Tissue Samples For Histological Examination Research Articles

An Exploration of the Sympathetic Component of the Recurrent Laryngeal Nerve

INTRODUCTIONHigh interest in the recurrent laryngeal nerve (RLN) morphology has been dictated by the frequent iatrogenic injures that can result in multifaceted functional losses such as dysphagia, voice alteration, and breathing. Thus, RLN has been extensively studied on the macroscopic and histological levels. According to the literature, RLN is a mixed nerve carrying motor, sensory, and preganglionic parasympathetic fibers to the larynx and displays asymmetry in branching from the vagus nerve. Even though gross anastomoses between RLN and the cervical sympathetic trunk have been observed, the presence of sympathetic postganglionic fibers within RLN have not been addressed. The present study was conducted to determine if catecholaminergic fibers are present within the RLN using immunohistochemical analysis for tyrosine hydroxylase (TH).METHODSRLN samples were obtained from 19 formalin‐preserved adult human cadavers (male n=11, female n=8). Anastomoses with sympathetic structures were noted and documented before obtaining tissue samples for histological examination. Samples were collected one centimeter distal to the RLN branching site. All sections were prepared using Luxol fast blue staining to reveal the presence of myelinated and unmyelinated fibers and TH antibody staining was used to determine the presence of catecholaminergic fibers. Histological slides were then photographed and quantitative analysis of the images was conducted with ImageJ software by measuring of the effective surface area (ESA), TH‐positive, myelinated, and unmyelinated. We reported results as mean ± SEM.RESULTSNeural communications between right RLNs and sympathetic ganglia were observed in two whole‐body donors. No statistically significant differences in the number of the fascicles, ESA, myelinated, and unmyelinated fibers between right and left RLNs were found. TH‐positive fibers were detected bilaterally or unilaterally in 89.5% of examined donors. Bilateral absence of TH activity throughout the effective surface area was observed in two cases. TH‐positive nerve fiber area within the RLNs varied from 0% to 22.14% (Figure 1). The average of TH‐positive fibers on the right was 0.045 ± 0.011 mm2 (4.47% ± 1.1% of ESA) and 0.05 ± 0.015 mm2 (5.03±1.5% of ESA) on the left. A positive correlation between the number of unmyelinated fibers and TH‐positive component was found (P=0.022 and P=0.0026 on the right and left, respectfully). All parameters, such as fascicles, ESA, myelinated, unmyelinated, and TH‐positive fibers, occurred independently of age, gender, or conditions (p>0.05).CONCLUSIONSympathetic postganglionic fibers within RLN nerve exist; however, there is a considerable difference in their number between individuals. However, the origin and functions of this component are ambiguous.SIGNIFICANCEKnowledge of the sympathetic component of RLN could assist in better understanding the physiological effects and adverse responses of vagus nerve stimulation therapy and the sequala of the RLN injury.

An Exploration of the Sympathetic Component of the Right Phrenic Nerve

Introduction The phrenic nerve is a mixed nerve that arises from the anterior primary rami of C3-C5 bilaterally and is the main motor supply to the diaphragm. The diaphragm muscle has a multifaceted impact on body functions- including breathing, visceral health, CSF flow, and emotional regulation. According to anatomical textbooks, the phrenic nerve receives catecholaminergic fibers from the middle and lower cervical ganglia. However, previous studies reveal that both phrenic nerves lack the sympathetic component at the diaphragm level, recovering it in the abdominal region supposedly from communication with a celiac plexus. Thus, the aim of the current study was to analyze the constitution of the supradiaphragmatic and abdominal divisions of the right phrenic nerve, targeting the presence of sympathetic fibers. Methods Six formalin-preserved adult human cadavers were dissected at the MSSU human dissection laboratory. The anatomical course of the supra and subdiaphragmatic portions of the right phrenic nerve was documented before obtaining tissue samples for histological examination. Samples were collected at the root of the neck, near the inferior vena caval diaphragmatic hiatus, where the phrenic nerve splits into two main trunks. Thoracic posterior trunk (TPT) enters the abdominal cavity, and thoracic anterolateral trunk (TALT) supplies the right thoracic hemidiaphragm. Samples were also collected from identified abdominal branches. All sections were prepared using H&E and Luxol Fast Blue staining. Antibody staining for tyrosine hydroxylase was used to determine the presence of catecholaminergic fibers. The results were processed with ImageJ software for quantitative analysis. Results Lack of communication was observed between the cervical phrenic nerve and sympathetic cervical ganglia. No TH activity was detected, indicating an absence of catecholaminergic fibers in this area. The TALT showed an absence of TH activity throughout the effective surface area. Whereas TPT displayed 15% and the abdominal phrenic nerve 27% of catecholaminergic fibers. A branch to IVC of the Celio–Phrenic communication was identified in three specimens with an effective surface area of 0.049mm2, and 46-71% of this area contained TH-positive fibers. Conclusions Immunohistochemical analysis revealed an absence of catecholaminergic activity in the cervical area. This finding contradicts previous knowledge regarding cervical phrenic nerve anatomy and requires further investigation. TH positive fibers were only observed in the posterior trunk and absent in the TALT. Also, the prevalence of sympathetic fibers in the abdominal course of the phrenic nerve was evident. Thus, the lack of apparent communication between TALT and abdominal sympathetic ganglia resulted in the absence of sympathetic activity in the branch. These findings further support previous studies regarding the celiac plexus being a primary contributor of catecholaminergic fibers to the right phrenic nerve. Significance Understanding of the function requires profound expertise of the structure. Knowledge of sympathetic component within the phrenic nerve would clarify the autonomic role of the nerve, emphasizing the impact of proper respiration on overall health.

