Histopathological effects of anthrax lethal factor on rat liver.

Bacillus anthracis, the causative agent of anthrax, has become an increasingly important scientific topic due to its potential role in bioterrorism. The lethal toxin (LT) of B. anthracis consists of lethal factor (LF) and a protective antigen (PA). This study investigated whether only lethal factor was efficient as a hepatotoxin in the absence of the PA. To achieve this aim, LF (100 µg/kg body weight, dissolved in sterile distilled water) or distilled water vehicle were intraperitoneally injected once into adult rats. At 24 h post-injection, the hosts were euthanized and their livers removed and tissue samples examined under light and electron microscopes. As a result of LF application, hepatic injury - including cytoplasmic and nuclear damage in hepatocytes, sinusoidal dilatation, and hepatocellular lysis - became apparent. Further, light microscopic analyses of liver sections from the LF-injected rats revealed ballooning degeneration and cytoplasmic loss within hepatocytes, as well as peri-sinusoidal inflammation. Additionally, an increase in the numbers of Kupffer cells was evident. Common vascular injuries were also found in the liver samples; these injuries caused hypoxia and pathological changes. In addition, some cytoplasmic and nuclear changes were detected within the liver ultrastructure. The results of these studies allow one to suggest that LF could be an effective toxicant alone and that PA might act in situ to modify the effect of this agent (or the reverse situation wherein LF modifies effects of PA) such that lethality results.

The comparison of the viability of crushed, morselized and diced cartilage grafts: a confocal microscopic study.

To compare the cellular viability of diced, crushed, and morselized cartilage used in nasal surgeries. In this study, cartilage was extracted from the ears of seven New Zealand rabbits and was subsequently either diced, crushed or morselized to an amorphous state, or left unmodified. The four types of grafts were then implanted in the back regions of the rabbits. After 3 months, the cellular viability from four groups was compared to a control group using confocal microscopy. Analysis of the data obtained from the enumeration of live cells showed no statistically significant difference between the unmodified graft group and the control group. The diced, crushed, and morselized cartilage groups did show a statistically significant difference in terms of live cell count with the highest number of live cells in diced cartilage group. A statistically significant decrease in live cell count was detected in crushed cartilage group. Our study shows that the viability of cells in diced cartilage grafts is greater than those in crushed or morselized cartilage grafts.

The use of surgical Nd:YAG laser in an oral pyogenic granuloma: a case report.

Pyogenic granuloma is a benign, non-neoplastic, mucocutaneous lesion and is especially common on the tongue, lips, and gums. This case report presents a large oral pyogenic granuloma of the gingiva and the surgical treatment of this lesion with Nd:YAG laser. A 14-year-old female patient referred with a complaint of a swelling and growth on the buccal side of her mandibular left premolar teeth. A comprehensive intraoral examination revealed a localized gingival mass between mandibular left premolar teeth on the buccal aspect. The treatment selected was surgical removal using Nd:YAG laser with the following irradiation parameters: power output 4 W, energy 100 mJ, frequency 40 Hz, and pulsed emission mode. During surgery, complications including hemorrhage were not observed, and no scarring developed after surgery. The excised area gradually improved within 1 month. The use of Nd:YAG laser in the treatment of pyogenic granuloma reduced bleeding during surgery, with a consequent reduction in operating time, promoted rapid postoperative hemostasis, and has better patient acceptance.

Evaluation of low-level laser therapy in rabbit oral mucosa after soft tissue graft application: A pilot study.

The aim of the present study was to assess the histopathological effects of low-level laser therapy (LLLT) on healing of the oral mucosa after soft tissue graft operations. The alterations at the end of healing in normal and LLLT-applied oral mucosa were studied in two healthy adult New Zealand white rabbits by taking specimens for light microscopic inspection. There was no adverse event reported in the study and no post-operative complications, such as swelling, bleeding, or edema, were observed in the rabbits. Complete wound healing was faster in the LLLT-applied rabbit. Compared to the normal rabbit oral mucosa, thickening of the stratum corneum (hyperkeratosis) was found in the epithelia of the rabbits. A significant increase in the epithelial thickness was found in the samples of rabbits, suggesting increased scar tissue following the wound repair. Additionally, many mitotic figures were present in the epithelia of the LLLT-applied rabbit, indicating epithelial cell hyperplasia. Long and irregular connective tissue protrusions projecting into the undersurface of the epithelium and mononuclear cell infiltrations were noted in the rabbits. The results suggest that LLLT used for soft tissue operations provides better and faster wound healing and that LLLT enhances epithelization.

