Elvan Ozbek

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

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.

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

Abstract 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

Abstract 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.

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.

Histopathological effects of anthrax lethal factor on rat liver

Abstract 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.