Top‐down inputs from the olfactory cortex in the postprandial period promote elimination of granule cells in the olfactory bulb

Elimination of granule cells (GCs) in the olfactory bulb (OB) is not a continual event but is promoted during a short time window in the postprandial period, typically with postprandial sleep. However, the neuronal mechanisms for the enhanced GC elimination during the postprandial period are not understood. Here, we addressed the question of whether top‐down inputs of centrifugal axons from the olfactory cortex (OC) during the postprandial period are involved in the enhanced GC elimination in the OB. Electrical stimulation of centrifugal axons from the OC of anesthetized mice increased GC apoptosis. Furthermore, pharmacological suppression of top‐down inputs from the OC to the OB during the postprandial period of freely behaving mice by γ‐aminobutyric acid (GABA)_A receptor agonist injection in the OC significantly decreased GC apoptosis. Remarkable apoptotic GC elimination in the sensory‐deprived OB was also suppressed by pharmacological blockade of top‐down inputs. These results indicate that top‐down inputs from the OC to the OB during the postprandial period are the crucial signal promoting GC elimination, and suggest that the life and death decision of GCs in the OB is determined by the interplay between bottom‐up sensory inputs from the external world and top‐down inputs from the OC.     

Lumbar spinal fusion with β-TCP granules and variable Escherichia coli–derived rhBMP-2 dose

Background contextThe ideal tissue-engineered solution for any bone graft substitute is to assist in the rapid formation of bone and facilitate fusion.PurposeThe present study aims to evaluate this E-BMP-2 (Escherichia coli–derived human bone morphogenetic protein-2) in ovine posterolateral lumbar fusion (PLF) to examine the influence of dose and overall performance in a model with similar graft size and diffusive challenges to the human.Study design/settingIn vivo large animal model study.MethodsAn adult ovine PLF was performed in 30 animals with groups of E-BMP-2 with a beta-tricalcium phosphate (β-TCP) carrier at three different dosages, β-TCP alone, and autograft from the iliac crest. The fusions were assessed by radiography (X-ray and microcomputed tomography), mechanical testing, and hard-tissue histology with bone labels at 6, 8, and 10 weeks along with routine paraffin histology at 12 weeks.ResultsResults showed increasing new bone and fusion rate with E-BMP-2 dose, whereas β-TCP alone was largely resorbed and did not achieve fusion in this model at 12 weeks. Autograft showed similar grading for the amount of bone between the transverse processes but a lower fusion rate than β-TCP/E-BMP-2 groups. Bone labels revealed new bone formation at all time points for the E-BMP2 groups, whereas the autograft group showed active bone formation at 10 weeks. Beta-tricalcium phosphate displayed reliable incorporation into the decorticated host bone, whereas limited new bone was found between the transverse processes. At the center of the fusion mass, increased E-BMP-2 dose led to increased incorporation of β-TCP by new bone.ConclusionsThese results suggest that E-BMP-2 was capable of producing posterolateral fusion in the ovine model that is equal to or superior to autologous graft in terms of fusion rate and mechanical strength. E-BMP-2 dose had considerable influence on β-TCP granule resorption.     

Rectal Cancer With Disseminated Carcinomatosis of the Bone Marrow: Report of a Case

We report a rare case of disseminated carcinomatosis of the bone marrow from rectal cancer with disseminated intravascular coagulation (DIC). A 65-year-old man was admitted with melena and low back pain at rest. X-ray examination showed rectal cancer with multiple bone metastases. Laboratory examination showed severe anemia and DIC. Histologic examination showed disseminated carcinomatosis of the bone marrow. The DIC was considered to be caused by disseminated carcinomatosis of the bone marrow from rectal cancer, and we immediately started treatment with anti-DIC therapy and anticancer chemotherapy with the modified FOLFOX6 regimen (mFOLFOX6). After some response to therapy, the patient''s general condition deteriorated, and he died 128 days after admission. This is the first English report showing disseminated carcinomatosis of the bone marrow from colorectal cancer treated with mFOLFOX6.Key words: Bone marrow neoplasms, Rectal neoplasms, Disseminated intravascular coagulationBone metastases diffusely invading the bone marrow with disseminated intravascular coagulation (DIC) and microangiopathic hemolytic anemia (MHA) tend to accompany solid tumors; this condition is called disseminated carcinomatosis of the bone marrow,¹ and it is associated with an extremely poor prognosis. Among solid tumors, DIC is most commonly associated with breast cancer, prostate cancer, and lung cancer^2,3; carcinomatosis arising from colorectal cancer is rare.Herein we report on a patient with disseminated carcinomatosis of the bone marrow with rectal cancer who developed acute DIC and was treated with a modified FOLFOX6 regimen (mFOLFOX6). We also review 11 similar previously reported cases.^4–10