Preliminary study: Health and performance assessment in broiler chicks following application of six different hatching egg disinfection protocols.

As part of a Germany-wide project that evaluates strategies for the reduction of multi-resistant bacteria along the poultry production chain, the impact of different hatching egg disinfectants on hatchability and health of the broiler chicks was evaluated. Animal trials were conducted with extended-spectrum beta-lactamase- (ESBL) producing Escherichia (E.) coli contaminated hatching eggs and six disinfection protocols that used formaldehyde, hydrogen peroxide, low-energy electron irradiation, peracetic acid and an essential oil preparation. Each protocol was tested on a group of 50 chicks. Equally sized positive and negative control groups were carried along for each trial. Hatchability, mortality and body weight were recorded as performance parameters. During necropsy of half of the animals in each group on day 7 and 14 respectively, macroscopic abnormalities, body weight, weights of liver and gut convolute were recorded and a range of tissue samples for histological examination were collected as part of the health assessment. A decrease in hatchability was recorded for spray application of essential oils. Body weight development was overall comparable, in several groups even superior, to the Ross308 performance objectives, but a reduced performance was seen in the hydrogen peroxide group. Histologically, lymphoid follicles were regularly seen in all sampled organs and no consistent differences were observed between contaminated and non-contaminated groups. Significances were infrequently and inconsistently seen. In conclusion, remarkable findings were a decrease in hatchability caused by the essential oils spray application and a reduced body weight development in the hydrogen peroxide group. Therefore, the essential oils preparation as spray application was deemed inappropriate in practice, while the application of hydrogen peroxide was considered in need of further research. The other trial results indicate that the tested hatching egg disinfectants present a possible alternative to formaldehyde.

A Robotic Biopsy Endoscope with Magnetic 5-DOF Locomotion and a Retractable Biopsy Punch.

Capsule endoscopes (CEs) have emerged as an advanced diagnostic technology for gastrointestinal diseases in recent decades. However, with regard to robotic motions, they require active movability and multi-functionalities for extensive, untethered, and precise clinical utilization. Herein, we present a novel wireless biopsy CE employing active five degree-of-freedom locomotion and a biopsy needle punching mechanism for the histological analysis of the intestinal tract. A medical biopsy punch is attached to a screw mechanism, which can be magnetically actuated to extrude and retract the biopsy tool, for tissue extraction. The external magnetic field from an electromagnetic actuation (EMA) system is utilized to actuate the screw mechanism and harvest biopsy tissue; therefore, the proposed system consumes no onboard energy of the CE. This design enables observation of the biopsy process through the capsule’s camera. A prototype with a diameter of 12 mm and length of 30 mm was fabricated with a medical biopsy punch having a diameter of 1.5 mm. Its performance was verified through numerical analysis, as well as in-vitro and ex-vivo experiments on porcine intestine. The CE could be moved to target lesions and obtain sufficient tissue samples for histological examination. The proposed biopsy CE mechanism utilizing punch biopsy and its wireless extraction–retraction technique can advance untethered intestinal endoscopic capsule technology at clinical sites.