Chronic treatment of haloperidol induces pathological changes in striatal neurons of guinea pigs: a light and electron microscopical study.

In the present work, we investigated whether there would be any change in histological structure of striatal neurons after haloperidol applications at different doses. Adult male guinea pigs were treated once-daily with saline (group 4, control) or haloperidol during 6 weeks, and the dose was 1, 2, or 3 mg/kg (groups 1, 2, and 3, respectively). After treatment, all animals were anesthetized and striata were dissected and examined. When striata were evaluated histologically, dark neurons and some degenerating striatal neurons had distinctive morphological changes consistent with cell death, including reduced neuronal size with nuclear and cytoplasmic shrinkage. Also, in sections of striata in groups 1 and 2, but not in group 3, more glial cells were observed than in those of the control group. In all treated groups, fibrous content of intersititium was paralelly increased by increasing dose. Ultrastructural investigation of striatal neurons in haloperidol-treated rats showed notched nuclei and many lysosomes. Moreover, degeneration of myelin, scarce microglial macrophages, expansion of nuclear intermembranous space, degenerated mitochondria, and vacuoles were found. Also, cytoplasmic swelling, lysosomes, and apoptotic bodies were present. These results suggest that haloperidol treatment may lead to damage in neurons via the necrotic process in both low- and high-dose applications.

Soft tissue pathosis associated with asymptomatic impacted lower third molars

Objective: The aim of this study was to identify the prevalence of pathological changes in the pericoronal tissue of asymptomatic impacted lower third molars and to assess the correlation between pathological changes and patient demographic, radiographic and morphological characteristics.Study Design: Follicles associated with fully impacted lower third molars were submitted for histological examination after surgical extraction from 50 patients. The correlation between pathological changes in the dental follicleand age, gender, depth of impaction, angular position, and coverage and tooth development was analyzed.Results: Cystic changes were observed in 10% of specimens and inflammatory changes in 62%. Incidence of pathological changes was significantly higher in Class B impacted teeth when compared to Class C impacted teeth. Asignificant correlation was found between epithelial cell activity and the completion of tooth development.Conclusion: We recommend monitoring all third molars whether or not they are symptomatic and conducting histopathological analyses on all surgically extracted follicle tissue (AU)

Effects of haloperidol on striatal neurons: relation to neuronal loss (a stereological study).

In the present work, we investigated the effect of chronic haloperidol administration on the number of striatal neurons in guinea pigs. For this purpose, adult male guinea pigs were given daily injections of 1, 2 or 3 mg/kg of haloperidol for 6 weeks. After treatment, the animals were anesthetized via brief inhalation of ether, the brains were removed and the corpus striatum was dissected. Then the tissues were processed and semi-thin sections were stained with toluidine blue for stereological and histopathological evaluation. The physical disector was used for measurements of nuclear height and numerical density of striatal neurons and also to evaluate both normal and degenerated neurons within the corpus striatum of treated animals and untreated controls. In the control group, the mean numerical density of neurons was calculated as 47.92 cell/mm3 and the mean nuclear height as 3.58 µm. Mean densities of all (both viable and degenerated) neurons were calculated to be 45.46 in the low-dose (p < 0.01), 39.73 in the medium-dose (p < 0.001) and 30.31 cell/mm3 in the high-dose group (p < 0.001). Mean densities of degenerated neurons in the low, medium and high dose group were 30.72, 22.93 (p < 0.001) and 15.56 cell/mm3 (p < 0.001) respectively. Mean nuclear heights were 2.804 (p < 0.0001), 2.78 (p < 0.0001) and 2.33 µm (p < 0.00001) in the low, medium and high dose group, respectively.

