Comparative in vitro study of contact- and image-based rigid registration for computer-aided surgery.

We present an in vitro study of rigid registration methods for computer-aided surgery. The goals of the study were to obtain accuracy measures empirically under optimal laboratory conditions, and to identify the weak links in the registration chain. Specifically, we investigated two common registration methods (contact-based registration and image-based landmark registration) and established a framework for comparing the accuracy of both methods. The phantoms, protocols, and algorithms for tool tip calibration, contact-based registration with an optical tracker, fluoroscopic X-ray camera calibration, and fluoroscopic X-ray image-based landmark registration are described. Average accuracies of 0.5 mm (1.5 mm maximum) and 2.75 mm (3.4 mm maximum) were found for contact-based and image-based landmark registration, respectively. Based on these findings, the camera calibration was identified as being the main source of error in image-based landmark registration. Protocol improvements and algorithmic refinements to improve the accuracy of image-based landmark registration are proposed.     

Objective measurement of the different collagen types in the corpus cavernosum of potent and impotent men: an immunohistochemical staining with computerized-image analysis

Summary Quantitative measurements of the collagen types (I, III, and IV) in the corpora cavernosa of potent and impotent men were carried out to investigate whether quantitative immunohistochemistry might contribute additional information as to the cause of erectile dysfunction. The study group consisted of 22 men with various etiologies of impotence and 4 normal, potent men. The quantitative immunohistochemistry measurements were performed by means of a cell-image processor. Three variables for each of the three types of collagen were studied, namely, the mean optical density (MOD), which relates to histochemical staining intensity; the labeling index (LI), which is positively related to the percentage of immunostaining; and the quick score (QS) index, which takes into account both LI and MOD values. None of the quantitative parameters taken individually (monovariate statistical analyses) made it possible to obtain any statistically significant difference between the types of collagen of the group under study. The mean QS value recorded for collagen type IV was significantly lower than that noted for collagen type I in the psychogenic (P = 0.019), arteriogenic (P = 0.012), and venogenic (P = 0.001) groups, whereas the MOD value was significantly lower in the normal (P = 0.043), arteriogenic (P = 0.013), and venogenic (P = 0.001) groups but not in the psychogenic group. The mean MOD of collagen type III was intermediate between that of the other types. In contrast, the mean LI value recorded for collagen type IV was significantly lower only in the venogenic (P = 0.032) and psychogenic (P = 0.049) groups as compared with the other groups. No objective qualitative change in the collagen types was observed that could be correlated to the etiology of erectile dysfunction. The significant difference seen in the quantitative parameters with regard to collagen type IV and the observed increase in the type I/III collagen ratio might attest to the notion that the response of the erectile tissue to ischemia is similar to that of other organs. The net effect of these changes is a restricted capacity for corporal expansion and alteration of the veno-occlusive mechanism.     

Periodontal manifestations of adult onset of histiocytosis X

Histiocytosis X, a reticuloendothelial disorder, includes the three clinical syndromes: Letterer-Siwe and Hand-Schuller-Christian diseases and eosinophilic granuloma of the bone. Twenty-eight cases of adult onset of histiocytosis X involving the head and neck region were found in the literature during the past 20 years; 15 cases were confined to this area, out of which 13 involved jaw bones. Characteristic signs and symptoms of periodontal disease were observed in 22 out of 28 cases (79%) with the lower molar area as a predominant site. A case report of a non-osseous chronic disseminated histiocytosis X with periodontal involvement is presented. The importance of histiocytosis X, as an entity that should be kept in mind as a differential diagnosis of a process where destructive periodontitis is involved, is discussed.     

Spermatozoa retrieved by electroejaculation: Should we prefer fresh or cryopreserved spermatozoa for intracytoplasmic sperm injection?

We aim to evaluate our experience, comparing intracytoplasmic sperm injection (ICSI) outcomes of cycle using fresh versus thawed electroejaculated spermatozoa. All consecutive couples undergoing ICSI cycles using electroejaculated spermatozoa, during a 16-year period, were evaluated. Embryological/laboratory variables of the ICSI cycles were assessed and compared between those utilising fresh (fresh group) versus thawed (thawed group) electroejaculated spermatozoa. Fifty-seven couples were evaluated, 30 used a fresh electroejaculated spermatozoa in 55 ICSI cycles, while 27 used a thawed sperm sample in 41 ICSI cycles. There were no in-between group differences in the mean numbers of oocytes retrieved per oocyte retrieval nor the percentage of MII oocytes. The fresh group demonstrated significantly higher fertilisation (71.5% vs. 64.1%, respectively, p < .05), top-quality embryos (66.5% vs. 54.9%, respectively, p < .02), clinical pregnancy per transfer (41.3% and 21.2%, respectively, p < .05) and cumulative clinical pregnancy (58.2% vs. 26.8%, respectively, p < .001) rates, as compared to the thawed group. Independent of the source of spermatozoa used, no pregnancy was achieved following ICSI utilising immotile spermatozoa. In conclusion, ICSI cycles using ejaculated spermatozoa of patients suffering from neurologic or psychogenic anejaculation are reassuring. The use of fresh ejaculated spermatozoa retrieved on the day of the female spouse oocyte retrieval might improve outcome. Whenever a thawed electroejaculated spermatozoa yield no motile spermatozoa, emergency electroejaculation is mandatory.     

