Memory precision and age differentially predict the use of decision-making strategies across the lifespan.

Memory function declines in normal aging, in a relatively continuous fashion following middle-age. The effect of aging on decision-making is less well-understood, with seemingly conflicting results on both the nature and direction of these age effects. One route for clarifying these mixed findings is to understand how age-related differences in memory affect decisions. Recent work has proposed memory sampling as a specific computational role for memory in decision-making, alongside well-studied mechanisms of reinforcement learning (RL). Here, we tested the hypothesis that age-related declines in episodic memory alter memory sampling. Participants (total N = 361; ages 18-77) performed one of two variants of a standard reward-guided decision experiment with additional trial-unique mnemonic content and a separately-administered task for assessing memory precision. When we fit participants' choices with a hybrid computational model implementing both memory-based and RL-driven valuation side-by-side, we found that memory precision tracked the contribution of memory sampling to choice. At the same time, age corresponded to decreasing influence of RL and increasing perseveration. A second experiment confirmed these results and further revealed that memory precision tracked the specificity of memories selected for sampling. Together, these findings suggest that differences in decision-making across the lifespan may be related to memory function, and that interventions which aim to improve the former may benefit from targeting the latter.

Marijuana and the hippocampus: A longitudinal study on the effects of marijuana on hippocampal subfields.

The psychoactive effects of cannabis, one of the most commonly used narcotics, have been documented extensively. Despite multiple studies being undertaken, there have been only a few longitudinal studies investigating the effect of long term usage of cannabis on various subcortical structures. This study aims at looking deeper into the effects of long term usage of cannabis on different hippocampus subfields.2 Participants were split into two groups, cannabis users and healthy controls. All the test subjects filled out the Cannabis Usage and Disorder Identification Test (CUDIT) and underwent T1-structural MRI scans twice, at a baseline and a followup 3 years later. The subfield volumes were measured using the software package Freesurfer with the LongitudinalHippocampalSubfields (v6.0) Module. Lifetime usage in grams was calculated for each participant until baseline and followup, independently, using linear interpolation. Usage of cannabis (lifetime consumption score) was correlated to increased volumes in certain subfields: the CA3 and CA4 in the right hemisphere and the presubiculum in both, the left and right hemispheres at baseline. Other tests including student's t-test and multivariate analysis of covariance were performed. Tests to understand the effects of varying consumption were also performed. Persistent usage of cannabis, however, did not result in atrophy of the subfields over time. Rather, there were lower growth rates observed in the healthy controls group as compared to that of the cannabis users in certain subfields.

New and emerging therapies in treatment of Clostridium difficile infection.

Clostridium difficile infection (CDI) represents one of the most serious nosocomial infections that have grown dramatically over the past decade. Vancomycin and metronidazole are currently used as a standard therapy for CDI. Metronidazole is recommended as a first-line therapy for mild-to-moderate infections and vancomycin is mainly used for severe and/or refractory cases. However, studies have demonstrated that there are quite high CDI relapse rates with both of these medications, which represents a challenge for clinicians. Over the last decade, a number of newer and novel therapeutic options have emerged as promising alternatives to these standard CDI therapies. The following review provides the updated summaries of these newer therapeutic agents and their status in the treatment of CDI.

Role of cannabis in digestive disorders.

Cannabis sativa, a subspecies of the Cannabis plant, contains aromatic hydrocarbon compounds called cannabinoids. [INCREMENT]-Tetrahydrocannabinol is the most abundant cannabinoid and is the main psychotropic constituent. Cannabinoids activate two types of G-protein-coupled cannabinoid receptors: cannabinoid type 1 receptor and cannabinoid type 2 receptor. There has been ongoing interest and development in research to explore the therapeutic potential of cannabis. [INCREMENT]-Tetrahydrocannabinol exerts biological functions on the gastrointestinal (GI) tract. Cannabis has been used for the treatment of GI disorders such as abdominal pain and diarrhea. The endocannabinoid system (i.e. endogenous circulating cannabinoids) performs protective activities in the GI tract and presents a promising therapeutic target against various GI conditions such as inflammatory bowel disease (especially Crohn's disease), irritable bowel syndrome, and secretion and motility-related disorders. The present review sheds light on the role of cannabis in the gut, liver, and pancreas and also on other GI symptoms, such as nausea and vomiting, cannabinoid hyperemesis syndrome, anorexia, weight loss, and chronic abdominal pain. Although the current literature supports the use of marijuana for the treatment of digestive disorders, the clinical efficacy of cannabis and its constituents for various GI disorders remains unclear.

Isolated axillary lymph node metastasis from serous ovarian cancer.

A 68-year-old female with past medical history of stage IIIc serous ovarian cancer after cytoreductive surgery and adjuvant chemotherapy came to clinic for regular follow-up visit. Physical examination was completely normal except for an isolated left axillary lymph node enlargement. Patient's abdominal sonogram and CT scan of abdomen and pelvis did not show any other new metastasis. Surgical excisional biopsy of the lymph node was performed and pathology revealed features of metastatic serous ovarian carcinoma.

A rare cause of acute pancreatitis: intramural duodenal hematoma.

We describe an interesting case of intramural duodenal hematoma in an otherwise healthy male who presented to emergency room with gradually progressive abdominal pain, nausea, and vomiting. This condition was missed on initial evaluation and patient was discharged from emergency room with diagnosis of acute gastritis. After 3 days, patient came back to emergency room and abdominal imaging studies were conducted which showed that patient had intramural duodenal hematoma associated with gastric outlet obstruction and pancreatitis. Hematoma was the cause of acute pancreatitis as pancreatic enzymes levels were normal at the time of first presentation, but later as the hematoma grew in size, it caused compression of pancreas and subsequent elevation of pancreatic enzymes. We experienced a case of pancreatitis which was caused by intramural duodenal hematoma. This case was missed on initial evaluation. We suggest that physicians should be more vigilant about this condition.