Adaptive response of resistant cancer cells to chemotherapy

Despite advances in cancer therapeutics and the integration of personalized medicine, the development of chemoresistance in many patients remains a significant contributing factor to cancer mortality. Upon treatment with chemotherapeutics, the disruption of homeostasis in cancer cells triggers the adaptive response which has emerged as a key resistance mechanism. In this review, we summarize the mechanistic studies investigating the three major components of the adaptive response, autophagy, endoplasmic reticulum (ER) stress signaling, and senescence, in response to cancer chemotherapy. We will discuss the development of potential cancer therapeutic strategies in the context of these adaptive resistance mechanisms, with the goal of stimulating research that may facilitate the development of effective cancer therapy.     

Microstructures of admixed amalgams produced from Pd-containing dispersants.

Blended Pd-containing dental amalgams were developed by substituting Pd for up to 20 w/o Ag or Cu in the Ag-Cu eutectic alloy. Melted ingots were lathe-comminuted to a particle size distribution of 1-45 microns. Alloy blends were created from two parts of a traditional amalgam and one part of experimental Ag-Cu-Pd particles. Amalgams with from 0.42 to 1.67 w/o Pd were fabricated by trituration of alloys and mercury at a Hg/alloy ratio of 1:1 with a mechanical triturator at 5000 rpm for 10 s and hand-condensed. XRD studies of these amalgams revealed the suppression of eta' (Cu6Sn5) phase with Pd addition and no gamma 2 (Sn8Hg) phase found. At 3.3 w/o Pd, the eta' (Cu6Sn5) concentration of the amalgam was below the detection limit of the instrumentation (1%). SEM micrographs revealed that reaction zones around eutectic particles decreased with increased Pd concentration.     

Evolution of cerebellar tonsillar ischemia to cerebellar tonsillar cysts in the Chiari I malformation: radiological,surgical, and histological evidence

Background

Rare reports in the literature have documented the presence of a cyst at the tip of the cerebellar tonsil in patients with Chiari I malformation. The current study aimed to better elucidate these cysts and identify their etiology via a histological and radiologically analysis.

Patients and methods

We prospectively reviewed all new Chiari I malformation (CM-I) patients who presented to our clinic during a 2-year period. This was a pediatric cohort made up of 340 children aged 3 to 18 years. Specifically, all patients were screened for ischemic or cystic lesions of the herniated cerebellar tonsils on MRI.

Results

Out of 340 patients, 2.9 % were found to have signal changes on MRI consistent with ischemia or cysts in the cerebellar tonsils. Of the 340 patients, 20 % underwent posterior fossa decompression. Of the 67 patients, cerebellar tonsillar ischemia was observed in 10.4 % and cerebellar tonsillar cysts were seen in 6 %. Four of the seven operative patients with cerebellar tonsillar ischemia and concomitant syringomyelia and three of these patients with tonsillar cysts concomitant syringomyelia and cerebellar tonsillar cysts underwent subpial dissection of some cerebellar tonsil to ensure that CSF egress from the fourth ventricle to the cervical subarachnoid space, and this transected tissue was also sent for histological analysis. Three of the four patients found to have intraoperative tonsillar cysts were noted to have tonsillar ischemic changes on preoperative imaging in this same region. For both ischemic and cystic cerebellar tonsils, histologically, the tissue demonstrated loss of Purkinje cells with concomitant Bergmann gliosis. The ischemic and cystic tissues were virtually the same, histologically.

Conclusions

Based on our findings, cerebellar tonsillar ischemia and cysts in patients with CM-I can often be seen radiologically. Histologically, these ischemic and cystic tissues are the same. Moreover, we document patients where ischemic lesions progressed to cysts, radiologically. Taken together, cerebellar tonsillar ischemia and cysts are on a continuum and represent chronic compression of this herniated part of the cerebellum.

     

Struma ovarii: management and follow-up of a rare ovarian tumour

INTRODUCTION

Struma ovarii represents about 1.0% of all ovarian tumours. While management involves surgery, there is a paucity of data regarding the extent and approach of surgery, and postoperative management. This study aimed to delineate the management of struma ovarii, its associated complications, and postoperative follow-up and investigations.

METHODS

We retrospectively reviewed cases of benign struma ovarii treated at KK Women’s and Children’s Hospital, Singapore, between January 2000 and May 2011.

RESULTS

A total of 68 patients underwent surgical removal of ovarian cyst or mass (24 cystectomy, 20 salpingo-oopherectomy and 24 total hysterectomy and bilateral salpingo-oopherectomy). Of the 68 surgeries, 39 (57.4%) included intraoperative frozen section sampling or procedures for staging of ovarian malignancy. The majority (73.5%) of surgeries were laparotomies. Histology revealed benign struma ovarii in all (98.5%) but one patient. Only 7 (10.3%) patients had postoperative complications – 3 wound-related, 2 thyroid-related, 1 incisional hernia and 1 nonspecific. The mean length of hospital stay was 4.2 days. During follow-up, 45 (66.2%) patients required no additional investigations. The most common investigation done was ultrasonography (n = 18, 26.5%). While no recurrences were diagnosed histologically, two patients were subsequently found to have complex/dermoid ovarian cysts on the ipsilateral side of the previous struma ovarii on ultrasonography.

CONCLUSION

Simple surgery is recommended for patients with struma ovarii, especially if they have fertility potential. Laparoscopic surgery is the recommended approach due to its shorter recovery time and lower morbidity. Most patients do not require extended periods of follow-up or postoperative investigations.     

Sialadenitis: A Possible Early Manifestation of COVID-19

Acute sialadenitis may be caused by viruses, including coronaviruses. Although there are anecdotal reports of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) salivary gland infections, there have been no well-documented cases of sialadenitis in patients with COVID-19 described in the literature. We report a case of parotitis and submandibular gland sialadenitis, as well as an isolated case of parotitis, in two patients with concurrent SARS-CoV-2 infections. Computed tomography imaging demonstrated parotid and submandibular gland enlargement with heterogenous enhancement and attenuation, consistent with sialadenitis. Medical management was sufficient for successful resolution of the acute sialadenitis. Laryngoscope, 130:2595–2597, 2020