Hemodynamic factor evaluation using computational fluid dynamics analysis for de novo bleb formation in unruptured intracranial aneurysms

Neurological Sciences - Although bleb formation increases the risk of rupture of intracranial aneurysms, previous computational fluid dynamic (CFD) studies have been unable to identify robust...     

Early tissue response to modified implant surfaces using back scattered imaging

PURPOSE: It is now well known that implant surface properties affect osseointegration. Grit-blasting with abrasives and coating by plasma are methods to modify implant surfaces. This study aimed to compare the direction of new bone formation associated with three types of surfaces. MATERIALS AND METHODS: Titanium (Ti) alloy rods grit-blasted with alumina abrasive (Group 1, G1), with apatitic abrasive (Group 2, G2), and with apatitic abrasive and plasma-sprayed with hydroxyapatite (Group 3, G3) were implanted in surgically created defects in tibias of New Zealand white rabbits for 2 and 4 weeks. After sacrifice, the implants and surrounding bones were obtained and analyzed using back scattered imaging. RESULTS: Differences in patterns of bone formation among the groups were observed: originating from the cortical bone towards the implant surface (Type A), surrounding the implant (Type B) and originating from the medullary cavity (Type C). G1 and G3 showed Types A and B while G2 exhibited Types A, B and C. After 4 weeks, greater amount of new bone was observed in G2 group compared with those in G1 and G3 groups. CONCLUSIONS: This study demonstrated that patterns of bone formation are influenced by methods of surface modification.     

Evaluation of QOL After Proximal Gastrectomy Using a Newly Developed Assessment Scale (PGSAS-45)

Background

Proximal gastrectomy with esophagogastrostomy (PGEG) has been widely applied as a comparatively simple method. In this study, we used a questionnaire survey to evaluate the influence of various surgical factors on post-operative quality of life (QOL) after PGEG.

Methods

In this post-gastrectomy syndrome assessment study, we analyzed QOL in 2,368 cases. Among these, 193 had undergone proximal gastrectomy and 115 had undergone PGEG. The Post-Gastrectomy Syndrome Assessment Scale (PGSAS)-45 is a questionnaire consisting of 45 items, including the SF-8, the Gastrointestinal Symptom Rating Scale (GSRS), and other symptom items seemed to be specific to post-gastrectomy. The 23 symptom items were composed of seven symptom subscales (SS), including esophageal reflux, abdominal pain, and meal-related distress. These seven SS, total symptom score, ingested amount of food per meal, necessity for additional meals, quality of ingestion SS, ability to work, dissatisfaction with symptoms, dissatisfaction with the meal, dissatisfaction with working, dissatisfaction with daily life SS and change in body weight were evaluated as main outcome measures. In PGEG cases, we evaluated the influence on QOL of various surgical factors, such as procedures to prevent gastroesophageal regurgitation and size of the remnant stomach.

Results

The scores for esophageal reflux and dissatisfaction with the meal were higher in patients who had not undergone an anti-reflux procedure. In most cases, the preserved remnant stomach was more than two-thirds the size of the pre-operative stomach. When comparing patients with a remnant stomach two-thirds the pre-operative size and those with more than three-quarters, the diarrhea SS and necessity for additional meals scores were lower in the group with more than three-quarters. The indigestion, constipation, and abdominal pain subscales, and the total symptom score, were higher in patients who had not undergone pyloric bougie than in those who had.

Conclusion

These results indicated that QOL was better in patients with a large remnant stomach. Procedures to prevent gastroesophageal reflux, and the use of pyloric bougie as a complementary drainage procedure, were considered effective ways to reduce the deterioration of QOL.     

Uroporphyrinogen I synthase from human erythrocytes: separation, purification, and properties of isoenzymes.

Uroporphyrinogen I synthase [porphobilinogen ammonia-lyase (polymerizing), EC 4.3.1.8] from human erythrocytes was separated into two active protein peaks (A and B on DEAE-cellulose, by ammonium sulfate fractionation, on Sephadex G-100, and on DEAE-Sephadex A-50 with a NaCl gradient. The final purification was 613 and 743 times for A and B, respectively. The corresponding yields were 2.2 and 3.4% Fraction A was separated further into two (A1 and A2) active protein bands and fraction B into three (B1, B2, and B3) on analytical polyacrylamide disc gel electrophoresis. Bands A1 and A2 were identical with B1 and B2; B3 represented a third isoenzyme. Molecular weights (mean +/- SEM), measured by gel filtration and sodium dodecyl sulfate/polyacrylamide gel electrophoresis, were 38,000 +/- 1000 for B1 and 40,000 +/- 1000 for B2 and B3. Isoelectric focusing on 4% polyacrylamide gel separated both fractions A and B into three active protein bands. Maximal activity of the enzyme was found in gel cuts (5-mm) at pH 5.6 for both fractions A and B.     