Soft tissue pathosis associated with asymptomatic impacted lower third molars.

OBJECTIVE: The aim of this study was to identify the prevalence of pathological changes in the pericoronal tissue of asymptomatic impacted lower third molars and to assess the correlation between pathological changes and patient demographic, radiographic and morphological characteristics. STUDY DESIGN: Follicles associated with fully impacted lower third molars were submitted for histological examination after surgical extraction from 50 patients. The correlation between pathological changes in the dental follicle and age, gender, depth of impaction, angular position, and coverage and tooth development was analyzed. RESULTS: Cystic changes were observed in 10% of specimens and inflammatory changes in 62%. Incidence of pathological changes was significantly higher in Class B impacted teeth when compared to Class C impacted teeth. A significant correlation was found between epithelial cell activity and the completion of tooth development. CONCLUSION: We recommend monitoring all third molars whether or not they are symptomatic and conducting histopathological analyses on all surgically extracted follicle tissue.

The effect of neodymium-doped yttrium aluminum garnet laser irradiation on rabbit dental pulp tissue.

OBJECTIVE: Neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers have been used for a wide range of dental applications. However, the safety of their clinical applications is still in question. The aim of the present study was to investigate histopathologic changes in rabbit dental pulp tissue following pulsed Nd:YAG irradiation through normal dental hard tissue. METHODS: Specimens from teeth treated with Nd:YAG laser irradiation from two healthy adult New Zealand white rabbits were examined by light microscopy. Each incisor and molar tooth was treated with different irradiation parameters: energy, 100 mJ; frequency, 10, 20, 30, or 40 Hz; power output, 1, 2, 3, or 4 W; emission mode, pulsed; time, 0.5 min. RESULTS: Histological investigation revealed that laser irradiation at different power outputs did not damage the pulp tissue. At power output of 4 W, however, a prominent depression in the dentin of the rabbit molar tooth was observed. CONCLUSION: Nd:YAG laser irradiation at the power outputs of 1-4 W did not produce any irreversible tissue damage in the pulp of rabbit teeth.

Can Helicobacter pylori invade human gastric mucosa?: an in vivo study using electron microscopy, immunohistochemical methods, and real-time polymerase chain reaction.

UNLABELLED: BACKGROUND-GOALS: We used transmission electron microscopy and immunohistochemistry (IHC) to investigate how Helicobacter pylori affects the gastric mucosa of humans. STUDY: Gastric biopsy specimens were obtained from 15 patients with gastric discomfort. The samples were processed using both microscopic examinations and a real-time polymerase chain reaction to detect H. pylori DNA. IHC staining was performed with an avidin-biotin complex immunoperoxidase kit for paraffin-embedded tissue sections. Polyclonal rabbit anti-H. pylori was used as a primary antibody. RESULTS: IHC-applied slides with brown-stained spiral bacteria on the luminal surface and in the intercellular spaces of the gastric epithelium; electron-dense spiral H. pylori of approximately 200 to 300 nm in diameter both in the gastric lumen and between the gastric epithelial cells; coccoid or ellipsoid H. pylori attached to the epithelial cells through egg-cup-like pedestals; coccoid H. pylori within the endocytotic vesicles in the apical cytoplasmic part of the epithelial cells, thus suggesting their internalization by phagocytosis; electron-dense spiral H. pylori within the membrane-bounded vacuoles of both the gastric epithelial cells, and the lamina propria; a prominent vacuolization of gastric epithelial cells invaded by H. pylori; and swollen and lytic gastric epithelial cells that suggest a mucosal erosion and may lead to peptic ulcer. All of these microscopic findings were not present in the H. pylori DNA-negative specimens that were used as the control group. CONCLUSION: This is the first histomicrobiologic study to show gastric cells invaded by H. pylori in patients with H. pylori infection confirmed by real-time polymerase chain reaction.

Evaluation of neodymium-doped yttrium aluminium garnet laser, scalpel incision wounds, and low-level laser therapy for wound healing in rabbit oral mucosa: a pilot study.