Cross-linking of human [125I]beta-endorphin to opioid receptors in rat striatal membranes: biochemical evidence for the existence of a mu/delta opioid receptor complex

In a modified Krebs buffer at 37 degrees C, the selective mu agonist [3H] D-Ala2,MePhe4,Gly-ol5]enkephalin [( 3H]DAMGO) and the nonselective mu/delta agonist human [125I]beta-endorphin [( 125I]beta-endH) bound to rat striatal membranes with a Kd of about 7 and 5 nM and a Bmax of about 95 and 260 fmol/mg of protein, respectively, consistent with labeling of mu receptors by the former ligand and labeling of both mu and delta receptors by the latter. The binding of 2 nM [125I]beta-endH was displaced by unlabeled DAMGO (IC50 30 nM), [D-Ala2-D-Leu5]enkephalin (IC50 60 nM) as well as by the selective delta agonists [D-Ser2(O-tert-butyl),Leu5]enkephalyl-Thr6 (DSTBULET, IC50 500 nM) and Tyr-Ala-Phe-Asp-Val-Val-Gly-NH2 (IC50 700 nM) in a monophasic manner within 2 to 3 log concentration units, suggesting an allosteric interaction between mu and delta sites labeled by [125I]beta-endH under these conditions. Accordingly, 500 nM DSTBULET caused almost 40% inhibition of the apparent Bmax without changing the apparent Kd of [3H] DAMGO. The kappa agonist U 50,488 was ineffective as competing ligand even at a concentration of 10 microM. Upon affinity cross-linking of [125I]beta-endH (2 nM) to rat striatal mu- and delta-opioid receptors, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the solubilized tissue under reducing conditions followed by autoradiography of the dried gels revealed a major broad band of covalently labeled protein with an apparent molecular weight of 80 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical evaluation of demineralized bone allograft in a hyaluronic acid carrier for sinus lift augmentation in humans: a computed tomography and histomorphometric study

OBJECTIVES: Natural and synthetic graft materials are used routinely in sinus floor augmentations to help support implants in atrophic maxillary ridges. This clinical study was based on the hypothesis that the clinical effectiveness of demineralized freeze-dried bone allograft/demineralized bone matrix (DFDBA/DBM) in sinus lifts varies when used in combination bone graft substitute materials. To test this hypothesis, DFDBA was used together with one of three materials: in saline plus anorganic bone (DFDBA: Bio-Oss; in hyaluronic acid (DFDBA: HY, 32 : 68, w/w; DBX alone; DBX plus Bio-Oss; and DBX plus tricalcium phosphate granules (beta-TCP). MATERIAL AND METHODS: Thirty-two sinus lift procedures, eight per group, were performed on 26 patients. Before surgery and at 8 months post-surgery when implants were placed, ridge heights were visualized by computed tomography (CT) and measured by morphometric analysis. Cores of bone were removed by trephine at the sites of implant placement; these biopsies from the graft sites were used for histomorphometric analysis. RESULTS: All 32 sinus lift elevations were successful when measured by CT, increasing from an average 2.84+/-0.2 mm before treatment to 15.2+/-0.6 mm after treatment. The percent of each biopsy that was occupied by new bone and incorporated bone graft materials varied with each treatment: DFDBA+Bio-Oss, DBX+Bio-Oss, or DBX alone was higher than that for DBX+beta-TCP by approximately 10%. When comparing only newly formed bone, DBX+beta-TCP treatment resulted in 50% less bone than the other three preparations. All grafted sites received implants as per the treatment plan for each patient. CONCLUSIONS: This study confirmed the hypothesis that new bone formation is dependent on the DFDBA formulation used and demonstrated that DBX, alone or in combination with other materials, can be used successfully for sinus floor elevation.     

Mammalian target of rapamycin inhibitors for the treatment of astrocytic hamartoma in tuberous sclerosis complex (TSC)

Graefe's Archive for Clinical and Experimental Ophthalmology - Tuberous sclerosis complex (TSC) is an inherited neurocutaneous disorder. Fifty percent of patients with TSC will develop retinal...     

Anti-Bv8 Antibody and Metronomic Gemcitabine Improve Pancreatic Adenocarcinoma Treatment Outcome Following Weekly Gemcitabine Therapy

Weekly gemcitabine therapy is the major treatment offered for patients with pancreatic adenocarcinoma cancer; however, relative resistance of tumor cells to chemotherapy, rapid regrowth, and metastasis are the main causes of death within a year. Recently, the daily continuous administration of chemotherapy in low doses – called metronomic chemotherapy (MC) – has been shown to inhibit primary tumor growth and delay metastases in several tumor types; however, its use as a single therapy is still in question due to its moderate therapeutic benefit. Here, we show that the combination of weekly gemcitabine with MC of the same drug delays tumor regrowth and inhibits metastasis in mice implanted orthotopically with pancreatic tumors. We further demonstrate that weekly gemcitabine, but not continuous MC gemcitabine or the combination of the two drug regimens, promotes rebound myeloid-derived suppressor cell (MDSC) mobilization and increases angiogenesis in this tumor model. Furthermore, Bv8 is highly expressed in MDSCs colonizing pancreatic tumors in mice treated with weekly gemcitabine compared to MC gemcitabine or the combination of the two regimens. Blocking Bv8 with antibodies in weekly gemcitabine-treated mice results in a significant reduction in tumor regrowth, angiogenesis, and metastasis. Overall, our results suggest that pro-tumorigenic effects induced by weekly gemcitabine are mediated in part by MDSCs expressing Bv8. Therefore, both Bv8 inhibition and MC can be used as legitimate ''add-on'' treatments for preventing post-chemotherapy pancreatic cancer recurrence, progression, and metastasis following weekly gemcitabine therapy.