Периоперационная ишемия neorectum’a. Экспериментальная модель

Objective. To experimentally determine and analyze the role of perioperative tissue tension in the intestinal area brought down to the proper topographic and anatomical position (neorectum) and its vascularization impairments during anorectoplasty. Materials and methods. This experiment performed on laboratory rats consisted of 3 parts: clinical (creation of an operation model and assessment of clinical parameters in the early postoperative period); morphological (histological examination of biopsy specimens taken from the surgical area); and laboratory (measurement of tissue hypoxia markers (including vascular endothelial growth factor-C (VEGF-C) and hypoxia-induced factor 1-alpha (HIF-1-alpha)) in serum and intestinal homogenate using enzyme-linked immunosorbent assay (ELISA) (specimens were collected 3 days postoperatively). Forty laboratory rats weighing from 370 to 550 g (mean weight 482 g) were divided into four equal groups: group I – ‘impaired neorectal vascularization;’ group II – ‘neorectal tension;’ group III – ‘rectal replantation;’ and the control group. During the first stage of the experiment (3 days), we assessed overall condition of the animals, number of stools, type of defecation, and pain severity. The animals received no treatment in the postoperative period. On day 3, all rats were euthanized. Tissue specimens were collected from the neorectum to evaluate its morphological characteristics and to produce intestinal homogenate for subsequent ELISA. Blood specimens were obtained by puncturing the left ventricle and then centrifuged at 3000g for 15 minutes. Blood supernatants and neorectum tissues were stored at -80°C for maximum 1 month before testing. Intestinal tissue samples for histological examination were stored in a 10% formalin solution. The levels of hypoxia biomarkers were measured in serum and intestinal homogenate using the Stat Fax 2100. Data analysis was conducted using the SPSS software (with no preliminary calculation of the sample size). We used the Mann–Whitney U-test [H.B.Mann, D.R.Whitney] and Kruskal–Wallis test [W.Kruskall, W.A.Walles]. The differences were considered significant at р < 0.05. Results. The most common morphological changes were caused by impaired vascularization of the rectum. We have found a significant increase (p < 0.001) in the levels of hypoxia markers in intestinal homogenates in all three experimental compared to controls. However, there was no significant difference in the levels of these markers between the experimental groups. The defecation process was abnormal in rats from groups I and II. Conclusion. In anorectoplasty, excessive mobilization of the rectum with its improper vascularization and formation of the anus under conditions of intestinal tissue tension lead to perioperative neorectal ischemia. This experiment should be continued to evaluate long-term results. The proposed models of perioperative neorectal ischemia can be used to analyze the role of many factors that can potentially affect the outcome of anorectal malformation correction. In the future, this problem may be investigated in clinical studies. Key words: anorectal malformations, perioperative ischemia, neorectum, tension, devascularization

Two cases of resectable pancreatic cancer diagnosed by open surgical biopsy after endoscopic ultrasound fine-needle aspiration failed to yield diagnosis: case reports

BackgroundTumor biopsy for histological diagnosis is required preoperatively and before initiating chemotherapy or radiation therapy for patients with pancreatic cancer (Cancer of the Pancreas: Clinical Practice Guidelines, European Society for Medical Oncology). Endoscopic ultrasound fine-needle aspiration (EUS-FNA) is widely applied to obtain tissue samples for histological examination. However, in some cases, EUS-FNA cannot be performed safely or tissue samples are insufficient to establish a definitive diagnosis. We present two cases of pancreatic cancer diagnosed by open surgical biopsy after EUS-FNA failed to yield a diagnosis.Case presentationCase 1 was a 50-year-old man. Computed tomography showed a hypovascular lesion in the uncus of the pancreas. Although EUS-FNA was conducted twice, we could not collect enough quantity of tissue samples to establish a definitive diagnosis. Open surgical biopsy revealed adenocarcinoma, and the patient underwent preoperative chemoradiation therapy followed by curative operation. Case 2 was a 68-year-old man. Computed tomography showed a hypovascular tumor in the uncus of the pancreas. EUS revealed a 14-mm hypoechoic lesion, but we could not perform EUS-FNA because the superior mesenteric vein was located in the puncture line. Open surgical biopsy revealed adenocarcinoma, and the patient underwent preoperative chemoradiation therapy followed by pancreaticoduodenectomy.ConclusionsEUS-FNA is the first choice in the diagnostic modalities of pancreatic neoplasm, but open surgical biopsy is an effective diagnostic method if EUS-FNA is unsuccessful.

