The Use of Dynamic Navigation Systems as a Component of Digital Dentistry.

The development of dynamic navigation system (DNS) has facilitated the development of modern digital medicine. In the field of dentistry, the cutting-edge technology is garnering widespread recognition. Based on the principles of 3-dimensional visualization, virtual design, and precise motion tracking, DNS is mainly composed of a computer, a tracking system, specialized tracer instruments, and navigation software. DNS employs a workflow that begins with preoperative data acquisition and imaging data reconstruction, followed by surgical instrument calibration and spatial registration, culminating in real-time guided operations. Currently, the system has been applied in a broad spectrum of dental procedures, encompassing dental implants, oral and maxillofacial surgery (such as tooth extraction, the treatment of maxillofacial fractures, tumors, and foreign bodies, orthognathic surgery, and temporomandibular joint ankylosis surgery), intraosseous anesthesia, and endodontic treatment (including root canal therapy and endodontic surgery). These applications benefit from its enhancements in direct visualization, treatment precision, efficiency, safety, and procedural adaptability. However, the adoption of DNS is not without substantial upfront costs, required comprehensive training, additional preparatory time, and increased radiation exposure. Despite challenges, the ongoing advancements in DNS are poised to broaden its utility and substantially strengthen digital dentistry.

[An endoscopic-assisted technique for the enlarged middle cranial fossa approach to the petroclival region: an anatomic study].

Objective:Through the observation and measurement of the adjacent anatomical structures exposed by the pure microscope and endoscopic-assisted technique for the enlarged middle cranial fossa approach to the petroclival region, quantitative compare the advantages of endoscopic-assisted technique and the pure microscope exposure. Method:The enlarged middle cranial fossa approach was performed on 10 cases (20 sides) fresh adult cadaveric head specimens in which the vessels were injected with colored silicone. At the end of every enlarged middle cranial fossa approachs, endoscope assisted technique was applied. The effective working areas were measured under pure microscope and endoscopic-assisted technique. Result:The distance between the trigeminal nerve root entering the pons and the upper limit of exposure to the middle of the ventral brainstem under the microscope was（15.95±0.48）mm；the distance from the initial point of the acoustic-facial bundle to the lower bound of exposure to the middle of the ventral brainstem under the microscope was（10.79±0.51）mm；The distance between the trigeminal nerve root entering the pons and the upper limit of exposure to the middle of the ventral brainstem under endoscopy was（18.88±0.36）mm；the distance from the initial point of the acoustic-facial bundle to the lower bound of exposure to the middle of the ventral brainstem under endoscopy was（14.56±0.64）mm. Conclusion:In the anatomic study of the enlarged middle cranial fossa approach to the petroclival region, the endoscopic assistance has a larger effective exposure space and flexible perspective compared with the operation under the microscope, which is helpful to accurately locate the position and size of the lesion during surgery, accurately identify the important nerves and blood vessels surrounding the lesion, so as to improve the resection rate and reduce the recurrence rate.

Magnetic resonance imaging features of vascular leiomyoma of the ankle.

Vascular leiomyoma is a benign soft tissue tumour with a predilection for middle-aged women. It is most often seen in the extremities, particularly in the lower leg. The typical lesion is a small, slow-growing subcutaneous nodule. These tumours are often unexpected or preoperatively confused with other soft tissue tumours including low-grade sarcomas, leading to wide surgical excision. This may partly be due to the relatively few studies delineating the characteristic imaging features of this entity. Here, the imaging findings of a case of vascular leiomyoma in the ankle are presented. Literature review of the magnetic resonance imaging findings of published reports and series of vascular leiomyomas of the extremities is also performed.

[Associated sedation of propofol and midazolam in small dosage and gastroscopy].

OBJECTIVE: To search for a sedative method that is more suitable for gastroscopy. METHODS: All of patients were randomly divided into control group and experimental group. The experimental group was treated with propofol and midazolam, the control group was treated with propofol alone. The cumulation dosage of propofol, sedative effect, variation of BP and SaO2 were observed in all patient. RESULTS: The cumulative dosage of propofol in the experimental group was lower than that in the control group [(73.21 +/- 18.67) mg and (117.23 +/- 21.57) mg respectively]; the oblivious degree in the experimental group was higher than that in the control group (95.65% and 80.00%); the onset time and the descendant range of BP and SaO2 were also lower in the experimental than those in the control group. There was not remarkable difference in sedative effect and veriviscont time between the control group and the experimental group. CONCLUSIONS: In such a rapid operation of gastroscopy, the dosage of propofol in the experimental group is obviously less than that in the control group, while it does not affect the effect of sedation, the diagnose and cure time in gastroscopy room, and has more security and less cost.

