 minutes after the death of the animals. When compared to perfusion fixation, the first significant changes were seen in the five minute group. The volume densities of myofibrils and glycogen decreased and the volume density of mitochondria increased. These changes were partly due to a shortening of individual sarcomeres. A gradual shortening of the sarcomeres was seen in the one, five and 10 minute groups. Distinct I bands were frequently seen only in the perfusion group. In the mitochondria a decreased matrix density and a partial disorganisation of the cristae were evident in the five minute group. Swelling of individual mitochondria was seen in the 10 minute group, but the increase in size of individual mitochondria was significant in the 25 minute group. After death, morphological changes occur very rapidly in heart muscle cells. This must be taken into consideration when, for example, slaughterhouse material is prepared and interpreted in ultrastructural studies.     

Ultrastructural changes in hereditary muscular hypertrophy in cattle.

Biopsies of skeletal muscle collected from 24 animals classified as “double muscled” were examined by light and electron microscopy. The muscle samples exhibited degenerative changes including the presence of vacuolations and lamellated structures, fragmentation of myofibers, accumulation of glycogen granules, disruption of neuromuscular junctions and disorganization of the sarcolemma. In the light of the excessive fragility of the erythrocyte membranes noted previously, the alteration in the sarcolemma suggests that a generalized cell membrane defect may be the most consistent feature of the “double muscling syndrome” in cattle.     

Ultrastructural effects of mestranol and norethindrone on guinea pig endometrial stromal cell.

The effect of exogenous contraceptive steroids on the ultrstructural features of the endometrial stromal cells was studied in 64 guinea pigs allotted to 4 treatment groups. Four guinea pigs from each group were killed 14, 28, 56, and 84 days after treatment with mestranol (0.01 mg/day in 1 ml of oil) or with norethindrone (0.2 mg/day in 1 ml of oil) or with a combination of both (0.001 mg of mestranol/day and 0.02 mg of norethindrone/day in 1 ml of oil) or with 1 ml of vegetable oil (oil-treated controls). An additional 12 normal guinea pigs (nontreated controls) were killed during the follicular and luteal phases of the estrous cycle, and uterine specimens were immediately collected to determine base line characteristics. During estrus, the stromal cells of these 12 guinea pigs had abundant dilated rough endoplasmic reticulum. The interstitium was filled with collagen. During the luteal phase. the cytoplasm of the stromal cells of the 12 guinea pigs contained a prominent nucleus and rough endoplasmic reticulum with undilated cisterns. The interstitium contained sparse amounts of collagen. The stromal cells of the oil-treated control guinea pigs seemed similar in ultrastructure to the stromal cells of the 12 nontreated control guinea pigs at the luteal phase. Mestranol-fed guinea pigs had dilated rough endoplasmic reticulum and well-developed Golgi apparatus within 2 weeks of initial treatment. The interstitium of mestranol-treated guinea pigs had more collagen than that of the oil-treated controls and nontreated controls during the luteal phase. Prolonged treatment with mestranol caused extensive dilation of the cisternae of the endoplasmic reticulum. The interstitium was filled with abundant collagen. Pronounced alterations in the cytoplasmic organelles or extracellular connective tissue were not ovserved in guinea pigs given norethindrone alone or norethindrone in combination with mestranol for 14 days. The stromal cells closely resembled the cells of the mature animal at luteal phase. However, the dilated rough endoplasmic reticulum that occurred in cells after mestranol treatment was not seen in stromal cells after 84 days of treatment with norethindrone. Dilation of rough endoplasmic reticulum was also observed when both the contraceptive steroids were given simultaneously for 84 days. The increased and extensively dilated rough endoplasmic reticulum seen during the follicular phase and after mestranol administration or after 84 days of treatment with mestranol and norethindrone probably indicates increased protein synthesis by the endometrial stromal cells.     

