Bubble dynamics in boiling histotripsy

Boiling histotripsy is a non-invasive, cavitation-based ultrasonic technique which uses a number of millisecond pulses to mechanically fractionate tissue. Though a number of studies have demonstrated the efficacy of boiling histotripsy for fractionation of solid tumours, treatment monitoring by cavitation measurement is not well studied because of the limited understanding of the dynamics of bubbles induced by boiling histotripsy. The main objectives of this work are to (a) extract qualitative and quantitative features of bubbles excited by shockwaves and (b) distinguish between the different types of cavitation activity for either a thermally or a mechanically induced lesion in the liver. A numerical bubble model based on the Gilmore equation accounting for heat and mass transfer (gas and water vapour) was developed to investigate the dynamics of a single bubble in tissue exposed to different High Intensity Focused Ultrasound fields as a function of temperature variation in the fluid. Furthermore, ex vivo liver experiments were performed with a passive cavitation detection system to obtain acoustic emissions. The numerical simulations showed that the asymmetry in a shockwave and water vapour transport are the key parameters which lead the bubble to undergo rectified growth at a boiling temperature of 100°C. The onset of rectified radial bubble motion manifested itself as (a) an increase in the radiated pressure and (b) the sudden appearance of higher order multiple harmonics in the corresponding spectrogram. Examining the frequency spectra produced by the thermal ablation and the boiling histotripsy exposures, it was observed that higher order multiple harmonics as well as higher levels of broadband emissions occurred during the boiling histotripsy insonation. These unique features in the emitted acoustic signals were consistent with the experimental measurements. These features can, therefore, be used to monitor (a) the different types of acoustic cavitation activity for either a thermal ablation or a mechanical fractionation process and (b) the onset of the formation of a boiling bubble at the focus in the course of HIFU exposure.     

Primary Inflammatory Myofibroblastic Tumors of the Breast with Metastasis: Radiographic and Histopathologic Predictive Factors

Primary inflammatory myofibroblastic tumors (IMTs) of the breast are uncommon and metastasis of IMTs is extremely rare. To date, the natural course of this disease is not fully understood. Although patients with IMTs should undergo regular follow-up after complete surgical resection of the tumor, the appropriate interval and method of follow-up are unclear. We report the case of a patient with an IMT of the breast that metastasized 2 years after complete surgical resection. This unusual case emphasizes the importance of preoperative examinations to determine whether the IMT has atypical features that should guide the interval and method of follow-up.     

Surgical Outcomes of Canalicular Trephination Combined with Endoscopic Dacryocystorhinostomy in Patients with Distal or Common Canalicular Obstruction

PurposeThis study investigated the surgical outcomes of canalicular trephination combined with endoscopic dacryocystorhinostomy (DCR) in patients with a distal or common canalicular obstruction. It also identified the factors affecting surgical success rates associated with this technique.MethodsWe retrospectively reviewed the medical records of 57 patients (59 eyes) in whom a canalicular obstruction was encountered during endoscopic DCR. All patients were treated with endoscopic DCR, followed by canalicular trephination and silicone tube placement. The surgical outcome was categorized as a functional success according to the patient''s subjective assessment of symptoms, including epiphora, and as an anatomical success according to a postoperative nasolacrimal duct irrigation test. Surgical success rates were compared based on age, sex, location of the obstruction, number of silicone tubes, and experience of the surgeon.ResultsFunctional success was achieved in 55 of 59 eyes (93%) at one month, 50 eyes (84%) at three months, and 46 eyes (78%) at six months. Anatomical success was achieved in 58 of 59 eyes (98%) at one month, 52 eyes (88%) at three months, and 50 eyes (84%) at six months. There was a statistically significant difference in surgical outcome according to the experience of the surgeon. The anatomical success rate at the six-month follow-up exam was 95.4% in the >5 years of experience group, and 53.3% in the <5 years of experience group (p = 0.008, Pearson chi-square test).ConclusionsThe success rate of canalicular trephination combined with endoscopic DCR in patients with a distal or common canalicular obstruction decreased gradually during the six-month follow-up period. In particular, patients undergoing procedures with experienced surgeons tended to show excellent surgical outcomes at the six-month follow-up exam.     