OBJECTIVE: The aim of the present randomized controlled clinical trial was to assess the clinical and histopathological effects of laser and low-level laser therapy (LLLT) on healing of the oral mucosa after vestibuloplasty surgery. METHODS: The alterations at the end of healing in scalpel- and laser-incised and LLLT-applied oral mucosa were studied in eight healthy adult New Zealand white rabbits by taking specimens for light microscopic inspection. For the evaluation of wound healing, the surgical areas were stained using a solution (Mira-2-tones), and the stained surfaces were measured horizontally immediately after the surgery and on postoperative days 4, 7, and 10. RESULTS: Although the stained surface areas of the groups were similar immediately after the surgical procedures, the LLLT-applied sites had significantly fewer stained surface areas than the other groups on postoperative days 4, 7, and 10. Areas of hyperkeratosis and parakeratinization were observed in the epithelia of the laser surgery groups. A significant increase in epithelial thickness was found, suggesting increased scar tissue after wound repair; long and irregular connective tissue protrusions projecting into the undersurface of the epithelium were noted in these groups. CONCLUSION: LLLT used for soft tissue operations provides better and faster wound healing, and LLLT enhances epithelization.

Overweight and structural alterations of the liver in female rats fed a high-fat diet: a stereological and histological study.

BACKGROUND/AIMS: The aim of the present study was to investigate the effects of a fatty diet on body weight and liver morphometry in rats via modern stereological methods accompanied by a histological evaluation. METHODS: Eight female "Sprague Dawley" rats were fed a diet constituted highly of fat (30%) for 3 months (the HFD group). Eight control rats were maintained with a standard rat chow. The naso-anal length and body weight of the animals were measured periodically to calculate body mass index. After 3 months, whole livers from the rats were removed, and the volume of each fresh liver was estimated using the water immersion method. After the histological procedure, the volume of paraffin-embedded livers was also estimated using the "Cavalieri" method. Additionally, volumes of the sinusoids and parenchyma were separately estimated with "Cavalieri" method. The mean numerical density, mean nuclear height, and total number of hepatocytes were calculated using the physical disector method. Liver sections were also examined at light and electron microscopic levels. RESULTS: The body mass indexs of the animals in the control and HFD groups were 4.536+/-0.221 kg/m2 and 5.581+/-0.42 kg/m2, respectively (p<0.01, Mann-Whitney U test). The mean liver volumes (LVs) measured with water immersion method in the control and HFD groups were 10.51 ml and 11.8 ml, respectively. LVs estimated with "Cavalieri" method were 9.98 ml in the control group and 11.095 ml in the HFD group. The differences in LVs between groups were statistically significant when estimated with both methods, indicating that the LV of the HFD group is higher than that of the control group (p<0.05, Mann-Whitney U test). There was no significant difference between LVs estimated via the two different methods in each group (p>0.05, Wilcoxon test). The volume of sinusoids was increased in the HFD group, but the volume of parenchyma was decreased (p<0.05, Mann-Whitney U test). The mean numerical density, mean nuclear height, and total number of hepatocytes were significantly decreased in the HFD group (p<0.05, Mann-Whitney U test). However, the numerical density and total number of binucleated hepatocytes were significantly higher in the HFD group compared with the control group (p<0.05, Mann-Whitney U test). Light and electron microscopic investigations of the HFD group showed a prominent sinusoidal dilatation, microvesicular steatosis, and an increase in connective tissue in the livers and highly dilated smooth endoplasmic reticulum, irregular mitochondria and microvilli and necrosis in the hepatocytes. CONCLUSIONS: We have shown that a fatty diet in rats causes obesity and may lead to morphological alterations in the liver such as hepatomegaly accompanied by histopathological changes.

The effects of high-fat diet on the renal structure and morphometric parametric of kidneys in rats.