Morphologic characterization of specific granules in Greyhound eosinophils

BACKGROUND: "Vacuolated" eosinophils (ie, eosinophils with empty, nonstaining granules) have been described previously in normal Greyhounds. However, to our knowledge, detailed studies of granules in vacuolated and normal eosinophils in this breed have not been performed. OBJECTIVE: The objective of this prospective study was to characterize some of the morphologic, ultrastructural, and cytochemical staining features of specific (primary) granules in both normal and vacuolated eosinophils in Greyhound blood. METHODS: Morphologic features of eosinophils in Wright's- and Diff-Quik-stained peripheral blood smears from 49 Greyhounds were compared with 200 blood smears from non-Greyhound dogs. Transmission electron microscopy was done on blood from 3 Greyhounds with vacuolated eosinophils and 3 with normal eosinophil granules. Blood smears from 4 of these dogs also were stained cytochemically with alkaline phosphatase (AP), chloracetate esterase (CAE), and alpha naphthyl butyrate esterase (ANBE). The morphologic features and tinctorial properties of vacuolated and normal eosinophils were compared. RESULTS: Twenty-six Greyhounds (53%) had vacuolated eosinophils and 23 (47%) had normal granulated eosinophils in smears stained with Wright's stain. Only 1% of eosinophils were vacuolated in non-Greyhound dogs. Twenty of the 23 (85%) Greyhounds with normal granulated eosinophils on Wright's-stained smears had vacuolated eosinophils in smears stained with Diff-Quik. Ultrastructurally, no morphologic differences were observed between granules of vacuolated and normal eosinophils. Both vacuolated and normal eosinophils in Greyhounds were positive for AP and negative for CAE and ANBE, as expected for normal dogs. CONCLUSION: Vacuolated eosinophils in Greyhounds likely reflect, at least in part, differential staining properties of the specific granules with different hematologic stains. Ultrastuctural and cytochemical features of eosinophil granules were similar in normal and vacuolated eosinophils from Greyhounds.     

Ultrastructural changes in liver of the rat fed hexachlorobenzene.

Changes in hepatic ultrastructure were observed in rats given hexachlorobenzene (HCB) as a component of the diet in concentrations of 5, 10, and 25 ppm for 3, 6, and 12 months. A significant change was in the cellular regions normally containing smooth endoplasmic reticulum (SER). Sometimes the SER proliferated and at other times it appeared to be replaced by quantities of storage product presumed to be glycogen. Proliferation of SER was often associated with the smaller doses of HCB and the increase in storage products with the larger doses of HCB. However, dose relationships were variable. The most significant changes were in mitochondria which became elongated or swollen. Swollen mitochondria were occasionally as large as nuclei. Usually only a fraction of the mitochondria in a cell appeared abnormal. Storage bodies 1 to 4 mum in diameter developed in some cells. These bodies were surrounded by a double membrane derived from the endoplasmic reticulum and may have been the partly digested remains of degenerated mitochondria.     

Ultrastructural observations on peritoneal exudate cells from the striped bass

An ultrastructural study was conducted of the principal cells recovered from the peritoneal exudate of striped bass (Morone saxatilis) injected with killed Bacillus cereus. The most frequently observed cells were identified as macrophages, eosinophils, and neutrophils on the basis of comparing their structure with that reported for other fish species and higher vertebrates. All three of the types of cells were phagocytic; however, the numbers of bacteria engulfed were limited. Like other studies of this type in fish, the peritoneum of the striped bass proved to be a good source of cells for morphological investigations of phagocytosis.     

哺乳动物卵泡发育过程中的超微结构变化

目前 ,动物腔前卵泡的体外培养正日益受到重视 ,并已取得了较大进展 ,已建立的培养体系可成功地使腔前卵泡发育到有腔阶段 ,猪、山羊等已可实现腔前卵泡卵母细胞体外成熟 ,体外受精并发育至囊胚阶段。但有关腔前卵泡体外成熟的机制仍不明了。本文通过对体内发育与体外培养之卵泡及其卵母细胞超微结构进行比较 ,从微细结构上客观评定体外培养卵泡的形态、活力、代谢状况及功能完整性 ,界定体外生长卵泡所处发育阶段 ,从而为确立和完善腔前卵泡体外培养体系并最终选择高质量的卵母细胞进行体外受精提供可靠的理论依据。1　体内发育卵泡及其卵…     

小尾寒羊复旧期子宫组织内胶原纤维的研究

从细胞、亚细胞水平来揭示羊子宫复旧过程中的组织学变化规律。用透射电子显微镜(TEM)对9只产程正常、健康的小尾寒羊子宫复旧期间子宫结缔组织内胶原纤维的变化进行了研究。试验结果表明:在产后1~7d,胶原纤维排列不规则,胶原呈片段存在,其内部溶解形成形态各异的空腔;从分娩第13天开始,胶原片段数量减少,排列较规则;到产后第25天时,胶原纤维束纵横交错排列,横纹清楚,无胶原片段。     

Ultrastructural changes in bovine lingual epithelium infected with vesicular stomatitis virus.

