Bactericidal effect of different laser systems in the deep layers of dentin

BACKGROUND AND OBJECTIVES: In recent years, various laser systems have gained importance in the field of laser-assisted endodontics, namely the Nd:YAG, the diode, the Er:YAG, and the Er,Cr:YSGG laser. Individual studies have been carried out so far, focusing on the respective wavelength, its specific bactericidal capabilities, and potential usefulness is root-canal disinfection. The present in vitro investigation however, was performed to compare the microbicidal effect of these laser systems under standardized conditions and to draw a conclusion upon their relative effectiveness in the deep layers of dentin. STUDY DESIGN/MATERIALS AND METHODS: In total, 360 slices of root dentin with a thickness of 1 mm were obtained by longitudinal cuts of freshly extracted human premolars. The samples were steam sterilized and subsequently inoculated with a suspension of either Escherichia coli or Enterococcus faecalis. After the incubation, the samples were randomly assigned to the four different laser systems tested. Each laser group consisted of two different operational settings and a control. The dentinal samples underwent "indirect" laser irradiation through the dentin from the bacteria-free side and were then subjected to a classical quantitative microbiologic evaluation. To assess the temperature increase during the irradiation procedure, additional measurements were carried out using a thermocouple. RESULTS: Microbiology indicated that all laser systems were capable of significant reductions in both test strains. At an effective output power of 1 W, E. coli was reduced by at least three log steps in most of the samples by the tested wavelengths, with the best results for the Er:YAG laser showing complete eradication of E. coli in 75% of the samples. E. faecalis, a stubborn invader of the root canal, showed minor changes in bacterial count at 1 W. Using the higher setting of 1.5 W, significant reductions of E. coli were again observed with all laser systems, where only the diode and the Er:YAG laser were capable of complete eradication of E. faecalis to a significant extent. There was no significant relation between the temperature increase and the bactericidal effect. CONCLUSIONS: The present study demonstrates that all the wavelengths investigated are suitable for the disinfection of even the deeper layers of dentin and may prove to constitute valuable tools in state-of-the-art endodontics.     

Does hypervascularity of liver metastases as detected on MRI predict disease progression in breast cancer patients?

OBJECTIVE: The aim of our study was to evaluate the association of the vascularity of liver metastases, as characterized by MRI, and disease progression in breast cancer patients. MATERIALS AND METHODS: Sixteen breast cancer patients with liver metastases who underwent MRI before and after systemic therapy were retrospectively identified. On the basis of comparison of each MRI examination with the previous examination, disease status of the patients was classified as complete response, partial response, stable disease, or progressive disease. Liver metastases were characterized as hyper- or hypovascular on the basis of the degree of enhancement in the arterial, portal, and interstitial phases of imaging after administration of a contrast agent. Fisher's exact test and ordinal logistic regression models, including the type of systemic therapy, presence of multiple metastases, and hormone receptor status, were used to estimate the unadjusted and risk-adjusted association between the presence of hypervascular liver metastases and disease progression. RESULTS: All patients in our sample (n = 16) were women and most (12/16, 75%) were white. Their median age was 51.5 years. In unadjusted analyses, the association between the presence of hypervascular liver metastases and disease progression was statistically significant (p < 0.0001). In multiple logistic regression analyses, hypervascular liver metastases were found to be an independent predictor of disease progression. Patients with hypervascular liver lesions were 20.5 times more likely to experience disease progression than patients without hypervascular metastases (odds ratio, 20.5; 95% confidence interval, 5.1-83.5; p < 0.0001). CONCLUSION: Our analysis provides suggestive evidence that disease progression can be predicted through MRI assessment of the vascularity of liver metastases in patients with breast cancer.     

Multiplanar functional imaging of the larynx and hypopharynx with multislice spiral CT

The purpose of this study is to evaluate multislice spiral CT (MSCT) in multiplanar functional imaging of the larynx and hypopharynx and to define the optimal image planes for the delineation of the tumor and specific anatomical structures. Forty patients with suspected tumors of the larynx or hypopharynx were examined with MSCT during quiet breathing (QB), E-phonation (EP) and modified Valsalva maneuver (VM). Images were read in the axial, coronal and sagittal planes. Overall image quality, delineation of the tumor and anatomic structures for different conditions and orientations were graded using a three-point scale; the conditional permutation test was applied to detect quality differences. Differences between image types were statistically significant. The axial plane was superior in overall image quality and the delineation of the tumor, pyriform sinus, vocal cords and fat within the parapharyngeal/visceral space. The coronal plane was best for delineating the ventricle and the paraglottic space, the sagittal plane for the retropharyngeal and the preepiglottic space. For tumor detection, sensitivity, specificity and accuracy were 0.92, 1.0 and 0.93 for QB.ax, 0.94, 0.8 and 0.92 for EP.ax and 0.85, 1.0 and 0.87 for VM.ax, respectively. Examination during QB should be the standard procedure; additional scanning with EP improved tumor assessment.     