To characterize the kidney in a high-fat-induced obesity model, we examined the renal structure of adult Sprague-Dawley rats fed a control diet or a high-fat diet for 3 months. Ten adult female Sprague-Dawley rats were fed a diet consisting highly of fat (30%) for a period of 3 months. Ten control rats were maintained with standard rat chow. All animals were weighed every 10 days for 3 months. At the end of the experiment, the naso-anal length of the anaesthetized rats was measured to calculate body mass index, and subsequently whole kidneys of intracardially formalin-perfused animals were removed. Quantitative features of the kidney were analysed with the Cavalieri and physical dissector methods applied to serial paraffin sections. Kidney samples were also examined histologically. The body mass indices of the control and treatment groups were 4.528 +/- 0.242 and 5.876 +/- 0.318 kg m(-2), respectively. The difference between the body mass indices of the two groups was statistically significant (P < 0.01, Mann-Whitney U-test), suggesting that the animals fed with a high-fat diet may be overweight. Stereological examination of the kidneys revealed differences in kidney weight, total kidney volume, volume of cortex, medulla, glomeruli, proximal and distal tubules, and numerical density of glomeruli and glomerular height in the treatment group compared with the control group. Light microscopic investigation showed a dilatation in blood vessels and Bowman's space, mononuclear cell infiltration, degeneration in nephrons, including glomerulosclerosis and tubular defects, and an increase in the connective tissue in the kidneys in the treatment group. We concluded that a fatty diet is responsible for the rats' obesity and may lead to renal deformities as a result of histopathological changes such as dilatation, tubular defects, inflammation and connective tissue enlargement of the kidney.

[Can Chlamydia trachomatis human biovars cause abortion in cattle? An immunohistochemical study on a new host-pathogen relationship]. / Chlamydia trachomatis'in insan biyotipleri sigirlarda düsük etkeni olabilir mi? Yeni bir konak-patojen iliskisini arastiran immünohistokimyasal çalisma.

Chlamydiae, which are obligate intracellular bacterial pathogens, have been radiated from single-celled eukaryotes into multi-celled hosts during their evolution. Chlamydia trachomatis one of the important species in this group, is classified into three biovars as a result of their evolution. Two of those biovars, Trachoma and LGV, are pathogens only in humans. Initially, the presence of a high specificity between the host and chlamydiae has been recognized and this relation has been considered as an adaptation mechanism. However, some studies have indicated that chlamydiae can also grow in laboratory animals, yolk sacs of embryonated eggs and in vitro cell cultures. The aim of this study was to investigate if C. trachomatis human specific biovars are possible infectious agents in the aborted bovine fetuses. Ninety aborted bovine fetuses were included in the study, and the bacteria which could be the causative agents for abortion were searched by conventional microbiological methods. Twenty-three (25.6%) abortion materials which have yielded negative results with these methods for the presence of bacterial agents other than chlamydiae, were further evaluated in terms of the presence of C. trachomatis. For this purpose the samples were inoculated into the yolk sac of embryonated eggs and the slides prepared from the yolk sac membranes of embryons died after 24 hours of inoculation, were examined for the presence of inclusion bodies by staining with Giemsa method. The presence of C. trachomatis specific antigens and glycogen inclusions in those 23 samples were also investigated by immunohistochemical and Lugol's iodine staining methods, in the fetal tissue samples which were embedded in paraffin. Immunohistochemical method was performed with immunoperoxidase staining by the use of specific antibodies against C. trachomatis major outer membrane proteins. As a result, 5 (21.7%) of the 23 samples were found positive for C. trachomatis with three of the methods (Giemsa, immunoperoxidase and lugol stainings). Although the data of our study have supported that chlamydiae can adapt to new host species other than humans, further advanced studies are needed on this subject. Our results have also emphasized that novel routes of transmission should be considered for C. trachomatis infections.

A stereological and histological analysis of spleen on obese female rats, fed with high fat diet.

