The Role of Dementia Diagnostic Delay in the Inverse Cancer-Dementia Association.

BACKGROUND: Cancer is inversely associated with dementia. Using simulations, we examined whether this inverse association may be explained by dementia diagnosis timing, including death before dementia diagnosis and differential diagnosis patterns by cancer history. METHODS: We used multistate Markov simulation models to generate cohorts 65 years of age and free of cancer and dementia at baseline; follow-up for incident cancer (all cancers, breast, prostate, and lung cancer), dementia, dementia diagnosis among those with dementia, and death occurred monthly over 30 years. Models specified no true effect of cancer on dementia, and used age-specific transition rates calibrated to U.S. population and cohort data. We varied the average lapse between dementia onset and diagnosis, including nondifferential and differential delays by cancer history, and examined observed incidence rate ratios (IRRs) for the effect of cancer on dementia diagnosis. RESULTS: Nondifferential dementia diagnosis delay introduced minimal bias (IRRs = 0.98-1.02) for all cancer, breast, and prostate models and substantial bias (IRR = 0.78) in lung cancer models. For the differential dementia diagnosis delay model of all cancer types combined, simulation scenarios with ≥20% lower dementia diagnosis rate (additional 4.5-month delay) in those with cancer history versus without yielded results consistent with literature estimates. Longer dementia diagnosis delays in those with cancer and higher mortality in those with cancer and dementia yielded more bias. CONCLUSIONS: Delays in dementia diagnosis may play a role in the inverse cancer-dementia relationship, especially for more fatal cancers, but moderate differential delays in those with cancer were needed to fully explain the literature-reported IRRs.

Metastatic right ventricular mass with intracavitary obliteration.

Metastatic cardiac tumors are more common than the primary cardiac tumors. Cervical cancer metastasizing outside of the pelvis is commonly spread to the lungs, liver, bones and lymph nodes than to the heart. Right-sided metastasis to the heart is more common than to the left side. Intramural spread is more common than intracavitary growth of metastatic cardiac tumors leading to delayed clinical presentation. Intracavitary mass can be confused with intracavitary thrombus which can be seen in the setting of pulmonary embolism. Transthoracic echocardiography plays a major role in the decision making and management of pulmonary embolism, and this modality can also be used to diagnose cardiac masses. Other modalities like TEE, cardiac CT, cardiac MRI and PET-CT scan have further utility in delineating these masses. This may help to plan appropriate management of the right ventricular mass particularly in cases where the patient history and CT pulmonary angiography results favor the diagnosis of pulmonary embolism. We present the case of a 49-year-old woman with a history of supracervical hysterectomy and salpingo-oophorectomy on oral estrogen therapy who was admitted with complaints of pleuritic chest pain and respiratory insufficiency after a long flight. Initial work-up showed sub-segmental pulmonary embolus in the right posterior lower lobe pulmonary artery, and the patient was managed on intravenous heparin. Lack of appropriate response to standard therapy led to further evaluation. Multimodality imaging and biopsies revealed a large right intracavitary ventricular metastatic squamous cell tumor, with the cervix as the primary source.

In vivo polymerization of poly(3,4-ethylenedioxythiophene) in the living rat hippocampus does not cause a significant loss of performance in a delayed alternation task.

After extended implantation times, traditional intracortical neural probes exhibit a foreign-body reaction characterized by a reactive glial sheath that has been associated with increased system impedance and signal deterioration. Previously, we have proposed that the local in vivo polymerization of an electronically and ionically conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), might help to rebuild charge transport pathways across the glial scar between the device and surrounding parenchyma (Richardson-Burns et al 2007 J. Neural Eng. 4 L6-13). The EDOT monomer can be delivered via a microcannula/electrode system into the brain tissue of living animals followed by direct electrochemical polymerization, using the electrode itself as a source of oxidative current. In this study, we investigated the long-term effect of local in vivo PEDOT deposition on hippocampal neural function and histology. Rodent subjects were trained on a hippocampus-dependent task, delayed alternation (DA), and implanted with the microcannula/electrode system in the hippocampus. The animals were divided into four groups with different delay times between the initial surgery and the electrochemical polymerization: (1) control (no polymerization), (2) immediate (polymerization within 5 min of device implantation), (3) early (polymerization within 3-4 weeks after implantation) and (4) late (polymerization 7-8 weeks after polymerization). System impedance at 1 kHz was recorded and the tissue reactions were evaluated by immunohistochemistry. We found that under our deposition conditions, PEDOT typically grew at the tip of the electrode, forming an ∼500 µm cloud in the tissue. This is much larger than the typical width of the glial scar (∼150 µm). After polymerization, the impedance amplitude near the neurologically important frequency of 1 kHz dropped for all the groups; however, there was a time window of 3-4 weeks for an optimal decrease in impedance. For all surgery-polymerization time intervals, the polymerization did not cause significant deficits in performance of the DA task, suggesting that hippocampal function was not impaired by PEDOT deposition. However, GFAP+ and ED-1+ cells were also found at the deposition two weeks after the polymerization, suggesting potential secondary scarring. Therefore, less extensive deposition or milder deposition conditions may be desirable to minimize this scarring while maintaining decreased system impedance.