Assessment of the biocompatibility of mineral trioxide aggregate, bioaggregate, and biodentine in the subcutaneous tissue of rats.

The objective of this study was to evaluate the tissue inflammation caused by three endodontic repair materials. The materials included micro mega-mineral trioxide aggregate (MM-MTA), bioaggregate (BA), and biodentine (BD), which were implanted into the subcutaneous tissue of rats. The tissue samples for histological examination were prepared. The infiltration of lymphocytes and macrophages into the tissue was examined to assess the inflammatory response. Lymphocyte infiltration: A significant increase was detected in the MM-MTA and BA groups on the 7th and 14th days as compared with the control (7th day P=0.0001, 14th day P=0.0176). There was no difference between the groups on the 45th day (P=0.1730). Lymphocyte infiltration had decreased over time in all groups. Macrophage infiltration: There was a significant increase by the 7th day in the test groups as compared to the control group (P=0.007). However, there was no difference between the experimental groups on the 14th (P=0.2708) and 45th (P=0.1291) days. While MM-MTA and BA showed a similar biocompatibility, BD was more biocompatible than MM-MTA and BA in the 1 st week of the experiment. However, there was no difference between the materials at the end of the 45th day. MM-MTA, BA, and BD can be considered suitable endodontic repair materials.

Laparoscopic liver biopsy in the diagnosis of hepatic epithelioid hemangioendothelioma: A case report.

Hepatic epithelioid hemangioendothelioma (HEH) is a rare vascular tumor of the liver, and its definitive diagnosis is completely dependent on histopathological verification. In the present study, we report the case of a patient whose percutaneous liver biopsy failed to reveal a diagnosis of HEH, twice, and who was ultimately diagnosed by laparoscopic liver biopsy. The patient was a 42-year-old female with mild right upper quadrant discomfort. Ultrasonography and magnetic resonance imaging showed multiple mass lesions scattered throughout the liver, but no evidence of extrahepatic diseases. The initial laboratory tests included liver function tests and tumor markers were within normal limits. Subsequently, two, ultrasound (US)-guided liver biopsies from the liver lesion were performed using an 18-gauge needle, and both of these showed massive hepatocellular necrosis. To obtain adequate tissue samples for histological examination, the patient underwent laparoscopic liver biopsy. The overall immunohistochemical findings supported the diagnosis of HEH. In the present case, two, US-guided percutaneous liver biopsies failed to diagnose HEH, and laparoscopic liver biopsy was safely performed to obtained adequate specimens for analysis. Although this method is not the preferred technique and has certain disadvantages, it is considered to be a useful and minimally invasive approach for liver lesions when other less-invasive diagnostic modalities fail or are difficult to be performed.

Calculation of melatonin and resveratrol effects on steatosis hepatis using soft computing methods

In this work, beneficial effects of melatonin and resveratrol drugs on liver damage in rats, induced by application of acute and chronic carbon tetrachloride (CCl4) have been examined. The study consists of three main stages:(1)Data acquisition: light microscopic images were obtained from 60 rats separated into 10 groups after the preparation of liver tissue samples for histological examination. Rats in first five experimental groups for the four-day and the other five groups for twenty-day were examined.(2)Data processing: by the help of histograms of oriented gradient (HOG) method, obtaining low-dimensional image features (color, shape and texture) and classifying five different group characteristics by using these features with artificial neural networks (ANNs), and support vector machines (SVMs) have been provided.(3)Calculation of drug effectiveness: firstly to determine the differences between group characteristics of rats, a pilot group has been selected (diseased group-CCl4), and the responses of ANN and SVM trained by HOG features have been calculated.As a result of ANN, it has been seen that melatonin and resveratrol drugs have %65.62–%75.12 positive effects at the end of the fourth day, %84.12–%98.89 positive effects on healing steatosis hepatis at the end of the twentieth day respectively and as a result of SVM, it has been seen that melatonin and resveratrol drugs have %62.5–%68.75 positive effects at the end of the fourth day, %45.12–%60.89 positive effects on healing steatosis hepatis at the end of the twentieth day respectively.