OBJECTIVE: To determine if there is an association between fatty diet induced obesity and spleen enlargement by means of Cavalieri principle, unbiased stereological method and light microscopic examination. METHODS: In this study, we used 16 adult female Sprague Dawley rats, weighing between 150-200 g. All animals were obtained from the Ataturk University Experimental Research and Applying Center, Turkey in 2005. We performed rat models, fed with normal or high-fat diet for duration of 3 months. After this controlled nutritional process, spleens are removed from all anesthetized rats and performed by routine histological process. Stereologically, we estimated the spleen volumes in consecutive serial sections using Cavalieri method in control and treatment groups. Then, we examined histologically all those sections by a light microscope with camera attachment. RESULTS: Mean spleen volumes were 1.40 ml in the control and 2.03 ml in the treatment group, suggesting splenomegaly. Volumes of spleens in 2 groups revealed statistical significant difference (p<0.05, independent samples t-test). In studying spleen slices, many macrophages and necrotic figures were defined. Also, sinusoidal dilatation and hemosiderin deposits were observed and we found macrophages, filled with hemosiderin droplets. In some sections, especially around small vessels, eosinophilic aggregations and lipid accumulations in dilated sinusoids were detected. CONCLUSION: Spleen enlargement at significant levels (38%) in obese patients was determined by Cavalieri stereologic volume calculation method; an unbiased stereological method. Finally, our results clearly indicated that high fat diet caused to splenomegaly via sinusoidal dilatation and intra-cellular or intercellular deposits.

[Histologic demonstration of adrenal macrophages as a member of mononuclear phagocytic system in guinea pig models]. / Mononükleer fagositik sistem üyesi olarak adrenal makrofajlarin histolojik olarak kobay modelinde gösterilmesi.

Macrophages as mononuclear phagocytes, function in removing foreign substances and in the initiation of the immune response. Although some tissue-specific macrophages such as Kupffer's cells and alveolar macrophages are well-known, any knowledge about the adrenal macrophages are not yet documented in the textbooks. The aim of this study was to demonstrate the resident macrophages in the adrenals of a total 16 (8 pregnant, 8 non-pregnant) guinea pigs. Four of the animals were injected with India ink (no intervention for the other animals), and after sacrificing all animals, removed adrenals were fixed in Bouin's solution, and embedded in paraffin. Sections were stained with haematoxylin-eosin (HE) and periodic acid-Schiff (PAS) methods. Many macrophages with yellowish-brown cytoplasm in HE slides, especially adjacent to sinusoids, were observed primarily in the zona reticularis, suggesting that they are rich in lipofuscin pigment. These cells were also PAS positive. Adrenals of India ink-injected animals demonstrated perisinusoidal macrophages phagocytosing the ink. Much more adrenal macrophages were seen in the pregnant animals in comparison with the non-pregnants. It has been previously reported that the number of human macrophages increases with rising concentrations of estrogen during pregnancy. Thus, higher number of adrenal macrophages in pregnant animals was an expected result. Since they secrete cytokines, macrophages are favorable cells in terms of interactions of the neuro-endocrine organs with the immune system. Some cytokines released by macrophages have been stated to induce adrenocortical steroidogenesis independent from adrenocorticotropic hormone through medullary catecholamines. Thus, macrophages may have a significant role in the immune-adrenocortical communications within the adrenal. Finally, resident macrophages of the adrenals wait to be documented in the textbooks.

Infection and replication sites of Spiroplasma kunkelii (Class: Mollicutes) in midgut and Malpighian tubules of the leafhopper Dalbulus maidis.

Spiroplasma kunkelii distribution and infection mechanisms in the intestines and Malpighian tubules of Dalbulus maidis were investigated by transmission electron microscopy. Spiroplasmas were found between microvilli and in endocytic vesicles of the midgut epithelium. At the basal part, cytoplasmic vesicles contained multiple spiroplasmas with tube-like extensions and spiroplasmas accumulated between the laminae rara and densa of the basal lamina. Tip structures of flask-shaped spiroplasmas pierced the lamina densa that was discontinuous in close proximity to spiroplasmas. Spiroplasmas were found in hemolymph, crossed the basal lamina of Malpighian tubule epithelium and accumulated at high numbers in muscle cells that had cytopathogenic changes. S. kunkelii had perithrochous approximately 8nm diameter structures determined to be fimbriae protruding from the cell surface, and similar structures were adhering to the basal lamina of midgut epithelium and to external lamina of muscle cells. Further, spiroplasmas had pili-like appendages at one or both cell poles and appeared to conjugate. This is the first time that fimbriae and pili have been observed in a mollicutes.