Lymphotoxin activation by human T-cell leukemia virus type I-infected cell lines: role for NF-kappa B.

Human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines constitutively produce high levels of biologically active lymphotoxin (LT; tumor necrosis factor-beta) protein and LT mRNA. To understand the regulation of LT transcription by HTLV-I, we analyzed the ability of a series of deletions of the LT promoter to drive the chloramphenicol acetyltransferase (CAT) reporter gene in HTLV-I-positive MT-2 cells. The smallest LT promoter fragment (-140 to +77) that was able to drive CAT activity contained a site that was similar to the immunoglobulin kappa-chain NF-kappa B-binding site. Since the HTLV-I tax gene activates the nuclear form of NF-kappa B, this finding suggested a possible means of HTLV-I activation of LT production. We found that the LT kappa B-like site specifically formed a complex with NF-kappa B-containing nuclear extract from MT-2, C81-66-45, and other activated T cells. Mutation of the LT kappa B site in the context of the LT promoter (-293 to +77) (mutant M1) reduced the ability of the promoter to drive the CAT gene in HTLV-I-infected and noninfected human T-cell lines. These data suggest a general role for NF-kappa B activation in the induction of LT gene transcription. Activation of LT in HTLV-I-infected cells may explain the pathology associated with HTLV-I infection, including the hypercalcemia that is prevalent in adult T-cell leukemia.

The murine lymphotoxin gene promoter. Characterization and negative regulation.

Murine lymphotoxin (LT; TNF-beta) gene upstream regulatory elements were identified by linking fragments of 5' DNA to the chloramphenicol acetyl transferase gene. Fragment LT1 (-293 to +77 in relation to the proximal cap site) exhibited promoter activity which drove CAT expression in transfected murine fibroblasts and T lymphomas. Primer extension analysis of endogenous LT message confirmed that LT1 contained the necessary elements required for promoter function. Promoter activity was not observed when LT2 (-662 to +77), LT3 (-1186 to +77), or LT3 delta AX (-1186 to +77 (delta-662/-269)) were ligated to the chloramphenicol acetyl transferase gene and transfected into fibroblasts or T lymphomas. At least one upstream repressor element is postulated to account for this promoter inhibition. In contrast to the results obtained with fibroblast and T cell transfectants, LT1 was inactive in the B cell transfectants A20 and P3X63. This suggests that some B cells express a repressor factor that inhibits the LT promoter and/or they lack the necessary positive regulatory factors.

Lymphotoxin: cloning, regulation and mechanism of killing.

The gene for murine lymphotoxin (MuLT) has been cloned from a cDNA library prepared using poly(A)+ RNA from an activated murine IL-2-maintained cloned T cell line (21C11). This was accomplished with a MuLT BamHI fragment isolated from a murine genomic library by hybridization to a human LT cDNA probe. Northern blot analysis with RNA from 21C11, an L3T4+ (CD4+-equivalent) ovalbumin-specific class II-restricted T cell line, revealed a 15S band that hybridized to this MuLT fragment. A cDNA library prepared with poly(A)+ RNA from 21C11 cells contained 36 colonies that hybridized with the MuLT BamHI fragment. A full-length cDNA has been isolated, sequenced, expressed in COS-1 cells and used to map MuLT to mouse chromosome 17. The sequence and structure of the MuLT gene has been determined. MuLT cDNA has been used to analyse mRNA expression in several L3T4+ and Lyt-2+ (CD8+-equivalent) T cell clones activated with antigen, mitogen, or antibody to the T cell receptor. LT is expressed by both class I- and class II-restricted T cells. The mechanism of killing by both LT and the functionally related molecule TNF-alpha includes the induction of DNA fragmentation in the target cell.

Validity of lung correction algorithms.

Our studies have compared the "effective tissue-air ratio (TAR) method" (ICRU Report No. 24), "equivalent TAR method," and the "generalized Batho method" (currently used by the TP-11 computer treatment planning system) with measured results for different energy photon beams using two lung inhomogeneities to simulate a lateral chest field. Significant differences on the order of 3%-15% were found when comparing these various methods with measured values.