Pancreatic head resection for chronic pancreatitis in patients with extrahepatic generalized portal hypertension

BACKGROUND: Five percent to 10% of chronic pancreatitis (CP) cases are complicated by portal venous occlusion leading to extrahepatic generalized portal hypertension (GPH). Pancreatic head resections (PHR) are regarded risky or contraindicated in patients with extrahepatic GPH. The aim of our study was to analyze the outcome of patients with extrahepatic GPH undergoing PHR for CP and to propose recommendations for surgical strategy. METHODS: Sixteen of 185 patients with PHR suffered from extrahepatic GPH. Perioperative and follow-up data were documented prospectively and analyzed to assess the outcome. RESULTS: Preoperative interventional thrombolysis of the portal vein was successfully performed in 5 patients and alleviated further PHR. Median operative time and blood transfusions were higher in patients with extrahepatic GPH compared with patients without extrahepatic GPH (P<.01). Overall complication rate was not statistically different (44% vs 34%). One death occurred in each group. At the end of follow-up (median, 18 months) 13 of 15 patients with extrahepatic GPH were free of pain. No variceal bleeding or cholestasis was documented. All patients judged their status as subjectively improved. CONCLUSION: Although technically demanding in the presence of extrahepatic GPH, PHR can be performed with an acceptable morbidity and mortality in an experienced center. Preoperative interventional recanalization of portal vein thrombosis may render PHR possible by restoring normal splanchnic blood flow in selected cases indicated for surgery.     

Muscle-type specific intramyocellular and hepatic lipid metabolism during starvation in wistar rats

The physiological dynamics of intramyocellular lipids (IMCLs) in different muscle types and of hepatocellular lipids (HepCLs) are still uncertain. The dynamics of IMCLs in the soleus, tibialis anterior, and extensor digitorum longus (EDL) muscles and HepCL during fed, 12- to 72-h starved, and refed conditions were measured in vivo by (1)H-magnetic resonance spectroscopy (MRS) in Wistar rats. Despite significant elevations of free fatty acids (FFAs) during starvation, HepCLs and IMCLs in soleus remained constant. In tibialis anterior and EDL, however, IMCLs increased significantly by 170 and 450% after 72 h of starvation, respectively. After refeeding, elevated IMCLs dropped immediately in both muscles. Total muscle long-chain acyl-CoAs (LCACoAs) remained constant during the study period. Hepatic palmitoleoyl-CoA (C16:1) decreased significantly during starvation while total hepatic LCACoAs increased significantly. Consistent with constant values for FFAs, HepCLs, IMCLs, and muscle LCACoAs from 12-72 h of starvation, insulin sensitivity did not change. We conclude that during starvation-induced adipocytic lipolysis, oxidative muscles dispose elevated FFAs by oxidation, while nonoxidative ones neutralize FFAs by reesterification. Both mechanisms might prevent impairment of insulin signaling by maintaining low levels of LCACoAs. Hepatic palmitoleoyl-CoA might have a special role in lipid metabolism due to its unique dynamic profile during starvation.     

Complex visual hallucinations (Charles Bonnet syndrome) in visual field defects following cerebral surgery. Report of four cases

The development of visual hallucinations after loss of vision is known as the Charles Bonnet syndrome. This phenomenon was first described in 1760 by Charles Bonnet and others during their observations of elderly patients with degeneration of the retina or cornea. To date a clear association between visual hallucinations and neurosurgical procedures has not been reported. Because of their clear demarcation, however, surgical lesions in the cerebrum offer a unique opportunity to determine the pathoanatomical aspects of visual hallucinations. During a 3-year period, 41 consecutive patients who acquired visual field defects after neurosurgery were examined for the occurrence of visual hallucination. Postoperatively, four of these patients experienced visual hallucinations. In two of them an upper quadrantanopia developed after the patients had undergone selective amygdalohippocampectomy. In the other two patients a complete hemianopia developed, in one case after resection of a parietal astrocytoma and in the other after resection of an occipital glioblastoma multiforme. The visual hallucinations were transient and gradually disappeared between 4 days and 6 months postoperatively. The patients were aware of the fact that their hallucinations were fictitious and displayed no psychosis. Electroencephalographic recordings were obtained in only two patients and epileptic discharges were found. Deafferentiation of cortical association areas may lead to the spontaneous generation of complex visual phenomena. In the present series this phenomenon occurred in approximately 10% of patients with postoperative visual field defects. In all four cases the central optic radiation was damaged between the lateral geniculate nucleus and the primary visual cortex. The complex nature of the visual hallucination indicates that they were generated in visual association areas.     

