Mineralization process during acellular cementogenesis in rat molars: a histochemical and immunohistochemical study using fresh-frozen sections

This study was designed to detect tissue non-specific alkaline phosphatase (TNSALP) by Azo-dye staining, calcium by glyoxal bis (2-hydroxyanil) (GBHA) staining, bone sialoprotein (BSP) and osteopontin (OPN) by immunoperoxidase staining in developing rat molars, and also to discuss the mineralization process during acellular cementogenesis. To restrain a reduction in histochemical and immunohistochemical reactions, fresh-frozen undemineralized sections were prepared. Where the epithelial sheath was intact, TNSALP reaction was observed in the dental follicle, but not in the epithelial sheath. With the onset of dentin mineralization, the BSP- and OPN-immunoreactive, initial cementum layer appeared. At this point, cementoblasts had shown intense TNSALP reaction and GBHA reactive particles (=calcium-GBHA complex) appeared on the root surface. With further development, the reaction of TNSALP and GBHA became weak on the root surface. Previous studies have shown that the initial cementum is fibril-poor and that matrix vesicles and calciferous spherules appear on the root surface only during the initial cementogenesis. The findings mentioned above suggest that: during the initial cementogenesis, cementoblasts release matrix vesicles which result in calciferous spherules, corresponding to the GBHA reactive particles. The calciferous spherules trigger the mineralization of the initial cementum. After principal fiber attachment, mineralization advances along collagen fibrils without matrix vesicles.     

The cryomicrotomy of rat dental tissues: a technique for histological and immunohistochemical analysis

Summary We have applied a method developed for the cryomicrotomy of non-decalcified bone to the histological preparation of the tooth and related dental tissues. Cryosections of rat mandible have been cut on a heavy-duty freezing microtome. Both cellular and extracellular structure was well preserved and the sections of tooth and bone appeared to be suitable for optical and scanning electron microscopy and for immunohistochemical analysis. However, there was an overall strong non-specific binding of immunohistochemical reagents to enamel which was not evident in the other mineralized tissues of the mandible. This may relate to important differences in the nature of this tissue.     

Lipid accumulation in the rat liver: a histological and biochemical study.

The sequential pattern of lipid accumulation and associated biochemical changes were studied in two commonly used experimental models of nutritional fatty liver in rats. Female rats were maintained for 8 weeks on high fat, low protein diets containing adequate methionine and choline, and drinking water ad libitum (Diet 1), or deficient in methionine and choline and containing 20% ethanol as a substitute for drinking water (Diet 2). Histologically, there was a progressive increase in liver lipids, mainly in the periportal areas. Occasional foci of liver cell necrosis with lipogranuloma formation occurred in areas of severe fatty change. These changes appeared earlier and were more marked in rats maintained on Diet 2. Electron micrographs revealed large lipid droplets in the liver cells, which sometimes contained myelin figures. The mitochondria were enlarged, distorted and appeared as amorphous structures with disorientated cristae in rats on Diet 1, whereas they had a condensed conformation in rats maintained on Diet 2. Rough endoplasmic reticulum was fragmented and degranulated particularly in rats on Diet 1, and smooth endoplasmic reticulum showed hyperplasia and vesiculation in rats on Diet 2. There was a progressive increase in the total liver lipids and triglycerides in both the groups of rats. This fatty change was accompanied by a significant increase in hepatic 3-hydroxybutyrate, acetoacetate, malate, 2-oxoglutarate, citrate, lactate, ammonia, glutamate, alanine and aspartate, and a significant decrease in oxaloacetate, urea and glucose concentrations. The mass action ratios for alanine aminotransferase, aspartate amino transferase, and glutamate dehydrogenase, generally moved in a parallel direction. Hepatic ATP content was considerably reduced accompanied by a decrease in [ATP]/[ADP] ratios and a significant increased in [lactate]/[pyruvate] and [3-hydroxybutyrate]/[acetoacetate] ratios. There was a corresponding decrease in the [NAD+]/[NADH] ratios both in the cytoplasmic and mitochondrial compartments. These biochemical changes were particularly severe in rats maintained on Diet 1 and Diet 2 for 8 weeks. There was a very good relationship between impaired mitochondrial and endoplasmic reticulum functions, redox and phosphorylation states, and the relevance of their changes to the fate of fatty liver cells.     

Distribution of different fiber types in whole cross-sections of human platysma. A histological and morphometric study

Analysis of cryostat cross-sections of the entire platysma muscle from human autopsies revealed enzyme histochemical and morphometric differences between normal human limb and facial muscles. The mean diameter of platysma fibers was about 50% of that of normal limb muscle fibers. Fiber type diameter increased from the medial to the lateral parts of the platysma. A variability coefficient of 356 indicated great variation in fiber caliber, with many fibers of 10 microns and less. Type I fibers showed an increase in density from the medial to the lateral parts of the muscle. The arrangement of histochemical fiber types was irregular with a tendency to form fiber type groupings.     