Feasibility and yield of a novel 22-gauge histology EUS needle in patients with pancreatic masses: a multicenter prospective cohort study

The option of obtaining tissue samples for histological examination during endoscopic ultrasound (EUS) has theoretical and practical advantages over cytology alone. The aim of this study was to evaluate the feasibility, yield, and diagnostic accuracy of a new EUS 22-G fine-needle biopsy (FNB) device in patients with solid pancreatic masses in a multicenter, prospective study. All consecutive patients who underwent EUS-guided fine-needle biopsy (EUS-FNB) using a newly developed 22-G FNB needle between September 2010 and October 2010 were enrolled in the study. The EUS-FNB technique was standardized among the participating endoscopists. Only a single needle pass was performed. A total of 61 patients (35 males, mean age64.2±12.4years) with solid pancreatic masses with a mean size of 32.4±8.5mm (range13-90mm) participated. EUS-FNB was performed through the duodenum in 35 cases (57.4%) and was technically feasible in all but one of the 61 (98.4%) patients without complications. Tissue samples for histological examination were obtained from 55 patients (90.2%) and were deemed adequate in 54 of the cases (88.5%). The diagnoses established by EUS-FNB were adenocarcinoma (39 patients), neuroendocrine tumors (5), chronic focal pancreatitis (5), sarcoma (2), lymphoma (1), acinar cellular tumor (1), and pancreatic metastasis from renal cell carcinoma (1). In an intention-to-treat (ITT) analysis, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the histologic diagnosis of a pancreatic mass were 87.5, 100, 100, 41.7, and 88.5%, respectively. EUS-FNB was technically feasible in 98% of patients with a solid pancreatic mass. A suitable sample for histological evaluation was obtained in 88.5% of the cases after only one single needle pass. The apparently low negative predictive value is likely to be improved by increasing the number of needle passes.

Ultrastructural changes of the peritoneum in a rabbit model of peritoneal dialysis

The number of patients with end-stage renal diseases treated with chronic dialysis is increasing over the last years. Long-term peritoneal dialysis is associated with progressive development of structural and functional alterations of peritoneal membrane. The aim of the study was to analyze ultrastructural alterations of mesothelial monolayer and submesothelial tissue in a modified nonuremic experimental model of peritoneal dialysis in rabbits. The study was performed on 5 healthy Chinchilla rabbits. Surgical procedures of implantation and removal of peritoneal catheter, prevention of catheter clothing, prevention of infection and dialysate instillation were performed according to previously described protocols. Peritoneal tissue samples were collected upon catheter placement and removal after a 5-week follow-up and processed for transmission electron microscopy (TEM) examination. The rabbits tolerated anesthesia, surgical procedure and the applied regimen of dialysate instillations well. The animals recovered completely and no adverse effects were noted. In the animals treated with peritoneal dialysis instillations, TEM revealed alterations of the mesothelial monolayer and submesothelial tissue. The mesothelial cells in direct contact with dialysis fluid were prone to shrinking. They lost the typical cobblestone morphology and assumed a flattened shape. The mesothelial cells were often detached from the basement membrane. These cells showed euchromatic nuclei, higher number of microvilli in their apical part and very numerous vesicles. A higher quantity of collagen fibers was noticed in the peritoneal lamina propria in close relation to the basement membrane of mesothelium. The nuclei of the fibroblasts were also euchromatic. Numerous mitochondria, granules and vesicles were present in their cytoplasm. The used rabbit model of peritoneal dialysis is simple, practical to perform, reproducible, not expensive and not requiring advanced devices. It is suitable for obtaining peritoneal tissue samples for histological examination and can be used to analyze the effects of dialysis solutions on the rabbit peritoneal membrane.

EUS-guided fine-needle tissue acquisition by using a 19-gauge needle in a selected patient population: a prospective study

The ability to obtain tissue samples for histological examination during EUS has theoretical advantages over cytology alone. To prospectively evaluate the feasibility and yield of EUS-guided fine-needle tissue acquisition (EUS-FNTA) with a large-gauge needle in patients in whom we expected histology to be more useful than cytology to reach a definitive diagnosis. Prospective cohort study. Tertiary care academic medical center. Consecutive patients with subepithelial lesions, esophagogastric wall thickening, mediastinal and abdominal masses/lymphadenopathy of unknown origin, or pancreatic lesions after nondiagnostic FNA. EUS-FNTA with a 19-gauge needle. Feasibility and yield of EUS-FNTA. A total of 120 patients with a mean age of 61 ± 14.6 years and mean lesion size of 38 ± 25 mm (range 8-140 mm) were enrolled. FNTA was successfully performed in all but 1 patient (98.9%), and adequate samples for histological examination were obtained in 116 of the 119 patients (97.5%) in whom EUS-FNTA was technically successful. A mean of 2.8 ± 0.8 passes per patient were performed. At the time of current follow-up, a definitive diagnosis was available in 117 of the 120 patients (97.5%), with only 8 false-negative results. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of EUS-FNTA in the 117 patients with a definitive diagnosis were 91.8%, 100%, 100%, 71.4%, and 93.2%, respectively. Single-center study with limited power. EUS-FNTA by using a large-gauge needle has a high yield and promising diagnostic accuracy and could be used when histology may be more useful than cytology to reach a definitive diagnosis.

