The use of rat brain slices as an in vitro model for mechanistic evaluation of neurotoxicity-studies with acrylamide

Biochemical mechanisms underlying acrylamide induced neurotoxicity were examined using an in vitro model consisting of sagittal slices of rat brain. Incubation of brain slices under oxygen in artificial cerebrospinal fluid containing acrylamide produced a dose and time dependent inhibition of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Lysosomal enzymes, acid phosphatase, N-acetyl glucosaminidase and beta-glucuronidase decreased in a similar manner, while no changes were observed in the activity of Na+K+ATPase, cytochrome c oxidase and lactate dehydrogenase. Incubation of slices with two structurally related compounds, acetamide (a non-neurotoxic amide) and methylene bis-acrylamide (a weak neurotoxin), indicated that acrylamide selectively inhibited GAPDH, enolase and N-acetyl glucosaminidase at low concentration; similar doses of acetamide and methylene bis-acrylamide did not have the same effect on brain slices. Incubation with acrylamide depleted glutathione levels in slices, and the addition of glutathione to the incubation medium prevented acrylamide induced inhibition of GAPDH and lysosomal enzymes. Time dependent inhibition of lysosomal enzymes was also observed in vivo, in the brain and sciatic nerve of rats following a single dose of acrylamide. These results demonstrate that both in vitro and in vivo, lysosomal enzymes are also inhibited following acrylamide exposure. The rat brain slice model exhibits both selectivity and sensitivity towards neurotoxicants and hence, may prove to be an useful in vitro model for the mechanistic evaluation of neurotoxicity.     

Adult presentation of spinal dysraphism and tandem diastematomyelia.

BACKGROUND CONTEXT: Diastematomyelia is a split-cord malformation often accompanied by other cord or column anomalies. PURPOSE: To report on an adult patient with diastematomyelia and discuss the embryological basis and related developmental sequelae of this split-cord malformation. STUDY DESIGN: Case report. METHODS: A summary of the management of a 54-year-old woman with recent clinical symptomatology related to an undiagnosed split-cord malformation is presented with accompanying literature review. RESULTS: A rare adult presentation of diastematomyelia with accompanying intradural extramedullary epidermoid tumor was repaired with resection of the soft-tissue mass and excision of the fibro-osseous septum. CONCLUSION: Initial presentation of diastematomyelia is rarely seen in adults; accompanying pathology includes scoliosis, tethered cord, and intradural tumors. Effective treatment involves identification of the primary pathology.     

Evaluation of specialized laparoscopic suturing and tying devices.

BACKGROUND: Laparoscopic suturing and tying constitute advanced minimally invasive surgery skills. Developing proficiency in the standard methods with needle drivers is often an arduous process. Recent advances in laparoscopic instrumentations has allowed for easier methods of suturing and tying. This study investigated the hypothesis that the use of a specialized suturing device and a specialized tying device allows inexperienced medical students to suture and tie laparoscopically. METHODS: Preclinical medical students who had not received any training in open or laparoscopic surgery were included in this investigation. Each student was given a 5-minute demonstration of a specialized suturing device and a specialized tying device. The medical students were not allowed to deploy either device before actual use. After the demonstration, each student was given the device to use in a porcine model. Times were recorded and a subjective grade was given for each student. RESULTS: Twenty medical students were involved in this study. All medical students were able to complete the task of suturing and tying. The average time to suture was 104.6 seconds and the average time to tying was 31.2 seconds. The average subjective performance grade was 90 (out of 100). CONCLUSION: Specialized devices are easy to learn and use for laparoscopic suturing and tying with minimal instruction even for inexperienced medical students. Even surgeons who are not well versed in laparoscopic surgery should be able to suture and tie with certain laparoscopic instruments.     

Crown augmentation using modified bilayered restoration for anchorage: A case report

An ankylosed tooth can be suitable for obtaining orthodontic anchorage. However, if such a tooth lacks adequate clinical crown height, the anchorage will not be effective. In those situations surgical luxation or restorative crown augmentation is suggested. This case report is about the restorative treatment of an ankylosed, infraoccluded tooth to enhance the anchorage for forced orthodontic eruption of impacted maxillary canines. A crown augmentation in the form of a modified bilayered (sandwich) restoration using GIC, Composite resin and Silver amalgam on left maxillary first molar (26) was successful in sustaining the anchorage for forced eruption and alignment of impacted canines.     

Monoclonal antibody K1 reacts with epithelial mesothelioma but not with lung adenocarcinoma.

Immunoperoxidase histochemical staining of cryostat sections from human tumor tissues revealed that a murine monoclonal antibody (MAb), K1, can distinguish epithelial mesotheliomas from lung adenocarcinomas. All of 15 epithelial-type mesotheliomas and all four mixed type mesothelioma samples, but none of 23 lung adenocarcinomas with different degrees of histologic differentiation demonstrated reactivity with antibody K1. Of the cell populations in each mesothelioma tested, 80% to 100% showed strong and homogeneous staining with MAb K1. Immunofluorescence analysis of live cultured cells from an epithelioid mesothelioma (H-meso) and several lung carcinoma cell lines as well as a pleural effusion of a patient with mesothelioma also showed selective reactivity of K1 with the mesothelioma cells. These data indicate that K1 can be useful as a mesothelial cell marker for the differential pathological diagnosis of the epithelial form of mesothelioma; K1 may also be useful in the study of the pathogenesis, immunodiagnosis, and immunotherapy of epithelial-type and mixed-type human malignant mesothelioma.