Bone debris: dead matter or vital osteoblasts

BACKGROUND: Mechanical manipulation, pressure, and temperature increase can induce bone necrosis during intramedullary reaming. METHODS: In this study, the bone debris obtained after reaming 18 sheep tibiae was analyzed to investigate its vitality by measuring alkaline phosphatase activity. Two different reamer designs were used for the project. Bone cells were first cultivated in a specific growth medium, counted 3 weeks after the reaming procedure, and then cultivated for another 5 weeks. RESULTS: At the end of the project, qualitative evaluation showed positive alkaline phosphatase activity in most of the cases, and quantitative evaluation also showed enzyme activity. The positive alkaline phosphatase results were independent of the reamer sizes and reamer design. No significant results were obtained from a comparison of different reamer sizes and designs. This indicates that osteoblasts survive after correctly performed reaming. CONCLUSION: The results prove the vitality of the bone debris and confirm clinical observations.     

Soft tissue reconstruction following total knee arthroplasty: treatment possibilities and retrospective analysis of plastic surgery therapy treatment possibilities

AIM: We performed a retrospective analysis of patients with soft tissue defects following total knee arthroplasty and therapy. Furthermore, we described the possibilities of covering soft tissue defects following knee arthroplasty. METHOD: In 5 patients, soft tissue defects following knee arthroplasty were covered with medial M. gastrocneminus flaps. Localisation and size of the defect, microbiology, risk factors, and interval between arthroplasty and the occurrence of the soft tissue defect were retrospectively analysed. RESULTS: On average, defects occurred 9 weeks after prosthesis implantation. In all cases, the soft tissue defect developed in the area of the incision. In 3 cases, wound infection was diagnosed. Four patients exhibited factors associated with wound-healing failure. No prosthesis was lost. CONCLUSION: The gastrocneminus muscle flap provides good quality coverage with small donor site defect, permits early mobilisation, and allows for fast rehabilitation. The risk of flap loss is minimal. Early and adequate defect coverage can reduce both prosthesis loss and amputation rates.     

Insurance status and race represent independent predictors of undergoing laparoscopic surgery for appendicitis: secondary data analysis of 145,546 patients

BACKGROUND: Studies have shown that racial and socioeconomic differences lead to inequality in access to health care. It is unknown whether insurance status and race affect the choice of surgical treatment for patients presenting with appendicitis. STUDY DESIGN: Patients with primary ICD-9 procedure codes for laparoscopic and open appendectomy were selected from the 1998, 1999, and 2000 Nationwide (US) Inpatient Samples. The primary predictor variables were insurance status (private, Medicare, Medicaid, other) and race (Caucasian, African American, Hispanic, other). Multiple logistic regression models were used to assess whether insurance status and race are associated with the choice of surgical procedure for patients presenting with appendicitis. RESULTS: Discharge abstracts of 145,546 patients were used for our analyses. There were 32,407 patients (22.3%) who underwent laparoscopic appendectomy and 113,139 patients (77.7%) who had open appendectomy. Although 24.2% of privately insured patients underwent laparoscopic appendectomy, only 16.9% of Medicare patients, 17.4% of Medicaid patients, and 19.6% of patients in the "other" insurance category were treated using the laparoscopic procedure (p < 0.001). Caucasian patients underwent laparoscopic surgery in 24.8%, African Americans in 18.6%, Hispanics in 19.6%, and other ethnicities in 18.8% of patients (p < 0.001). Compared with the Medicaid subset, and after adjusting for potential confounders such as age, gender, race, patient comorbidity, median ZIP code income, hospital location and teaching status, and presence of abscess or perforation, privately insured patients (odds ratio [OR] = 1.26, 95% [CI [1.20, 1.33], p < 0.001) and Medicare patients (OR = 1.17, 95% CI [1.05, 1.30], p = 0.004) were significantly more likely to undergo laparoscopic surgery. Caucasian patients (OR = 1.42, 95% CI [1.33, 1.51], p < 0.001) and Hispanics (OR = 1.12, 95% CI [1.04, 1.20], p = 0.002) were significantly more likely to have laparoscopic appendectomy, compared with African Americans, even after adjusting for the previously mentioned confounders and insurance status. CONCLUSIONS: Even after adjusting for potential confounders, insurance status and race are marked independent predictors of having laparoscopic surgery in patients treated for appendicitis in this sample.