Significance of COX‐2 and VEGF expression in histopathologic grading and invasiveness of meningiomas

Meningiomas are slow‐growing neoplasms that recur locally. Their morphologic grading does not always correlate with patient outcome. We evaluated the status of several immunohistochemical markers with histopathologic parameters in various grades of meningioma.Eighty‐eight meningioma specimens were examined immunohistochemically to determine the status of Ki‐67, cyclin D1, epidermal growth factor receptor (EGFR), cyclooxygenase‐2 (COX‐2), vascular endothelial growth factor (VEGF), and bcl‐2. Several clinical and pathological parameters were investigated.Forty‐nine Grade I, 33 Grade II, and 6 Grade III meningiomas were observed. VEGF and Ki‐67 expression was correlated with higher tumor grade. The association between grade and other immunohistochemical markers expression was not significant. A correlation was observed between COX‐2 expression and invasiveness to the brain or adjacent soft tissue. Tumor recurrence was correlated with brain or adjacent soft tissue invasion. We also observed a relationship between VEGF level and COX‐2 expression, and they were both correlated with necrosis.Immunohistochemical evaluation of VEGF, COX‐2, and Ki‐67 expression can provide information regarding the behavior of meningiomas, particularly for cases in which histological grading is not straightforward.     

A Case of Nonalcoholic Steatohepatitis and Small Intestinal Bacterial Overgrowth with Peripheral Edema Caused by Intestinal Bypass Surgery and Relieved by Repair

Intestinal bypass surgery, particularly jejuno-ileal bypass surgery, performed for the purpose of weight reduction may cause an unexpected exacerbation of nonalcoholic steatohepatitis (NASH). Here, we report a case of NASH caused by small intestinal bacterial overgrowth, which developed after jejuno-colic bypass surgery and resolved dramatically after surgical correction.     

Effect of PRX-1 Downregulation in the Type 1 Diabetes Microenvironment

Type 1 diabetes (T1D) is caused by dysregulation of the immune system in the pancreatic islets, which eventually leads to insulin-producing pancreatic β-cell death and destabilization of glucose homeostasis. One of the major characteristics of T1D pathogenesis is the production of inflammatory mediators by macrophages that result in destruction or damage of pancreatic β-cells. In this study the inflammatory microenvironment of T1D was simulated with RAW264.7 cells and MIN6 cells, acting as macrophages and pancreatic β-cells respectably. In this setting, peroxiredoxin-1, an anti-oxidant enzyme was knocked down to observe its functions in the pathogenesis of T1D. RAW264.7 cells were primed with lipopolysaccharide and co-cultured with MIN6 cells while PRX-1 was knocked down in one or both cell types. Our results suggest that hindrance of PRX-1 activity or the deficiency of this enzyme in inflammatory conditions negatively affects pancreatic β-cell survival. The observed decrease in viability of MIN6 cells seems to be caused by nitric oxide production. Additionally, it seems that PRX-1 affects previously reported protective activity of IL-6 in pancreatic β cells as well. These results signify new, undiscovered roles for PRX-1 in inflammatory conditions and may contribute toward our understanding of autoimmunity.     

Neo-Adjuvant Chemotherapy Followed by Surgery for Extensive Calvarial Metastases of a Neuroblastoma

Neuroblastoma is a common tumor of children. We report a patient with extensive calvarial metastases of a neuroblastoma as an initial presentation. A 2-year-old girl presented with a history of gradually increasing head size and fever. A brain CT showed a multilobulated, large, extra-axial tumor involving both frontotemporoparietal areas with a sunray-spiculated hyperostosis of the skull and marked contrast enhancement. A brain MRI demonstrated extensive calvarial lesions with simultaneous involvement of the orbits. A biopsy was performed and a ganglioneuroblastoma was diagnosed. On systemic evaluation, an enlarged abdominal mass was detected. After neo-adjuvant chemotherapy, most of the tumors disappeared except for a tumor in the left parietal area; there was a corresponding decrease in the circumference of the head. We performed surgery for the remnant mass. Intensive chemotherapy was administered and a bone marrow transplantation was performed. Adequate neo-adjuvant chemotherapy followed by surgery to the neuroblatoma with extensive metastases to the skull and orbit may be helpful.