The possible alleviating effect of garlic supplement on the neural retina in a rat model of hypercholesterolemia: A histological and immunohistochemical study

The purpose of this work was to prove that oxidative stress is the main mechanism responsible for retinal neurodegenerative changes, subsequent apoptosis, and inflammatory cytokine release in rats fed with a high cholesterol diet (HCD) and determine the role of garlic in alleviating these changes. Forty rats were equally divided into four groups: control, garlic-treated (positive control), HCD, and HCD + garlic-treated (HCD + G). By the end of the experiment (24 weeks) blood samples were collected for assessment of serum lipid profile, oxidative stress parameters, and plasma levels of IL-6 and TNF-α. Both eyes of the rats were enucleated; one was used for light microscopic examination and the other for electron microscopic examination. There was a significant increase in the levels of serum lipids, oxidative stress parameters, IL-6 and TNF-α, and area of expression of caspase-3 in the HCD group compared to both the control and HCD + G groups. Histological examination revealed degenerative changes in all layers of the neural retina in the HCD group. Garlic administration resulted in a significant improvement in the biochemical, immunohistochemical, and histological characteristics of hypercholesterolemic rats. These findings support the hypotheses that garlic has strong antioxidant, anti-apoptotic, and anti-inflammatory properties. Garlic ameliorates the neurodegenerative changes in the neural retina of hypercholesteremic rats.Key words: Hypercholesterolemia, garlic, neural retina     

Vascular and cellular events in post-mastectomy seroma: an immunohistochemical study

This study aimed to describe the vascular and cellular histopathological changes that occurred in post-mastectomy seroma in an animal model. Unilateral mastectomies were conducted on 45 female albino rabbits. On day seven, the skin flap and the underlying tissues of the mastectomy regions were dissected and processed for histopathological examination using immunohistochemical staining of the T- and B-lymphocytes and macrophages (CD3, CD20, and CD68 respectively), and the vascular endothelia. The post-mastectomy regions in the seroma group showed a large number of inflammatory cells and newly formed blood vessels that lost the integrity of their endothelial cell linings, as revealed by the von Willebrand factor staining, as well the basement membrane, as revealed by the histochemical stain. The post-mastectomy seroma beds showed many CD3 and CD20+ve lymphocytes and CD68+ve macrophages. These macrophages were producing angiogenic factors, resulting in the persistent and continuous formation of new blood vessels. These new blood vessels were defective and represented an underlying cause of seroma formation.     

A study by interference microscopy of the different cellular types in the rat salivary glands under various experimental conditions

Summary Cytomorphological features and dry mass in single histological elements of the submaxillary and sublingual glands of adult male rats, fasted for 5 hrs or 24 hrs and 90 mins or 7 hrs after intraperitoneal injection of pilocarpine (40 mg/kg), have been studied by interference microscopy.Cryostat sections either unfixed or fixed in formol or ethanol were examined under the Leitz double beam microrefractometer. Prolonged fasting and pilocarpine treatment cause clear and characteristic increases in dry mass per unit area.Histological fixation may cause reduction in dry mass dependent on the type of cells and on the functional condition.The results are discussed from a strictly methodological viewpoint and also in more general terms, considering their possible cytochemical significance. A histofunctional interpretation is also given.     

Ovarian follicular atresia in two teleost species: a histological and ultrastructural study

Follicular atresia is a common phenomenon in vertebrate ovaries involving the oocyte and the follicular wall degeneration. Female Astyanax bimaculatus lacustris and Leporinus reinhardti were kept in aquaculture cages inside tanks from February 1994 to January 1995 for the study of the characteristics of different stages of follicular atresia. Histological and ultrastructural analysis demonstrated similarities in the degenerative events and in the resorption of oocytes in both species. Degradation of organelles, such as mitochondria, cortical alveoli, and annulate lamellae occurred in the peripheral ooplasm during the initial stage of the process. Follicle cells showed marked phagocytic activity with digestive vacuoles, myelin figures, and lipofuscin granules during the intermediate and advanced stages of follicular atresia. Granulocytes were in activity during the final stage of follicle resorption. The duration of follicular atresia was 4 months in Leporinus reinhardti and 7 months in Astyanax bimaculatus lacustris. When submitted to induced reproduction in December 1995, 50-60% of the females of both species responded to induced spawning, indicating the recovery of gonadal activity. It is suggested that, in captive conditions, follicular atresia is shorter in total-spawning fishes when compared to those showing partial spawning, and that it has no apparent deleterious effects on induced reproduction in the subsequent cycle.     

两个不同子房类型糜子酯酶同工酶的研究

采用聚丙烯酰胺凝胶垂直板电泳方法对黑龙江省集贤县单子房型(单粒)糜子和双子房型(双粒)糜子的酯酶同工酶进行了测定、分析,结果表明：两种不同子房型糜子酯酶同工酶均具有明显器官特异性;两种不同子房型糜子遗传基础已经趋异。     

Xanthine oxidase activities: evidence for two catalytically different types.