OC.11.6: IN PATIENTS WITH PANCREO-DUODENAL RESECTION, PANCREO-GASTRO ANASTOMOSIS PRODUCES A MORE SEVERE PANCREATIC DERANGEMENT THAN PANCREO-JEJUNAL ANASTOMOSIS. RESULTS OF A LONG TERM RANDOMISED STUDY

tissue acquisition (EUS-FNTA) utilizing a 19-gauge needle to obtain tissue samples for histological diagnosis and Ki-67 expression in patients with suspected PETs. Material and methods: 25 consecutive patients (mean age 54±15 yrs; M/F 11/14) with suspicious of PETs on previously performed imaging studies who, between August 2009–September 2010, underwent attempted EUS-FNTA using a 19G needle. The collected specimens were placed directly in formalin for histological examination. Results: All patients had a single lesion localized in the pancreatic head in 5, in the uncinate process in 2, in the isthmus in 4, in the body in 5, in the tail in 6, and at the body-tail junction in 3. In 18 patients EUS-FNTA was performed using the conventional linear echoendoscope, while in the other 7 patients the newly developed forward viewing echoendoscope was used. The mean size of the biopsied lesions was 15.6±7.3 mm (range 7-100mm). Overall, EUS-FNTA could be performed in all patients without complications. A mean of 2.7±0.5 passes per patient were performed. Tissue samples for histological examination were retrieved in 23 out of the 25 patients (92%) and were sufficient to make a diagnosis of NETs in all these patients. Ki-67 determination could be performed in 21 of the 23 patients (91.3%) with available tissue from EUS-FNTA. In the 6 patients who underwent surgery, preand post-surgical Ki-67 values were concordant in 4, while in 2 patients upgrading of the Ki-67 in the post-surgical specimen occurred. Conclusions: In patients with suspected PETs, retrieval of tissue specimens with EUS-FNTA using a 19G needle is safe and feasible, with a high diagnostic accuracy even in those with small lesions localized in difficult segment of the pancreas to be sampled. Determination of Ki-67 on tissue samples acquired through this technique can be of help in guiding further management decision.

Flexible transgastric peritoneoscopy and liver biopsy: a feasibility study in human beings (with videos)

Multiple studies have demonstrated the feasibility of natural orifice transluminal endoscopic surgery in animal models. To determine the feasibility of transgastric peritoneoscopy and liver biopsy in human beings. Our institutional review board approved the procedures in the operating room with the patients under general anesthesia. During laparoscopic gastric bypass surgery a flexible endoscope was introduced into the peritoneal cavity through the gastric-wall incision. A peritoneoscopy with a liver biopsy was performed, then the flexible endoscope was withdrawn into the stomach, and gastric bypass surgery was completed laparoscopically. Three patients who were morbidly obese (mean weight 115.22 +/- 9.07 kg [254 +/- 20 lb]). The ability to navigate a flexible endoscope inside the peritoneal cavity, to visualize the intra-abdominal organs, and to perform a liver biopsy without laparoscopic assistance. It was very easy to navigate the flexible endoscope inside the abdomen by using torque, advancement, and withdrawal of the endoscopic shaft, as well as by movement of the endoscope tip. The flexible endoscope provided an excellent view and adequate illumination of the peritoneal cavity. The orientation of the flexible endoscope inside the peritoneal cavity was technically easy, even in the retroflex position. Systematic visualization of the liver, the spleen, the omentum, and the small and large intestine was easily achieved through the flexible endoscope without laparoscopic assistance. A liver biopsy was successfully completed in all cases by obtaining adequate tissue samples for histologic examination. This was a pilot feasibility study. Transgastric flexible endoscopic peritoneoscopy in human beings is technically feasible, simple, and can become a valuable tool that complements and facilitates laparoscopic interventions inside the peritoneal cavity.