Vesicular stomatitis virus was inoculated into the dorsal lingual epithelium of three cows. The reaction that developed in 72 h was characterized by severe acute diffuse glossitis with intercellular edema and necrosis of keratinocytes. Virions budded from the plasma membrane and were in the intercellular spaces. Reduplication of desmosomes was a prominent alteration, and normal desmosomes were within the cytoplasm. Intracytoplasmic desmosomes appeared to be formed by endocytosis after breaks occurred in the plasma membrane of one cell; endocytosis of loops of plasma membrane containing desmosomes; and formation of desmosomes on invagination of the plasma membrane.     

A radiographic study of breed‐specific vertebral heart score and vertebral left atrial size in Chihuahuas

Although echocardiography is the gold standard for the diagnosis of cardio‐structural disease, thoracic radiography is a rapid, cost‐effective, and widely accessible method for evaluating cardiac size in dogs. The vertebral heart score (VHS) and the vertebral left atrial size (VLAS) are established as objective measures of cardiomegaly on thoracic radiographs. However, several studies have shown significant variations in the VHS among different breeds. The Chihuahua is predisposed to both congenital and acquired cardiac diseases. The aim of this prospective, single‐center, cross sectional study was thus to evaluate the VHS and the VLAS in healthy adult Chihuahua dogs. A total of 30 Chihuahuas were included. The VHS values in our sample population of Chihuahuas were 10.0 ± 0.6 (95% range, 8.9‐11.0). This was significantly greater than the canine reference value of 9.7 ± 0.5 established by Buchanan and Bücheler (P = .002). The VLAS of Chihuahuas in our study was 1.8 ± 0.2 (95% range, 1.3‐2.1). This was significantly lower than the values previously reported by Malcolm et al (2.07 ± 0.25; P = .0004). The VHS and the VLAS were not influenced by sex, body weight, short or long hair, and body condition score in normal Chihuahuas. Our results indicated that breed‐specific reference values for radiographic VHS and VLAS are needed. In Chihuahuas, the values found in this study can be used as a normal reference in order to help avoid overinterpretation of cardiomegaly in these dogs.     

Ultrastructural observations on the platelets of the Arabian tahr (Hemitragus jayakari)

The ultrastructure of platelets was studied in specimens of peripheral blood from 18 healthy adult Arabian tahrs (Hemitragus jayakari). The platelets were characterized by their extreme polymorphism. The number of alpha granules, typically one to six per cell, was considerably less than that reported for most animal platelets. Similar to humans, the platelets of the Arabian tahr had nucleoids within the alpha granules. However, nucleoids were not a consistent finding. One or more electron-dense granules, most commonly contained within clear vesicles, was commonly observed. A unique feature was the lack of an open canalicular system, which is considered a hallmark feature of this cell type in most mammalian and reptilian platelets.     

Ultrastructural observations on the platelets of the Arabian oryx (Oryx leucoryx)

An ultrastructural study on the platelets from peripheral blood samples from 20 healthy adult Arabian oryx (Oryx leucocoryx) was performed. Characteristic was the extreme polymorphism of both the platelets, as well as their alpha granules. They vary in size from 100 to 800 nm in diameter and their numbers typically are less than those reported for humans and other animal species. Also, the alpha granules in contrast to those of humans and animals, such as the Arabian tahr, do not have nucleoids. Typically, the oryx platelets exhibit only 1–2 electron‐dense bodies per cell and they lack an open canalicular system. Of particular interest is the presence of Type I multivesicular bodies, which have previously only been described in human megakaryocytes and are hypothesized as being intermediate development stages of alpha and dense granules.