Xanthine dehydrogenase (EC 1.2.1.37) from mouse small intestine was accompanied by 20% as much xanthine oxidase (EC 1.2.3.2) activity (dehydrogenase-associated oxidase). NAD⁺ and oxygen did not compete as electron acceptors. Upon incubation at 37 °C, the dehydrogenase activity was gradually transformed to oxidase activity. Unexpectedly, the oxidase thus formed (dehydorgenase-derived oxidase) had catalytic properties different from those of the dehydrogenase-associated oxidase. The activation energy for the dehydrogenase-associated oxidase was 20,600 cal/mol, whereas that for the dehydrogenase-derived oxidase was 13,500 cal/mol. The activation energy for the dehydrogenase was 14,000 cal/mol. Between pH 6.4 and 8.5, the activity of the dehydrogenase-associated oxidase was essentially pH independent, whereas the activities of the dehydrogenase-derived oxidase and the dehydrogenase were enhanced with increasing pH. Use of the transformation inhibitor, dithiothreitol, and the protease inhibitor, diisopropylfluorophosphate, showed that these catalytic differences were not the result of partial proteolysis of the enzyme. The data demonstrate the existence of two catalytically different types of mammalian xanthine oxidase activities: A dehydrogenase-associated oxidase and a dehydrogenase-derived oxidase.     

Comparison of glycopeptide in lung cancer tissues of different histological types

The glycopeptide was studied in the pulmonary cancer tissues of three different histological types including squamous cell carcinoma, undifferentiated cell carcinoma, and adenocarcinoma. The glycopeptide preparation was made by digesting the lung cancer tissues with proteolytic enzymes followed by removal of enzymes and undigested protein. The comparison of the relative proportion of the glycopeptide, which migrated toward the anode slower than hyaluronic acid, and was stained with both alcian blue and PAS, and contained higher sialic acid, was carried out among three different histologic types of lung cancer. This glycopeptide was highest in adenocarcinoma, followed by undifferentiated cell carcinoma, and was lowest in squamous cell carcinoma.     

Reduction of maxillary molars in Homo sapiens sapiens: a different perspective.

Crown and cusp areas, and buccolingual and mesiodistal diameters of maxillary molars of complete upper tooth rows (30 males, 30 females) were analysed in order to quantify changes in size and shape from the first to the third molar. Uni- and multivariate analyses revealed the mesial cusps, in particular the protocone (mesiolingual cusp), to be more stable than the other cusps. Although there is a gradient in size from the first to third molar, shape changes were found to be marked. Overall, the findings are in keeping with the field theory and the hypotheses of environmental constraints on later developing teeth. However, not all of the results could be entirely explained by these concepts. Functional aspects seem to account for the relative stability of the protocone and the buccolingual crown diameter. It appears that this functional complex is relatively stable despite the overall reduction of tooth size, which is probably secondary to processes occurring in the jaws and the cranium. This finding may have implications for studies on tooth reduction between populations of different time periods.     

Microclimate in two types of rat cages

The microclimate in two types of rat cages (a Makrolon type IV with a solid floor and a stainless steel cage with a wire mesh floor (five rats per cage)) placed in the same macro-environment was compared. The temperature, relative humidity and ammonia concentration in the cages were measured twice a day for 8 days. The cages were cleaned every 4 days. The greatest difference between the cage types was in the ammonia build-up. In Makrolon cages the ammonia concentration never reached 5 ppm, whereas in steel cages it showed a constant increase and already exceeded the threshold limit for man (25 ppm for 8 h per day) on the third day after cleaning.     

Effects of scrotal hyperthermia on Leydig cells in long-term: a histological,immunohistochemical and ultrastructural study in rats

We have previously demonstrated that scrotal hyperthermia induce Leydig cell (LC) damage in short-term. The objectives of this pilot study were to investigate morphological changes and regulation of steroidogenesis on LC in long-term and the time of observation were extended to investigate whether the LC would eventually make a recovery after scrotal hyperthermia. The rats were randomly allotted into one of four groups: A (control), B (70 days after scrotal hyperthermia), C (105 days after scrotal hyperthermia), D (140 days after scrotal hyperthermia); each group contain seven animals. Scrotal hyperthermia was carried out in a thermostatically controlled water bath at 43°C for 30 min once daily for six consecutive days. Control rats were treated in the same way, except the testes were immersed in a water bath maintained at 22°C. Hyperthermia applied rats were sacrificed under 50 mg/kg ketamine anaesthesia after 70, 105 and 140 days, and biopsy materials of testes were obtained for light and electron microscopic examinations. Morphologically normal and the number of testosterone positive LC was significantly higher in 140 days after last heat than all other heat treatment groups. In heat treated groups, a dilated smooth endoplasmic reticulum, swollen mitochondria, and vanished mitochondrial cristae were observed. In the 140 days after scrotal hyperthermia, the severities of degenerative changes of LC were less than that observed in the other heat treated groups. We conclude that, scrotal hyperthermia cause morphological damaging and impaired steroidogenesis in LC and recovery of these findings were noted first time in 140 days after the last heat treatment.