Intracranial abscess caused by Rhodococcus equi infection in a foal

A 4-month-old Missouri Fox Trotter colt was examined for a 5-week history of head tilt after treatment for suspected pulmonary Rhodococcus equi infection. Computed tomography revealed osteolysis of the occipital, temporal, and caudal portion of the parietal bones of the left side of the cranium. A soft tissue mass compressing the occipital region of the cerebral cortex and cerebellum was associated with the osteolytic bone. A rostrotentorial-suboccipital craniectomy approach was performed to remove fragmented occipital bone, debulk the intracranial mass, and obtain tissue samples for histologic examination and bacterial culture. All neurologic deficits improved substantially within 3 days after surgery. Bacterial culture of the resected soft tissue and bone fragments yielded R equi. Intracranial surgery in veterinary medicine has been limited to dogs and cats; however, in select cases, extrapolation of surgical techniques used in humans and small animals can assist with intracranial procedures in horses.

EUS-guided fine needle tissue acquisition by using high negative pressure suction for the evaluation of solid masses: a pilot study

The capability of obtaining tissue samples for histologic examination during EUS has theoretical advantages over cytology alone. The objective was to evaluate the feasibility and the yield of EUS-guided FNA tissue acquisition (EUS-FNTA) by using high negative pressure suction. The study design is a prospective, observational pilot study set at a tertiary referral center. Twenty-seven patients with a solid mass amenable to sampling with EUS were included in the study. FNA with a 22-gauge needle was used for a total of 5 passes. An additional pass with the same needle was performed by applying continuous high negative pressure suction using the Alliance II inflation system. The main outcome measurements were the rate of tissue acquisition and the diagnostic accuracy of EUS-FNTA. Tissue samples were obtained in 26 of the 27 patients (96%). Malignancy was detected in 20 of the 26 biopsy specimens obtained by FNTA and in 20 of the 27 FNA specimens. In 3 patients, EUS-FNTA failed to disclose malignancy, which in two of the patients was diagnosed by FNA. Conversely, EUS-FNTA diagnosed a recurrent malignant thymoma and a schwannoma in two FNA-negative patients. In 3 patients with both FNTA and FNA negative for malignancy, a definitive diagnosis could not be established. Overall, diagnostic accuracy was 76.9% for both EUS-FNTA and EUS-FNA. When combined, a correct diagnosis was achieved in 84.6% of the patients. Immunostaining of the retrieved tissue allowed characterization of the primary tumor in 5 cases and the diagnosis of a schwannoma and two neuroendocrine tumors. Limitations of the study were small sample size and a pilot study. EUS-FNTA has a high yield for the retrieval of core tissue samples. Further studies in which EUS-FNTA is performed before FNA and with variable number of passes are needed to better define its diagnostic role and performance characteristics.

Fluorescence biodistribution and photosensitising activity of toluidine blue o on rat buccal mucosa.

The antimicrobial activity of toluidine blue O (TBO) in the presence of red light has been demonstrated for a wide range of microorganisms. The response of tissues to TBO-induced photosensitisation is an important factor in assessing the clinical usefulness of this technique for the treatment of infectious diseases. The aims of this study were to determine the effect of TBO-mediated photosensitisation on rat buccal mucosa and the biodistribution of the photosensitiser in this tissue. An aqueous solution of TBO was applied to one side of the buccal mucosa of the animals. A 6 mm diameter area was then exposed to light (633 nm) from a copper vapour pumped-dye laser. The opposite, untreated, side of the buccal mucosa served as a control. TBO concentrations of 25, 50 and 200 microg/ml, laser light doses of 110, 170 and 340 J/cm(2) were assessed. Control groups of animals were subjected to 340 J/cm(2) laser light alone or to 200 microg/ml TBO alone. Serial sacrifices were performed after 72 h to obtain mucosal tissue samples for histological examination. For the determination of TBO biodistribution, additional groups received the same TBO doses and were sacrificed after 1 min or 10 min. Specimens were removed and frozen immediately for digital fluorescence imaging. No necrotic or inflammatory changes were found in the buccal mucosa of the animals with any of the treatments (using up to 200 microg/ml TBO and 340 J/cm(2) laser light). A high TBO fluorescence in the epithelium, particularly in the keratinised layer, with almost no fluorescence in the underlying connective tissue was demonstrated by the digital imaging. The results of this study suggest that TBO-mediated PDT (within the concentrations and light doses tested) could be a safe antimicrobial approach for the oral infections without damaging the adjacent normal tissue.