Enrichment of intracellular sulphur cycle –associated bacteria in intertidal benthic foraminifera revealed by 16S and aprA gene analysis

Benthic foraminifera are known to play an important role in marine carbon and nitrogen cycles. Here, we report an enrichment of sulphur cycle -associated bacteria inside intertidal benthic foraminifera (Ammonia sp. (T6), Haynesina sp. (S16) and Elphidium sp. (S5)), using a meta barcoding approach targeting the 16S rRNA and aprA -genes. The most abundant intracellular bacterial groups included the genus Sulfurovum and the order Desulfobacterales. The bacterial 16S OTUs are likely to originate from the sediment bacterial communities, as the taxa found inside the foraminifera were also present in the sediment. The fact that 16S rRNA and aprA -gene derived intracellular bacterial OTUs were species-specific and significantly different from the ambient sediment community implies that bacterivory is an unlikely scenario, as benthic foraminifera are known to digest bacteria only randomly. Furthermore, these foraminiferal species are known to prefer other food sources than bacteria. The detection of sulphur-cycle related bacterial genes in this study suggests a putative role for these bacteria in the metabolism of the foraminiferal host. Future investigation into environmental conditions under which transcription of S-cycle genes are activated would enable assessment of their role and the potential foraminiferal/endobiont contribution to the sulphur-cycle.Peer reviewe

Are Postoperative Complications More Common with Single-Stage Bilateral (SBTKR) Than with Unilateral Knee Arthroplasty: Guidelines for Patients Scheduled for SBTKR

A significant number of patients with degenerative arthritis of the knee require bilateral knee arthroplasty. Single-stage bilateral total knee arthroplasty (SBTKR) has been associated with increased patient morbidity and mortality. At our institution, the following steps have been taken to minimize the risks to patients undergoing this procedure: regional anesthesia and analgesia, invasive monitoring, postoperative observation in an intensive care unit setting, and aggressive management of hemodynamic aberrations. We reviewed the medical records of 462 sequential total knee arthroplasty patients, consisting of 169 SBTKR and 293 unilateral total knee arthroplasty (UTKR) cases. A total of 122 patients from each group were matched for age, weight, and a history of ischemic heart disease and hypertension. Patients for SBTKR exhibited a significantly higher incidence of fat embolism syndrome and cardiac arrhythmias than UTKR patients. There were no deaths in either group and the incidence of other serious postoperative complications was low and similar between the two groups. Elderly patients (∼75 years old) had more postoperative complications. With aggressive clinical management SBTKR can be safely performed in selected patients. Guidelines for the selection of these patients are presented

Ketamine as an Adjunct to Postoperative Pain Management in Opioid Tolerant Patients After Spinal Fusions: A Prospective Randomized Trial

Management of acute postoperative pain is challenging, particularly in patients with preexisting narcotic dependency. Ketamine has been used at subanesthetic doses as a N-methyl d-aspartate (NMDA) receptor antagonist to block the processing of nociceptive input in chronic pain syndromes. This prospective randomized study was designed to assess the use of ketamine as an adjunct to acute pain management in narcotic tolerant patients after spinal fusions. Twenty-six patients for 1–2 level posterior lumbar fusions with segmental instrumentation were randomly assigned to receive ketamine or act as a control. Patients in the ketamine group received 0.2 mg/kg on induction of general anesthesia and then 2 mcg kg−1 hour−1 for the next 24 hours. Patients were extubated in the operating room and within 15 minutes of arriving in the Post Anesthesia Care Unit (PACU) were started on intravenous patient-controlled analgesia (PCA) hydromorphone without a basal infusion. Patients were assessed for pain (numerical rating scale [NRS]), narcotic use, level of sedation, delirium, and physical therapy milestones until discharge. The ketamine group had significantly less pain during their first postoperative hour in the PACU (NRS 4.8 vs 8.7) and continued to have less pain during the first postoperative day at rest (3.6 vs 5.5) and with physical therapy (5.6 vs 8.0). Three patients in the control group failed PCA pain management and were converted to intravenous ketamine infusions when their pain scores improved. Patients in the ketamine group required less hydromorphone than the control group, but the differences were not significant. Subanesthetic doses of ketamine reduced postoperative pain in narcotic tolerant patients undergoing posterior spine fusions