Narrow band imaging-guided endoscopic biopsy for intraventricular and paraventricular brain tumors: clinical experience with 14 cases

Background

Narrow-band imaging (NBI) has been confirmed as a useful endoscopic technique to distinguish neoplasm from normal tissue, on the basis of the enhanced neovascularity of tumor tissue. NBI-guided tissue biopsy for laryngopharyngeal and digestive lesions is a novel methodology, but the feasibility for central nervous system tumors remains unclear. The aim of our study was to evaluate the feasibility of NBI-guided biopsy for intraventricular and paraventricular tumor.

Methods

Fourteen patients with intraventricular or paraventricular tumors underwent neuroendoscopic biopsy using a videoscope with NBI. Ventricular walls and tumors were observed using conventional imaging, followed by NBI. Colors of ventricle walls and tumors visualized using NBI were compared to those visualized under conventional imaging. Extracted specimens were stained using CD31 antibody and numbers of microvessels in each specimen were counted for analyzing vascular density.

Results

Normal ventricle walls were a similar color under conventional imaging and NBI. Tumor surfaces appeared to be cyan in color under NBI. Vessels on the tumor were more clearly visualized with NBI than with conventional imaging. NBI was able to identify tumor surfaces that were not perceptible on conventional imaging. All specimens in the lesion surfaces from cyan-colored areas under NBI contained tumor cells. Specimens extracted from regions that appeared cyan in color under NBI (51.0 vessels/mm²) had significantly greater vascular density than regions that appeared a normal color (17.4 vessels/mm²; p = 0.039).

Conclusion

NBI-guided biopsy of intraventricular and paraventricular tumors is feasible for visualizing tumor surface-enhancing neovascularities. NBI would contribute to accurate histological diagnosis while minimizing injury to surrounding structures.     

Detectability of Neural Tracts and Nuclei in the Brainstem Utilizing 3DAC‐PROPELLER

Despite clinical importance of identifying exact anatomical location of neural tracts and nuclei in the brainstem, no neuroimaging studies have validated the detectability of these structures. The aim of this study was to assess the detectability of the structures using three‐dimensional anisotropy contrast‐periodically rotated overlapping parallel lines with enhanced reconstruction (3DAC‐PROPELLER) imaging. Forty healthy volunteers (21 males, 19 females; 19‐53 years, average 23.4 years) participated in this study. 3DAC‐PROPELLER axial images were obtained with a 3T‐MR system at four levels of the brainstem: the lower midbrain, upper and lower pons, and medulla oblongata. Three experts independently judged whether five tracts (corticospinal tract, medial lemniscus, medial longitudinal fasciculus, central tegmental and spinothalamic tracts) and 10 nuclei (oculomotor and trochlear nuclei, spinal trigeminal, abducens, facial, vestibular, hypoglossal, prepositus, and solitary nuclei, locus ceruleus, superior and inferior olives) on each side could be identified. In total, 240 assessments were made. The five tracts and eight nuclei were identified in all the corresponding assessments, whereas the locus ceruleus and superior olive could not be identified in 3 (1.3%) and 16 (6.7%) assessments, respectively. 3DAC‐PROPELLER seems extremely valuable imaging method for mapping out surgical strategies for brainstem lesions.     

The effects of histamine on the concentrations of immunoreactive thyrotropin-releasing hormone in the stomach and hypothalamus in rats

The effects of histamine and its related compounds on the concentrations of immunoreactive thyrotropin-releasing hormone (ir-TRH) in the stomach, gastric juice and hypothalamus in rats were studied. Histamine, ranitidine or ethanolamine was injected intraperitoneally, and the rats were decapitated at various times after the injection. Ir-TRH concentrations in the stomach, gastric juice and hypothalamus were measured by a radioimmunoassay. Ir-TRH concentrations in the stomach decreased significantly after histamine injection and increased significantly after ranitidine injection in a dose-dependent manner, but did not change with ethanolamine. Ir-TRH concentrations in the gastric juice increased in a dose-dependent manner, peaking at 30 min after histamine injection, and its effect was blocked with ranitidine. Ir-TRH concentrations in the hypothalamus elevated significantly after histamine injection and reduced significantly after ranitidine injection, but did not change with ethanolamine. The effects of histamine on ir-TRH concentrations in the stomach and hypothalamus were significantly blocked with ranitidine, but not with ethanol-amine. These findings suggest that histamine stimulates ir-TRH release from the stomach and inhibits ir-TRH release from the hypothalamus, and that these effects of histamine on ir-TRH release are mediated via an H₂-receptor. Portions of this work were presented at the 75th annual meeting of Japanese Society of Gastroenterology. March 1989 in Yokohama, Japan.